Nbme 18 Answers

June 22, 2018 | Author: Usmle Usmle | Category: Management Of Hiv/Aids, Kidney, Blood Pressure, Hypertension, White Blood Cell


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Block 1 part 11. 56-year-old man comes with vague right-sided flank pain and 7-lb weight loss over past 6 weeks. No recent trauma or back strain. Urine is darker than usual over 2 weeks. Renal ultrasound shows 1.5-cm solid mass in upper portion of right kidney. Urine shows 50 erythrocytes, 6 leukocytes, no bacteria. Dx? - Renal cell carcinoma 2. 22-year-old man who is a professional cyclist undergoes extensive physiologic testing as part of his training regimen. His resting pulse is 33/min, and blood pressure is110/62 mm Hg. Echocardiography shows dilated ventricles with normal function and a left ventricular ejection fraction of 75%. Which of the following best describes the findings in this patient? - Eccentric hypertrophy 3. During a clinical study of calcium and phosphorus metabolism, a 50-year-old man undergoes series of lab studies. His serum Ca, PO4 and PTH are normal. He is given infusion 2 g Calcium chloride over 2 hours. His serum Ca concentration now is 11.5mg/dl. Compared with pre infusion levels, the serum concentration of which of the following substances is likely to be increased at this time? - 24,25-Dihydroxycholecalciferol 4. 70-year-old man comes with skin blistering for 1 week. No oral lesions. Physical shows tense bullae in joint folds of upper and lower extremities. Biopsy shows subepidermal blister formation. Immunofluorescence microscopy shows antibodies against proteins at the dermal-epidermal junction. Target by antibodies? - Hemidesmosome 5. 63-year-old man with abnormal blood pressure. 6 months ago, bp was 135/85. Today bp 170/98. Bruit heard over left renal artery. CT angio shows left arterial stenosis. Labs? - Total peripheral resistance increased, plasma renin activity increased, serum aldosterone concentration increased 6. 35-year-old woman with 3-month progressive shortness of breath with exertion. RR 26. Physical shows jvd and prominent a wave. Lungs clear. Cardiac exam shows loud pulmonic component of S2 and right-sided S4 gallop. Increased pulmonary expression of what? - Endothelin-1 7. 30-year-old woman with 2-years of numbness, blanching, and bluish color to ears, fingers and toes after emotional upset or cold exposure. Vitals and PE normal. Avoid taking which drug? - Phenylephrine 8. 35-year-old woman with 2-day history of blistering lesions on sun-exposed face, arms and hands. Recurrent episodes of skin lesions over several years. Taking oral contraceptives for 15y. PE shows fluid-filled vesicles and bullae. Labs: AST increased, ALT increased, total porphyrin increased, urine uroporphyrin III increased. Precursor to uroporphyrin? - Succinyl CoA 9. 65-year-old with sudden onset generalized tonic-clonic seizures. Personality change last 6 months; used to be mild mannered and now verbally abusive. CT shows single mass enhances with contrast in right frontal lobe and crosses to left hemisphere through corpus callosum. Dx? - High-grade fibrillary astrocytoma 10. 3-week-old male newborn with recurrent vomiting after feeding since birth, and eager to feed after vomiting. Abdominal exam shows firm, mobile mass in epigastrum to right of midline. Dx description? - Single primary development defect 11. 39-year-old man with 1-week of red spots on shins, joint pain and fatigue. PE shows purpura over lower extremities. Liver palpated 4 cm below costal margin. Labs: WBC 10,000, AST 142, ALT 154, hepatitis C virus RNA positive, anti-hepatitis C virus antibody positive, cryoglobulins positive, C4 120 (N=350-600), urine protein 4+, urine RBC numerous. Hypersensitivity reaction? - Type III (immune complex-mediated) 12. 45-year-old man with hypertension not compliant with medications. bp 160/100. Cardiac exam shows apical impulse displaced laterally, loud S2 and S4 gallop. Echo shows thickening of left ventricular wall. Mechanism of change in cardiac muscle? - Transcription factor c-Jun: increased, beta-myosin heave chain: increased, endothelin: increased 13. 70-year-old man with early morning awakening, decreased energy, difficulty concentrating, anhedonia, psychomotor retardation, depressed mood for 3 months. He had myocardial infarction and nonsustained ventricular tachycardia 2 years ago. Tx? - Paroxetine 14. 5-year-old boy with motion sickness. Planning vacation to Australia, and wants diphenhydramine for motion sickness. Mechanism of action for motion sickness? - Antagonist at muscarinic-3 (M3) receptors 15. Newborn is found to have a cervical rib. Transformation of seventh cervical segment to thoracic identity. Which is true of HOX gene alteration? - Expression of a HOX gene normally expressed only caudal to C7 16. 28-year-old man with ulcerative colitis, history of partial colectomy, and improved rectal bleeding and diarrhea since then. Meds include mesalamine, hydrocodone and acetaminophen. He says, "I've been taking so much of my opiate prescription that I ran out and stole some from my job." Next step? - Discuss treatment options and a referral for detoxification program 17. 66-year-old man dies 7 days after myocardial infarction. Gross of heart shown (perforated interventricular wall). Histology? - Erythrocytes, cellular debris, macrophages, and early granulation tissue 18. 16-year-old boy who frequently thinks about sex, daydreams about girls before going to sleep, and masturbates one to two times daily. After counseling about safe sex, best next step? - Schedule next routine examination 19. 18-year-old man comes with cracked lips and peeling sunburned skin. Works as lifeguard. PE shows desquamation of sunburned skin. Lips are dry and cracked. Petrolatum to lips may reduce lip symptoms by which of following effects of the compound? - Barrier 20. 29-year-old woman comes to the physician because of irregular menstrual periods since menarche at the age of 12. She is 5.3Ft and weighs 86kgs. BMI 34. She is evaluated and a diagnosis of PCOS is made. After explaining the diagnosis, the physician discusses behavioral changes, including dietary modification and exercise as part of her treatment. Which of the following will ensure adherence? - Provide follow ups to monitor progress in attaining her goal 21. 30-year-old man in bicycle collision and hits right shoulder forcefully. Unable to flex right elbow with decreased sensation to pinprick over right lateral forearm. Brachial plexus lesion? - E (musculocutaneous nerve) 22. 67-year-old man with 1 year progressive difficulty writing and walking. Pt is stooped and talks slowly. PE shows bland facial expression, fine resting tremor in both hands, no tremor when moves, walks with difficulty starting and stopping, cogwheel rigidity. Brain tissue histology shown as well as gross cross sections of midbrain both normal and diseased. Substance referred to by arrow? - Alpha-synuclein 23. 25-year-old woman with polycystic kidneys and 3-month history of weakness, fatigue, headaches, hypertension, loss of appetite and itching. Cr 4. Labs? - bicarb (HCO3-) decreased, inorganic phosphorous (PO4) increased, parathyroid hormone increased 24. 32-year-old woman brought in after 10-foot fall from ladder. PE suggests severe hemorrhage and shock. Xray shows fracture of left ninth and tenth ribs. Organ injured? - Spleen 25. 26-year-old man comes in 2 hours after injuring arm skiing. Sensation to pinprick absent over lateral aspect of shoulder. Xray of right shoulder shown (fracture of surgical neck of humerus). Nerve damaged? - Axillary Block 1 Part 26. 50-year-old woman with COPD comes with 3 months of progressive shortness of breath. Physical shows JVD, loud pulmonary component of S2. Pulmonary function tests show FEV1:FVC ratio of 20% and decreased diffusing capacity for carbon monoxide. Which is decreased in pulmonary vascular smooth muscle? - Endothelial nitric oxide synthase production 27. An experimental animal is created that has a defect in an innate gastrointestinal defense mechanism. Organism is found to have decreased HCl prod. After 2 months on biopsy gastric fundus and body show decreased mucosal thickness and hyperplasia of enterochromaffin like cells. This closely resembles? - Chronic gastritis 28. 63-year-old woman with 2-week history of daily episodes of severe, lancinating, left-sided facial pain. Pain lasts 30 to 60 seconds and shoots down ear along jawline. Precipitated by chewing or brushing teeth. Dx? - Trigeminal neuralgia 29. 45-year-old homeless man found unconscious. Breath smells of alcohol. Vitals stable. PE shows bronzed skin and spider angiomata on chest. Labs: hemoglobin 10, hematocrit 30%, MCV 110, WBC 9000, platelets 160,000, ferritin 200, b12 500, folate 20. Blood smear shows hypersegmented neutrophils and 3+ oval macrocytes. Labs? - Methylmalonic acid: normal, Homocysteine: increased 30. 68-year-old man with creatinine 2.3 due to chronically increased hydrostatic pressure in Bowman space. Cause? - Benign prostatic hyperplasia 31. 70-year-old woman comes to the physician because of increasingly severe pain in the right knee over the past 3 months. She has fallen repeatedly. She has a 10 year history of symptomatic osteitis deformans. She has bowed tibia and tenderness of the proximal right tibia. an X ray shows a fracture of the proximal tibia with elevated periostium and sunburst pattern. an xray of lungs shows pulmonary nodules of various sizes. which of the following findings is most likely on biopsy. - Pleomorphic neoplastic cells producing new woven bone 32. 30-year-old woman with a long-standing history of pelvic inflammatory disease has surgical resection of a scarred segment of a fallopian tube. Which of the following inflammatory cells is most likely to be found in the resected specimen? - Macrophages 33. 67-year-old woman with atrial fibrillation with sudden onset severe abdominal pain. Ex-lap shows embolus in superior mesenteric artery with complete occlusion of middle colic artery. Ischemic changes where? - Small intestine, ascending colon, and part of the transverse colon 34. 68-year-old man with alcoholism comes for fever, chills and productive cough of purulent sputum for 3 days. Blood cultures positive. Gram stain: gram-positive, lancet-shaped diplococci. Vaccine is against which bacterial component? - Capsular polysaccharide 35. Patient making sexual advances towards physician. Appropriate measure? - Have a chaperone join them 36. Cholera toxin catalyzes transfer of ADP-ribose to an arginine residue in stimulatory G protein resulting in inhibition of GTPase activity. Which increases in cells as a result? - Concentration of cAMP 37. 8-year-old boy with pain on back and head since he fell off swing. Tender 2.5cm swollen mass over right occiput. CT shows osteolytic and soft-tissue mass in skull with inward displacement of dura. Biopsy shows sheet-like infiltrate of pale eosinophilic cells with bean-shaped nuclei. Cells positive for CD1a. Electron microscopy of cells shows Birbeck granules. Abnormal cell type? - Langerhans cells 38. 60-year-old man 1 day of fever, chills, confusion and memory loss. Returned from Gulf coast where he walked barefoot. Hx of severe cirrhosis and portal hypertension. T 39C (102.2 F), RR 22, bp 90/48. Physical shows early blister formation on right lower extremity. Blood culture: gram-negative, lactose- fermenting organism. Bug? - Vibrio vulnificus 39. 20-year-old woman at 27 weeks' gestation is admitted to the hospital because of a 12-hour history of intense uterine contractions occurring every 8 minutes. Her membranes ruptured 32 hours ago. Her temperature is 39.1�C(102.4�F), and pulse is 115/min. Physical examination shows tenderness of the uterus. Pelvic examination shows a closed cervix that is not effaced. The fetal heart rate is 210/min. Which of the following is the primary stimulus for her uterine muscle contractions? - Inflamed maternal decidua release of prostaglandin 40. Child with XXY karyotype, genetic studies showed he received the extra "x" from his father. An error of chromosome segregation occurred during anaphase at which of the following stages of spermatogenesis in the patient's father? - Primary spermatocyte 41. 10-year-old boy with 4 days nosebleeds and easy bruising. Three weeks ago, upper respiratory tract infection. PE ecchymoses on upper and lower extremities. Labs shows hemoglobin and leukocyte count normal, and decreased platelet count. Bone marrow smear shows increased megakaryocytes. Mechanism of dz? - Antibodies against glycoprotein (Gp) IIb/IIIa complex 42. 34-year-old man with a 3 month history of a progressive rash on his feet. Rash is not itchy or painful. A photograph of feet is shown. HIV+. In addition to HAART, which of the following pharmacotherapy is most appropriate? - Antineoplastic 43. 55-year-old man with elevated LDL cholesterol is prescribed lovastatin. This treatment would result in which adaptive responses at the cellular level? - Increased transcription of HMG-CoA reductase 44. A new antiplatelet agent is developed for the prevention of recurrence of stroke. In a large randomized clinical trial with equal numbers of men and women, the rates of stroke are lower in patients receiving the new agent than in patients receiving the standard treatment. Results are shown: Recurrent Stroke Rates per 1000 Person-Years Standard Treatment vs. New Antiplatelet Drug Women .12 .04 Men .24 .08 Overall .18 .06 Based on these results, which of the following is the relative risk reduction in women? - 67% 45. 52 yo man is brought to er 30min after the onset of chest pain and shortness of breath. He had played tennis all day and he does not remember how much fluid he had consumed. His temperature is 36.7 oC, pulse 122min, respirations 28min and BP 90/50 mmHg. PE shows dry skin and decreased capillary refill. An ECG and evaluation of cardiac enzymes show no abnormalities. Which of the following findings in the nephron best describes the tubular osmolarity, compared with serum in this patient? PT //macula densa //medullary collection duct - Isotonic, hypotonic, hypertonic (?) 46. Persons are at risk of influenza are vaccination every year because of antigenic variation, which can be drift (minor) or shift (major). Mechanism of antigenic shift? - Reassortment 47. 63 yo man with mild emphysema has smoked 1 pack for 45 years sudden headache, myalgia and rising temperature. A dry cough develops, with chill and chest pain. Examination of gram stain of sputum disclose neutrophils, but bacteria are not evident. An X-ray of the chest is consistent with severe pneumonia. A culture of sputum is negative, but culture of bronchoscopy specimen on a highly specialized bacteriologic medium yields gram negative rods. The identity of these bacteria is confirmed by staining with specific fluoroscent antibodies. The patient respond therapy with macrolide Ab. Mechanism? - Inhalation of aerosol from an environmental source (Legionella) 48. A sexually active 32-year-old woman has vaginal pain with urination. Pelvic examination show bilateral vesicoulcerative lesions of introitus. Tx? - Acyclovir 49. 4-day-old boy with vomiting after breastfeeding. PE shows lethargy and dry mucous membranes. Labs: Na 139, Cl 90, K 7, HCO3 17, Glucose 42, BUN 25, Cr 0.4, 17-hydroxyprogesterone increased. Enzyme deficiency? - 21-hydroxylase 50. 7-year-old boy is about undergo an appendectomy. An intravenous catheter needs to be inserted, but the patient is fearful of being stuck with needle. The most appropriate anesthesia administered by mask to anesthetize this patient quickly would have which of the following characteristics? - Low blood solubility Block 2 Part 1 1. 23-year-old woman g1p1, not felt well since delivery 2 weeks ago; ongoing fatigue, inability to breast-feed, light-headedness in upright position. Pregnancy complicated by preeclampsia and required cesarean delivery, after she required blood transfusions because of hypotension. PE appears lethargic. HR 80, BP 100/50, HR standing 85, BP standing 86/44. Hb 11.6, hct 36%. Serum hormone concentrations? Prolactin/ACTH/TSH/Aldosterone - decreased, decreased, decreased, increased 2. 21-year-old woman with 2-days history of urinary frequency and pain with urination. T 39 C (102.2 F), pulse 125, bp 96/60. Urine grows gram-negative bacteria. Virulence factor for adherence to bladder? - Fimbriae 3. Man comes to doc for cast removal. Fracture of left humerus that required open reduction, internal fixation, cast immobilization. Muscle strength is 2/5 with extension of elbow and 1/5 with extension of wrist and fingers. Patient most likely sustained a fracture at (which location in humerus)? - Radial groove (radial N. is the extensors of arm, wrist and fingers) 4. 36-year-old F with 2 week history of fatigue, bleeding of the gums, and bone pain. Physical examination shows pallor, hepatosplenomegaly, and ecchymotic lesions over extremities. Labs: Hb 8g/dl Ht 25% Leukocytes: 36,000 segm neutr 4% eosinophils 4% lymph 6% mono 6% promyelo 80% platelets 25,000 Polymerase chain reaction test shows an mRNA corresponding to the retinoic acid receptor- alfa/promyelocytic leukemia fusion gene resulting from a reciprocal translocation of chromosomes 15 and 17. Treatment w/ all-trans retinoic acid is started. In response to the therapy, the fusion protein will most likely attract which of the following proteins to form a pre-transcriptional complex? - Histone acetylase 5. 98-year-old woman who lives with daughter and grandson comes for routine exam with type 2 diabetes and hypertension but no complaints. She has had 14-lb weight loss since last visit 3 months ago. BMI 15. PE shows multiple ecchymoses in various stages of healing upper extremities and torso. Physician should ask? - "Are you safe at home?" 6. 18-year-old woman comes 12 hours after ingesting 100 aspirin tablets in suicide attempt. PE shows tachypnea. Labs? pH/pCO2/HCO3- - 7.32/15/8 7. 10-day-old male newborn 1-day history red eyes with discharge. Pregnancy uncomplicated but no prenatal care in third trimester. PE bilateral conjunctival injection with water discharge. Cause? - Chlamydia trachomatis (gonorrhea occurs earlier and is more purulent) 8. 14-year-old girl with 4 months of heavy menstrual flow. Menarche at 13 with regular intervals. History of frequent nosebleeds and easy bruisability. Father has problems with nosebleeds and clotting. PE shows mild gum bleeding and ecchymoses. Labs: hb 8.2, hct 24.6, platelet 250,000, bleeding time 10, PT 14 (INR 1.5), PTT 60. Dx? - von Willebrand disease 9. Prevalence of high-grade cervical intraepithelial neoplasia in unscreened population is 5%. Prevalence in population with negative Pap smear results is as high 0.2%. Prevalence decreases, which also decreases? - Predictive value of a positive test result 10. 57-year-old man with alcoholism dies of klebsiella pneumonia. Abscess cavities filled with purulent exudate on autopsy. Pattern of necrosis in lung tissue? - Liquefaction 11. 35-year old man w several episodes of squeezing chest pain gets angiogram... gets IV NE. Question shows a graph of coronary blood flow with a drop after the NE and then a rise. Which substance causes increased total coronary blood flow 1-2 mins after NE? - Adenosine 12. 24-year-old woman overdose on drug X and has serum concentration of 32. Drug X follows first-order kinetics. 6 hours later, the serum concentration is 16. Cannot be moved from intensive care unit until concentration 1.1 or lower. Which is minimum number of hours from first blood sample (32) that patient must remain in icu? - 30 hours (5 half lives) 13. 4-year-old boy with fatigue and irritability for 2 months. Family visited rural Louisiana 5 months ago and ran around barefoot. Conjunctivae are pale. Labs shows normal wbc with 15% eosinophils. Stool prep shows parasite egg (picture). Cause of fatigue? - Microcytic anemia (strongyloides) 14. 35yo F has congestive cardiomyopathy and pitting edema. Her serum urea nitrogen concentration is 25mg/dl and serum creatinine is 1.8mg/dl. Furosemide therapy is started. After 5 days, labs show: Na 130 K 4.5 Cl 90 HCO 30 BUN 85 Creatinine 2.2 Albumin 3 Urine specific gravity 1.023, rbc 0 wbc0 sediment none Urinary fractional excretion of sodium is less than 1%. Explanation? - Prerenal azotemia 15. Investigator studying immune response to fungi. Fungi express beta-glucans on cell surface and that triggers innate immune response. Which tx decreases glucan expression? - Caspofungin 16. 72-year-old woman comes to the physician because of a 6-month history of increased bruising on her forearms. She appears alert and well nourished. Physical examination shows extensive wrinkling, scaly erythematous patches on the face, and irregularly shaped brown macules on the face and forearms. There are ecchymoses in various stages of healing on both forearms; the ecchymoses are more numerous on the right side. Laboratory studies, including a complete blood count and coagulation studies, are within the reference ranges. She has noticed no bleeding from her gums after brushing her teeth. Which of the following is the most likely cause of the ecchymoses in this patient? - Extensive solar elastosis 17. Heart of 76-year-old woman shows concentric enlargement of left ventricle. Micro exam shows enlarged myocardial cells with large nuclei. Dx that causes this cardiac enlargement? - Hypertension 18. 45-year-old woman dx with cholelithiasis. She asks why abdominal pain is intermittent and not constant. Pain is produced when gallbladder contracts against gallstone obstructing cystic duct. Where is hormone released from that causes gallbladder contraction? - Enteroendocrine cells of the small intestine (CCK) 19. 73-year-old man has poor appetite and lost 25 lb over 4 months. Labs show normochromatic normocytic anemia. Xray of chest shows 2-cm perihilar mass. Biopsy shows small cell carcinoma of lung. Which is responsible for weight loss? - Cytokine effect 20. 34-year-old man burned hands firing pots 3 months ago. He has no pain during or after burn. PE shows mild atrophy of arms and hands, absence of deep tendon reflexes in upper extremities, and decreased pain and temperature sensations in C4 to T1 dermatomes. Touch is preserved. Dx? - Syringomyelia 21. 2-year-old girl with febrile seizure. PE shows nuchal rigidity and bacterial meningitis suspected. LP and immediate abx therapy planned, but parents unavailable for consent. Next step? - Initiate the procedure and treatment without consent 22. 51-year-old with Graves disease develops ulcerating pharyngitis after 6 months of propylthiouracil. What's the underlying cause of ulcerative pharyngeal disease? - Agranulocytosis 23. 54-year-old man with normal renal functions gets a heart transplantation. One year later, bp 170/110 and serum creatinine 2.1. Which drug caused these findings? - Cyclosporine 24. 44-year-old woman 15 weeks' gestation with uterus consistent size with gestational age. Amniocentesis shows increased alpha-fetoprotein (AFP). Fetus at greatest risk for which defect? - Spina bifida 25. 28-year-old man infertility, weight lifter and takes anabolic steroids. Mechanism of infertility? - Suppression of gonadotropins Block 2 Part 2 26. 34-year-old man with herniated lumbar intervertebral disc. Laminectomy and removal of hernia scheduled. CT scan of vertebrae shown, which is surgical entrance location into neural canal? - D (the lamina - called a laminectomy) 27. 68-year-old man with 3 days of increasingly severe chest pain, shortness of breath, stridor, hoarseness, difficulty swallowing and nonproductive cough. Long- standing hx of hypertension. Smokes 2 packs of cigarettes for 45 years. T 99 F, pulse 80, rr 15, bp 160/94. PE shows visible pulsation above the manubrium of the sternum and displacement of the trachea to the right. Murmur second right intercostal space. Dx? - Aortic aneurysm 28. 35-year-old with Chagas disease and 2-hour history of moderate chest pain. 4.4 lb weight loss in 2 months. Vitals stable. Barium swallow shows dilated esophagus with beak-like narrowing at lower esophageal sphincter (LES). Biopsy shows? - Loss of neurons in myenteric plexus 29. 62-year-old woman with 3-day hx of fever, shaking chills, and left flank pain. Dx acute pyelonephritis and treated with ciprofloxacin. Five days after, sudden onset watery diarrhea and lower abdominal cramps. T 100.9 F, pulse 80, rr 18, bp 124/88. PE moderate tenderness to palpation in lower quadrants especially on right and increased bowel sounds. Stool is brown and occult blood negative. Next step? - Test of the stool for Clostridium difficile toxin 30. 33-year-old woman who three weeks ago, underwent oophorectomy for epithelial ovarian cancer. Recommends adjuvant chemotherapy with paclitaxel. Mechanism? - Inhibits microtubule disassembly 31. 45-year-old man comes to physician for follow up after appendectomy. There is mild scleral icterus and well healing surgical incision. Lab values show Total bilirubin 3.2 Direct: 0.2 Indirect 3 mg/dL Dx? - Gilbert 32. 3-year-old boy 7 days after dx with severe chronic diarrhea due to Giardia. Immunological studies show peripheral leukocytes that express both CD3 and CD4 and fail to express CD40 ligand. Based on this, the immunoglobulin isotype that predominates has which biological properties? - Complement activation 33. 18-year-old woman get general anesthesia for wisdom teeth extraction. After 5 minutes, gets hypertonicity of skeletal muscles and increased body temperature. The treatment is a drug that decreases? - Sarcoplasmic Ca release 34. 22-year-old nulligravid woman has menses that occur at irregular 26- to 32-day intervals. Height 5 ft 4 in and weighs 187 lb. BMI 32. PE shows mild hirsutism and velvety brown, thickened skin at the base of the neck and around axillae. Patient has which condition? - Hyperinsulinemia 35. 5-year-old girls with severe leg pain 1 day after fell off sled. Immigrate to USA from Iceland. Has had three bone fractures since birth. Parents are vegan and don't give diary products. PE shows tenderness, swelling, and limited range of motion of left lower extremity. Xray shows fracture of fibula. Pt has vitamin deficiency that affects which of the following? - Intestinal calcium absorption 36. 36-year-old woman diagnosed with HIV. Two months ago, started antiretroviral therapy with efavirenz, emtricitabine, and tenofovir. Labs: CD4 352 and undetectable HIV viral load. Two months ago, CD4 count was 158 and plasma HIV viral load was 5500. Next step? - Continue efavirenz, emtricitabine, and tenofovir with no changes 37. 35-year-old man with several episodes of dizziness and fainting during the past 2 months. Father and several paternal uncles died suddenly. PE and lipid studies normal. Angiography shows no coronary artery blockage. ECG shows prolonged QT. Decreased activity in which of following causes this? - Outward (delayed) rectifying potassium channel 38. 4-month-old boy with 1-day respiratory distress. Has progressive weakness and difficulty feeding for a month. RR 50/min. PE shows enlarged tongue and generalized hypotonia. Increased lactate, pyruvate, glucose, and uric acid. CXR shows cardiomegaly. Biopsy of skeletal muscle shows increased glycogen. Enzyme impaired? - alpha-1,4-Glucosidase 39. 50-year-old man with pulmonary embolus. Treated with intravenous heparin. 24 hours later, warfarin added. Day 2, partial thromboplastin time is 52 seconds (control 26 sec), and prothrombin time is 12 seconds (control 12.1 sec; INR = 1). Best explanation for normal prothrombin time and INR? - Long half-life of factor II (prothrombin) (?) 40. An investigator conducts a meta-analysis of three genome-wide association studies of Crohn Disease. The studies encompassed 3200 cases and 4800 controls, all of European descent. The initial studies identified 11 significant loci with odds ratios above 1.3 and 1.5; the combined meta-analysis identified an additional 21 loci with odd ratio of 1.1 to 1.3. It is estimated that the 32 loci identified explain about 10% of the variance in disease risk with 2 loci accounting for 2% of the variance. Previous studies of twins indicated a 50% heretability rate for Crohn's disease. Which of the following best explains these results? - The identified loci account for a relatively small part of the variance 41. 6-year-old boy with 5-day history of intermittent vomiting and 3-month hx of progressive clumsiness. Can no longer ride bicycle and difficulty getting out of car. Funduscopic exam shows bilateral papilledema. Neuro exam shows impaired upward gaze and pupil response to light. Walks shuffling gait. CT shows enlarged lateral and third ventricles and a 2-cm mass. Location of mass? - Pineal gland 42. 67-year-old woman comes to the physician because of a 1-month history of low back pain. She has hypertension well controlled with a thiazide diuretic. Her pulse is 140/min, and blood pressure is 140/85 mm Hg. Physical examination shows tenderness to palpation over the L2-3 vertebrae. Laboratory studies show: Hemoglobin 13.5 g/dL Hematocrit 41% Leukocyte count 10,500/mm3 Segmented neutrophils 65% Eosinophils 1% Basophils 1% Lymphocytes 30% Monocytes 3% Platelet count 250,000/mm3 Serum electrophoresis shows a monoclonal spike of IgG kappa. A chest x-ray shows cardiomegaly with bilateral pleural and pericardial effusions. An x-ray of the spine shows a lytic lesion. Echocardiography shows an echodense thickened left ventricle and poor diastolic compliance. A photomicrograph of a specimen obtained on myocardial biopsy is shown. Which of the following is the most likely cause of the cardiac findings in this patient? - Amyloid infiltration 43. 45-year-old woman with joint pain due to rheumatoid arthritis comes for infective treatment with over-the-counter agents. Initiate disease-modifying antirheumatic drug (DMARD). Delayed onset of action of DMARD, so physician prescribes another until DMARD is effective. Drug? - Prednisone 44. 8-year-old boy with persistent disruptive behavior. Teacher says he's in "constant motion" and never completes assignments. Treated in ER several times because of skateboarding injuries. Tx? - Methylphenidate 45. A transcription factor that activates expression of HMG coA reductase is identified, this TF is initially synthetized as a large precursor protein, with 2 membrane spanning domains. The transcriptional domain is released by proteolysis when the membrane has a decreased cholesterol concentration. The precursor protein is mot likely initially produced in which of the following labeled area on this labeled diagram of a hepatocyte? - F, Rough Endoplasmic Reticulum (ER) Labeled organelle is the rough endoplasmic reticulum, site of protein synthesis 46. 3-year-old boy with progressive fever and skin lesions during 24 hours. T 102.9 F, pulse 120, RR 20, bp 110/60. PE shows large, flaccid, bullous lesions over trunk and abdomen. Another finding in pt? - Positive nares culture for toxin-producing Staphylococcus aureus 47. A study is conducted to compare the incidence of myocardial infarction in patients undergoing two different types of angioplasty or an operative procedure to manage single-vessel coronary artery disease. A total of 1000 patients are enrolled. Through a chance process, 500 are assigned to undergo the operative procedure, 250 are assigned to undergo one type of angioplasty, and 250 are assigned to undergo a second type of angioplasty. All patients are followed for 3 years to determine the incidence of myocardial infarction. Which of the following best describes this study design? - Randomized clinical trial 48. 48yo man with possible hypertension. based on 20 measurements, his average diastolic pressure is 94mmHg, SD is 8mmHg. If only four measurements were made rather than 20, which of the following statements would best describe the width of the 95% CI with regard the mean blood pressure? - Larger 49. 66-year-old man with 1-month hx of nonproductive cough and 6 months shortness of breath. Bilateral end-inspiratory crackles heard. CT chest shows diffuse reticular opacities at periphery and bases of lungs. Micro exam of biopsy shows patchy interstitial fibrosis, several fibroblastic foci and no granulomas. Dx? - Idiopathic pulmonary fibrosis 50. 65-year-ld man with cancer of cecum found to have metastatic lesion to liver. Venous route of mets? - Ileocolic --> superior mesenteric --> portal --> right hepatic branch of portal Block 3 Part 1 1. 60-year-old man for routine health examination. Has had normal blood pressure measurements. BP today 170/95mmHg. Physical examination shows no other abnormalities. Serum show hypokalemia and metabolic alkalosis. Plasma renin activity and serum aldosterone concentrations are increased. Following the administration of captopril, there is a marked increase in plasma renin activity. Which of the following is the most likely cause of the findings in this patient? - Renal artery stenosis 2. 8-year-old girl is brought to the physician by her mother because of a 3 week history of poor feeding chronic diarrhea and pale foul smelling stools. Mother says the symptoms began with colicky abdominal pain following introduction of solid food to the infant's diet. History of gluten sensitivity. 60th percentile for length and 25th percentile for weight. Which cell is dysfunctional? - Enterocyte 3. 25-year-old woman comes for counseling prior to conception. Has seizure disorder on valproic acid. Fetus at greatest risk for drug-related adverse effect during which pregnancy stage? - 3 to 8 weeks 4. Study designed to test the effectiveness of a new drug in the treatment of endometriosis, 100 women randomly assigned to one of two groups. 48 of women receive new drug, 52 receive standard therapy. The primary purpose of this method of assigning patients to different groups is to create which of the following ? - Two groups with similar underlying characteristics 5. 65-year-old woman with 6 hour Hx fever and shaking chills. 4 hours ago, she took 325 mg aspirine tablets. Temp 39.4 C, pulse 96/m, respiration 18/m and blood pressure 102/60 mmHg. Physical examination shows marked tenderness bilaterally in the costovertebral areas. Lab studies show : Hb 13 g/dl Ht 39% Leukocyte count 32.000/mm3 Urine ph 6 Nitrites 4+ Leukocyte esterase 4+ A photograph of wright stained peripheral blood smear, which the most likely cause this patient leukocytosis ? - Leukemoid reaction 6. 68-year-old man with a 10-month history of shortness of breath and swelling of his feet, family history of cardiovascular disease. He smoked 2 packs of cigarettes daily for 50 years. Pulse 80/min, rr 24/min, BP 150/80. PE: 3+pitting edema of lower extremities. Diffuse, scattered wheezes are heard bilaterally on auscultation of the chest. Grade 2/6 pansystolic mumur heard best at lower left sternal border, which increases on inspiration. Maximal impulse palpated in sub-xiphoid area. S1 and S2 sounds are distant. Liver span 14 cm. Diagnosis? - Cor pulmonale 7. 48-year-old woman with gradual onset back pain past 2 weeks. No trauma. Doesn't smoke cigarettes, drink alcohol or use drugs. Hemogram, serologic studies and urinalysis unremarkable. Xray of spine shows two lytic lesions, in T-10 and L-1. Dx? - Metastatic carcinoma of the breast 8. 17-year-old boy brought by mother with concern that puberty is delayed. When mother leaves room, patient states, "I'm fine. I don't know what's the matter with her. She wants me to be tall like my dad." Patient is 175 cm (5 ft 9 in) tall and weighs 70 kg (155 lb); BMI 23. Sex development is Tanner stage 4. Most appropriate next statement to mother? - "Tell me more about your concerns about your son's height." 9. 35-year-old from group home comes for worsening behavior for 2 weeks. He believes CIA is spying on him through television set. Reports hearing voices in hall outside and that CIA now plans to kill him. Appears disheveled with unkempt hair and poor hygiene, difficulty answering questions because listening to internal stimuli. Mental status exam will show which? - Flattened affect 10. 17-year-old boy in septic shock unresponsive to ADH (vasopressin). Treat is discontinued, and high-dose dopamine in started. Which receptors are stimulated? - alpha1-adrenoreceptors 11. After operation, 65-year-old patient has lung region that is underventilated but well perfused. Which increases? - Physiologic shunt 12. 32-year-old man with X-linked recessive disease has deafness, hematuria and progressive renal failure. Protein abnormality? - Type IV collagen 13. 52-year-old with chronic pancreatitis is deficient in which enzymes that causes inability to digest triglycerides? - Colipase 14. 47-year-old woman with irregular, raised, multicolored dark lesion on left forearm with frequent sunlight exposure. Biopsy shows malignant pigmented cells. Worst prognosis with involvement of which layer? - Subcutaneous tissue 15. 33-year-old man dx with epilepsy age 10 years. Most recent generalized tonic- clonic was 5 years ago. Medication was adjusted. Current meds include carbamazepine. He's never had any collisions while driving his motor vehicle. Patient's status with respect to driving? - He is medically qualified to drive 16. 45-year-old woman with 4-month joint pain, muscles aches and fatigue. Had a renal calculus 6 months ago and had cholecystectomy 1 year ago. Appears fatigue, depressed, there is mucosal pallor. No masses palpated in neck. Labs: erythrocyte count 3 million, K+ 4, Cl- 106, Ca2+ 13, phosphorous 2.7, alk phos 125. Technetium- 99m scan shows 1.2 cm nodule in neck. Mutation? - MEN1 17. 25-year-old man just returned from work as worker from Africa begins oral chloroquine therapy for malaria caused by Plasmodium vivax. His initial therapeutic response is good, but he develops recurrent parasitemia 2 months later. Which of the following best explains the recurrence ? - Chloroquine is ineffective on the exoerythrocytic malaria tissue stages 18. 32-year-old man with HIV infection follow up examination, has been treated with HAART for the past 6 years HIV plasma viral load has been undetectable. HIV viral load now increase, antiretroviral resistance suspected. HIV genotype analysis confirms that the virus has resistance mutations, which of the following most likely mutated? - Reverse transcriptase and protease (the two targets of HAART therapy, therefore if therapy stopped working, must be these two target proteins of virus mutated) 19. 58-year-old woman with 6-month shortness of breath and chronic nonproductive cough. 2-year history difficulty swallowing, joint stiffness, diffuse tightening of skin on face, neck, shoulders, arms, fingers. Sensitivity to cold weather, turn white. Hx of esophageal reflux. Biopsy showed atrophy of epidermis and deposition of collagen throughout dermis with loss of dermal appendages. PE cutaneous ulceration, clawlike flexion deformity, decreased joint mobility. At risk for which pulmonary disorder? - Pulmonary hypertension (dx: systemic sclerosis/CREST) 20. Workbench wiped down with alcohol, successfully inactivates viruses with which characteristic? - Enveloped virion 21. 35-year-old woman pain in left leg 2 days. PE shows deep venous thrombosis. Labs: platelet 200,000, PT 12 (INR 1), PTT 37. Heparin started. Five days later, platelet 120,000. Reason for decreased platelets? - Drug-related antibodies 22. 6-year-old girl with 15-minute history of severe shortness of breath. Diagnosed with throat tumor 3 years ago. RR 32. PE nasal flaring. Laryngoscopy shows multiple raised, finger-shaped lesions from vocal cords and epiglottis. Lesions excised and shows finger-shaped fibrovascular cores lined with benign squamous epithelium. Causal virus? - Human papillomavirus, type 6 23. A 68-year-old man comes to the physician because of a 1-month history of light- headedness and tightness in his chest with exertion. He adds that the pain is worse after arguing with his wife, and the symptoms resolve with rest. He has a past history of lower gastrointestinal bleeding; evaluation at that time was negative on upper endoscopy and colonoscopy. His temperature is 37�C (98.6�F), pulse is 85/min, respirations are 15/min, and blood pressure is 110/75 mm Hg. Physical examination shows no abnormalities. His hemoglobin concentration is 8.2 g/dL, and hematocrit is 24%. Test of the stool for occult blood is positive. An ECG shows no abnormalities. Repeat colonoscopy shows no abnormalities. Which of the following is the most likely cause of this patient's gastrointestinal symptoms? - Angiodysplasia 24. A 25-year-old woman comes to the physician because of a 2-year history of intermittent, diffuse, cramping lower abdominal pain. The pain is usually associated with2 to 6 days of loose, watery stools, and is typically relieved with defecation. Between these episodes, her stools are normal. Her vital signs are within normal limits. Physical examination shows no abnormalities. Laboratory studies, including complete blood count, metabolic panel, and thyroid function tests show no abnormalities. A drug targeting which of the following mechanisms of action is most appropriate for this patient? - Accentuation of �-opioid myenteric plexus receptor 25. 69-year-old woman with 3-week history of muscle cramps, weakness, abdominal pain, and constipation. Hypertension treated with metoprolol and hydrochlorothiazide for past 4 months. Labs show hypokalemia. Which drug should be added? - Triamterene (potassium-sparing) Block 3 Part 2 26. A 70-year-old woman comes to the physician for a routine pelvic examination. During speculum examination of the vagina and cervix, the Valsalva maneuver causes a bulge of the anterior vaginal wall. Which of the following is the most likely cause of this finding? - Cystocele 27. 2-month-old boy well child exam, mother with no concerns. 25th percentile for length and 30th percentile for weight. Cardiac exam shows blowing holosystolic murmur best heard at lower left sternal border. Cause? - Ventricular septal defect 28. 2-year-old boy 2-day history of fever, sore throat, rash. T 101.7 F (38.7 C). Widespread, red, sandpaper-like rash on extremities. Purulent exudate over tonsils. Dx streptococcus pyogenes (group A) infection. Cause of skin findings? - Erythrogenic toxin 29. 1-year-old boy with rash for 2 weeks. 10th percentile for height and weight. PE scaly, seborrheic eruption over scalp, palms, back, diaper region and soles of feet. Generalized lymphadenopathy and hepatosplenomegaly. Xray of skull shows osteolytic lesions. EM biopsy of skin shows tennis racket-shaped bilamellar granule in cytoplasm. Immuno studies show CD1a antigen expression. Abnormal cells in patient are derived from which cell? - Dendritic cells 30. 21-year-old man loses 15% total blood volume 2 minute after motor vehicle collision. Finding most likely? - Increased sympathetic nerve traffic to sinoatrial node 31. 58-year-old man comes to physician for benzodiazepine prescription for situation at work. Feels anxious and thinks he can complete last 2 years of work if anxiety decreases. Gives 1-month regimen of benzodiazepine. Wife calls, "My husband got fired! I know it was because he was taking too much of that drug you gave him. Didn't you know he had history of alcoholism?" Initial action? - Contact the patient to discuss the situation 32. 32-year-old woman has operation for hyperparathyroidism. Three parathyroid glands found but one does not appear in normal superior location on right side. Embryologic event that led to this? - Abnormal migration of endoderm from fourth pharyngeal pouch 33. 52-year-old female with a history of breast cancer who received 4week course of radiations 6 months ago comes for followup. Exam shows no cancer recurrence. rr 26/min. CT chest shows b/l atelectasis in upper lung fields. Primary pathophysiological cause? - Contraction (secondary to radiation) 34. 4-year-old boy (pedigree shown) has clumsy gait for past year. Exam calf hypertrophy and proximal muscle weakness. Creatine kinase increased. Muscle biopsy shows loss of muscle tissue, regenerating muscles fibers and fibrosis. Maternal uncle had similar findings and died at 15 years. Patient's sister is pregnant. Ultrasound identifies male fetus. Probability fetus has disorder? - 1/4 35. 55-year-old man northern European descent with 2-month weakness, altered skin color, bilateral knee pain. Siblings have type 2 diabetes and cirrhosis. PE bronzed skin, hepatomegaly, arthritis. Increased saturation of transferrin and ferritin. Liver biopsy increased iron content and cirrhosis Greatest risk? - Hepatocellular carcinoma 36. 35-year-old woman with infertile, receive injection of contrast material into cervix. On hysterosalpingogram (shown), contrast material (indicated by arrows) also seen in peritoneal cavity, which explain this finding? - Spillage of contrast which normal 37. 27-year-old man for psychiatric eval sent by employer because he is "very odd." Is a computer repair specialist and lives alone. Refuses to socialize and has no friends. Extremely preoccupied with science fiction, occult, afterlife. Personality disorder? - Schizotypal 38. 46-year-old woman with 1-week low-grade fever and joint pain. Has chronic headaches and takes ibuprofen several times. PE diffuse maculopapular rash. UA 2+ protein, 10-20 WBC and eosinophils. Renal biopsy would show what? - Inflammatory infiltrates in the interstitium 39. 19-year-old woman 2-day history of pain in left index finger. Injured it when catching a ball. PE shows erythema of left index finger. Unable to flex the distal phalanx when proximal interphalangeal joint metacarpophalangeal joints restratined. Xray normal. Injured structure? - Flexor digitorum profundus tendon 40. 25-year-old-man who has a history of facial flushing and rapid heart rate each time he consumes a small amount of alcohol participates in study of alcohol intolerance. Molecular analysis shows presence of a lysine (K487, oriental variant) for glutamate (E487, native variant) substitution in aldehyde dehydrogenase. Kinetic characteristics of the enzyme variants shown: Enzyme Km (NAD+) microM Kcat (min-1) E487 37 180 K487 5600 9.5 based on these findings, which of the following is the most likely cause of this man's condition? - Decreased catalytic efficiency of K487 41. 45-year-old man bmi 26, total cholesterol 200, HDL 50, triglycerides 550. Which drug to prescribe? - Fenofibrate 42. 21-year-old woman with 10-days difficulty walking. Two years ago had loss of vision in left eye which improved. Neuro exam shows decreased visual acuity in left eye with pallor of optic disc. Has past-pointing on a finger-nose test. Broad-based gait. MRI shows brain lesions in white matter of cerebellum. Pathogenesis? - CD4+ T lymphocytes are activated by myelin basic protein 43. 63-year-old man 2-week sensation of fullness in left upper quadrant. Has lethargy and shortness of breath. 20-lb weight loss during 3 months. PE shows pallor. Spleen tip palpated. Labs: hb 9, hct 27%, wbc 4000, serum uric acid 15. Peripheral blood smear numerous erythrocytes with abnormal shapes and sizes, nucleated erythrocytes and myelocytes. Aspiration of bone marrow dry tap. Biopry shows thickened bony trabeculae with increased reticulum. Dx? - Myelofibrosis 44. 1-year-old has numerous infection of skin and oral mucosa since birth. Infections slow to respond to antibiotic therapy. T 100.4F. PE multiple erythematous lesions of skin some with superficial ulceration. WBC 21,000 77% segmented neutrophils, 6% bands, 14% lymphocytes and 3% monocytes. Biopsy shows no neutrophils in dermis or epidermis. Culture of lesion grows Staphylococcus aureus. Defective - An integrin 45. 45 yr old man with SOB on exertion x 6 months, nosebleeds since adolescence, 2 pics: clubbing + hemorrhagic lesions in tongue, inhaled albuterol doesn't improve his symptoms. Cause of symptoms? - Pulmonary AV shunting Disease is osler weber rendu 46. 27-year-old primigravid woman at 18 weeks gestation comes to physician for routine prenatal examination. The uterus consistent in size with 18 week gestation. Ultrasonography shows a male fetus. The collecting system and pelvis of the left kidney is dilated and the renal cortex appears compressed. The left and right ureters are not dilated. The right kidney appears normal. Amniotic fluid volume is normal. Which causing renal finding in this fetus ? - Incomplete recanalization of proximal ureter 47. 24-year-old man with 3-day progressive numbness of both feet ascended to thighs. Last 24 hours, numbness and tingling of hands. PE ataxic gait. Deep tendon reflexes diminished in upper extremities and absent in knees and ankles. Vibration and joint position absent in fingertips and feet bilaterally. Mild weakness distal upper extremities ad moderate weakness of lower extremities. Structure involved? - Myelinated primary afferents 48. 82-year-old woman comes to the physician because of constant severe lower abdominal pain and fever for 24 hours. Laproscopic examination shows severe diverticulosis and perforated diverticulitis. In spite of appropriate therapy she dies 2 days later. Liver autopsy shown. Which of the following is the primary component of the material shown on the hepatic surface? - Fibrin 49. 28-year-old woman comes to the physician because of a 4-day history of palpitations, severe neck pain, fatigue, and malaise. Her pulse is 120/min and regular. Physical examination shows a diffusely tender, mildly enlarged thyroid gland. There is no exophthalmos. Serum studies show a thyroid-stimulating hormone concentration of 0.01 �U/mL. Which of the following is the most likely diagnosis? - Subacute granulomatous thyroiditis 50. 35-year-old primigravid woman 36 weeks' gestation with 6-hour history of heavy vaginal bleeding. No prenatal care. Ultrasound shows placenta over cervical os. Can't stop bleeding and has cesarean. Dx? - Placenta previa Block 4 Part 1 1. 39-year-old man with polycystic kidney disease has 6-month history intermittent blood in urine. T 98.6 F HR 100 RR 24 BP 160/90. Urea nitrogen 100, creatinine 8. UA shows blood. Arterial blood gas shows? pH/pCO2/HCO3- - 7.22/28/11 2. 48-year-old man 2-month increasing abdominal girth and inability to achieve erection. Smoked 1 pack cigarettes for 20 years and drug 1 pint of liquor daily. Vitals normal. PE shows scleral icterus, spider angiomata, gynecomastia, ascites and prominent umbilical venous pattern. Tests small. Cause of gynecomastia? - Failure of liver to degrade estrogen 3. 19-year-old woman is admitted to the hospital for antibiotic treatment of meningococcal meningitis. She is stabilized. Three days later, her pulse is 120/min, and blood pressure is 60/30 mm Hg. Physical examination shows bilateral flank tenderness. Serum studies show a sodium concentration of128 mEq/L, potassium of 5.4 mEq/L, and bicarbonate of 20 mEq/L. Which of the following is the most appropriate next step to determine the cause of this patient's hypotension? - Adrenocorticotropic hormone stimulation test 4. 50-year-old man undergoes operative repair of inguinal hernia. Surgeon has received written informed consent from patient. After epidural received, patient decides he does not want to have surgery. Best response? - "Tell me about your concerns and why you want to cancel the operation." 5. A 25-year-old man is admitted to the hospital because of severe crush injuries to the chest and extensive burns over 30% of his body surface area. Three hours later, he develops tachypnea and dyspnea. Arterial blood gas analysis on room air shows a decreased Po2 and Pco2. A chest x-ray shows bilateral interstitial and alveolar infiltrates. The patient is intubated and mechanically ventilated. Damage to which of the following is most likely to preclude restoration of normal tissue architecture and pulmonary function in this patient? - Basement membranes 6. Studying epithelial repair of small intestine in experimental animal. Wants to identify most active cell division location. Where is this cell activity found? - Base of the crypt 7. 16-year-old girl calls the physician on a Friday night 2 hours after a condom broke during sexual intercourse with her boyfriend. She asks the physician to prescribe an emergency oral contraceptive. The physician on call is not the patient's regular physician and does not dispense emergency contraception for moral reasons. After the physician respectfully informs the patient that he does not prescribe this contraceptive, it is most appropriate for the physician to state which of the following? - "I can have one of my colleagues call you back to further discuss your concerns." 8. 20-year-old woman with 2-week fever, shaking chills, headaches, fatigue, and joint and muscle pain. Spent summer workin as lifeguard in Long Island, New York. Has splenectomy for motor vehicle collision 6 years ago. T 102.4 F. Peripheral blood smear shows small intraerythrocytic rings. Polymerase chain reaction for Plasmodium is negative. Causal organism from bite of? - Tick 9. 67-year-old man who eight months ago dx with primary lung carcinoma involving adrenal glands, liver, and bone. Had 17.6-lb weight loss during 3 months. PE shows cachexia and significant muscle wasting. Intracellular components increased in patient's muscle cells? - Autophagic vacuoles 10. 2-month-old female with T 102F, vomiting, diarrhea, dehydration. Exam of stool shows viral particles with wheel-like shape. Properties of virus? Type of nucleic acid/envelop/capsid symmetry - Double-stranded RNA, segmented/no/icosahedral 11. 14-year-old girl with type 1 diabetes mellitus and 4-hour history of lethargy, confusion, disorientation. Symptoms gradually developed and she did not take her usual insulin dose during a sleepover. HR 110, RR 24 deep and rapid, bp 95/75. Labs: glucose 450, arterial pH 7.15. ABG? pCO2/HCO3-/Anion gap - decreased/decreased/increased 12. Investigator studying vancomycin-resistant strain of Enterococcus faecalis. Ten generations created. Culture inoculated and resulting bacterial colonies are screened for vancomycin resistance. Vancomycin-sensitive colonies observed at frequency of one per 100 cells. Mechanism of decreased vancomycin resistance? - Plasmid loss 13. Male newborn delivered at 28 weeks, neonatal respiratory distress syndrome, ABG shows decreased pH, decreased Po2 increased PCO2. A deficiency in which of the following most likely caused the disorder? - Dipalmitoylphosphatidylcholine 14. 65-year-old man with 4-hour history of intermittent severe pain in flank area radiating to genital region. History of hypercalciuria and renal calculi. Drug decrease the urinary excretion of calcium? - Hydrochlorothiazide 15. 45-year-old man comes to the physician because of an enlarging face shoulders and trunk and thinning of his arms and legs. Physical examination shows a large plethoric face, fat pad over the upper thoracic spine and purple striae on the abdomen. Serum studies show undetectable ACTH and an increased cortisol concentration. Administration of low dose dexamethasone would most likely result in which of the following sets of serum findings? - ACTH no change, cortisol no change 16. 12-year-old boy with mother concerned about enlarged left breast and family history of breast cancer. Left breast is slightly larger than right, nipple mildly tender. Penis slightly enlarged and pubic hair curling and beginning to darken at base. Best next step? - Reassure the mother that physical findings are not uncommon for his age 17. 55-year-old woman who is a physician has fractured femur during motor vehicle collision. 2 days after admission, has tachycardia, restlessness, diaphoresis, anxiety, seeing "vague shapes" on walls. Dx? - Alcohol withdrawal 18. 35-year-old woman with fever and sharp chest pain for 3 days. T 101.3F. Friction rub heard. All cuases of secondary pericarditis ruled out. Cause of primary pericarditis? - Virus 19. 35-year-old man with severe back pain, gained 8 kg in the past 6 months, decreased peripheral vision, compression fracture spine at T10 and L1, healing left rib fracture at T6, imaging shows pituitary macroadenoma. This tumor produces which? - ACTH 20. 35-year-old woman passed out while washing dishes. Began to feel weak and dizzy, husband shares with nursing staff history of bulimia nervosa, and has been binging more frequently. Suspected she has been vomiting. Labs of patient? K+/HCO3-/Anion Gap/pH - decreased/increased/normal/increased 21. 67-year-old man with 3 months fatigue and shortness of breath. Vitals HR 90, RR 15, bp 150/98. PE conjunctival pallor. Labs: hb 8.5, hct 26%, MCV 90, RDW 14.4% (N=13-15%), Cr 2.9, Ferritin 144, Iron 24, Transferrin saturation 23% (N=20-50%). Besides iron supplementation, most appropriate tx? - Erythropoietin 22. 15-year-old girl comes with lack of improvement of facial acne. Tried topical clindamycin and benzoyl peroxide PE severe acne vulgaris. Says, "Please help me." She has never been sexually active. Tx? - Isotretinoin 23. 18-month-old girl with 2 day progressive cough and hoarseness. T 102.2F, HR 88, RR 24, bp 100/70. Oxygen saturation 95%. PE mild erythema of oropharyngeal and laryngeal mucosa no exudate, harsh, barking cough heard. Improves within 4 days. Cause? - Parainfluenza 24. 38-year-old man 1-week shortness of breath with exertion, light palpation of carotid artery shows upstroke is abnormally brisk and downstroke falls precipitously. Cause of finding? - Aortic Regurgitation 25. Retrospective study of incidence and outcome of subarachnoid hemorrhage. Incidence is 15 per 100,000 people, mortality is 6 per 100,000 people. Incidence remains constant, case fatality rate? - 40% Block 4 Part 2 26. 64-year-old with non-Hodgkin lymphoma and 3-day history of abdominal pain and nausea. T 99.7F, HR 100, bp 130/80. Abdominal exam tenderness of flanks and lower quadrants. BUN 34 and creatinine 3.8. CT shows bilateral hydronephrosis and lymphadenopathy compressing ureters. Tx to improve renal function? - Bilateral stents in the ureters 27. 71-year old woman with coronary disease and well-controlled hypertension is brought to the physician 2 hours after sudden onset of weakness of her left leg. Her BP 145/85 mmHg. Neurologic exam: weakness and decreased sensation over the left lower extremity. There are no other sensory or motor deficits. Which labeled structure is site of injury? - A (Pre/postcentral gyrus; motor/sensory cortex) 28. Girl has chronic cough with thick sputum, abdominal cramps in RLQ, and frequent resp infections. Clubbing of fingers, hyperresonance on chest percussion. Diffuse crackles and scattered wheezes. On xray - diffuse hyperinflation of the right upper lobe. She has a healthy brother. What's the likelihood he is a carrier for the condition? - 2/3 29. 4-year-old male with recurrent UTIs, left kidney found small and non functional; right is normal. Nephrectomy is done, and the picture shown (dilated ureter and renal calyx). Microscopic exam of kidney will show which? - Tubular atrophy 30. Patient with orthostatic hypotension, loose stools for 1 year, and history of type 1 DM. Stool studies are normal. What is the pathophysiological mechanism of the diarrhea? - Motility disorder 31. In a 25-year-old patient who underwent splenectomy, target cells are seen on peripheral smear. These cells are seen due to loss of function of which portion of spleen? - Red pulp 32. 58-year-old man comes to the physician because of a 4-year history of recurrent cough productive of increased sputum. Use of over-the-counter cough suppressants has not resolved his symptoms. He has smoked 2 packs of cigarettes daily for 35 years. He has no family history of lung disease. His temperature is 37�C (98.6�F), pulse is 72/min, and respirations are 18/min. Physical examination shows cyanosis. Diffuse wheezing is heard on auscultation. Which of the following pulmonary cell types is most likely to be abnormal in this patient? - Pseudostratified columnar epithelial cells 33. Researching new cancer drug, effective at killing rapidly dividing cells, in mice caused profound myelosuppression. In patients, most appropriate to follow which when at risk for infectious complications? - Neutrophil counts 34. 48-year-old recently diagnosed with lupus and difficulty working as schoolteacher because of severe pain and swelling of joints. Current meds include prednisone, hydroxychloroquine, and oxycodone for pain. Best action to adapt to illness? - Encourage the patient to participate in a support group for persons with her condition 35. 19-year-old man with gastrointestinal bleeding. Laparotomy done and 5-cm blind outpouching on antimesenteric side of terminal ileum 15 cm from ileocecal valve resected. Pathology shows? - Heterotopic gastric mucosa 36. 17-year-old boy with syncopal episode, fever, nausea, muscle aches, progressive confusion. T 103.5F, palpable bp 80. PE rash on lower extremities. WBC 26,000. Blood and CSF cultures grow oxidase positive, gram negative diplococcus. Brother with similar infection at same age. Immune disorder? - Late component of complement deficiency 37. Randomized controlled trial evaluating tx of acute otitis media. No statistically significant differences found between infants receiving the antibiotic and those with standard tx. Which aspect results in type II error? - Number of subjects in the study 38. 17-year-old boy whose mother concerned about physical development. 10th percentile for height and 25th for weight. FSH is 5, testosterone 8 (N=10-35). Physical finding on patient? - Gynecomastia 39. To decrease risk for cv disease 24 yo man begins diet. 1.53 95 kg BMI 32, Intends to lose 16 kg by limiting caloric intake to 2000 cal. to maintain the recommended protein intake (56g day); a balanced decreased in carbs and fat is required (caloric radio of fat and carbs is 30:55). which best describes number of calories that should be provided by fat in this its diet each day? - 630 40. 20-year-old woman with palpable lump in right breast 4 months, no pain, swelling or nipple discharge. Lump is smooth, firm, round, mobile, nontender, well delineated. No skin change. Dx? - Fibroadenoma 41. 65-year-old woman comes to the physician because of a 1-week history of a swollen, painful left knee. Her temperature is 38�C (100.4�F), and blood pressure is 110/65 mm Hg. Examination of the left knee shows erythema and swelling of the joint and decreased range of motion. A photomicrograph of synovial fluid obtained by arthrocentesis is shown. This patient's synovial fluid most likely contains which of the following? - Uric acid 42. 56-year-old exposed to possible chemical attack. Respirations labored, diaphoresis, excessive lacrimation, increased salivation, muscle strength 2/5, urinary and fecal incontinence. Besides atropine, another tx? - Pralidoxime 43. 71-year-old man admitted for prostatic resection. Normal mental status. 2 days after surgery, confused and restless. Cannot sleep and restless, seeing little men coming through window. Dx? - Delirium 44. 32-year-old woman has new neuro finding while being tx for acute infection of sphenoid sinus. Imaging shows cavernous sinus thrombosis on left. Additional finding most likely? - Inability to abduct the eye 45. 66-year-old woman is brought to the emergency department by her daughter because of a 2-day history of fever, flank pain, pain with urination, and nausea. Ten days ago, she was admitted to the hospital for similar symptoms and was diagnosed with acute pyelonephritis. She was discharged with instructions to take oral ciprofloxacin after a 3-day course of intravenous ciprofloxacin resulted in improvement. She also has hypertension, hyperlipidemia, and osteoporosis. Current medications also include alendronate, calcium carbonate, ezetimibe, hydrochlorothiazide, and simvastatin. Her temperature is 39.1�C (102.4�F), and blood pressure is130/80 mm Hg. The most likely cause of this patient�s current condition is an interaction between her current oral antibiotic and which of the following medications? - Calcium carbonate 46. 34-year old man is brought to the ER semiconscious and combative. In addition to sedation , a short-acting neuromuscular blocking agent is administered for intubation to prevent aspiration. Within a few seconds after admin of the drug, he has transient muscle fasciculations in his face ; he develops generalized paralysis within 1 minute. Forty five minutes after completion of the procedure , he is still paralyzed. A genetic abnormality of which of the following enzymes is the most likely cause of his unusually slow recovery from paralysis? - Pseudocholinesterase 47. Full-term newborn in respiratory distress. Imaging shows abdominal contents in left pleural cavity. Maldevelopment of which structure led to diaphragm defect? - Left pleuroperitoneal membrane 48. 83-year-old with arteriosclerosis undergoes repair of infrarenal abdominal aortic aneurysm. Graft extends just below the renal arteries to the bifurcation of the aorta. Which organ will lose primary blood supply and rely on collateral circulation? - Descending colon 49. 62-year-old with angina pectoris is referred for cardiac catheterization. Patient worried about hospital-associated infection. Studies show 30% of patients require admission after procedure, and 2 percent of admitted patients acquire hospital infection. Patient's risk for infection overall? - 6/1000 50. 25-year-old woman with fatigue for 3 wks and intermittent fever for 7 days, had teeth cleaned a month ago, no abx for prophylaxis, and had rheumatic fever as child and endocarditis 4 y ago. PE shows 2/6 murmur, ultrasound shows abnormal mitral valve. Photo of growth from blood cultures shown (GP cocci in chains). Characteristic of causal organism? - Greening reaction on blood agar 1. 56-year-old man comes with vague right-sided flank pain and 7-lb weight loss over past 6 weeks. No recent trauma or back strain. Urine is darker than usual over 2 weeks. Renal ultrasound shows 1.5-cm solid mass in upper portion of right kidney. Urine shows 50 erythrocytes, 6 leukocytes, no bacteria. Dx? - Renal cell carcinoma Why it�s right: This is a patient with recent weight loss, flank pain and hematuria, which at his age, is 100% renal cell carcinoma (RCC) until proven otherwise. The typical triad is the latter two symptoms (flank pain, hematuria) plus palpable mass. But the triad doesn�t always need to be completed, and they even further support the dx of RCC by sharing the ultrasound results � a solid mass. Cystic mass is more favorable for a benign process, and here the word �solid� directs the test-taker towards malignancy. Why the others are wrong: Metastasis from another cancer wound not have such prominent urinary findings, and they would have to give other signs/symptoms (s/s) of another malignancy elsewhere in the body. An abscess is less likely to be a solid mass � similarly, a hematoma would also not be a solid mass, but a combination of cysts, fluid, etc. An abscess would also present with fever and have an acute onset with bacteria and WBCs (more than just 6, which is borderline normal) in the urine. Finally, transitional cell carcinoma is referring to cancer of the ureter or pelvis, located either in the ureter or in the inner portion of the kidney (the pelvis). The cancer described is not only typical of RCC but also is located on the upper portion of the kidney, or in the cortex, and therefore must derive from the renal cortex parenchyma itself. Take home point: Patient >50 YO with weight loss, hematuria, and flank pain is RCC until proven otherwise. 2. 22-year-old man who is a professional cyclist undergoes extensive physiologic testing as part of his training regimen. His resting pulse is 33/min, and blood pressure is110/62 mm Hg. Echocardiography shows dilated ventricles with normal function and a left ventricular ejection fraction of 75%. Which of the following best describes the findings in this patient? - Eccentric hypertrophy Why it�s the right answer: �Dilated ventricles� is the key phrase in the stem. A dilated heart is built from eccentric hypertrophy, or in-line (or in-series) building and enlargements of muscle cells/fibers. In contrast, a thick heart of normal size (not dilated) is built from concentric hypertrophy, or parallel building and enlargement of muscle cells. This is a key concept for the boards that is repeatedly tested. Furthermore, this patient doesn�t necessarily have anything wrong with him. He is a professional athlete and works his heart to the max, so much so that it has become big, and not in a pathological way, since his EF is still preserved and actually more than it should be at 75% (normal is ~55-65%). Why the others are wrong: All of the other choices are suggestive of a pathological process. Congestive cardiomyopathy would have a decreased EF. Diastolic dysfunction is incorrect because although in diastolic dysfunction there is preserved EF with impaired relaxation, the ventricles are not dilated but usually hypertrophied and thicker; the same reason why also hypertrophic cardiomyopathy and increased myocardial stiffness are incorrect � both may have a normal to increased EF, but the ventricles would be thick not dilated. Take home point: Eccentric hypertrophy results in dilation, concentric hypertrophy results in thickening. 3. During a clinical study of calcium and phosphorus metabolism, a 50-year-old man undergoes series of lab studies. His serum Ca, PO4 and PTH are normal. He is given infusion 2 g Calcium chloride over 2 hours. His serum Ca concentration now is 11.5mg/dl. Compared with pre infusion levels, the serum concentration of which of the following substances is likely to be increased at this time? - 24,25-Dihydroxycholecalciferol Why it�s the right answer: First off, it is important to know the sequence of vitamin D metabolism for step 1 because this concept incorporates not only physiology, biochemistry, and nutrition, but also high-yield diseases like kidney disease (problem with alpha-1-hydroxylase), crohn�s colitis (issue with vitD absorption), and sarcoidosis (elevated Ca++). So lets take a look: 1) So we start with Vitamin D3 (AKA cholecalciferol, from diet like fortified dairy products and fish oils; or synthesized from 7-dehydrocholesterol in the skin when exposed to UV rays) � (via the liver) � 2) 25-hydroxyvitamin D3� (via the kidney) � 3) (a) 1,25-dihydroxyvitamin D3 (by enzyme 1-alpha-hydroxylase located in the kidney and gets positive feedback from PTH) (b) 24,25-dihydroxyvitamin D3 (by enzyme 24-alph-hydroxylase also in the kidney) Now, the question is asking about negative feedback. When there is a high level of calcium, there is negative feedback on the amount of PTH released (because PTH leads to increased calcium). PTH increases the enzymatic activity of 1-alpha- hydroxylase, an enzymes that converts 25-Vitamin D3 to 1,25- Dihydroxycholecalciferol. Conversely, low PTH does not activate 1-alpha-hydroxylase when calcium levels are high (such as in the clinical scenario above). So 25- Vitamin D3 is shunted to the other pathway and converted to 24,25-Dihydroxylase (by another enzyme that is not important for purposes of the boards). The other choices are ruled out based on the above explanation. This is one of the most difficult questions on NBME 18 because it requires that you not only know the metabolism of vitamin D as well as the back of your hand, but it also requires that you know the concept of enzyme kinetics, positive and negative feedback, and specifically where Vitamin D3 goes if its not being converted to 1,25-Vitamin D and shunted to the other pathway. Take home point: PTH gets positive feedback from low Ca++ and negative feedback from high Ca+. PTH increases Ca++, and does so in part by increasing the activity of enzyme 1-alpha-hydroxylase, which converts vitamin D3 to 1,25-Vitamin D, the active form of vitamin D that increases Ca++ absorption from the gut. When vitamin D3 isn�t being converted to 1,25-Vitamin D, it�s being shunted to its other pathway that forms 24,25-Vitamin D. For more information, and a great schematic on what I said above in words regarding vit D metabolism, follow this link: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2879391/ 4. 70-year-old man comes with skin blistering for 1 week. No oral lesions. Physical shows tense bullae in joint folds of upper and lower extremities. Biopsy shows subepidermal blister formation. Immunofluorescence microscopy shows antibodies against proteins at the dermal-epidermal junction. Target by antibodies? - Hemidesmosome Why it�s the right answer: This is a pretty basic question on bullous pemphigoid, which is the dx presented in the vignette. In this autoimmune disease, antibodies are directed against the hemidesmosomes, which link the dermis to the overlying epidermis. You either know this one or you don�t, basically. Take home point: Bullous pemphigoid is a disease of the hemidesmosomes and characterized by a linear immunofluorescent pattern that highlights the dermal and epidermal junction. Conversely, pemphigus vulgaris, the other high-yield autoimmune skin disease that�s tested on the boards, is a disease in which autoantibodies target desmosomes, creating a circular immunofluorescence pattern INTRAdermally. Bullous pemphigoid: Layer - deep, age - elderly, blisters - tense/firm, oral lesions - rare, Nikolsky's sign - negative, Immunofluorescence - Basement membrane, target antigen - hemidesmosome, blister content - hemorrhagic Pemphigus vulgaris: Layer - superficial, age - middle-age (not always), blisters - flaccid, easily rupture, oral lesions - common, Nikolsky's sign - positive, Immunofluorescence - intraepidermal, circular, target antigen - desmosome, blister content - fluid-filled 5. 63-year-old man with abnormal blood pressure. 6 months ago, bp was 135/85. Today bp 170/98. Bruit heard over left renal artery. CT angioshows left arterial stenosis. Labs? - Total peripheral resistance increased, plasma renin activity increased, serum aldosterone concentration increased Why it�s the right answer: The board examiners love these up and down arrow questions, and they are not something to be intimidated by because they are usually pretty straight forward as long as you�re able to break down the clinical vignette. Here, there�s a guy that had good, well-controlled blood pressure 6 months ago, but now has very high blood pressure that is a result of gradual onset renal artery stenosis. When there is a blockage of one or two renal arteries, the kidney(s) are starved by blood. In reaction the kidneys think blood pressure is low, so they release factors to increase the pressure in the form of the RAAS cascade (silly little kidneys). One factor/hormone they release is renin (from the juxtaglomerular cells) Renin then causes a cascade of other hormones to be released, including aldosterone, which increases blood pressure so the kidneys are happy and no longer starved. In other words, total peripheral resistance (TPR) is increased. The other important thing to remember is the columns do not go in order necessarily� they should really in fact be reversed to show first increases renin, which increases aldosterone, which increases TPR � so don�t be fooled by that. Take home point: Low kidney perfusion (from things like renal artery stenosis or fibromuscular dysplasia) leads to activation of the RAAS cascade and an overall increase in BP/TPR. 6. 35-year-old woman with 3-month progressive shortness of breath with exertion. RR 26. Physical shows jvd and prominent a wave. Lungs clear. Cardiac exam shows loud pulmonic component of S2 and right-sided S4 gallop. Increased pulmonary expression of what? - Endothelin-1 Why it�s the right answer: Dx is pulmonary hypertension secondary to pulmonary fibrosis. An important point I want to bring up here is that the boards don�t always follow the demographic rules we know and love � i.e. a middle-aged woman is the classic demographic category for idiopathic pulmonary fibrosis. However, the board examiners know that everyone is going to get the answers right if they put that there, so they try to make the question harder (sometimes) by changing it up and maybe giving you a 40-50-year-old MAN with pulmonary fibrosis. So again, don�t be tripped up. This clinical vignette is still pretty obvious sans the demographics of the patient based on physical exam alone. And one of the factors that is upregulated in pulmonary fibrosis is endothelin-1. Another KEY point is that the lungs is the ONLY organ system, that when starved for blood, vasoconstricts instead of vasodilating. Vasodilation is a normal response to decreased blood flow � to let more blood flow in!! However, the vessels in the lungs CONSTRICT and mainly do so through endothelin-1. And the reason they constrict? To not promote further deoxygenation through a V/Q or shunt defect. Finally, know the drug to treat this condition, which decreases pulmonary hypertension by antagonizing the endothelin receptor: Bosentan. It could be on your test (wink wink). Take home point: Pulmonary artery hypertension (PAH) results from increase in release of endothelin-1. PAH is a consequent of pulmonary fibrosis. Bosentan is a medication frequently used to treat PAH through antagonization of the endothelin receptor. 7. 30-year-old woman with 2-years of numbness, blanching, and bluish color to ears, fingers and toes after emotional upset or cold exposure. Vitals and PE normal. Avoid taking which drug? - Phenylephrine Why it�s the right answer: Dx is Raynaud�s phenomenon, which is vasospasm of arteries and arterioles, impairing circulation and resulting in color changes in extremities, commonly the hands. The mechanism of vasoconstriction is alpha agonism, so you would absolutely at all costs avoid drugs that act as agonists on alpha receptors. The only drug listed that is an alpha agonist is phenylephrine, specifically a selective alpha1-adrenergic receptor agonist. Take home point: Avoid alpha agonists in Raynaud�s phenomenon. 8. 35-year-old woman with 2-day history of blistering lesions on sun-exposed face, arms and hands. Recurrent episodes of skin lesions over several years. Taking oral contraceptives for 15y. PE shows fluid-filled vesicles and bullae. Labs: AST increased, ALT increased, total porphyrin increased, urine uroporphyrin III increased. Precursor to uroporphyrin? - Succinyl CoA Why it�s the right answer: Dx is porphyria, which describes a group of disorders, resulting in defective heme synthesis. The most common type of porphyria is porphyria cutanea tarda. The deficient or defective enzyme is uroporphyrinogen decarboxylase. At the start of heme synthesis, succinyl CoA and glycine combine to form ALA (via ALA synthase), the very start of heme synthesis. Take home point: Porphyria is a group of disorders that result in defective heme synthesis and the buildup of uroporphyrin, an intermediate compound. The very beginning of heme synthesis starts with succinyl CoA and glycine. 9. 65-year-old with sudden onset generalized tonic-clonic seizures. Personality change last 6 months; used to be mild mannered and now verbally abusive. CT shows single mass enhances with contrast in right frontal lobe and crosses to left hemisphere through corpus callosum. Dx? - High-grade fibrillary astrocytoma Why it�s the right answer: It is pretty clear from the question that this is cancer, and that is why the rest of the answer choices are also all cancers, and we need to figure out which type of cancer this patient has. The key tip-offs to knowing this is an astrocytoma are the location and characteristic crossover from one hemisphere to the other. Astrocytomas love the supretentorial region, specifically the frontal lobe, and therefore present with personality changes. Furthermore, the classic �butterfly lesion� that goes from one hemisphere to the other is also characteristic of astrocytomas. Why the others are wrong: A meningioma usually presents with localized neurological deficits since it normally has a mass effect and pushes on the cerebral hemispheres. It also is described on imaging as a mass with a tail, since it is �sprouting� from the meninges (or at least that�s how I remember it). A schwannoma is classically located in the cerebellar-pontine junction (know where this is on imaging), and therefore intratentorial, and also will come with other s/s of hearing loss, tinnitus, ect. Metastasis is typically 2+ lesions, not just the one, but this could have easily been mets as well, its just that astrocytoma is a better fit for the clinical picture presented. Take home point: Astrocytomas are single lesions that are often in the frontal lobe, presenting with personality changes therefore, and �butterfly� from lobe to the other through the corpus callosum.
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