A Guide to Sudoscan New

March 30, 2018 | Author: Laura B. Bautista | Category: Peripheral Neuropathy, Medicine, Nervous System, Health Sciences, Wellness


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 Interpretation  Guide  to         Eccrine   sweat   glands   are   innervated   by   long,   thinly   myelinated   and   unmyelinated   C   fibers   of   the   sympathetic   nervous   system   that   are   prone   to   early   damage   in   many   neuropathic   processes,   including   dysautonomia.   Small   fiber  neuropathy  (SFN)  may  be  the  first  manifestation  of  systemic  disease  and  can  predict  progression  to  a  more   diffuse  neuropathy,  making  this  early  diagnosis  important  for  the  treatment  of  patients.     SUDOSCAN  results  will  enable  you  to  perform  an  objective  assessment  of  small  and  peripheral  sympathetic  nerve   fiber  function.  This  will  help  you  to  identify  the  etiology  of  the  disease,  keeping  in  mind  that  about  33%  of  small   fiber  neuropathies  remain  idiopathic  despite  appropriate  diagnostic  evaluation.  Objective  evaluation  of  the  disease   with   regular   interval   retesting   can   increase   patient   compliance   and   can  be  particularly   important     in   the   treatment   of  neuropathic  pain,  if  present.     The   results   of   SUDOSCAN   tests   are   provided   as   hand   and   foot   Electrochemical   Skin   Conductances   (ESC)   that   indicate   sweat   dysfunction   and   are   a   marker   of   small   fiber   peripheral   neuropathy.   ESC   are   expressed   in   microSiemens   (μS),   ranging   from   0   to   100.     In   general,   ESC   in   the   ‘green’   zone   are   healthy,   ESC   in   the   ‘yellow’   zone   indicate  moderate  dysfunction,  and  ESC  in  the  ‘orange-­‐red’  zone  correspond  to  severe  dysfunction.       The  two  main  points  to  consider  for  correct  interpretation  of  SUDOSCAN  results  are:     § Asymmetry.   If   greater   than   20%   it   suggests   damage   limited   to   a   single   side.     This   is   only   valid   when   the   contralateral   ESC   scores   are   in   the   ‘green’   zone.     If   the   contralateral   ESC   is   itself   in   the   ‘yellow’   or   ‘red’   zone,  then  bilateral  dysfunction  exists.   § Location  of  disturbances  (hands  or  feet)  to  evaluate  length  dependency  of  the  damage.       In  the  diagnostic  strategy  the  following  questions  should  also  be  answered:     § What:  Are  there  other  signs  or  symptoms  of  autonomic  dysfunction?  Are  sensory  or  motor  nerves  (large   fibers)  involved?       § When:  If  symptoms  are  present,  how  long  have  they  been  present  and  was  their  onset  acute  or  chronic?     § Context:   What   are   the   patient’s   medical   history,   current   or   past   medications,   family   history   (hereditary   diseases)?                     Interpretation  guide  to  SUDOSCAN   1       Causes  of  SUDOSCAN  disturbances    validated  by   Suggested  evaluation   clinical  studies*   1 Diabetes  or  glucose  intolerance     Fasting  glucose,  2-­‐hour  oral  glucose  tolerance  test ;  due  to   high  rate  of  coexistance,  Vit  B12,  thyroid,  Vit  D,  and  lipid   levels  should  also  be  measured   Diabetic  peripheral  neuropathy   Clinical  neurological  examination,  other  assessments   2 based  on  NE  exam  and  usual  diabetes  care   3,4   Diabetic  nephropathy     Medical  history,  renal  function  testing Peripheral  and  cardiac  autonomic  neuropathy   Heart  rate  variability,  Ewing  tests,  appropriate  specialist   5   referral Familial  Amyloid  Polyneuropathy   Medical  and  family  history,  genetic  testing,  appropriate   6   specialist  referral Fabry  disease  (analysis  ongoing)                                                                                                                                                                                                                                                                                                                                                                           *classified  according  to  frequency  of  occurrence;  potential  causes  are  not  mutually  exclusive   Possible  causes  of  SUDOSCAN  disturbances,   Suggested  evaluation   not  currently  validated  by  research       8-­‐10   Connective  tissue  diseases,  autoimmune   See  details  for  specific  diagnostic  testing  in  references diseases,  hereditary  conditions  (Fabry,  HSAN,   Tangier’s,  vasculitis)   Hyperlipidemia   Fasting  lipid  panel   Chronic  alcohol  abuse,  history  of  alcoholism   Medical  history,  clinical  examination,  liver  function  tests   Pharmacological  toxins  (statins,  anti-­‐ Medical  history  including  current  and/or  past  medications   retrovirals),  chemotherapy     Environmental  Toxins,  Infections  (HIV,   Toxin  exposure  history,  specialized  toxicological  and  infectious   8-­‐10   Hepatitis  C,  Lyme  disease)   disease  studies Hypothyroidism   Medical  history,  clinical  examination,  TSH  and  free  T4  levels     Potential  unverified  causes  of  asymmetry  in     Suggested  evaluation   SUDOSCAN  results   Nerve  entrapment:    spinal  or  peripheral     Medical  history,  physical  and  neurological  examination,   (carpal  tunnel,  tarsal  tunnel)   unilateral  extremity  weakness   Peripheral  Artery  Disease  (PAD)   Ankle  brachial  index,  arterial  Duplex  ultrasound,  angiography   Extremity  Trauma/Injury     Medical  history  (comminuted  fracture),  imaging  study   Dorsal  root  ganglion,  sympathetic  ganglion   Neurological  examination,  appropriate  referral,  imaging  study   chain  disease   Complex  Regional  Sympathetic  Dystrophy   Medical  history,  physical  examination,  imaging  study   Interpretation  guide  to  SUDOSCAN   2       Effect  on  SUDOSCAN   Potential  confounding  factors  to   Examples  and  Comments   SUDOSCAN  results,  not  fully  validated   by  research   ELEVATE  SUDOSCAN   Angiotensin-­‐converting  enzyme  (ACE)   May  falsely  elevate  SUDOSCAN   SCORES   Inhibitors  and  angiotensin  II  receptor   scores   blockers  (ARB)   DECREASE  SUDOSCAN   Medications  with  anti-­‐cholinergic   Tricyclic  antidepressants,   SCORES   effects     antihistamines,  antimuscarinics,   anti-­‐Parkinson  agents,  ranitidine,   11   muscle  relaxants may  decrease     ESC   Beta-­‐blockers     Propranolol,  labetalol,  timolol  may   decrease  ESC  scores   Second  and  Third  degree  burns  (of   Medical  history,  clinical   the  palms  or  soles),  palmoplantar   examination   keratodermas   Acute  Alcohol  Intake     Heavy  alcohol  ingestion  within  the   last  24  hours  may  lower  ESC   scores       REFERENCES     [1]     Schwarz   P,   Brunswick   P,   Calvet   JH.   EZSCAN   a   new   tool   to   detect   diabetes   risk.   British   Journal   of   Diabetes   &   Vascular  diseases.  2011;11(4):204-­‐9.   [2]     Casellini   CM,   Parson   HK,   Richardson   MS,   Nevoret   ML,   Vinik   AI.   Sudoscan,   a   Noninvasive   Tool   for   Detecting   Diabetic  Small  Fiber  Neuropathy  and  Autonomic  Dysfunction.  Diabetes  Technol  Ther.  2013;15(11).   [3]   Ozaki   R,   Cheung   KK,   Wu   E,   Kong   A,   Yang   X,   Lau   E,   Brunswick   P,   Calvet   JH,   Deslypere   JP,   Chan   JCN.   A   new   tool   to   detect   kidney   disease   in   Chinese   type   2   diabetes   patients—comparison   of   EZSCAN   with   standard   screening   methods.  Diabetes  tech  &  ther.  2011;13(9):937-­‐43.   [4]   Freedman  BI,  Bowden  DW,  Smith  SC,  Xu  J,  Divers,  J.  Relationships  between  electrochemical  skin  conductance   and  kidney  disease  in  type  2  diabetes.    In  Press.   [5]   Yajnik  CS,  Kantikar  V,  Pande  A,  Deslypere  JP,  Dupin  J,  Calvet  JH,  Bauduceau  B.  Screening  of  cardiovascular   autonomic  neuropathy  in  patients  with  diabetes  using  non-­‐invasive  quick  and  simple  assessment  of  sudomotor   function.  Diabetes  Metab.  2013  Apr;39(2):126-­‐31.     [6]   Adams  D,  Cauquil  C,  Mincheva  Z,  Theaudin  M,  Beaudonnet  G,  Labeyrie  C,  Depuydt  S,  Iliescu  I,  Lacroix  C,  Grisoni   ML.    Sudomotor  function  assessment  by  SUDOSCAN  in  FAP  patients:    the  NNERF  experience.    Poster   presentation.    Peripheral  Nerve  Society.    Saint-­‐Malo,  France,  June  2013.   [8]   Burns  TM,  Mauermann  ML.  The  evaluation  of  polyneuropathies.  Neurology.  2011  Feb  15;76(7  Suppl  2):S6-­‐13.   [9]   Freeman  R.  Autonomic  peripheral  neuropathy.  Lancet  2005;365:1259-­‐1270.   [10]   Tavee  J,  Zhou  L.  Small  fiber  neuropathy:  a  burning  problem.  Cleve  Clin  J  Med.  2009  May;76(5):297-­‐305.   [11]   Pharmacist’s  Letter/Prescriber’s  Letter  –  Document  #271206.    Therapeutic  Research  Center.  December  2011.   Available  at  www.pharmacistletter.com.       Interpretation  guide  to  SUDOSCAN   3       Case  Studies  Illustrating  Various  Scenarios  of     Abnormal  SUDOSCAN  results       Peripheral  autonomic   Case  1   and  small  fiber     dysfunction     Background   33   year-­‐old   African   American   female,   BMI   32,   consults   her   primary   care   physician   for   burning   in   her   feet   in   the   evening  after  working  at  the  pizza  parlor  all  day.         SUDOSCAN  report       > Feet  Mean  ESC:    26  μS,  10%  asymmetry   > Hands  Mean  ESC:    72  μS,  1%  asymmetry             Discussion   Results  are  suggestive  of  a  peripheral  autonomic  and  small  fiber  dysfunction.    From  the  brief  history,  the  most  likely   clinical  suspicion  should  be  dysglycemia,  whether  metabolic  syndrome,  impaired  glucose  tolerance,  or  diabetes.    An   appropriate   work-­‐up   and   intervention   should   be   conducted;   SUDOSCAN   should   be   repeated   in   3   months   or   as   medically   necessary   after   treatment   is   instituted.     If   low   feet   scores   persist,   consider   screening   for   cardiac   autonomic  neuropathy  risk.     Interpretation  guide  to  SUDOSCAN   4         Effect  of     Case  2     alcohol     Background   55  year-­‐old  Caucasian  male  with  past  medical  history  of  mild  hypertension,  BMI  29;  he  is  asymptomatic.       SUDOSCAN  report   At  t=0         > Feet  Mean  ESC:  38  μS,  19%  asymmetry   > Hands  Mean  ESC:  56  μS,  5%  asymmetry               After  48  hours       > Feet  Mean  ESC:  87  μS,  3%  asymmetry   > Hands  Mean  ESC:  88  μS,  0%  asymmetry             Discussion   The  patient  was  a  physician  attending  a  medical  conference  and  was  scanned  following  ingestion  of  a  large  amount   of   alcohol   earlier   in   the   day.     He   was   obviously   impaired   at   time   of   testing.     Alcohol   may   result   in   a   chronic   neuropathy,   but   may   also   impair   SUDOSCAN   scores   following   moderate   consumption.     Repeat   testing   after   48   hours  of  sobriety  showed  completely  normal  SUDOSCAN  results.                     Interpretation  guide  to  SUDOSCAN   5         Effect  of   Case  3     medication     Background   55   year-­‐old   female   treated   with   amitriptyline   for   depression   with   insomnia.     No   other   significant   past   medical   history.         SUDOSCAN  report     § SUDOSCAN  score  while  on  amitriptyline             > Feet  ESC  8  μS,  Hands  ESC  22  μS               § SUDOSCAN  report  24  hours  after  stopping  amitriptyline                                                               >      Feet  ESC  38  μS  ,  Hands  ESC  56  μS                 § SUDOSCAN  report  48  hours  after  stopping  amitiriptyline         > Feet  ESC  60  μS  ,  Hands  ESC  46  μS         Discussion   Amitriptyline,   a   tricyclic   antidepressant,   has   significant   anti-­‐cholinergic   effects.     This   is   most   likely   the   reason   for   this   patient’s   dramatically   low   ESC   scores,   considering   she   has   no   known   neuropathy   and   sympathetic   nerve   endings   on   sweat   glands   predominantly   release   acetylcholine   as   a   neurotransmitter.     ESC   scores   eventually   returned  to  normal  after  removal  of  amitryptiline.   Interpretation  guide  to  SUDOSCAN   6         Effect  of  ethnicity  and   Case  4   nerve  entrapment       Background   45  year-­‐old  right-­‐handed  African  American  female  with  tingling  and  numbness  in  her  right  hand.    Diagnosed  2  years   ago   with   Type   2   DM;   treated   with   Metformin   BID   with   HbA1c   stable   at   7.0%;   BMI   30.     She   is   employed   as   a   receptionist/administrative  assistant  at  your  colleague’s  family  practice  clinic.         SUDOSCAN  report       > Feet  Mean  ESC  69  μS,  0%  asymmetry   > Hands  Mean  ESC  63  μS,  29%  asymmetry   > Left  hand  ESC  is  73  μS  and  right  hand  ESC  is  52  μS           Discussion   Several   factors   may   be   contributing   to   a   peripheral   autonomic   neuropathy   in   this   patient.     Being   African   American,   her  scores  may  be  normal  though  lower  than  a  similar  Caucasian  patient.    On  this  scan,  her  feet  scores  appear  in   the  green  zone  and  are  considered  normal  for  her  racial  background.    This  is  reassuring  in  a  diabetic  patient  with   reasonable  control  of  her  diabetes.    Losing  some  weight  may  help  improve  this  score  further.   Her  hand  symptoms  and  SUDOSCAN  suggest  RIGHT  hand  dysfunction;  clinical  neurological  examination  will  most   likely   expose   a   carpal   tunnel   syndrome,   which   is   more   common   among   diabetics   than   the   general   population.     Appropriate   treatment   should   be   instituted   and   a   follow-­‐up   SUDOSCAN   may   be   used   to   follow   therapeutic   effectiveness.     Interpretation  guide  to  SUDOSCAN   7    
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