RT Book, Section
A1 Amato, Anthony A.
A1 Barohn, Richard J.
A2 Kasper, Dennis
A2 Fauci, Anthony
A2 Hauser, Stephen
A2 Longo, Dan
A2 Jameson, J. Larry
A2 Loscalzo, Joseph
SR Print(0)
ID 1138108436
T1 Peripheral Neuropathy
T2 Harrison's Principles of Internal Medicine, 19e
YR 2014
FD 2014
PB McGraw-Hill Education
PP New York, NY
SN 9780071802154
LK accesspharmacy.mhmedical.com/content.aspx?aid=1138108436
RD 2019/12/06
AB Peripheral  nerves  are  composed  of  sensory,  motor,  and  autonomic  elements.  Diseases  can  affect  the  cell  body  of  a  neuron  or  its  peripheral  processes,  namely  the  axons  or  the  encasing  myelin  sheaths.  Most  peripheral  nerves  are  mixed  and  contain  sensory  and  motor  as  well  as  autonomic  fibers.  Nerves  can  be  subdivided  into  three  major  classes:  large  myelinated,  small  myelinated,  and  small  unmyelinated.  Motor  axons  are  usually  large  myelinated  fibers  that  conduct  rapidly  (approximately  50  m/s).  Sensory  fibers  may  be  any  of  the  three  types.  Large-diameter  sensory  fibers  conduct  proprioception  and  vibratory  sensation  to  the  brain,  while  the  smaller-diameter  myelinated  and  unmyelinated  fibers  transmit  pain  and  temperature  sensation.  Autonomic  nerves  are  also  small  in  diameter.  Thus,  peripheral  neuropathies  can  impair  sensory,  motor,  or  autonomic  function,  either  singly  or  in  combination.  Peripheral  neuropathies  are  further  classified  into  those  that  primarily  affect  the  cell  body  (e.g.,  neuronopathy  or  ganglionopathy),  myelin  (myelinopathy),  and  the  axon  (axonopathy).  These  different  classes  of  peripheral  neuropathies  have  distinct  clinical  and  electrophysiologic  features.  This  chapter  discusses  the  clinical  approach  to  a  patient  suspected  of  having  a  peripheral  neuropathy,  as  well  as  specific  neuropathies,  including  hereditary  and  acquired  neuropathies.  The  inflammatory  neuropathies  are  discussed  in  Chap.  460.