Nejm 1992;326:1130; Ann Neurol 1990;27:s21

Cause:Often viral, probably several types including Epstein-Barr virus (7/24 children—Nejm 1975;292:392); and Campylobacter jejuni(Nejm 1995;333:1374), 1/3 cases have a h/o such as a precedent. Occasionally/rarely follows flu shots (Nejm 1998;339:1997), CMV, and HIV

Pathophys:Allergic polyneuropathy leads to demyelination and decreased conduction velocity, esp at root exit on cord dorsum (hence areflexia); must get ventral root too, though pathologically unimpressive. Can experimentally mimic by sensitizing animals with injections of dorsal root homogenates and Freund's adjuvant

All ages, both sexes equally; 1-2 cases/100 000/yr

Sx:URI, mild, precedes by 1-3 wk. Vague sensory losses, including, often early on, paresthesias of toes and fingers, which then extend proximally; deep aching at onset is very characteristic; proximal muscle weakness evolves over 24 h

Si:No sensory losses; afebrile; diminished reflexes always; proximal weakness >> distal involvement; always symmetric; no mental changes; facial nerve palsies (60%): cranial nerves X, XI, XII often; V occasionally; II, III, IV, VI rarely

Deteriorate after admission; start improving within 3 wk; back to normal in 16 mo, though slight decrease in reflexes and foot drop may persist; no relapses. Campylobacter type has worse outcome w 60% at 1 yr still w moderate to severe disability, compared to only 25% for other causes (Nejm 1995;333:1374)

Insidious respiratory paralysis, monitor by having count to 20 in 1 breath

r/o cord compression, esp if CSF protein 2.5 gm %; collagen vascular disease; diabetic neuropathy; multiple sclerosis; polio; diphtheria; myasthenia; heavy metal toxicity; infectious mono; amyloid; rabies (Nejm 1979;300:603); botulism; red tide disease; Lyme disease; HIV; CNS neoplasia; sarcoid meningitis; chronic, HLA-associated; tick paralysis (Nejm 2000;342:90), rapidly ascending paralysis, rx'd by finding and removing tick; chronic inflammatory demyelinating polyneuropathy (Nejm 2005;352:1343)

Lab:

CSF: Increased protein to 120-300 mg % by end of 1st week; wbc's <5000-6000

Noninv: Nerve conduction velocities profoundly decreased; if normal several days into course, find another dx

Rx:

1st: Supportive care including respirator; iv steroids no help (Lancet 1993;341:586)

2nd: Immune globulin iv high dose, eg, 0.4 gm/kg/d × 5 d if can't walk and <2 wk of sx; will help 1/2 in 1 mo (Nejm 1992;326:1130); or plasmapheresis/exchange at a tertiary care center for patients who can't walk or are progressing rapidly; both equieffective, though combination use not (Neurol 2003;61:736)