1646 - Acute demyelinating peripheral polyneuropathy of the sensorimotor type

Case Diagnosis: Acute demyelinating peripheral polyneuropathy of the sensorimotor type

Case Description: Patient is a 69 year-old male with no significant past medical history who presented to his PCP complaining of a two-week history of new onset difficulties in walking, weakness in his right shoulder, and progressive numbness and tingling in hands and feet bilaterally. Patient was started on a prednisone taper with orders for Lyme disease panel and electrodiagnostic testing. Lyme panel was negative, but electrodiagnostic studies showed absence of sensory and motor evoked responses throughout upper and lower extremities with decreased recruitment in key muscles of the lower legs bilaterally. No F waves were observed, but A waves were noted in tibial nerves bilaterally. Patient was sent to ED from electrodiagnostic lab and treated with IVIG, achieving full recovery.

Discussions: Sensorimotor AIDP accounts for 90% of GBS cases in the western world, with an incidence of approximately 1-2 cases per 100,000 person-years. The pathophysiology involves a mixed Type II and Type IV hypersensitivity reaction against peripheral myelin, preferentially targeting proximal segments. Classically, GBS occurs as a rare response to infections from organisms such as C. jejuni, but can be idiopathic as in this case. The natural history is characterized by a 2-4 week period of progressive ascending weakness, a plateau period of another 2-4 weeks, and a recovery period of up to 6 months, with a small fraction of patients experiencing chronic neurologic deficits. IVIG therapy +/- plasma exchange is gold standard; despite being an autoimmune condition, steroids have been shown to be ineffective for treatment of AIDP, perhaps due to reduction of macrophage-mediated myelin debris clearance.

Conclusions: AIDP is a rare but potentially deadly demyelinating peripheral nerve disease that requires prompt treatment with IVIG and close inpatient monitoring, but typically has a good prognosis. Patient made a complete walking recovery at six-month followup.