Poster 60: Postinfectious Autoimmune Polyradicular Neuropathy With Asymptomatic Encephalitis: A Case Report

Abstract

Setting: University hospital, inpatient ward, and outpatient clinic. Patient: A 23-year-old woman with 2 weeks of postinfectious progressive weakness. Case Description: The patient presented with progressive weakness and soreness of distal lower extremities and gait changes 10 days following diagnosis of gastroenteritis. She denied sensory loss, visual changes, or bowel and bladder dysfunction. There was no recent travel abroad. On exam, there was distal greater than proximal upper- and lower-extremity weakness and no sensory abnormalities. Distal reflexes diminished on day 2. Magnetic resonance imaging (MRI) head findings were consistent with focal encephalitis versus demyelination of left frontal lobe. MRI spine showed focal enhancement of upper ventral roots of cauda equina and conus with edema and enhancement of paraspinal musculature. Abnormal laboratories included a sedimentation rate of 53mm/h. Cerebrospinal fluid showed lymphocytic predominance without elevated protein, elevated immunoglobulin G index, or elevated GM1 ganglioside antibody level. Atypical Guillain-Barreé syndrome was considered and she was treated with intravenous immunoglobulin (IVIG) for 5 days. Proximal greater than distal strength and reflexes improved and she remained without sensory symptoms. She was discharged after 5 days. Electromyography 3 months later showed polyradiculoneuropathy, purely motor, with multifocal conduction blocks and axonal damage. After 2 months of physical therapy, strength markedly improved. Repeat electromyography, 5 months after discharge, showed purely motor polyradiculoneuropathy, now without conduction block, and evidence of reinnervation. Assessment/Results: History and clinical data support a diagnosis of postinfectious autoimmune polyradicular neuropathy. Discussion: Polyradicular neuropathies of this type are most often due to campylobacter (67%) or Haemophilus (13%) and are rare in the United States. Weakness is typically distal greater than proximal with the cranial nerve involved 25% of the time. Lab findings show positive antibodies to GM1 ganglioside in 40% to 50% of cases. Conclusions: Documented here is a case of polyradicular neuropathy following infection resulting in progressive weakness without sensory changes. Treatment is IVIG and/or plasmapheresis.