Seropositive PERM associated with leucocytoclastic vasculitis

Abstract

Background: Progressive encephalomyelitis, rigidity, and myoclonus (PERM) is a variant stiff-person plus syndrome consisting of brainstem and pyrimidal dysfunction, muscular rigidity, stimulus-evoked spasms, and dysautonomia. Continuous motor-unit activity from ectopic anterior horn cell discharges underlies the myotomal hyperactivity. Case Report: A 51-year-old man with an 8-year history of “spasmodic” mid and low back pain presented with increasing stiffness, hyperekplexia-induced opisthotonus-like posturing, urinary retention, long-tract motor signs, and diplopia. He had a recent history of biopsy-confirmed leucocytoclastic vasculitis-associated diffuse maculopapular rash. He responded well to IVIg treatment manifested by improved 1) gait fluidity, 2) bowel and bladder function 3) tolerance to startle, and 4) vision. Results: Serological testing revealed positive anti-glycine receptor antibodies. Anti-glutamic acid decarboxylase and voltage-gated K+-channel antibodies were absent. A chest CT was unremarkable. Conclusions: This is the second case of seropositive PERM in Canada and the first associated with leucocytoclastic vasculitis. Pathologic findings in PERM reveal perivascular lymphocytic cuffing in the rhombencephalon and spinal cord. Glycine receptor localization correlates with neurologic dysfunction. Mid-brain involvement may underlie the autonomic dysfunction but evidence of direct glycinergic inhibition of the external urethral sphincter in Onuf’s nucleus may be responsible for urinary retention.