Abstracts

Rationale: Patients working at a pork plant in Minnesota have been identified with a progressive inflammatory neuropathy (PIN), Lachance et al. (MMWR 2008;57:122-124). This subsequently has been demonstrated to be an immune mediated sensory predominant polyradiculoneuropathy, Lachance et al.(American Academy of Neurology 2008). As of April 2008, a total of 18 workers at one plant had been identified. The median age of the patients was 34 years (range: 20-54 years). One patient presented with transverse myelitis and relapsed as a polyradiculoneuropathy. All had serological evidence of a novel autoantibody. Cerebrospinal fluid (CSF) often revealed an elevated protein (median: 116 mg/dL; range: 23-231 mg/dL) with no or minimal pleocytosis. One hypothesis for the development of PIN is exposure to aerosolized pig neural protein might have induced an autoimmune-mediated peripheral neuropathy. Methods: We present a patient who developed a progressive encephalopathy associated with refractory status epilepticus. There was no evidence for an infectious, metabolic or neoplastic etiology for her disorder. The patient was working at a local pork plant at the time of the illness that was associated with PIN. The comprehensive evaluation supported the diagnosis of an autoimmune encephalopathy. Results: A previously healthy 28 year old woman had a one month history of headache, nausea and vomiting, confusion and behavioral changes. The EEG was markedly abnormal showing findings compatible with focal status epilepticus with recorded complex partial seizures. The background EEG also showed very severe nonspecific generalized slowing. MRI showed subtle increased T2 signal within the centrum semiovale bilaterally consistent with an inflammatory process. The CSF protein was mildly elevated. Bilateral internal carotid, bilateral carotid bifurcations, and left vertebral artery angiogram were negative. Brain biopsy (right frontal lobe) revealed mild chronic meningoencephalitis associated with vasculitis and perivasculitis. The patient subsequently developed prolonged refractory status epilepticus that required continuous video-EEG monitoring, endotracheal intubation and treatment with general anesthesia. Extensive studies for viral disease (including HIV), mycobacterium tuberculosis, fungal disease, bacterial meningitis, metabolic illness, drug intoxication or withdrawal, or paraneoplastic disorder were negative. The patient was treated with corticosteroids and immunosuppressant agents, e.g., cyclophosphamide, and antiepileptic drug medication for a presumed autoimmune encephalopathy. There has been a gradual improvement in her neurological disorder. The patient was found to have a unique antibody that previously has been seen in patients with PIN. Conclusions: This patient presents with an acute encephalopathy associated with refractory status epilepticus. This represents the first reported patient demonstrating an association between exposure at a pork plant and autoimmune encephalopathy.