Central nervous system symptoms occur in a substantial portion of patients with systemic lupus erythematosus. However, coma is a rare presentation and is usually secondary to complications such as subarachnoid hemorrhage, seizure, or ischemia. Here, we present a 49-year-old woman with lupus erythematosus and a history of recurrent aseptic meningitis and mild subarachnoid hemorrhage who presented with altered mental status and lethargy that progressed rapidly over hours to the herniation syndrome of coma, extensor posturing, and unilateral pupillary dilation. Spinal fluid showed massive protein elevation (>1600), and head computed tomography revealed global cerebral edema. The clinical and radiologic findings rapidly reversed with intravenous corticosteroids and mannitol within 24 hours, and her mental status improved to baseline.
Her course was complicated by 2 episodes of recurrent encephalopathy when corticosteroids were tapered; these resolved after resuming high dosing. Because of ongoing pancytopenia, chemotherapy immunosuppression was delayed, and instead she received intravenous immunoglobulin with improvement in the pancytopenia. She remained cognitively intact during subsequent corticosteroid tapering. Rapid development of coma in lupus patients may be due to a primary process of the disease impacting blood brain barrier integrity. Although rare, this potentially fatal complication may be reversible with acute corticosteroid administration.