Neuropsychiatric systemic lupus erythematosus presenting as amyotrophic lateral sclerosis

A 61-year-old woman with a history of photosensitive dermatitis and recurrent mouth ulcers presented with progressive weakness typical of amyotrophic lateral sclerosis (ALS), and subsequently underwent extensive neurologic and rheumatologic testing. We investigated whether ALS-like motor neuron disease associated with a positive antinuclear antibody (ANA) is really ALS or rather neuropsychiatric systemic lupus erythematosus (NPSLE). On neurologic evaluation, she had prominent bulbar involvement with dysarthria and dysphagia associated with profound lingual fasciculations and a denervating pattern on electromyogram. MRI showed no evidence of cerebral ischemia. Laboratory studies revealed a positive ANA (1:2560 titer), positive antiphospholipid antibodies (GPL and MPL), circulating lupus anticoagulant, and depressed C3 and C4. Repeat MRI studies at 4 and 11 mo revealed an evolving infarct in the paramedian pons consistent with the presence of NPSLE. Therapy was initiated with corticosteroids and intravenous cyclophosphamide, and the neurologic condition did not improve, but also did not progress inexorably as would be expected with ALS. NPSLE, presumably through the mechanism of ischemic vasculopathy, may present as motor neuron disease clinically indistinguishable from ALS.