Distinct subtypes of myelitis in systemic lupus erythematosus

Objective. Myelitis causes pain, weakness, and sphincteric deficits, and is 1,000-fold more prevalent in patients with systemic lupus erythematosus (SLE) than in the general population. For the last century, descriptions of SLE myelitis have been primarily limited to case reports. In contrast, larger-scale cohort studies have revealed that myelitis occurring in the idiopathic demyelinating diseases (i.e., multiple sclerosis versus neuromyelitis optica) represents distinct syndromes. This study was undertaken to determine whether SLE myelitis similarly encapsulates distinct syndromes. Methods. We analyzed a cohort of 22 patients with SLE and myelitis. Patients were assessed for neurologic variables related to myelitis and for clinical and serologic features of SLE. Magnetic resonance images of the spine, cerebrospinal fluid profiles, and autoantibody profiles were obtained. Results. Eleven patients presented with signs of gray matter dysfunction (i.e., flaccidity and hyporeflexia), whereas 11 patients presented with signs of white matter dysfunction (i.e., spasticity and hyperreflexia). Patients with gray matter dysfunction were more likely to have irreversible paraplegia (P < 0.01), despite presenting with a monophasic versus polyphasic course (P = 0.01), higher levels of SLE activity (mean SLE Disease Activity Index 9.8 versus 2.0; P = 0.01), and a cerebrospinal fluid profile indistinguishable from bacterial meningitis. Prior to irreversible paraplegia, these patients presented with prodromes of fever and urinary retention, but were misdiagnosed by physicians of different specialties as having urinary tract infections. Patients with white matter dysfunction were more likely to meet criteria for neuromyelitis optica (P = 0.04) and were also more likely to have antiphospholipid antibodies (lupus anticoagulant) (P = 0.01). Conclusion. Our findings indicate that SLE myelitis encapsulates 2 distinct and previously unrecognized syndromes that can be distinguished clinically by gray matter versus white matter findings. Recognition of fever and urinary retention as prodromes of irreversible paraplegia may allow earlier diagnosis and treatment in SLE patients presenting with gray matter findings.