Hyperviscosity Syndrome in Undifferentiated Connective Tissue Disease: A Case Report

Hyperviscosity Syndrome (HVS) is an oncologic emergency characterized by a triad of bleeding, visual disturbances and neurological deficits. Given its potentially fatal complications, the initial response in HVS is symptomatic treatment with a focus on decreasing blood viscosity to limit its serious clinical consequences. After symptomatic management with apheresis, the underlying cause of HVS must then be addressed. In this report, we present a case of a 45-year-old woman with extensive rheumatologic history admitted with syncope following several months of decreased oral intake. The patient had clinical signs of HVS and an M spike with elevated gamma globulins. She was treated with pulse dose steroids following plasma exchange and continued on a prednisone taper along with biologic therapy. This case is unique in that a patient with undifferentiated connective tissue disease, not previously documented, presented with hyper-viscosity syndrome secondary to increased IgG gamma globulins with a monoclonal spike, a presentation, to our knowledge, not yet described in the literature. The treatment regimen designed for this case was plasmapheresis with pulse dose steroids followed by rituximab-based therapy for induction with Mycophenolate mofetil and Hydroxychloroquine for maintenance therapy. While the use of rituximab has been associated with a clinically significant IgM flare, which would theoretically lead to worsening of hyperviscosity, in this case rituximab showed clinical effectiveness in the treatment of HVS.