A 61-year-old man presented to the emergency department with one-month history of intermittent lightheadedness and dizziness. His symptoms were worse when standing from sitting position. He denied vomiting, diarrhea, and his appetite was stable. His past medical history was remarkable for IgM multiple myeloma for which he underwent stem cell transplant a year ago and was now on maintenance chemotherapy with lenalidomide. His physical examination was remarkable for supine blood pressure of 118/68 mm Hg and standing blood pressure of 97/55 mm Hg. There were no focal neurological signs and fundoscopic examination did not reveal any retinal venous engorgement. Laboratory evaluation showed total protein of 10.1 g/dL and elevated albumin gap. Magnetic resonance imaging of brain with contrast was within normal limits. Patient was treated with fluid resuscitation and midodrine was initiated. On day 2, patient did not show any significant improvement with therapy. An oncology evaluation was obtained and his symptoms were suspected to be from hyperviscosity syndrome. A serum viscosity level was checked and plasmapheresis was started. After receiving three days of plasmapheresis, patient’s symptoms improved significantly and his orthostatic vital signs were negative. Serum viscosity level came back high at 5.6 centipoise (>4 is consistent with hyperviscosity syndrome).
Discussion:
Hyperviscosity syndrome (HVS) is a rare complication secondary to increase in serum viscosity secondary to circulating proteins. Waldenstrom’s macroglobulinemia and multiple myeloma are two important causes of HVS. The classic symptom triad of HVS includes mucosal or skin bleeding, visual abnormalities, and focal neurological deficits. The clinical manifestations of HVS result from the relative hypoperfusion caused by sluggish blood flow. The neurological manifestations of HVS can be varied and include headache, ataxia, vertigo, dizziness, nystagmus, stupor and coma. Classic physical exam finding is retinal vein engorgement on fundoscopic examination. The diagnosis can be established on the basis of signs and symptoms and laboratory evidence of increased serum protein levels and increased serum viscosity. Prompt treatment with plasmapheresis is warranted to prevent further morbidity and mortality.
Conclusions:
Orthostatic hypotension is a rare neurological presentation of hyperviscosity syndrome. The diagnosis requires a high clinical suspicion and should be considered in patients presenting with dizziness and underlying history of multiple myeloma. Prompt therapy with plamapheresis and hydration is warranted to prevent life threatening complications.