Hyperviscosity Syndrome: A 30-Year Experience in a Tertiary Referral Center in Mexico City

Background: The hyperviscosity syndrome (HVS) is a rare entity which refers to clinical consequences of the high blood viscosity due to abnormal increase in the cellular or acellular blood components. It frequently presents secondary to plasma cell dyscrasias but it also occurs in autoimmune diseases and chronic infections.

Methods: Retrospective and descriptive study. Clinical records of patients with HVS were analyzed between the period of January 1^st 1984 and June 30^th 2015. We reported etiology, clinical and biochemical features, treatment and outcome.

Results: During this period we evaluated 20 episodes of HVS in 14 patients (50% men). The mean age was 59 years. Ten patients (71%) debuted with HVS as the initial presentation of the underlying disease. Diseases associated to HVS were: five cases of multiple myeloma (MM) (35.7%), 4 Waldenström's macroglobulinemia (WM) (28.5%), 4 Sjögren's syndrome (SS) (28.5%) and 1 case with non-Hodgkin lymphoma (NHL). Seventy percent of the episodes were due plasma cells dyscrasias (IgM 55%, IgG 20%, IgA 10%). Neurological symptoms were present in 100% of the episodes, hemorrhagic manifestations in 70%, visual symptoms in 65% and cardiovascular in 30%. Visual symptoms were more frequent in SS in comparison with MM and WM (p=0.022, p=0.001, respectively). The mean of serum viscosity at diagnosis was 12.6±14.4 (higher in WM and SS, p=0.0216 and p=0.0285, respectively), and after treatment 3.7±2. The mean time elapsed between diagnosis and first session of plasmapheresis and diagnosis and specific treatment of the cause was 3.8±3.8 and 7.95±7.28 days, respectively. In all patients one plasma exchange for session was done and the median of sessions required was 2 (range 1-3). Twenty eight percent of the patients (4/14) had at least one relapse. Seven of the fourteen patients died during follow-up, none due to HVS. All deaths were secondary to infectious complications associated with underlying disease. The median of overall survival was 2071 days (CI95% .000-6201.386). Overall survival divided by diagnosis was different (p=0.002). One and 5 year overall survival were 84 and 58%, respectively. Progression-free survival was 485 days (CI95% .000-1975.58)

Conclusions: In 70% of cases the HVS was the initial presentation of the underlying disease. The main causes were multiple myeloma followed by Waldenström's macroglobulinemia and Sjögren's syndrome. The predominant clinical manifestations were neurological and hemorrhagic symptoms, however visuals symptoms predominated in SS. The highest serum viscosity mean was present in WM and SS. No patient died as a consequence of HVS.

This is the largest study of HVS in Latin America and one of the largest series of HVS worldwide.