Blood hyperviscosity syndrome revealing multiple myeloma in emergency department: report of a new case.

Abstract

Introduction: Blood hyperviscosity syndrome (BHVS) is a rare and serious complication of multiple myeloma (MM). It is an unusual mode of MM revelation. Case presentation: A 60-year-old man admitted to the emergency department for hemorrhagic syndrome. Two days before his admission, he presented epistaxis with neurosensory signs. Blood count showed platelets at 139000 / mm3, normochromic normocytic anemia. Peripheric blood smear showed erythrocytes in rolls. Serum protein electrophoresis showed monoclonal gammapathies and immunonephelometric assay showed an IgG Kappa. The myelogram showed a plasmocyte infiltration at 55%. There was no bone lytic lesion visible on standard X-ray. The diagnosis of IgG Kappa stage III multiple myeloma was retained. Discussion: BHVS is a therapeutic emergency; it is defined by all the manifestations related to the elevation of blood viscosity. Raising the concentration of plasma proteins increases the plasma viscosity in a variable, inter-individual and multi-elemental manner, including molecular weight (MW), structure, concentration, and ability to form aggregates which could explain the rarity of IgG involvement in the genesis of blood hyperviscosity (low MW, isomeric structure). This IgG is secreted by a plasmocytic clone invading the bone marrow characterizing MM.