Hyperviscosity syndrome

From Dog

Hyperviscosity syndrome is caused by massive hyperproteinemia that usually is associated with a monoclonal gammopathy.

The gammopathy is produced in response to intense immunostimulation, due to exo- or endo-antigen stimulation.

This condition is not unique to one particular disease, and has been described in:

- Bartonella henselae infection[2]
- Ehrlichia canis[3]

Changes in the vascular hemodynamics results in sludging of blood and reduced flow within blood vessels. As a consequence, the heart has to work harder to function properly. Affected dogs often develop a gallop rhythm, left ventricular hypertrophy secondary to the increased cardiac output, and afterload. Impairment of cardiac function can detrimentally affect vascular perfusion and subsequently the body will experience tissue hypoxia.

Hyperviscosity syndrome also may cause bleeding or hemorrhagic diathesis in addition to severe thrombocytopenia. Paraproteins will coat the platelets and decrease membrane reactivity. Platelet factor III does not function properly and the ability of the platelets to adhere to surfaces and aggregate to form clots is drastically decreased.

Treatment of this condition requires addressing the underlying disease process and treating with IV fluids to attempt to improve vascular flow.


  1. Ramaiah SK et al (2002) Biclonal gammopathy associated with immunoglobulin A in a dog with multiple myeloma. Vet Clin Pathol 31(2):83-89
  2. Tabar MD et al (2011) Gammopathy in a Spanish dog infected with Bartonella henselae. J Small Anim Pract 52(4):209-212
  3. Hoskins JD et al (1983) Serum hyperviscosity syndrome associated with Ehrlichia canis infection in a dog. J Am Vet Med Assoc 183(9):1011-1012
  4. Gentilini F et al (2005) Different biological behaviour of Waldenström Macroglobulinemia in two dogs. Vet Comp Oncol 3(2):87-97
  5. Leifer CE & Matus RE (1986) Chronic lymphocytic leukemia in the dog: 22 cases (1974-1984). J Am Vet Med Assoc 189(2):214-217