Hyperviscosity syndrome

A clinical manifestation of altered physiology related to plasma hyperviscus state.

Refers to a group of symptoms triggered by increase in the viscosity of the blood.

Types of hyperviscosity syndromes vary by pathological process.

The syndrome occurs when increased blood viscosity compares blood flow or the coagulation cascade.

Serum hyperviscosity may cause neurologic or ocular disorders.

Polycythemic hyperviscosity results in reduced blood flow or capillary perfusion and increased organ congestion.

The increased viscosity of the blood is caused by an increase in protein content, which is universally monoclonal.

Hyper-viscosity caused by reduced deformability of red blood cells, often evident in hemoglobinopathies such as sickle cell anemia.

High cell counts in polycythemia or leukemia, especially in acute leukemic blast crises may be associated with HS.

HS may occur with a white blood cell count greater than 100,000.

Normal plasma viscosity is between 1.4 and 1.8 centipoise.

Symptoms from hyperviscosity typically occur with greater than 4 centipoise, which is about 4 times more viscous than water.

Symptoms from hyperviscosity typically require emergency treatment, and treatment may need to be started prior to obtaining the official viscosity level.

Plasmapheresis may be used to decrease viscosity in the case of myeloma, or Waldenstroms macroglobulinemia, whereas leukapheresis or phlebotomy may be employed in a leukemic or polycythemic crisis, respectively.

Blood transfusions are used with caution as they can increase serum viscosity.

Hydration is a temporizing measure.

Most commonly due to Waldenström’s macroglobulinemia associated with a monoclonal IgM spike.

May be associated with multiple myeloma with a IgA or IgG3 abnormality.

Signs and symptoms of HS include: Visual impairment due to retinal hemorrhage or retinal detachment, headache, dizziness, vertigo, mucosal bleeding, nystagmus, hearing loss, somnolence, seizures, coma, congestive heart failure, respiratory insufficiency, coagulation abnormalities, fatigue, peripheral neuropathy, anemia, and anorexia.

Mucocutaneous bleeding is the most common symptom.

Ocular symptoms, such as blurred vision or double vision or common, and the minority of patients develop central retinal enough occlusion and retinal detachment.

Retinal exam usually reviews dilated, sausage shape retinal veins.

Bleeding is the most common sign and retinal examination correlates with symptomatic threshold of disease.

Neurologic symptoms include: vertigo, tinnitus, and ataxia, while seizures, stroke, and some somnolence can occur.

In Waldenström’s macroglobulinemia the IgM protein may exceed 4 g/dL, and the relative plasma viscosity can exceed 4 cm centipoise and HS can occur.

Waldenström’s macroglobulinemia is associated with 90% of all cases of hyperviscosity syndrome.

The majority of remaining cases are due to IgG myeloma.

IgM is predominantly distributed intravascularly and increased viscosity can become exponential above a concentration of 3 g/dL.

Therapeutic plasma exchange is an effective treatment.

Plasma exchange can reduce plasma viscosity by 20-30% per therapeutic session, and 1-2 procedures can return plasma viscosity to near normal.

In asymptomatic patients with serum viscosity of 3-3.5 cp, and IgM concentration more than 3-4 g/dL, or both, prophylactic therapeutic plasma exchange can be done prior to starting drug therapy as a transient increase in IgM levels can occur following single agent rituximab therapy in Waldenström’s macroglobulinemia in 30-70% of patients.

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