Hyperviscosity syndrome
As hyperviscosity syndrome ( HVS ) is a complex of clinical symptoms will be referred to, which is due to the increase in the concentration of the proteins of the blood plasma parameters. Due to the increased viscosity leads to a reduction of the fluidity of the blood.
Pathology
The viscosity of the blood depends upon the concentration of dissolved para- proteins and their physical and chemical properties.
Wherein the IgG is a linear increase in the viscosity of the blood is observed when the concentration of IgG paraproteins of 120 g / l exceeds.
In IgA and specific IgG in plasma of the sub-groups, insoluble precipitates by the formation of disulfide bonds.
Wherein the Waldenstrom IgM is a large molecule composed of five Y-shaped subunits. Thus, in this condition to form a sufficient HVS a concentration of 40 g / l.
Specifically, in the IgG3 can form reversible complexes, which may also increase the viscosity of blood at low temperatures and high concentrations. One speaks of cryoglobulins, which can lead to the extremities to Raynaud's disease -like symptoms.
Epidemiology
The hyperviscosity syndrome is caused by paraproteins found in malignancies like multiple myeloma and Waldenstrom's macroglobulinemia. In a variety of benign diseases of the HVS can also occur, these include, inter alia, the Felty's syndrome, lupus erythematosus, and rheumatoid arthritis.
HVS D.F. occurs in up to 10% in multiple myeloma and in up to 30 % D. F. in M. Waldenstrom on.
Clinic
General patients complain of fatigue, weakness and shortness of breath. Anemia is caused by mucosal and nosebleeds, as it comes to a disorder of platelet function. This platelet dysfunction is based on a barrier of the necessary receptors for coagulation, as the platelet surface is covered by the paraproteins and there may be an interaction with the formation of fibrin. The result is thus a symptom, which is similar to a microangiopathy. In bedridden patients may be considerably increases the thrombosis and Thrombemboliegefahr.
Laboratory
Typical findings in the HVS include a greatly elevated ESR with more than 100 mm / h, with serum electrophoresis is paraproteins show. Measurement of blood viscosity using a capillary viscometer indicates an increase in the values . Rare, important for the differential diagnosis, a Pseudohyponatriämie paraproteins is reflected in the electrolyte because the free water of the plasma binding.
Diagnosis
Difficulties in blood collection by clogged cannulae can give a first indication of the HVS. Most HVS occurs only with certain underlying conditions. In support of diagnosis, the laboratory tests as well as blood counts and bone marrow examinations can serve.
Treatment and prognosis
When therapy is symptomatic of the viscosity of symptoms, by means of a plasmapheresis and plasma exchange. By a cell separator, the plasma and the cellular components are separated. Plasma exchange is only in emergency situations indicated ( coma, seizures, heart failure ), in this case the plasma is replaced by a substitution solution. So up to 6 liters of plasma exchanged in emergency situations. Otherwise, ranging up to conducted twice a week Plasmpherese from the excess immunoglobulin to remove from the blood.
The curative treatment consists of treating the underlying disease, which also determines the prognosis.