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Anaphylactoid Reactions in Dialysis Patients: Pathogenesis and Management

During dialysis large volumes of blood are exposed to the surface components of the extracorporeal circuit, including the tubing and the dialyzer membrane, as well as other foreign substances related to the manufacturing and sterilization of the dialyzer. This blood-extracorporeal contact can result in a host of reactions both allergic and nonallergic in origin ( I ) . Two major types of reactions or syndromes have been described: (i) type A or anaphylactoid reactions and (ii) type B reactions, also known as first-use syndrome. The latter reactions are typically manifested as chest and back pain that occurs 20 to 40 min after dialysis is initiated. Type B reactions have typically been reported with the use of cuprophane dialysis membranes and acetate dialysate; they have tended to disappear with dialyzer reuse. They have been attributed to complement activation by the dialyzer membrane. For some reason the incidence of such reactions appears to be decreasing, and indeed the existence of such syndrome has been questioned (2). In this article, we discuss the most severe of dialysis-related reactions: anaphylactic and anaphylactoid reactions. Anaphylaxis is an allergic condition characterized by hypotension and angioedema. It results primarily from an antigen-antibody reaction that takes place immediately after an antigen to which the person is sensitive has entered the circulation. Anaphylaxis involves specific immunoglobulins of the IgE class, which can bind to specific receptors on the membrane of mastocytes and basophils. One of the principal effects of the antigen antibody reaction is to cause the basophils in the blood and the mast cells in the pericapillary tissues to release histamine, histamine-like substances, and perhaps other vasoactive substances. These, in turn, cause (i) venous dilatation resulting in an increase in vascular capacity; (ii) dilatation of the arterioles with resultant greatly reduced arterial pressure; and (iii) a