an unusual condition characterized by deficiencies or dysfunctions of any of the 11 serum proteins known as complement and designated C1-C11. The most common abnormalities are C2 and C3 deficiencies and C5 familial dysfunction. Patients with complement abnormalities may be more susceptible to infections and to collagen vascular diseases. Primary complement abnormalities may be inherited whereas secondary complement abnormalities may stem from immunological reactions, such as drug-induced serum disease, which depletes complement. Complement deficiencies may be associated with other illnesses, such as acute streptococcal glomerulonephritis, acute systemic lupus erythematosus, and dermatomyositis.
observations Increased susceptibility to systemic bacterial infection is associated with C2 and C3 deficiencies and with C5 familial dysfunction. Chronic renal failure and lupus erythematosus may also be associated with C2 deficiency. Signs of C5 dysfunction are malaise, diarrhea, and seborrheic dermatitis. Diagnosis of complement abnormalities is difficult and often expensive. Some indications are electrocardiographic conduction abnormalities; detection of complement and immunoglobulins in the walls of blood vessels in glomerulonephritis; cerebrospinal fluid pleocytosis; increased erythrocyte sedimentation rate; and presence in the urine of red blood cells (RBCs), RBC casts, and protein.
interventions Replacement of complement-fixing antibodies and control of infection and associated illnesses are part of standard treatment for complement abnormalities. The patient commonly receives transfusion of fresh plasma to replace antibodies. Bone marrow transplantations and injection of gamma globulin may also be used, but the former carries the risk of a fatal graft-versus-host reaction. Complement abnormalities are usually corrected temporarily by replacement therapy, but no permanent cure is available.
nursing considerations Patients should be carefully monitored, especially if they are receiving gamma globulin injections. Gamma globulin is injected into a large muscle mass, which is massaged well after each injection. More than one site is usually selected if the dosage is more than 1.5 mL. If frequent doses are ordered, the injection sites are rotated. With plasma infusions, careful matching of leukocytes for human leukocyte antigen cell types is important to prevent a graft-versus-host reaction and other undesirable responses. Bone marrow transplantation requires close monitoring for transfusion reactions and is usually followed by instructions to the patient for scrupulous hygiene, prompt treatment of even the smallest wounds, and avoidance of crowds or persons with active infections. The nurse should be alert for early signs of ataxia or slight changes in mental activity that may signal neurological damage caused by infection.