Health Maintenance

Penicillin prophylaxis

Penicillin prophylaxis in children is probably the most important recent advance in the care of patients with sickle cell disease (1). All patients between the ages of 4 months and 5 years should receive prophylactic penicillin (or erythromycin for children who are allergic to penicillin). A more recent study looking at prophylactic penicillin in older children showed no benefit (2). An extrapolation can be made to adults, who likewise probably do not benefit from prophylactic penicillin.

Immunizations

Patients with sickle cell disease should be immunized with the polyvalent pneumococcal vaccine one every five years . The vaccine does not eliminate overwhelming pneumococcal sepsis, but does reduce the incidence of this deadly complication in children under the age of 2 years (3). The vaccine is recommended in older children and adults, although the evidence for benefit here is less compelling. Immunization against hepatitis B is recommended universally. Patients with sickle cell disease certainly should be included in this recommendation. Children with sickle cell disease may benefit from immunization against Hemophilus influenzae (4). This pathogen is a common in all children but can be deadly in children with sickle cell disease. We do not know whether immunization against Hemophilus influenzae benefits adults.

Opthalmology Examinations

Proliferative retinopathy is a common and insidious problem for patients with sickle cell disease. Retinopathy correlates with no external manifestations, and particularly does not correlate with vaso-occlusive pain crises. The affected areas of the retina are at the outer margins, far beyond the region visualized with direct opthalmoscopy. For unclear reasons, proliferative retinopathy is more common in people with hemoglobin SC disease than in those with homozygous SS sickle cell disease (5). Patients often have sudden vision loss due to a vitreous hemorrhage as the first manifestation of sickle retinopathy. Some patients with hemoglobin SC disease who have had particularly mild manifestations do not realize that they have a sickle syndrome before sudden vision loss. Laser therapy of proliferative retinopathy can save vision for patients with sickle cell disease. Yearly examinations by an ophthalmologist is true health maintenance.

Extended Phenotype Blood Matching

Patients with sickle cell disease develop alloantibodies more readily than most people when they are transfused (6). Antibodies can limit the availability of transfusion at times when blood can be life-saving. A significant cause of rapid alloimmunization is that blood donations are made primarily by people of European background. Minor red cell antigens normally present little problem in transfusion and are therefore not looked for with typing and crossmatching. Some of these antigens, such as Kell, Kidd and Duffy, are expressed at different frequencies in people of African ancestry. Some of these problems can be minimized by extended phenotype matching in which the expression of these minor antigens are determined. The closer the antigens of the transfused blood matches that of the recipient, the less likely that problems will occur.