COMMON INFECTIONS

Children with HIV infection have an increased frequency of minor bacterial infections such as otitis media, sinusitis, impetigo, cellulites, urinary tract infection, and pneumonia. More serious infections reported include meningitis, osteomyelitis, septic arthritis, deep tissue abscesses, and bacteremia. Although the majority of children have hypergammaglobulimia, some present with hypogammaglobulinemia and these children are particularly susceptible to infection. In children, the development of two or more serious bacterial infections within a 2-year period of time is an AIDS-defining condition. The causative organisms are usually common childhood pathogens, particularly Streptococcus pneumoniae, Haemophilus influenzae type b, and Salmonella species. In children in terminal stages of illnesses and with frequent hospitalizations, Staphylococcus aureus and Gramnegative pathogens, including Pseudomonas spp., take on increased importance.

This increased susceptibility to infection occurs as a result of B cell dysfunction induced by the virus, which leads to a decreased or absent antibody response to specific antigens. This dysfunction affects children to a greater extent than adults, probably because children are infected at a time when the immune response is immature and they do not have preexisting memory cells. The ability to produce antibody to a vaccine antigen can be used as a method to determine the response to other antigens in vivo and as an assessment of B cell function.

Children with HIV infection and recurrent infection may given from intravenous gamma globulin (IVIG) given monthly or bimonthly. A multicenter, doubleblind, placebo-controlled study comparing intravenous gamma globulin with an albumin placebo given to children with HIV infection showed that there was an increased time to development of a serious infection in those children with a CD4+ lymphocyte count greater than 200 mm³.

Tuberculosis continues to be public health problem in the USA. Since 1985, the number of cases have increased over the expected rate, and this is thought to be due to the increased number of cases among patients with HIV. Fourteen children with HIV infection with concomitant infection with tuberculosis have been reported. Of nine children reported from Miami, Florida, eight had pulmonary tuberculosis and four had extrapulmonary disease. Cough, fever, and anorexia were the most common symptoms at presentation. Only one child had a positive skin test reaction to purified protein derivative, and four had no known exposure to tuberculosis. In children with HIV infection, a tuberculin skin test reaction of 5 mm or greater is considered positive. In the severely immunodeficient child, the skin test for tuberculosis may not be reliable, and a control skin test using diphtheria toxoid or Candida antigen should be applied as a control to detect anergy. The diagnosis of pulmonary tuberculosis in the HIV-infected child should be suspected in the presence of perihilar or paratracheal nodes with a chronic lung infiltrate and in those children with pneumonia who are unresponsive to the usual antibiotic therapy. Diagnosis should be confirmed by culture of gastric aspirates in the young infant and child and sputum in older children. Initial therapy should include at least three drugs and these should be continued for at least a 1-year period. Short-course therapy or other abbreviated treatment schedules should not be used for therapy in this population. If multiple drug-resistant tuberculosis organisms are prevalent in the community, the four-drug therapy should be instituted pending results of culture and sensitivity. This epidemic has necessitated a reevaluation of the use of bacillus Calmette-Guerin (BCG) vaccine for those parts of the USA with a high incidence of tuberculosis and/or with a high incidence of drug-resistant strains of Mycobacterium tuberculosis.