Pediatric HIV infection: an imaging update

Thoracic Disorders in the Immunocompromised Child

Immunodeficiencies in children may be caused by primary immunodeficiency syndromes or can result from secondary disorders of immune regulation. Thoracic complications in immunocompromised children are frequent and may vary according to the type of the immunodeficiency. Imaging plays a pivotal role in detection and distinction of the variety of sequelae. It is important for the radiologist to understand both the spectrum of pediatric immune disorders, and the mechanisms underlying these disorders.

Chest imaging in the immunocompromised child

The immunodeficiency states in children may be sub-divided into two major groups; congenital (primary), and acquired (secondary). The spectrum of illness and imaging appearances are similar, regardless of the underlying cause of immunodeficiency. All immunodeficiency states are associated with an increased susceptibility to infection and neoplasia, with the lymphoproliferative disorders being the most frequent. However, the type of infections encountered and the risks of neoplasia are influenced by the underlying defect (whether predominantly humoral or cell mediated), the use of immunosuppressive drugs or radiotherapy as well as the length of immunosuppression.A working knowledge of the underlying likely immune defect is therefore important when interpreting imaging findings in children with immunodeficiency states. The typical imaging appearances of the common infectious, non-infectious and neoplastic complications of immunodeficiency are described.

Pictorial review: the radiological spectrum of vertically-acquired HIV infection

Anonymous antenatal and newborn screening demonstrates a positive HIV seroprevalence of one in 400 in areas of inner city London. European Collaborative Study data show a vertical transmission rate of 15% and suggests that 23% of infected children will develop clinical manifestations of AIDS before reaching 1 year of age [1], meaning that recognition of the radiological findings in vertically-acquired HIV is important. 75 serial cases of vertically-acquired HIV (age range 6 weeks to 12 years, mean age 35 months) presenting to a national referral centre over 48 months were reviewed; the radiographic findings we describe constitute a core of typical abnormalities together with a selection of the rarer manifestations of vertically-acquired HIV.

Pneumothorax as the presenting sign of Pneumocystis carinii infection in an HIV-positive child with prior lymphocytic interstitial pneumonitis

An HIV-positive child presented with a pneumothorax secondary to cavitary Pneumocystis carinii pneumonia (PCP). Lymphocytic interstitial pneumonitis had been evident on earlier radiographs but had resolved, concurrent with a decrease in her CD4 counts, before the radiographic changes of PCP became evident. As immune function declines in HIV-positive children, the chest radiograph may paradoxically clear. In such a setting, development of focal lung disease, including pneumothorax, may herald Pneumocystis carinii infection.