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.