Introduction to the Immunocompromised Patient

Evaluation of neoplastic and infectious diseases in immunocompromised patients and their complications is difficult. Knowledge of the type of immunodeficiency remains the best tool for the formulation of an appropriate and timely diagnosis. Several strategies are helpful when interpreting imaging studies of patient with potential immune compromise. If the patient is HIV (+), correlation with the CD4 lymphocyte count is imperative as different diseases occur at the various CD4 count levels. When a patient’s HIV status is unknown and imaging findings suggest an HIV-related disease, the clinician should be encouraged to actively search for pertinent risk factors, and HIV testing should be offered. Likewise, correlation with the medical chart is also critical in the assessment of all other immunocompromised patients: congenital immunosupression, diabetes, transplantation, preexisting lung disease (e.g. asthma and COPD). The following chapters emphasize imaging findings as correlated with clinical and laboratory abnormalities in a variety of common immunodeficiencies.