Infections in the Compromised Host

This chapter discusses the background, prevention, diagnosis, treatment, and prognosis for infections in the compromised host. The immune system is composed of a large network of cells and organs working together. As a strong immunity is important for heath, nature has provided a number of overlapping immune systems to cope with an entire range of microbes. In a number of medical conditions, the immune system is not able to protect against infections due to underlying causes. Patients with severe unusual or recurrent infections have defects in the immune system from non-genetic causes. These are called secondary immune defects. The underlying causes are likely to be anatomic obstruction, previous organ damage, untreated allergy, immunosuppression given for other diseases, viral infections, malignancy, or malnutrition. The goal of treatment is to define the type of infection, the cause of the illness, and evaluate if protective measures can be instituted.