opportunistic infection
Infection caused by organisms that typically do not cause disease in immunocompetent hosts.
Full Definition
An opportunistic infection is caused by pathogens that typically do not cause disease in individuals with normal immune systems but can cause serious illness in immunocompromised patients. In pediatric practice, opportunistic infections are seen in children with primary immunodeficiencies, HIV infection, cancer receiving chemotherapy, or those on immunosuppressive medications. Common pediatric opportunistic infections include Pneumocystis pneumonia, cytomegalovirus disease, and invasive fungal infections. Recognition of unusual pathogens or atypical presentations should prompt evaluation for underlying immunodeficiency.
Usage
Usage note: Specify the causative organism when possible. May abbreviate as OI in established immunocompromised patient care contexts.
In Context
- "The patient's Pneumocystis pneumonia suggested an underlying immunodeficiency predisposing to opportunistic infections." — infectious disease consultation
- "Document the specific organism when describing opportunistic infections to guide appropriate therapy." — clinical documentation standard