Idiopathic means pertaining to a disease of unknown cause.

• A. Idiopathic
• B. Iatrogenic
• C. Nosocomial
• D. Congenital

Answer: (A)

Understanding etiology terms: idiopathic means a disease with no identifiable cause after evaluation. It comes from Greek idios (one’s own, peculiar) and pathos (disease), signaling that the origin isn’t determined despite investigation. This makes it the best description when a condition is said to have an unknown cause. Other terms describe different origins: iatrogenic refers to a condition caused by medical treatment or procedures; nosocomial means acquired in a hospital setting; congenital indicates a condition present at birth. For example, idiopathic Parkinson’s disease has no known cause, while an iatrogenic reaction might result from a drug, a nosocomial infection is contracted during a hospital stay, and a congenital defect is something the person is born with.