Fever during treatment of infective endocarditis.

In 83 episodes of culture-positive infective endocarditis (IE) of a native valve, fever persisted or recurred in 42 (50%) despite appropriate bactericidal antibiotics. The commonest cause of fever was extensive infection of the valve ring and adjacent structures, even when the infecting organisms were viridans streptococci; urgent surgery was required. Less frequent causes were systemic and pulmonary emboli and drug hypersensitivity. Infected intravenous access sites were seldom responsible. In no case was fever due to antibiotic resistance of the infecting organism. In patients with a definite microbiological diagnosis who have been given appropriate antibiotics, the temptation to alter antibiotic therapy because of persistent or recurrent fever should be resisted unless there are features of drug hypersensitivity. When fever persists or recurs during treatment of IE, the opinions of a cardiologist and cardiac surgeon should be obtained as soon as possible; delay in valve replacement may prove fatal in patients with extensive infection.