Bacteremia in narcotic addicts at the Detroit Medical Center. II. Infectious endocarditis: a prospective comparative study.

For one year all narcotic addicts admitted to the Detroit Medical Center with infectious endocarditis (74 cases) were compared with a control group of bacteremic addicts who had other infections (106 cases). Endocarditis was caused by Staphylococcus aureus (60.8% of cases), streptococci (16.2%), Pseudomonas aeruginosa (13.5%), mixed bacteria (8.1%), and Corynebacterium JK (1.4%). S. aureus endocarditis most frequently involved the tricuspid valve; streptococci infected left-sided valves significantly more often than other organisms (P = .001). Biventricular and multiple-valve infections were commonest in patients with pseudomonas endocarditis (P = .05). Two-dimensional echocardiography, when combined with an abnormal chest roentgenogram, was highly predictive of endocarditis. Bacteremia in the absence of endocarditis was associated with primary skin and soft tissue infection, mycotic aneurysm at the site of narcotic injection, septic arthritis, septic thrombophlebitis, pneumonia, osteomyelitis, mediastinal abscess, and unclassified infection. Polymicrobial bacteremia in the nonendocarditis group was associated with markedly increased morbidity. Mild hyponatremia occurred in 41% of all patients and was also associated with significantly increased morbidity. Analysis of the two groups disclosed similarities and differences with implications for the pathophysiology and treatment of addicts with bacteremic infection.