Pulmonary embolism in younger adults.

To test the hypothesis that the clinical presentation and outcomes are different when pulmonary embolism occurs in younger (age 18 to 40 years) as compared to older (age greater than 40 years) adults, 40 younger patients were compared with older patients. No risk factors could be identified in 28 percent of the younger group. Normal physical examinations were more common (58 vs 28 percent, p = 0.01) among younger as compared with older adults. Hypoxemia was absent in 29 percent of the younger and 3 percent of the older group (p = 0.004); P(A-a)O2 was significantly lower among younger patients even after controlling for age. Mortality was decreased sevenfold (2.5 vs 18 percent, p = 0.03) among younger patients. These data indicate that pulmonary embolism tends to have a subtle presentation in younger adults. When diagnosed and treated, the mortality rate is substantially less among younger as compared with older patients.