Answer

Abstract

T he correct answer to this Diagnostic Challenge is swimming-induced pulmonary edema (SIPE). Cardiogenic pulmonary edema is an unlikely diagnosis in this case. Even without knowing the results of serial troponin determinations, the diagnosis of acute myocardial infarction leading to severe congestive heart failure would be almost impossible with a normal ECG; and as indicated below. Of note, a delayed echocardiogram revealed a normal ejection fraction, suggesting a non-cardiogenic etiology.Food-associated, exercise-induced anaphylaxis has been described, 1 especially in teenaged women, and it can produce pulmonary edema; 2 however, this patient lacked wheals and gastrointestinal symptoms, as well as vascular collapse, which are key features of the syndrome.Cold urticaria may often involve the respiratory tract (hoarseness, dyspnea and wheezing), gastrointestinal and the cardiovascular systems (hypotension, tachycardia and arrhythmia), 3 and shock-like symptoms have been reported after aquatic exposures. 4,5 However, most typically patients with this condition develop diffuse pruritus and wheals with angioedema, 3 and our patient had none of these manifestations. CommentaryIn racing thoroughbreds, marked increases in pulmonary vascular pressures contribute to stress failure of pulmonary capillaries 6,7 causing lung bleeding. After brief, vigorous exercise in elite human athletes with a previous history suggestive of lung bleeding, increased concentrations of red blood cells and protein have been demonstrated in broncho-alveolar lavage fluid. These findings imply that intense exercise can impair the integrity of the pulmonary capillaries of the blood-gas barrier (BGB). 8 Chest CT scans of highly trained athletes after a triathlon competition demonstrated enhanced lung density and greater numbers of opacities suggesting an increase in pulmonary extravascular fluid. 9 Although rare in people exercising on land, pulmonary edema is more routinely reported in individuals participating in swimming or other immersion-related sports. 10 Adir and coworkers describe a series of 70 teen athletes who, over a 3-year period, developed SIPE. 10 All cases occurred in trainees who were swimming semi-reclined in warm https://www.cambridge.org/core/terms. https://doi