After running a marathon on a hot summer day, a 25-year-male collapses at the finish line. His blood pressure is very low, and although he is overheated (body temperature 103°F), he is not sweating. During observation in the hospital for several hours he is anuric. What is the likely cause of his anuria?

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Quizplus · Accepted Answer

The marathoner has probably lost a significant percentage of his total body water through sweating during the race. He now has a fever and is not sweating, indicators of heatstroke. Anuria (absence of urinary output) is probably the result of inadequate perfusion of the kidneys, likely because this patient's intravascular volume has been depleted. The other answers are very unlikely. Young men do not typically have enlargement of the prostate gland (prostatic hypertrophy), and, in any case, enlargement of the gland does not cause hypotension (low blood pressure) and collapse. Urinary tract infections are also rare in young men (although they are fairly common in young, sexually active women). Kidney stones can form in dehydrated people, but they typically cause intense, colicky pain. This patient is pain free.

After Running a Marathon on a Hot Summer Day, a 25-Year-Male