A 26-year-old female complains of generalized weakness, fatigue, and muscle aches. She reports dark urine and dysuria. Vital signs show BP 108/60, P 60, R 20. What is the most likely diagnosis?

Study for the Medical FIDSAP v2 Test. Sharpen your skills with flashcards and multiple-choice questions, complete with hints and explanations. Prepare effectively for your upcoming test!

Generalized weakness with muscle aches plus dark urine points to muscle breakdown releasing pigment into the urine. When muscle fibers break down rapidly, myoglobin is released into the bloodstream and filtered by the kidneys, giving dark urine and risking kidney injury. This pattern fits rhabdomyolysis, which often follows intense exercise, trauma, drugs, or other stress on muscles. The dysuria might be incidental, but the key clue is the dark urine reflecting myoglobinuria rather than a simple urinary pigment from dehydration or a heat-related illness.

Heat stroke would require hyperthermia and central nervous system changes, which aren’t described here. Dehydration can cause fatigue and dark urine, but it doesn’t typically produce a marked myoglobin release with persistent muscle pain. Heat cramps involve painful contractions during heat exposure and don’t explain the dark urine from myoglobin. In rhabdomyolysis, expect elevated CK and potential electrolyte abnormalities; management centers on rapid IV fluids to prevent kidney injury.