This patient is most likely suffering from rhabdomyolysis following a prolonged loss of consciousness (and resultant pressure necrosis) secondary to a heroin overdose. The resultant release of potassium from muscle cells may result in hyperkalemia and fatal cardiac arrhythmias, thus an EKG should be obtained immediately.
Rhabdomyolysis results from the acute breakdown of skeletal muscle and leakage into the circulation. This condition is most commonly caused by crush injuries, overexertion, alcohol abuse, certain medications and toxic substances (such as cocaine). McArdle's disease and Duchenne's muscular dystrophy are well known genetic diseases that can result in this condition. This is a medical emergency requiring early recognition and prompt management with IV fluids, electrolyte monitoring, EKG and placement of a urinary catheter for detection of oliguria that might be seen with acute kidney injury from myoglobin.
Sauret et al. examine the presentation and complications of rhabdomyolysis. As in this case, tea-colored urine is usually the first clue to the presence of rhabdomyolysis. A positive urinalysis for heme but negative for blood is characteristic. Multiple complications can occur and are classified as early or late. Early complications include severe hyperkalemia that can result in cardiac arrhythmia and arrest. A devastating late complication is acute renal failure (ARF).
Scharman et al. report on the prevention of of rhabdomyolysis-associated ARF. IV fluids should be initiated within the first 6 hours after muscle injury, with a goal urine output in adults of 300 mL/h or more for at least the first 24 hours. Sodium bicarbonate should be administered only if a systemic acidosis is present and mannitol if urine output remains < 300 mL/h despite adequate fluid administration.
Image A is an example of myoglobinuria seen with rhabdomyolysis.
Illustration A is an EKG of a patient with hyperkalemia, highlighting the diminished p waves and peaked T waves.
Answer 1: Mannitol is used adjunctively in the management of rhabdomyolysis but only after an EKG and fluids administration.
Answer 2: Calcium gluconate is the treatment of choice for rhabdomyolysis-induced cardiac arrhythmias but only following EKG-proven abnormalities.
Answer 3: Furosemide has no role in the acute management of rhabdomyolysis.
Answer 4: Obtaining a CPK level is essential in the management of rhabdomyolysis but only after an EKG.
Sauret JM, Marinides G, Wang GK. Rhabdomyolysis. Am Fam Physician. 2002 Mar 1;65(5):907-12.
PMID:11898964 (Link to Abstract)
Scharman EJ, Troutman WG. Prevention of kidney injury following rhabdomyolysis: a systematic review. Ann Pharmacother. 2013 Jan;47(1):90-105.
PMID:23324509 (Link to Abstract)