A 32-year-old man with a known history of recreational substance abuse is brought to the emergency department. The patient was found by a friend on the floor of his apartment with a pool of urine around him. He has been previously hospitalized for alcohol intoxication. The patient is confused, not oriented to time or place, and does not recall recent events. Temperature is 37.3 C (99.1 F), blood pressure is 90/70 mm Hg, pulse is 67/min, and respirations are 12/min. He is drowsy and moves all his extremities. The pupils are small. Skin is mottled over the upper back, buttocks, and posterior thighs. Cardiopulmonary examination is normal. The abdomen is soft and nontender. Laboratory findings are the following: Urine toxicology screen is positive for opioids. Over the next 2 days, this patient is at greatest risk for which of the following?

Question

A 32-year-old man with a known history of recreational substance abuse is brought to the emergency department.  The patient was found by a friend on the floor of his apartment with a pool of urine around him.  He has been previously hospitalized for alcohol intoxication.  The patient is confused, not oriented to time or place, and does not recall recent events.  Temperature is 37.3 C (99.1 F), blood pressure is 90/70 mm Hg, pulse is 67/min, and respirations are 12/min.  He is drowsy and moves all his extremities.  The pupils are small.  Skin is mottled over the upper back, buttocks, and posterior thighs.  Cardiopulmonary examination is normal.  The abdomen is soft and nontender.  Laboratory findings are the following:  Urine toxicology screen is positive for opioids.  Over the next 2 days, this patient is at greatest risk for which of the following?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d4fc_6476_bc81_ffa7c4c30463_MD0003_00 This patient, who has a history of substance use (opioid, alcohol) and was found down by a friend, has laboratory findings consistent with rhabdomyolysis and is at greatest risk of developing acute kidney injury (AKI). Rhabdomyolysis results from large-scale skeletal muscle necrosis via mechanisms that include crush injury, ischemic injury, overexertion, and direct myocyte toxicity. Opioids and other CNS depressants (eg, ethanol, benzodiazepines) can cause rhabdomyolysis by inducing impaired consciousness with prolonged immobilization and ischemic compression of dependent areas of skeletal muscle (eg, mottled skin over back, buttocks, and posterior thighs). Opioids AKI in rhabdomyolysis predominantly results from decreased renal perfusion (due to intravascular volume depletion from shifting of fluid into damaged muscle tissue) and direct renal tubular toxicity of heme pigments, which are contained in myoglobin proteins released from lysed muscle cells. An increase in serum creatinine is often delayed from presentation but can be profound over the ensuing days. Other laboratory abnormalities indicative of rhabdomyolysis (all of which are seen in this patient) include: Hyperkalemia and hyperphosphatemia, which result from the release of these electrolytes from lysed muscle cells into the bloodstream. Hypocalcemia, which is often present due to deposition of calcium in damaged muscle tissue. Moderate transaminase elevations, which characteristically show greater elevation in aspartate aminotransferase (AST) than alanine aminotransferase (ALT) due to relatively higher levels of AST in skeletal muscle. (Choices B, C, and D) Patients with chronic alcohol abuse are at an increased risk of intracranial hemorrhage (subdural hematoma), necrotizing fasciitis, and osmotic demyelination syndrome; however, AKI is more likely in this patient with history and laboratory findings consistent with rhabdomyolysis. Osmotic demyelination syndrome, which results from rapid correction of hyponatremia, is particularly unlikely given that this patient's serum sodium is normal on presentation and will not require correction. (Choice E) Splenic infarction can occur due to embolic disease (eg, atrial fibrillation, infective endocarditis) or in the setting of myeloproliferative disease (eg, myelofibrosis). It is unlikely to occur in this patient with no cardiac murmurs or rhythm abnormalities on physical examination and no hematologic abnormalities other than mild leukocytosis. Educational objective: Rhabdomyolysis can result from prolonged immobilization with ischemic compression of skeletal muscle, a scenario that may occur following ingestion of a CNS depressant (eg, opioids). Affected patients commonly develop acute kidney injury due to decreased renal perfusion and direct renal tubular toxicity of heme pigment, which is contained in the myoglobin protein released from lysed skeletal muscle cells. References: Rhabdomyolysis: an evaluation of 475 hospitalized patients. (http://www.ncbi.nlm.nih.gov/pubmed/16267412)

A 32-Year-Old Man with a Known History of Recreational Substance