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Zorluk: OrtaMedical History Evaluation

A 68-year-old man is evaluated in the outpatient clinic for a 3-week history of progressive muscle aching, profound fatigue, and dark-colored urine. His medical history includes type 2 diabetes mellitus, hypertension, hyperlipidemia, and symptomatic paroxysmal atrial fibrillation. One month ago, he was evaluated by a cardiologist who started him on amiodarone for rhythm control. His other daily medications include metformin, simvastatin 40 mg, and lisinopril. He recently started a light walking program to improve his cardiovascular health. He does not use tobacco, alcohol, or illicit drugs. Vital signs are within normal limits. Physical examination demonstrates diffuse muscle tenderness in the proximal upper and lower extremities. Laboratory testing reveals a serum creatine kinase of 12,500 U/L and a serum creatinine of 2.4 mg/dL (baseline 1.0 mg/dL). Which of the following specific historical elements represent the primary interacting factors that precipitated this patient's acute presentation? Select all that apply.

  1. Long-term therapy with simvastatinCevap
  2. Recent addition of amiodaroneCevap
  3. C
    Initiation of a new walking program
  4. D
    Long-term therapy with metformin
  5. E
    Long-term therapy with lisinopril

Cevap

The primary interacting factors that precipitated this patient's rhabdomyolysis are the long-term therapy with simvastatin and the recent addition of amiodarone.
This patient's clinical presentation of severe muscle pain, dark urine (myoglobinuria), marked creatine kinase elevation, and acute kidney injury is highly characteristic of rhabdomyolysis. A critical part of medical history evaluation is reviewing the medication list for potentially dangerous drug-drug interactions. Simvastatin is a lipid-lowering agent heavily metabolized by the hepatic cytochrome P450 3A4 (CYP3A4) isoenzyme. Amiodarone, a Class III antiarrhythmic, is a potent inhibitor of CYP3A4. The recent initiation of amiodarone decreased the metabolism and clearance of simvastatin, leading to toxic systemic levels of the statin. This pharmacokinetic interaction directly precipitated the patient's acute myopathy and subsequent rhabdomyolysis. Therefore, both medications represent the primary interacting factors in his history.

Adım Adım Çözüm

1
Analyze the clinical presentation and laboratory findings.
The patient has progressive muscle aching, dark urine, a massively elevated CK level, and acute kidney injury.
To establish the primary diagnosis of rhabdomyolysis complicated by acute kidney injury.
2
Review the patient's medical history and medication list for potential etiologies.
The medication list includes simvastatin, amiodarone, metformin, and lisinopril. The history includes a recent light walking program.
To identify triggers for rhabdomyolysis, which include trauma, extreme exertion, or drug toxicity.
3
Evaluate for pharmacokinetic interactions among the patient's medications.
Simvastatin is metabolized by CYP3A4. Amiodarone is a potent CYP3A4 inhibitor. Concurrent use leads to toxic simvastatin levels.
To determine the specific iatrogenic cause of the severe myopathy and rhabdomyolysis.

Anahtar Kavram

Statin-induced myopathy and rhabdomyolysis can be precipitated by the addition of cytochrome P450 3A4 (CYP3A4) inhibitors, such as amiodarone, to a patient's medication regimen.
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Medical History Evaluation

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