Rhabdomyolysis, Drug Induced


Step 1: View clinicals

A 41 year old man presents with diffuse abdominal pain, generalized myalgia, and dark urine for 2 days. He did not experience dysuria, frequency or urgency. There is no history of recent trauma, NSAID use, recreational drug abuse, or travel to a foreign country. His medical history is significant for HIV infection for 2 years, for which he is on ritonavir-boosted atazanavir, tenofovir and emtricitabine. He was tested in this regard 1 week ago, and found have a CD4 count of 450 cells/mm3 with consistent viral suppression. He was also diagnosed with dyslipidemia 1 month ago, and after poor control with diet alone, started on simvastatin 20 mg daily. He does not smoke and only drinks socially. A full blood count is found to be normal.

Step 2: Order all relevant investigations

Serum CPK + Myoglobin

Serum Creatine Phosphokinase (CPK): 56,570 IU/l (normal: 5-100) Serum Myoglobin: 21,600 mcg/L (< 90)

Serum Electrolytes

Sodium: 138 mEq/L (135-145) Potassium: 5.6 mEq/L (3.5-5.0) Phosphorous: 4.9 mg/dL (2.5 - 4.5) Calcium: 8.1 mg/dL (8.5 - 10.3)

Renal Function Tests

Serum creatinine: 0.64 mg/dL (0.6-1.2)

Cytochrome P450 Activity Assay

The results will be available in a few days.

Step 3: Select appropriate management

IV Furosemide
Stop Simvastatin
Aggressive IV Fluid Therapy

Score: ★★☆