UMEM Educational Pearls

Title: Muscle weakness

Keywords: Weakness (PubMed Search)

Posted: 8/2/2018 by Kathy Prybys, MD (Updated: 8/31/2018)
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A 68 year old male presents to the ED complaining of weakness to his legs. He states today his yard chores took him over 2 hours to complete instead of the usual 15-20 minutes due need to take frequent breaks for rest due to leg pain. He denied any chest pain or shortness of breath. Past medical history included hypercholesteremia, HTN, and CAD. He is taking aspirin and recently started on rosuvastatin.

His physical exam was unremarkable.

Results showed normal EKG and CBC. Bun was 70, Creatinine was 3.4, and CPK of 1025.

This patient has statin induced rhabdomyolysis and acute renal failure.

Take Home Points:

Rhabdomyolysis is characterized by muscle necrosis which causes the release of myoglobin into the bloodstream.
Clinical manifestations can range from asymptomatic elevation of CPK to life-threatening cases with extremely high CPK levels, electrolyte imbalance, and acute renal failure.
Classic triad is: muscle aches and pains, weakness, and tea-colored urine.
Numerous recreational drugs, pharmaceuticals, and toxins can alter myocyte function. Ethanol, statins, and cocaine in particular have high risk to cause rhabdomyolysis.
50% of cases of statin-induced-rhabdomyolysis were due to drug interactions.

Additional Information

References

A reappraisal of risks and benfits of treating to target with cholesterol lowering drugs. Alla VM, et al. Drugs. 2913 Jul; 73 (10) :1025-54.

Malignant drug-induced rhabdomyolysis. Gheshlaghi F. J Nephropathology. 2012; 1(1): 59-60.

Nontraumatic drug induced thabdomyolysis: Background,laboratory features, and acute clinical management. Köppel, C. Med Toxicol Adverse Drug Exp (1989) 4: 108.