–Jonathan A. Handler, M.D.
Question-A-Day for Monday: What are the most common causes of rhabdomyolysis?
Answer: Alcohol, drugs, infections, trauma and seizures are the leading causes of rhabdomyolysis.
Question-A-Day for Tuesday: How frequently are the classic complaints of myalgia (muscle pain) or muscle weakness seen in rhabdomyolysis?
Answer: These symptoms are unreliable. In one study, only 50% of patients with proven rhabdomyolysis had these complaints.
Question-A-Day for Wednesday: How frequently do patients with rhabdomyolysis present with the classic examination of the disorder: muscle weakness, tenderness, and swelling with discoloration of overlying skin?
Answer: These signs are present less than 20% of the time (seen 4% to 15% of the time).
Question-A-Day for Thursday: How sensitive is a urine dipstick for blood in detecting rhabdomyolysis?
Answer: The urine “dip” for blood is not only non-specific, it appears to lack adequate sensitivity for diagnosis of this disorder. In one large study, about 1/4 of the patients with serologically proven rhabdomyolysis had negative “dips” for blood.
Question-A-Day for Friday: What is the most commonly encountered electrolyte abnormality in rhabdomyolysis?
Answer: Hypocalcemia (low calcium) is the most commonly encountered electrolyte abnormality in this condition. It occurs very early in the course of the disease. It is usually self-limited and rarely requires therapy.
Question-A-Day for Saturday: In patients with rhabdomyolysis, why should treatment with calcium be avoided in asymptomatic hypocalcemic patients?
Answer: In these patients, calcium may raise intracellular calcium levels and promote further muscle injury.
Question-A-Day for Sunday: What is the mainstay of therapy for rhabdomyolysis?
Answer: Administration of a large volume of intravenous fluid (usually normal saline) is the mainstay of therapy. It’s purpose is to prevent the most lethal complication of rhabdomyolysis: acute renal failure. Effective therapy aims for a urine output of 200-300 cc/hour. Many advocate alkalinization of the urine as well. In an acid urine, myoglobin is toxic and uric acid can crystallize.
Reprinted with permission from Question-A-Day (QAD), an online archive offering a daily question, answer and reference from Emergency Medicine core texts. QAD was created by Craig Feied, M.D., Director of the National Center for Emergency Medicine Informatics, and is edited by Jonathan Handler, M.D., Director of Research and Informatics at Northwestern University Department of Emergency Medicine.