Polymyositis: The Daily PANCE Blueprint
A 60-year-old man presents with a 5-month history of progressive muscle weakness. He reports difficulty climbing stairs and rising from a seated position. On physical examination, he has weakness in his proximal muscles, including the deltoids and quadriceps. There is no evidence of muscle atrophy or sensory loss. Which of the following laboratory findings is most likely to be associated with his condition?
A. Elevated serum creatinine kinase
B. Decreased serum creatinine kinase
C. Elevated serum calcium
D. Decreased serum potassium
E. Normal serum creatinine kinase
Answer and topic summary
The answer is A. Elevated serum creatinine kinase
Polymyositis is an idiopathic inflammatory myopathy characterized by chronic muscle inflammation and weakness, particularly affecting the proximal muscles such as the shoulders, hips, and thighs. This condition often presents with progressive muscle weakness over several months without sensory deficits. Elevated serum creatinine kinase (CK) is a key diagnostic marker, reflecting muscle damage and inflammation. Patients typically have difficulty with tasks involving the proximal muscles, such as climbing stairs or lifting objects. Diagnosis is supported by clinical findings, elevated CK levels, electromyography, and muscle biopsy showing inflammatory infiltrates and muscle fiber necrosis. Treatment often includes corticosteroids and immunosuppressive agents to reduce inflammation and improve muscle strength.
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Covered under ⇒ PANCE Blueprint Musculoskeletal (8%) ⇒ ⇒
