Initial Workup and Management for Muscle Ache

Diagnostic Approach

The American College of Cardiology suggests beginning with a focused history to distinguish muscle pain from muscle weakness, as weakness suggests myositis while isolated pain typically indicates a less serious etiology 1
A thorough history should include onset and duration to determine if symptoms are acute or chronic, associated symptoms such as fever or rash, medication history including statins or immune checkpoint inhibitors, and pre-existing conditions like autoimmune diseases or cardiovascular disease 1, 2

The American Heart Association recommends first-tier testing including creatine kinase (CK) as a primary marker of muscle inflammation, transaminases (AST, ALT), lactate dehydrogenase (LDH) and aldolase as additional muscle inflammation markers, inflammatory markers (ESR and CRP), and troponin to evaluate for myocardial involvement 1, 2
Second-tier testing may include an autoimmune panel, paraneoplastic antibodies, viral hepatitis B and C, and TB testing if necessary 1, 2

For mild pain, the American College of Cardiology recommends starting with acetaminophen 500-1000 mg every 6-8 hours as first-line therapy, and continuing normal activities while monitoring symptoms 3, 1
For moderate pain or elevated CK with weakness, hold any potentially causative medications, refer to rheumatology or neurology early, and consider oral prednisone 10-20 mg/day for 4-6 weeks 1, 2
For severe weakness, markedly elevated CK, or myocardial involvement, urgent rheumatology/neurology referral and hospitalization may be necessary, with initiation of prednisone 0.5-1 mg/kg/day or IV methylprednisolone 1, 2

The American Heart Association suggests using a stepped-care approach prioritizing agents with lowest cardiovascular risk for patients with cardiovascular disease, starting with acetaminophen, then progressing cautiously through NSAIDs 4, 5, 6
Avoid COX-2 selective NSAIDs in patients with established cardiovascular disease due to increased thrombotic risk, and consider adding low-dose aspirin 81 mg with proton pump inhibitor for gastroprotection if NSAIDs are necessary 7, 5, 6

Serial CK, ESR, CRP to assess treatment response, and monitor for infections and medication side effects in patients on immunosuppression 1, 2