**2.3 Musculoskeletal**

A comprehensive physical examination is of utmost importance in patients with a potential musculoskeletal infection as laboratory evaluation in these patients is generally non-diagnostic. Poor circulation and neuropathy are important risk factors for the development of musculoskeletal infections, and, as such, patients may not be able localize the source of their infection. Examination should include turning the patient to examine the back, palpation of the large joints, and examination of the feet and genitourinary regions for skin changes, which are often the only clue to the presence of a musculoskeletal infection [20, 21]. Comparison with the contralateral side can help to provide a baseline with which to compare for abnormalities. Practitioners should also evaluate for the presence of decubitus ulcers, which can become a nidus for osteomyelitis or bacteremia. Crepitus or pain out of proportion to examination should prompt concern for necrotizing soft tissue infection. Erythema, swelling, or pain with passive motion in a joint are concerning for a septic joint, with the knee and hip being the most common sources [22]. Risk factors for musculoskeletal infections include vasculopathy, diabetes, surgery, and immunocompromise [20]. *Staphylococcus aureus* or *Streptococcus pyogenes-*associated cellulitis is the most common cause of sepsis secondary to musculoskeletal infection [20]. While magnetic resonance imaging (MRI), surgical pathology, or culture is often necessary for the definitive diagnosis of most musculoskeletal infections, this should not delay early and aggressive source control in the ED.
