Differential Diagnosis for Crepitation on Shoulder Motion

• Single most likely diagnosis
  • Osteoarthritis of the shoulder: This is the most likely diagnosis given the patient's age, symptoms of crepitation on shoulder motion, general atrophy of the periarticular muscles, limited range of motion due to pain, and the absence of a palpable joint effusion. Osteoarthritis is a common condition in older adults that can cause these symptoms.
• Other Likely diagnoses
  • Aseptic necrosis of the humeral head: This condition can also cause shoulder pain and limited range of motion, especially if the necrosis is advanced. It is more common in certain populations (e.g., long-term corticosteroid users, heavy alcohol drinkers) but should be considered in the differential.
  • Biceps tendinitis: While this condition typically presents with anterior shoulder pain and tenderness, it could contribute to limited range of motion and pain, especially if the tendinitis is severe.
  • Chronic rupture of the biceps brachii: A chronic rupture might lead to muscle atrophy and potentially some limitation in range of motion, although it might not fully explain the crepitation.
• Do Not Miss diagnoses
  • Septic arthritis due to blood-borne transmission of infection from coexisting bacterial sinusitis: Although less likely given the absence of a palpable joint effusion and systemic symptoms of infection, septic arthritis is a medical emergency that requires prompt diagnosis and treatment to prevent joint destruction and other complications.
• Rare diagnoses
  • Other rare conditions such as hemochromatosis (which can lead to osteoarthritis and chondrocalcinosis), Charcot joint (in the context of diabetes or other neuropathic conditions), or tumors (e.g., synovial chondromatosis) could also present with similar symptoms but are less common and would typically have additional distinguishing features.