Differential Diagnosis for Shoulder Pain
Single Most Likely Diagnosis
- Subacromial Bursitis/Tendinitis: This is the most common cause of shoulder pain, often resulting from repetitive motion, overuse, or direct trauma to the shoulder. The two-month duration of symptoms supports this diagnosis, as it allows time for inflammation and irritation of the tendons and bursae.
Other Likely Diagnoses
- Adhesive Capsulitis (Frozen Shoulder): Characterized by gradual onset of pain and stiffness, leading to limited range of motion. It's a common condition that could present with a duration of symptoms similar to the one described.
- Rotator Cuff Strain: A strain or partial tear in one of the rotator cuff muscles or tendons can cause shoulder pain, especially with certain movements. The chronic nature of the pain could indicate a strain that has not fully healed.
- Osteoarthritis of the Shoulder: Although less common than in other joints, osteoarthritis can cause shoulder pain, especially in older adults. The pain is typically worse with movement and improves with rest.
Do Not Miss Diagnoses
- Fracture: While less likely given the duration and potential for previous evaluation, a fracture (especially a stress fracture) could present with chronic pain and must be considered to avoid missing a significant injury.
- Infection (Septic Arthritis or Osteomyelitis): Infections in the shoulder joint or bone can cause severe pain and have serious consequences if not promptly treated. Although rare, they are critical not to miss.
- Referred Pain from the Cervical Spine: Pain from cervical spine disorders (e.g., herniated discs, cervical spondylosis) can refer to the shoulder. Missing a cervical spine issue could lead to inadequate treatment and potential neurological complications.
- Pancoast Tumor: A rare type of lung cancer located at the apex of the lung, which can cause shoulder pain due to local invasion of structures. It's a critical diagnosis not to miss due to its severe implications.
Rare Diagnoses
- Avascular Necrosis of the Humeral Head: A condition where the blood supply to the humeral head is interrupted, leading to necrosis of the bone tissue. It's rare but can occur due to trauma, steroid use, or other factors.
- Polymyalgia Rheumatica: An inflammatory condition that affects the muscles, leading to pain and stiffness, typically in the shoulders and hips. It's more common in older adults and can be associated with giant cell arteritis, making it important to diagnose.
- Sickle Cell Crisis: In patients with sickle cell disease, a crisis can cause severe pain, including shoulder pain, due to vaso-occlusive episodes.