Differential Diagnosis for Right Shoulder Pain

The patient presents with sudden onset of sharp shoulder pain radiating down the arm, worsened by fast movements, and a history of prior shoulder issues. The following differential diagnoses are considered:

• Single Most Likely Diagnosis

  • Rotator Cuff Tendinopathy or Tear: The patient's symptoms of sharp pain at the shoulder joint, aching sensation radiating down the arm, and pain worsening with rapid movements are consistent with rotator cuff tendinopathy or tear. The limited active internal rotation and shoulder abduction, along with the inability to move the hand off their back on external rotation against resistance, further support this diagnosis.

• Other Likely Diagnoses

  • Subacromial Bursitis: The patient's pain pattern and exacerbation with rapid movements could also be indicative of subacromial bursitis, which often presents with pain and limited mobility in the shoulder.
  • Early Stages of Adhesive Capsulitis: Although the patient has a full range of motion in the neck and no significant tenderness on palpation, the limited active internal rotation and shoulder abduction could suggest early stages of adhesive capsulitis, also known as frozen shoulder.

• Do Not Miss Diagnoses

  • Thoracic Outlet Syndrome: Although the patient denies neck pain, thoracic outlet syndrome could present with shoulder and arm pain, and it is essential to consider this diagnosis to avoid missing a potentially treatable condition.
  • Referred Pain from Cardiac or Pulmonary Causes: The patient's age and history of smoking (although quit in 2014) increase the risk of cardiac or pulmonary conditions. Although the patient denies chest pain or shortness of breath, it is crucial to consider referred pain from these sources, as missing a cardiac or pulmonary condition could be life-threatening.

• Rare Diagnoses

  • Osteonecrosis of the Humeral Head: Although rare, osteonecrosis of the humeral head could present with shoulder pain and limited mobility, especially in patients with a history of steroid use or hip replacement.
  • Infectious or Inflammatory Arthritis: The patient's history of prior shoulder issues and lack of recent trauma or injury could raise the possibility of infectious or inflammatory arthritis, although the absence of fever, swelling, or erythema makes this less likely.