Differential Diagnosis for Elderly Gentleman with Shoulder Pain

The patient's presentation of severe shoulder pain on anterior flexion and weakness on abduction of both shoulder joints after a fall on outstretched arms suggests several possible diagnoses. These can be categorized as follows:

• Single Most Likely Diagnosis

  • Rotator Cuff Injury: The mechanism of injury (fall on outstretched arms) and the symptoms (shoulder pain on movement, particularly anterior flexion, and weakness on abduction) are highly suggestive of a rotator cuff injury. The rotator cuff is prone to injury in falls, especially in the elderly, due to decreased muscle and tendon resilience.

• Other Likely Diagnoses

  • Shoulder Fracture: A fracture of the shoulder (e.g., proximal humerus fracture) could also present with pain and weakness after a fall. The pain on anterior flexion and weakness on abduction could be due to a fracture that affects the mechanical integrity of the shoulder joint.
  • Adhesive Capsulitis (Frozen Shoulder): Although less likely given the acute onset after a fall, adhesive capsulitis could present with pain and restricted movement. However, the weakness on abduction might be less pronounced in early stages.
  • Brachial Plexus Injury: A stretch or injury to the brachial plexus during the fall could result in shoulder pain and weakness, particularly if the injury involves the upper trunk of the plexus, which affects shoulder abduction.

• Do Not Miss Diagnoses

  • Thoracic Outlet Syndrome: This condition, involving compression of the nerves and/or blood vessels that pass into the thoracic outlet, could present with shoulder pain and weakness, especially if there is a component of nerve compression affecting the brachial plexus.
  • Vertebral Fracture: A fracture of the vertebrae, particularly in the cervical or thoracic spine, could radiate pain to the shoulder and cause weakness if there is spinal cord or nerve root involvement. Given the potential for serious complications, including spinal cord injury, this diagnosis must not be missed.
  • Pulmonary Embolism: Although less directly related to the mechanism of injury, severe shoulder pain can occasionally be a presenting symptom of a pulmonary embolism, especially if the pain is pleuritic in nature. This is a critical diagnosis not to miss due to its high mortality rate if untreated.

• Rare Diagnoses

  • Septic Arthritis or Osteomyelitis: Infection of the shoulder joint or bone could present with severe pain and limited movement. While rare in this context, especially without other symptoms of infection, it's an important consideration, especially in immunocompromised patients.
  • Tumor: A pathological fracture through a bone tumor could present with sudden onset of pain after a minor trauma like a fall. This would be rare but is an important consideration in the differential diagnosis, especially if the patient has a history of cancer.