Differential Diagnosis for 64-year-old Female with Right Shoulder Injury

Single Most Likely Diagnosis

• Rotator Cuff Strain or Tear: The patient's inability to raise her arm laterally and the location of the injury along the lateral bicep with lateral flexion suggest a rotator cuff injury, which is common in this age group and can occur from a fall.

Other Likely Diagnoses

• Bicipital Tendinitis: Given the location of the pain along the lateral bicep, bicipital tendinitis is a possible diagnosis, especially if the patient has a history of repetitive shoulder movements or has experienced similar injuries before.
• Shoulder Impingement Syndrome: This condition, where the shoulder blade puts pressure on the underlying tissues when the arm is lifted, could also explain the patient's symptoms, particularly the difficulty in raising the arm laterally.
• Proximal Biceps Tendon Rupture: Although less common, a rupture of the proximal biceps tendon could occur from a fall and would result in significant pain and weakness in the affected arm.

Do Not Miss Diagnoses

• Fracture (e.g., Proximal Humerus Fracture): While the patient's symptoms might not immediately suggest a fracture, it's crucial to rule out this possibility, especially given the mechanism of injury (fall) and the patient's age, which could affect bone density.
• Axillary Nerve Injury: Damage to the axillary nerve could result from a fall and would lead to weakness and sensory changes in the shoulder region, making it a critical diagnosis not to miss.
• Brachial Plexus Injury: Although less likely, a brachial plexus injury could occur from a fall, especially if the arm was stretched or compressed during the incident, and would require prompt diagnosis and treatment.

Rare Diagnoses

• Osteonecrosis of the Humeral Head: This condition, although rare, could be a consideration if the patient has risk factors such as long-term steroid use or excessive alcohol consumption, and presents with persistent shoulder pain after a fall.
• Infectious or Inflammatory Conditions (e.g., Septic Arthritis, Rheumatoid Arthritis): While uncommon as a direct result of a fall, these conditions could present with shoulder pain and limited mobility, especially if the patient has underlying health issues or is immunocompromised.