Differential Diagnosis for Right Arm Drops with Certain Movement
- Single most likely diagnosis
- Rotator Cuff Injury: This is the most likely diagnosis because the rotator cuff is a common source of shoulder pain and weakness, especially with certain movements. A tear or strain in the rotator cuff muscles or tendons can cause the arm to drop due to pain or weakness.
- Other Likely diagnoses
- Adhesive Capsulitis (Frozen Shoulder): This condition can cause stiffness and pain in the shoulder, leading to limited mobility and weakness, which may result in the arm dropping with certain movements.
- Cervical Radiculopathy: Nerve root compression in the cervical spine can cause weakness, numbness, and pain in the arm, potentially leading to arm drop with specific movements.
- Thoracic Outlet Syndrome: Compression of the nerves or blood vessels in the thoracic outlet can cause pain, weakness, and numbness in the arm, which may result in arm drop.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Stroke or Transient Ischemic Attack (TIA): Although less likely, a stroke or TIA can cause sudden weakness or numbness in the arm, which may be mistaken for a musculoskeletal issue. Missing this diagnosis can have severe consequences.
- Spinal Cord Injury: Trauma to the spinal cord can cause sudden weakness or paralysis in the arm, which may be mistaken for a peripheral musculoskeletal issue.
- Rare diagnoses
- Muscular Dystrophy: A group of genetic disorders that progressively weaken muscles, potentially causing arm drop.
- Neurodegenerative Diseases (e.g., Amyotrophic Lateral Sclerosis): Rare conditions that affect the nervous system and can cause progressive muscle weakness, including arm drop.
- Tumors (e.g., Pancoast Tumor): Rarely, a tumor in the lung or spine can compress nerves or blood vessels, causing arm weakness or drop.