Differential Diagnosis for Right Arm Weakness over the Bicep
- Single Most Likely Diagnosis
- Cervical Radiculopathy (C6 nerve root impingement): This is the most likely diagnosis because the bicep muscle is primarily innervated by the C6 nerve root. Compression or irritation of this nerve root can cause weakness in the bicep muscle, leading to arm weakness.
- Other Likely Diagnoses
- Brachial Plexopathy: Injury or compression of the brachial plexus, a network of nerves that originates in the spinal cord and controls muscle movements in the arm, can cause bicep weakness.
- Muscular Dystrophy (e.g., Becker's or Duchenne's): These genetic disorders can cause progressive muscle weakness, including in the biceps.
- Peripheral Neuropathy: Damage to the peripheral nerves, such as from diabetes or trauma, can cause muscle weakness, including in the biceps.
- Do Not Miss Diagnoses
- Stroke or Transient Ischemic Attack (TIA): Although less likely, a stroke or TIA can cause sudden arm weakness, including in the biceps. Missing this diagnosis could be catastrophic.
- Spinal Cord Injury or Compression: Trauma or other conditions that compress the spinal cord can cause arm weakness, including in the biceps.
- Tumor (e.g., Pancoast tumor): A tumor in the lung or spine can compress nerves, causing arm weakness.
- Rare Diagnoses
- Amyotrophic Lateral Sclerosis (ALS): A progressive neurological disease that affects nerve cells in the brain and spinal cord, causing muscle weakness, including in the biceps.
- Guillain-Barré Syndrome: A rare autoimmune disorder that causes rapid muscle weakness, including in the biceps.
- Mononeuritis Multiplex: A condition that causes damage to multiple peripheral nerves, leading to muscle weakness, including in the biceps.