Differential Diagnosis for Arm Weakness with Pain or Muscle Fatigue
Single Most Likely Diagnosis
- Musculoskeletal Strain or Overuse Injury: This is a common condition that can cause arm weakness, pain, and muscle fatigue, especially if the patient has recently engaged in new or strenuous activities. The symptoms lasting for days in the forearms support this diagnosis.
Other Likely Diagnoses
- Cervical Radiculopathy: Compression or irritation of the cervical nerve roots can cause arm weakness, pain, and fatigue. The symptoms can radiate to the forearms, making this a plausible diagnosis.
- Thoracic Outlet Syndrome: Compression of the nerves and/or blood vessels that pass through the thoracic outlet can cause arm weakness, pain, and fatigue, particularly in the forearms.
- Peripheral Neuropathy: Conditions such as diabetic neuropathy or neuropathy due to other causes can lead to arm weakness, pain, and muscle fatigue, although the symptoms might be more widespread.
Do Not Miss Diagnoses
- Acute Coronary Syndrome or Cardiac Conditions: Although less common, cardiac conditions can sometimes present with arm pain or weakness, especially if there is associated chest pain or shortness of breath. Missing a cardiac cause could be fatal.
- Stroke or Transient Ischemic Attack (TIA): Sudden onset of arm weakness is a classic symptom of stroke or TIA. While the duration of days might not fit the typical stroke presentation, it's crucial not to miss this diagnosis due to its severe implications.
- Multiple Sclerosis: This autoimmune disease can cause a wide range of neurological symptoms, including arm weakness and fatigue. Early diagnosis is crucial for management.
Rare Diagnoses
- Amyotrophic Lateral Sclerosis (ALS): A progressive neurological disease that affects nerve cells in the brain and spinal cord, leading to loss of muscle control. ALS is rare but should be considered in cases of progressive arm weakness.
- Plexopathy: Inflammation or damage to the networks of nerves (plexuses) can cause arm weakness and pain. This is less common but could be a consideration if other diagnoses are ruled out.
- Myasthenia Gravis: An autoimmune disorder that leads to muscle weakness and fatigue, which worsens with activity and improves with rest. While rare, it's an important diagnosis to consider due to its treatable nature.