Differential Diagnosis

Given the symptoms and test results, the following differential diagnoses are considered:

• Single most likely diagnosis

  • Thoracic Outlet Syndrome (TOS): This condition involves compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib). It could explain the bilateral symptoms in the arms and hands, and potentially led to the development of cubital tunnel syndrome in the left elbow due to compensatory mechanisms or shared underlying factors.

• Other Likely diagnoses

  • Cervical Radiculopathy: Although the nerve test found all nerves to be okay except for the left elbow, it's possible that there's an issue with the cervical spine that's not fully captured by the tests, affecting both arms.
  • Peripheral Neuropathy: Despite the lack of an immune response disorder, other forms of peripheral neuropathy (e.g., due to metabolic issues, toxins, or vitamin deficiencies) could be affecting both arms.
  • Repetitive Strain Injury or Overuse: Bilateral symptoms could be due to repetitive activities or overuse, potentially exacerbated by poor posture or ergonomic issues.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

  • Multiple Sclerosis: Although blood tests found no immune response disorder, MS can sometimes present with atypical or subtle findings on initial tests. It's crucial to consider due to its potential impact on quality of life and the importance of early treatment.
  • Vascular Conditions (e.g., Arteritis, Vasculitis): Conditions affecting blood vessels could lead to bilateral arm symptoms and are critical to diagnose early to prevent serious complications.
  • Spinal Cord Lesions or Tumors: Any lesion or tumor affecting the spinal cord could lead to bilateral symptoms and requires prompt diagnosis and treatment.

• Rare diagnoses

  • Amyloidosis: A condition characterized by the deposition of amyloid (a particular type of protein) in various tissues, which can lead to neuropathy among other symptoms.
  • Sjögren's Syndrome: An autoimmune disorder that can cause neuropathy, among other symptoms, though it was mentioned that there's no immune response disorder, it's worth considering given the breadth of potential presentations.
  • Charcot-Marie-Tooth Disease: A group of inherited disorders that affect the peripheral nerves, potentially leading to bilateral symptoms in the arms and hands.

Each of these diagnoses requires careful consideration of the patient's full clinical picture, including detailed history, physical examination, and potentially additional diagnostic tests to determine the underlying cause of the symptoms.