Differential Diagnosis

• Single most likely diagnosis
  • Acute Transverse Myelitis (ATM): The patient's symptoms of bilateral upper and lower extremity weakness, pain, and sensation deficits, particularly the rapid progression and the involvement of the posterior scapular region, suggest an inflammatory process affecting the spinal cord. ATM is a condition characterized by inflammation across a segment of the spinal cord, which can cause a range of neurological symptoms depending on the level and extent of the inflammation.
• Other Likely diagnoses
  • Multiple Sclerosis (MS): Given the patient's age and the nature of his symptoms, MS is a consideration. MS can present with a wide range of neurological symptoms, including sensory deficits, weakness, and pain, often affecting different parts of the body at different times. The involvement of both upper and lower extremities and the presence of sensory symptoms could suggest a relapsing-remitting pattern.
  • Neuropathy (e.g., Brachial Plexopathy or Mononeuritis Multiplex): The patient's initial symptoms in one arm with subsequent spread to the other arm and then the leg could suggest a neuropathic process. Conditions affecting the nerves directly, such as brachial plexopathy or mononeuritis multiplex, could explain the pattern of weakness and sensory deficits.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Spinal Cord Infarction: Although less common, spinal cord infarction can present with sudden onset of neurological deficits, including weakness, sensory loss, and pain. It is crucial to consider this diagnosis due to its potential for severe and permanent neurological damage if not promptly recognized and treated.
  • Spinal Epidural Abscess: This is a medical emergency that can present with neurological deficits, pain, and systemic signs of infection. Prompt diagnosis and treatment are essential to prevent serious complications, including paralysis and death.
  • Guillain-Barré Syndrome: An autoimmune disorder that can cause rapid-onset muscle weakness and often follows a minor infection. It can lead to significant morbidity, including respiratory failure, if not recognized and managed appropriately.
• Rare diagnoses
  • Sjögren's Syndrome with Neuropathy: A systemic autoimmune disease that can cause neurological symptoms, including neuropathy and myelopathy, although this would be less common.
  • Vasculitis (e.g., Giant Cell Arteritis, Polyarteritis Nodosa): These conditions can cause neurological symptoms due to inflammation of blood vessels, leading to ischemia or infarction of neural tissues. They are less common but important to consider due to their potential for serious complications.
  • Lyme Disease with Neurological Involvement: Although the patient denies recent outdoor activities that might increase the risk of tick exposure, Lyme disease can cause a range of neurological symptoms, including neuropathy and, rarely, myelopathy.