Differential Diagnosis for 21 yo with Subacute Progressive Confusion, Blue Weakness and Numbness
Single Most Likely Diagnosis
- Vitamin B12 Deficiency: This condition can cause subacute progressive neurological symptoms including confusion, weakness, and numbness. The normal brain and cervical MRI, as well as normal CSF, do not rule out this diagnosis as it primarily affects the peripheral nerves and spinal cord.
Other Likely Diagnoses
- Multiple Sclerosis: Although the MRI is normal, it's possible that the lesions are not visible or are in a location not easily detected by standard MRI protocols. Clinical presentation and further testing like evoked potentials could support this diagnosis.
- Chronic Inflammatory Demyelinating Polyneuropathy (CIDP): This condition can present with progressive weakness and numbness, and while CSF protein is often elevated, it can be normal in some cases.
- Toxic or Metabolic Disorders: Exposure to certain toxins (e.g., heavy metals) or metabolic disorders (e.g., porphyria) could explain the symptoms, especially if there's a history of exposure or systemic symptoms.
Do Not Miss Diagnoses
- Spinal Arteriovenous Malformation (AVM): Although the MRI is reported as normal, it's crucial to ensure that the imaging was adequate to rule out spinal AVM, which could cause progressive neurological symptoms due to spinal cord compression or steal phenomenon.
- Cervical Spinal Stenosis: Even with a normal MRI, dynamic imaging or specific sequences might be needed to fully evaluate for spinal stenosis, which could cause neurological symptoms.
- Lyme Disease: Neuroborreliosis can cause a wide range of neurological symptoms, including confusion and numbness, and is important to consider, especially in endemic areas.
Rare Diagnoses
- Adrenoleukodystrophy: A rare genetic disorder that affects the brain and spinal cord, primarily in males, and can present with a variety of neurological symptoms.
- Tangier Disease: A rare inherited disorder that can cause neuropathy among other symptoms, due to severe reduction in HDL cholesterol.
- Mitochondrial Disorders: Conditions like MELAS syndrome can present with a combination of neurological and systemic symptoms, including confusion, weakness, and numbness, although they are rare and often have distinctive features like seizures or hearing loss.