II. Pathophysiology
- Nitrous Oxide inhalation interferes with Vitamin B12 Metabolism
- Longterm abuse results in Vitamin B12 Deficiency
- Long segmental changes involving the Posterior Columns
III. Signs
- Progressive ascending Polyneuropathy (especially sensory)
- Distal extremity Paresthesias (starting with legs, ultimately involving arms)
- Lower extremity weakness or Incoordination (ultimately involving arms)
- Ataxia
- Lower extremity Deep Tendon Reflexes diminished or lost
- Positive Babinski Reflex
IV. Differential Diagnosis
V. Labs
- Macrocytic Anemia
- Decreased Serum Vitamin B12
VI. Management
- Vitamin B12 Replacement with 1000 mcg orally daily