What is the treatment for Vitamin B12 deficiency encephalopathy?

Treatment of Vitamin B12 Deficiency Encephalopathy

For vitamin B12 deficiency encephalopathy, immediate treatment with intramuscular hydroxocobalamin is essential: 1 mg on alternate days until no further improvement is seen, followed by maintenance therapy of 1 mg every 2 months for life. 1

Diagnosis and Clinical Presentation

Vitamin B12 deficiency encephalopathy presents with various neurological symptoms that often precede hematological abnormalities:

• Unexplained sensory and/or motor symptoms
• Gait abnormalities
• Peripheral neuropathy
• Paresthesia and numbness
• Impaired proprioception
• Sensory ataxia
• Cognitive changes and behavioral disturbances
• Seizures (in severe cases, particularly in infants) 2

Laboratory confirmation should include:

• Serum vitamin B12 levels
• Consider methylmalonic acid (MMA) and homocysteine levels if B12 levels are low-normal 3

Treatment Protocol

For Patients with Neurological Involvement:

1. Initial Treatment:

   • Hydroxocobalamin 1 mg intramuscularly on alternate days until no further improvement is observed 1
   • Do not delay treatment if B12 deficiency is suspected, as neurological damage may become irreversible if left untreated 3

2. Maintenance Treatment:

   • Continue with hydroxocobalamin 1 mg intramuscularly every 2 months for life 1
   • Urgent specialist advice should be sought from a neurologist and hematologist 1

For Patients without Neurological Involvement:

1. Initial Treatment:

   • Hydroxocobalamin 1 mg intramuscularly three times a week for 2 weeks 1

2. Maintenance Treatment:

   • Hydroxocobalamin 1 mg intramuscularly every 2-3 months for life 1

Critical Considerations

Important Precautions:

• Never administer folic acid before treating vitamin B12 deficiency - this may mask the hematologic manifestations while allowing neurological damage to progress 1, 4
• Vitamin B12 deficiency left untreated for longer than 3 months may produce permanent degenerative lesions of the spinal cord 4
• Monitor serum potassium closely during the first 48 hours of treatment and replace if necessary 4

Special Populations:

• Post-bariatric surgery patients: Require 1000 μg oral B12 daily indefinitely, or monthly injections if ileal resection >20 cm 3
• Vegetarians/vegans: Require regular supplementation (250-350 μg daily or 1000 μg weekly) 3

Monitoring:

• Assess symptom improvement within 4-8 weeks of starting therapy
• Monitor serum B12 levels to ensure adequate replacement
• Continue treatment until complete resolution of symptoms 3
• For initial treatment, monitor hematocrit and reticulocyte counts daily from the fifth to seventh days of therapy and then frequently until the hematocrit normalizes 4

Prognosis

Early diagnosis and prompt treatment are crucial for preventing irreversible neurological damage. With appropriate vitamin B12 replacement therapy, many patients show significant clinical improvement, though some neurological symptoms may persist if treatment is delayed 5. The prognosis is generally good with early intervention, with studies showing clinical improvement of neurological symptoms after receiving vitamin B12 treatment 6.

Prevention

For patients with confirmed B12 deficiency, lifelong supplementation is necessary to prevent recurrence of symptoms. Patient education about the importance of adherence to treatment is essential, as failure to continue supplementation will result in return of anemia and development of incapacitating and irreversible damage to the nerves of the spinal cord 4.