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Vitamin B12 Deficiency and Pernicious Anemia

Causes, neurological complications and replacement strategies

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Hematoloji department. Book Appointment →

What is Vitamin B12 Deficiency and Pernicious Anemia?

Vitamin B12 (cobalamin) is essential for DNA synthesis, methylation reactions and myelin maintenance.

Pernicious anemia is autoimmune gastritis with loss of intrinsic factor and atrophy of gastric parietal cells.

Other causes include strict vegan diet, ileal disease (Crohn, resection), bacterial overgrowth, fish tapeworm, gastric bypass and medications (proton pump inhibitors, metformin).

Diagnosis uses serum B12 plus methylmalonic acid and homocysteine; intrinsic factor and parietal cell antibodies confirm pernicious anemia.

Macrocytic anemia, hypersegmented neutrophils and pancytopenia in severe cases reflect ineffective hematopoiesis.

Symptoms

Fatigue, weakness, breathlessness, palpitations and pallor.
Smooth, beefy red tongue (atrophic glossitis), oral ulcers and weight loss.
Subacute combined degeneration of spinal cord causes paresthesias, numbness, gait ataxia, weakness and impaired position sense.
Cognitive symptoms include memory loss, irritability, depression and rarely dementia or psychosis.
Autonomic and visual disturbances and orthostatic hypotension may occur in advanced cases.

Risk Factors

Older age, female sex and northern European ancestry for pernicious anemia.
Vegan or strict vegetarian diet without supplementation.
Long-term proton pump inhibitor or H2 blocker use, gastric surgery or bariatric procedures.
Ileal disease, resection, bacterial overgrowth or fish tapeworm infection.
Coexisting autoimmune disease such as type 1 diabetes, vitiligo, Hashimoto thyroiditis or Addison disease.

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • Unexplained fatigue, breathlessness, palpitations or pallor warrants complete blood count evaluation.
  • Numbness, tingling, ataxia, balance problems or memory loss require neurological assessment for B12 deficiency.
  • Patients on long-term acid suppression, after gastric surgery or with autoimmune disease should be screened periodically.
  • Severe macrocytic anemia or pancytopenia with hypersegmented neutrophils needs urgent hematology referral.
  • Suspected pernicious anemia with negative B12 levels but classic neurological signs requires methylmalonic acid testing.

Treatment Methods

01
Initial parenteral therapy uses intramuscular hydroxocobalamin or cyanocobalamin 1000 micrograms daily for 1 to 2 weeks then weekly until response, then monthly maintenance for life.
02
Oral high-dose B12 (1000 to 2000 micrograms daily) is effective in many cases including pernicious anemia for selected patients.
03
Sublingual and intranasal preparations are alternatives for adherence or absorption issues.
04
Address underlying causes: dietary counseling, treatment of bacterial overgrowth, parasite eradication or medication review.
05
Monitor response with reticulocyte count, hemoglobin, MCV and resolution of neurological symptoms; lifelong follow-up screens for gastric cancer, autoimmune comorbidities and adherence to maintenance.

Which Department to Visit?

You can visit our Hematoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About Hematoloji Department

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.