Vitamin B12 deficiency resulting from decreased
production and availability of intrinsic factor secondary to
autoimmune-induced gastric mucosa atrophy.
Biermer-Erhlich Anemia; Hunter-Addison Anemia; Lederer Anemia;
Macrocytic Achylic Anemia; Biermer Anemia; Addison-Biermer Anemia.
It affects males and females equally. The most common
form, Adult Onset Pernicious Anemia, affects people after the age of 35 years. Studies suggest that about
1% of the elderly population is affected. Congenital Pernicious Anemia is very rare and has an onset
of age between 4 and 28 months. Juvenile Pernicious Anemia has symptoms similar to the adult-onset
type, seems to occur between the ages of 4 and 20 years. North America and
in Europe among people of Scandinavian, English, or Irish descent has the
higher prevalence. It is extremely rare among Asians. Approximately
1.9% of cases may go undiagnosed. Pernicious anemia shows a 10-fold
increase in patients with multiple myeloma and a 250-fold increase in adults
with immunoglobulin deficiency.
Autosomal dominant inheritance with incomplete
Autoantibodies against gastric parietal cells
account for the defect in intrinsic factor production and availability. The
resultant vitamin B12 deficiency produces megaloblastic changes in red
cells and neuropathies. The latter result from demyelination with the
accumulation of odd-chain fatty acids secondary to impaired
cobalamin-dependent degradation of methylmalonyl coenzyme A to succinyl-CoA.
Decreased oral absorption of cobalt-60-labeled vitamin
Usual symptoms of anemia. Sore tongue. Patients
may present with symptoms and signs of lateral and posterior spinal column
involvement with progression to paraplegia and bowel/bladder dysfunction if
Patients with anemia should have the
red cell indices examined to exclude megaloblastic changes. Document
preexisting neurologic deficits. Investigations: CBC, red cell indices.
Avoid nitrous oxide administration in
patients with increased mean corpuscular volume or in patients with
documented vitamin B12 deficiency. Regional anesthesia may be
relatively contraindicated in patients with preexisting neurologic deficits.
Irreversible oxidation of coenzyme
B12 and methionine synthase by N2O. It has been shown that
patients with preexisting B12 deficiencies can develop megaloblastic
anemia and neurologic deficits after 2 hours or less of nitrous oxide
exposure. The neurologic deficits developed 2 to 6 weeks postoperatively and
improved with B12 therapy.
Congenital Transcobalamin II Deficiency (Transcobalamine II Deficiency): Retinal
degeneration and megaloblastic anemia in early infancy that is caused by impairment of
Acquired Vitamin B12 Deficiency: This can
occur in infants breast-fed by a vegetarian mother, in vegetarian children,
and in children who have undergone large resection of the small bowel
(ileum) and who do not receive supplemental vitamin B12. Infection with
the fish tapeworm Diphyllobothrium latum is nowadays a rare cause of pernicious anemia.
Marie RM, Le Biez E, Bisson P, et al: Nitrous oxide anesthesia-associated myelopathy.