^

Health

A
A
A

What provokes megaloblastic anemia?

 
, medical expert
Last reviewed: 19.10.2021
 
Fact-checked
х

All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.

If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.

There are following reasons for the development of megaloblastic anemia.

Deficiency of vitamin B 12 :

Alimentary deficiency (vitamin B 12 <2 mg / day, vitamin B 12 deficiency in the mother, resulting in a reduced vitamin B 12 content in breast milk);

Violations of absorption of vitamin B 12 :

  • Inadequacy of the internal factor (Castle factor):
    • pernicious anemia;
    • surgical intervention on the stomach:
    • total gastrectomy;
    • partial gastrectomy;
    • gastric bypass;
    • action of caustic substances;
  • functional anomaly of internal factor;
  • biological competition:
    • excess bacterial growth in the small intestine;
    • anastamosis and fistula;
    • blind loops and pockets;
    • strictures;
    • scleroderma;
    • achlorhydria;
    • helminths (Diphylobothrium latum);
  • infringements of a suction in an ileum:
    • family selective impairment of absorption of vitamin B 12 (Imerslund-Gresbek syndrome);
    • drug-induced violation of absorption of vitamin B 12;
    • chronic diseases of the pancreas;
    • Zollinger-Ellison syndrome;
    • hemodialysis;
    • diseases affecting the ileum:
    • resection and shunt of the ileum;
    • local enteritis;
    • celiac disease;

Disorders in the transport of vitamin B 12 :

  • hereditary deficiency of transcobalamin II;
  • transitory deficiency of transcobalamin II;
  • partial deficiency of transcobalamin I;

Metabolic disorders of vitamin B 12 :

  • hereditary:
    • deficiency of adenosylcobalamin;
    • deficiency of methyl malonyl-CoA mutase (muf, mut);
    • combined deficiency of methylcobalamin and adenosylcobalamin;
    • deficiency of methyl cobalamin;
  • purchased:
    • liver disease;
    • protein deficiency (kwashiorkor, marasmus);
    • Drug-induced (eg, aminosalicylic acid, colchicine, neomycin, ethanol, oral contraceptives, metformin).

Deficiency of folate:

  • alimentary deficiency;
  • increased need:
    • alcoholism and cirrhosis of the liver;
    • pregnancy;
    • newborn;
    • diseases associated with increased cell proliferation;
  • congenital malabsorption of folic acid;
  • drug-induced violation of absorption of folic acid;
  • extensive intestinal resection, resection of jejunum.

Combined deficiency of folic acid and vitamin B 12 :

Congenital DNA synthesis disorders:

  • orotic aciduria;
  • Lesha-Nihan syndrome;
  • thiamine-dependent megaloblastic anemia;
  • deficiency of enzymes necessary for the metabolism of folic acid:
    • N5-methyl-tetrahydrofolate-transferase;
    • formiminotransferase;
    • dihydrofolate reductase;
  • deficiency of transcobalamin II;
  • abnormal transcobalamin II;
  • homocystinuria and methylmalonic aciduria.

Drug and toxin-induced DNA synthesis disorders:

  • folate antagonists (methotrexate);
  • Purine analogues (mercaptopurine, azathioprine, thioguanine);
  • pyrimidine analogs (fluorouracil, 6-azauridine);
  • inhibitors of ribonucleotide reductase (cytosine arabinoside, hydroxycarbamide);
  • alkylating agents (cyclophosphamide);
  • Nitric oxide;
  • arsenic;
  • chloroethane.

In addition, megaloblastic anemia can be caused by erythroleukemia.

You are reporting a typo in the following text:
Simply click the "Send typo report" button to complete the report. You can also include a comment.