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Megaloblastic anemias
Medical expert of the article
Last reviewed: 12.07.2025
Megaloblastic anemias are a group of diseases characterized by the presence of megaloblasts in the bone marrow and macrocytes in the peripheral blood.
In more than 95% of cases, megaloblastic anemia develops as a result of a deficiency of folates and vitamin B 12 or a congenital anomaly of their metabolism.
[ Causes of megaloblastic anemia
The following causes of megaloblastic anemia development are identified.
Vitamin B 12 deficiency:
- nutritional deficiency (dietary vitamin B12 content < 2 mg/day; maternal vitamin B12 deficiency leading to reduced vitamin B12 content inbreast milk).
Pathogenesis
Megaloblastic anemias comprise a group of acquired and hereditary anemias, the common feature of which is the presence of megaloblasts in the bone marrow.
Regardless of the cause, patients are diagnosed with hyperchromic anemia with characteristic changes in the morphology of red blood cells - red blood cells are oval in shape, large (up to 1.2 - 1.4 µm or more). Red blood cells with basophilic puncturing of the cytoplasm are found, and many of them contain remnants of the nucleus (Jolly bodies - remnants of nuclear chromatin, Cabot rings - remnants of the nuclear membrane that look like a ring; Weidenreich specks - remnants of nuclear matter).
Symptoms of Folate and Cobalamin Deficiency
Initial manifestations (may be observed for several months before the appearance of a full-blown clinical picture):
- megaloblastic anemia;
- paresthesia;
- soreness of the tongue or the entire oral cavity;
- red smooth ("varnished") tongue;
Diagnosis of megaloblastic anemia
When collecting the patient's anamnesis, attention is paid to:
- long-term use of antibiotics and anticonvulsants;
- diet/nutrition type;
- presence and duration of diarrhea;
- surgical interventions on the gastrointestinal tract.
How to examine?
What tests are needed?
Treatment of megaloblastic anemia
It is essential to eliminate the cause of vitamin B12 or folic acid deficiency (poor feeding, helminthic infestation, medication intake, infections, etc.).
For vitamin B 12 deficiency
In case of vitamin B12 deficiency, its preparations are prescribed - cyanocobalamin or oxycobalamin. The therapeutic dose (saturation dose) is 5 mcg/kg/day for children under one year; 100-200 mcg per day - after one year, 200-400 mcg per day - in adolescence.