Megaloblastic Anemia

Megaloblastic anemia is a group of anemias caused by deoxyribonucleic-acid (DNA) synthesis failure, mainly due to vitamin B12 or folate deficiency; it may also arise from hereditary or drug-induced acquired DNA-synthesis defects. Features: macrocytic anemia, marrow shows megaloblastic series, and giant cell forms also appear in granulocytes/megakaryocytes and even some proliferating somatic cells. Megaloblasts are easily destroyed in marrow, producing ineffective erythropoiesis. About 95% of cases are nutritional anemia from folate and/or B12 deficiency; early isolated folate/B12 deficiency is not uncommon clinically. Nutritional megaloblastic anemia has regional distribution: in China it is common in northwestern areas such as Shanxi/Shaanxi with prevalence up to 5.3%; pernicious anemia is rare in China.

Common Symptoms

Ascites; peripheral neuritis; bleeding tendency; hepatosplenomegaly; mental disturbance; glossalgia; ataxia; shortness of breath

Causes and Pathogenesis

B12 deficiency megaloblastic anemia from intake insufficiency, increased requirement, absorption or utilization failure; pure intake failure is rare, seen only in long-term strict vegans. Increased requirement occurs in pregnancy, infants/toddlers, hemolytic anemia, infection, hyperthyroidism, malignancy. Folate deficiency: inadequate intake/increased requirement in infants/children/pregnancy; malnutrition from insufficient fresh vegetables/animal protein; increased requirement in chronic hemolysis, myeloproliferative disease, malignancy, hyperthyroidism, exfoliative dermatitis; chronic alcoholic cirrhosis reduces folate intake/stores. Other causes: intestinal malabsorption, folate-utilization failure, hemodialysis losses. Many antimetabolites (6-MP, 5-FU, hydroxyurea, cytarabine); hereditary diseases (orotic aciduria, Lesch-Nyhan syndrome, formiminotransferase or N5-methyl-THFA-transferase deficiency); also vitamin-B6-responsive and vitamin-B1-responsive megaloblastic anemia.

Treatment

Drug therapy, supportive therapy

Preventive Measures

Strengthen nutrition education; correct food faddism and incorrect cooking; promote breastfeeding and proper feeding; timely complementary foods; pregnant women should eat more fresh vegetables and animal protein, with folate supplementation in late pregnancy; in high-prevalence areas promote dietary improvement; give folate prophylaxis to chronic hemolytic anemia or long-term anticonvulsant users; total-gastrectomy patients should receive monthly prophylactic intramuscular B12.

Department to Visit

It is recommended to visit the Hematology department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.