Vitamin B12 deficiency anemia
Description of the disease
This is anemia, developed due to impaired DNA synthesis in the cell nucleus. This disorder is caused by a deficiency of vit.B12 and/or folic acid. Meanwhile, in the bone marrow, the production of erythrocytes (red blood cells responsible for oxygen transport) is reduced due to ineffective erythropoiesis – cells disintegrate before leaving the bone marrow.
The prevalence of this form of anemia is 9 cases per 100,000 population per year.
Vit.B12 is not synthesized in the body and must be obtained from food. The daily dose is 5 mg. Liver reserves are about 2mg, which would be enough for 6 years. The daily dose of folic acid is 100 mg, during pregnancy – 400 mg. Liver reserves of folic acid are not replenished, which would last for up to 3 months.
Vitamin B12 deficiency anemia develops due to strict vegetarianism, impaired vit.B12 absorption due to partial removal of the stomach, lack of intrinsic Castle factor (found in the stomach), corrosive gastritis, intestinal pathology (e.g., resection of the small intestine, presence of a parasite – tapeworm). Also, this vitamin deficiency occurs during pregnancy, in cases of hyperthyroidism, and in the development of malignant tumors.
Folic acid deficiency occurs due to low intake of folates in the diet (in alcoholics, elderly people), partial removal of the intestine, fistula, diverticula, strictures, Crohn’s disease, amyloidosis, lymphoma, etc. Also, due to the use of certain medications (oral contraceptives), congenital folate malabsorption. During pregnancy, in infants, children, adolescents, when taking methotrexate, biseptol, the consumption of folates is greatly increased, leading to their deficiency.
Symptoms
Clinical symptoms usually manifest gradually, sometimes several years pass from the onset of symptoms to the diagnosis. Main symptoms: fatigue, decreased work capacity, pallor, skin resembling straw color (resembles coffee with milk color), vitiligo. Tongue changes are also characteristic – the tongue is smooth and red, appetite decreases, taste sensation is disturbed, a sensation of tingling is felt, discomfort in the epigastrium, heartburn. Possible vomiting, abdominal bloating, intermittent abdominal pain.
Neurological symptoms also appear – tingling, numbness (often in the toes, later – in the feet and hands), sensory disturbances. Legs become unresponsive, heavy, stumbling, gait becomes uncoordinated, “swaying” to the sides. In the late stage, limb weaknesses, partial paralysis occur.
Diagnosis
Important medical history (whether there is alcoholism), presenting symptoms. Blood tests are performed – decrease in hemoglobin, hematocrit, red blood cell count, while iron levels, LDH, and indirect bilirubin concentration in the blood serum increase. Characteristic erythrocyte morphology signs are observed under a microscope. In the bone marrow – stem cells remain unchanged, and the production of blood cells is inefficient, the amount of sideroblasts increases, iron accumulates in bone marrow macrophages.
Additional tests are always necessary to help determine the cause of anemia.
Treatment
The cause of anemia is eliminated. Intravenous vit.B12, folic acid preparations are prescribed. A balanced diet is recommended, and alcohol consumption is prohibited.
Source | Author Doctor Nikas Samuolis, reviewed by Prof. Virginijus Šapoka | Vilnius University | Faculty of Medicine | Head of the Department of Internal Medicine, Family Medicine, and Oncology