Megaloblastic type of anemia is due to Vitamin B 12 or folic acid deficiency.
Many thalassemias, particularly those with variations in the content of the individual chains, present as microcytic anemias.
Some anemias are the result of problems in the bone marrow where RBCs are produced. RBC production can be reduced or impaired by chemicals or viruses that attack the marrow.
The objective of treatment is to determine the cause of the anemia, and the treatment depends upon the cause. Anemias related to vitamin deficiencies are discussed separately.
Pernicious anemia refers to a type of autoimmune anemia . In addition to the cells being large, the inner contents of each cell are not completely developed. The disease was named pernicious anemia because it was fatal before treatment became available, first as liver therapy and, subsequently, as purified vitamin B-12. The term pernicious is no longer appropriate, but it is retained for historical reasons. Diseases of the small intestine that cause malabsorption may cause vitamin B12 deficiency. Vegans (individuals who consume absolutely no foods of animal origin) are at risk of vitamin B12 deficiency due insufficiency of this vitamin in their diet. But it takes a long time to deplete all the vitamin B12 that is stored in the liver. There is a congenital form of pernicious anemia due to defect of intrinsic factor at birth that is clearly inherited as an autosomal recessive trait with the affected child having received two copies of the gene, one from each parent. Vitamin B12 helps in this shrinking process. Without vitamin B12, there are insufficient numbers of red blood cells, and those that are in the circulation are large and quickly become damaged. This leads to anemia, meaning that there is a deficiency of normal red blood cells. Symptoms, which usually begin gradually, include loss of appetite, diarrhea , paleness, fatigue, and headache. Tingling of the hands and feet, as well as the onset of spastic movements, may indicate that the nervous system has been affected. The word "pernicious" means highly injurious, destructive, or deadly. "Pernicious" comes from the Latin root "nex" meaning "violent death." Pernicious anemia was once quite deadly.
Megaloblastic anemia is a type of anemia characterized by very large red blood cells.xThe patient often has antibodies in the blood called intrinsic factor and parietal cell antibodies While the term pernicious anemia is reserved for patients with vitamin B-12 deficiency due to a lack of production of IF in the stomach, vitamin B-12 absorption is complex and other causes of vitamin B-12 deficiency exist and are described briefly in this article. They combine in the stomach and pass into the small intestine where the intrinsic factor helps the vitamin B12 get absorbed into the circulation. Doctors diagnose pernicious anemia when a patient with a low red blood cell count has large red blood cells and white blood cells with large, multi-lobed nuclei. Through the circulation, the vitamin is transported to the liver where it is stored, being released back into the circulation as needed. Without intrinsic factor, vitamin B12 is not absorbed and pernicious anemia occurs. Enlargement of liver and spleen (hepatosplenomegaly) may also occur, accompanied by yellow discoloration of the skin (jaundice) or pallor. Weakness, heart palpitations, difficulty breathing, as well as pain in the limbs are other possible symptoms. Mouth and tongue infection may also occur. Neurological lesions , irritability, and abnormal feelings (e.g. of heat and cold) may also be present. Megaloblastosis can also be caused by disorders in which cobalamin and folate uptake and metabolism are not affected. Myeloproliferative syndromes and viral infections (eg, HIV) can lead to megaloblastosis by disrupting DNA synthesis.
Causes of Megaloblastic Anemia
There are many factors which may cause Anemia, some common causes are listed below:
- Inadequate intake e.g. Elderly people
- Malabsorption in digestive system
- Chronic alcoholism
- Abdominal or intestinal surgery that affects intrinsic factor production or absorption
- Crohn's disease
decreased production of intrinsic factor (this disease entity is called pernicious anemia)
- intestinal malabsorption (due to an enteritis, celiac disease or other causes)
Intestinal malabsorption disorders
- Fish tape worm
- Disorders of terminal illness e.g cancers
Causes of Folic Acid Deficiency
- Atrophy or loss of gastric mucosa (eg, pernicious anemia, gastrectomy, ingestion of caustic material, hypochlorhydria, histamine 2 [H2] blockers).
- Inadequate proteolysis of dietary Cbl .
- Insufficient pancreatic protease (eg, chronic pancreatitis, Zollinger-Ellison syndrome).
- immune hemolytic anemia - drug-induced.
- Administration of folate will correct the anaemia but will not reverse any neurological disease - approximately 5% show no other symptoms but neurological disorder.
- Certain medications, specifically ones that prevent seizures, such as phenytoin, primidone, and phenobarbital, can impair the absorption of folic acid
- Folic acid is present in foods such as green vegetables, liver, and yeast.
- Dysfunctional uptake and use of cobalamin by cells (eg, defects in cellular deoxyadenosylcobalamin [AdoCbl] and methylcobalamin [MeCbl] synthesis).
Symptoms of Megaloblastic Anemia
The following are the most common symptoms of megaloblastic anemia. However, each child may experience symptoms differently. Symptoms may include:
- abnormal paleness or lack of color of the skin
- decreased appetite
- lack of energy or tiring easily (fatigue)
- difficulty walking
- numbness or tingling in hands and feet
- smooth and tender tongue
- weak muscles
The symptoms of megaloblastic anemia may resemble other blood conditions or medical problems. Always consult your child's physician for a diagnosis.
Treatment of Megaloblastic Anemia
Here is the list of the methods for treating Megaloblastic Anemia :
- To establish that the patient has Cbl deficiency
- Monitor the reticulocyte count (should return to normal in 2-3 weeks) and the Hb concentration (20-30g/L rise every week until normal)
- Intramuscular hydroxy-cobalamin daily for a week (regime will depend on the cause of the anaemia)
- You can treat vitamin B-12 deficiency related to a poor diet with changes in your diet along with vitamin B-12 supplementation, under a doctor's supervision.
- To confirm the diagnosis by documenting that specific therapy is effective
- your child's tolerance for specific medications, procedures, or therapies
- In some cases, blood transfusions and the medication erythropoeitin will correct anemia.
- To ensure administration of adequate quantities of Cbl for the lifespan of the patient
- your opinion or preference