Home » Macrocytic Anaemia – Symptoms, Causes, Treatment

Macrocytic Anaemia – Symptoms, Causes, Treatment

RBCs in macrocytic anemias appear larger than normal cells on a peripheral blood smear. The MCV (mean cell volume) is typically greater than 100 fL (normal: about 90 fL). When macrocytic changes are evident in the RBCs of the bone marrow as well as in the peripheral blood, the anemia is termed megaloblastic.

Macrocytic Anemia may occur at any age, but its incidence is more prevalent in elderly groups because the causes of macrocytosis are more prevalent in older persons, but alcoholism can lead to this condition disregarding age, as well as congenital predisposal. Diagnosis of the etiology of macrocytosis is required before the morbidity and mortality can be determined.

Vitamin B12 is essential not only as a prevention to avoid the development of Macrocytic Anemia, but also as a part of normal nervous system functions and blood cell production. A well balance diet including the main sources of vitamin B12, such as eggs, meat, and dairy products, give to the organism the required amount absorbed by the body in healthy individuals. It must bind to intrinsic factor, a protein secreted by cells in the stomach. With mal-absorption condition the first signs appear in the form of paleness, shortness of breath, fatigue and weakness

What are the causes of macrocytic anemia?

Dietary deficiency of vitamin b-12 can result from the lack of intrinsic factor in individuals who have Pernicious Anemia (Megaloblastic Anemia) or with post-gastrectomy status, or mal-absorption of vitamin b-12 secondary to small bowel, as well as overgrowth, tapeworm, familial factors, drugs, ileal bypass, ileal enteritis, or sprue or inherited disorders of DNA.

The most common cause of macrocytic anemia is a deficiency of either vitamin B12 or folic acid (or both) due either to inadequate intake or insufficient absorption. Folate deficiency normally does not produce neurological symptoms, while B12 deficiency does.

This may result from stomach disorders such as carcinoma, gastrectomy or deficiency intake of protein food.

Intestinal conditions such as chronic helminthiasis (especially severe infection by ancylostoma), chronic ameobiasis, sprue, pellagra, fatty diarrhea, extensive resection of the intestine or stenosis of the ileum.

In some cases gross disorganization of the liver as in cirrhosis and other diffuse liver disease is responsible.

In pregnant women the cause may be deficiency of folic acid and/or vitamin B12, deficiency of a different haemopoietic factor present in crude liver and autolysed yeast extracts or the erythrocyte-maturing factor is not absorbed and not stored in sufficient quantity.

In some cases the bone marrow may be unable to make adequate use of the antianemic factor. This result in macrocytic anemia.

Taken all these together, the subjects are often adults rarely ill-nourished infants wither male or female and the main factor is deficiency of folic acid.

Alcoholism can cause macrocytic anemia.

Drugs that inhibit DNA replication, such as methotrexate, can also cause macrocytic anemia. This is the most common etiology in nonalcoholic patients.

What are the signs and symptoms of macrocytic anemia?

Macrocytic Anemia symptoms and signs are attributable to the underlying condition that caused the anemia or to the anemia itself, including dyspnea, headache, fatigue, sore tongue, diarrhea and other gastrointestinal symptoms.

Other physical signs include certain manifestations including glossitis, tachycardia, flow murmurs, splenomegaly, conjunctival pallor, and other neurological disorders such as ataxia, loss of deep tendon reflexes, particularly ankle reflex, loss of posterior column sensations, and confabulation.

Since the cause that leads to Macrocytic Anemia is mainly vitamin b-12 deficiency, early diagnosis and prompt treatment to reestablish the normal vitamin levels and restore the body’s retention are significant to limit the severity of the anemia and neurological complications.

A clinical history of alcohol abuse may be an important clue in the diagnose and treatment because it used to be the cause of the increased MCV, the same as a thorough examination of the individual’s medication regimen, crucial in the workup of macrocytosis.


There is no evidence of complications and Macrocytic Anemia is directly attributable to the increased size of the red cell, although those complications when they occur are attributed to the condition causing the macrocytosis.

Individuals with obstructive jaundice or hepatic disease have a macrocytosis that is secondary to increased cholesterol and phospholipids deposited on the membranes of circulating RBCs.


The treatment for vitamin B12-deficient macrocytic and pernicious anemias was first devised by William Murphy who bled dogs to make them anemic and then fed them various substances to see what (if anything) would make them healthy again. He discovered that ingesting large amounts of liver seemed to cure the disease.

Vitamin B12 is essential not only as a prevention to avoid the development of Macrocytic Anemia, but also as a part of normal nervous system functions and blood cell production.