Megaloblastic anemia

Megaloblastic Anemia

File:Hypersegmented neutrophil.png

A hypersegmented neutrophil, often seen in megaloblastic anemia.

Megaloblastic anemia is a type of anemia characterized by the presence of unusually large, structurally abnormal, immature red blood cells (RBCs) in the bone marrow. These cells are known as megaloblasts. The condition is often due to impaired DNA synthesis, which affects cell division and leads to the production of large, dysfunctional RBCs.

Causes

Megaloblastic anemia is most commonly caused by deficiencies in vitamin B12 or folate, both of which are essential for DNA synthesis. Other causes can include certain medications, alcoholism, and rare genetic disorders affecting DNA synthesis.

Vitamin B12 Deficiency

Vitamin B12 deficiency can result from inadequate dietary intake, malabsorption syndromes such as pernicious anemia, or surgical removal of parts of the stomach or small intestine.

Folate Deficiency

Folate deficiency may occur due to poor diet, increased requirements during pregnancy, or malabsorption conditions like celiac disease.

Pathophysiology

The hallmark of megaloblastic anemia is the presence of megaloblasts in the bone marrow. These cells arise due to defective DNA synthesis, which causes a delay in nuclear maturation relative to cytoplasmic maturation. This results in large, immature, and dysfunctional RBCs.

File:Hypersegmented neutrophil.png

Hypersegmented neutrophils are a diagnostic feature of megaloblastic anemia.

Clinical Features

Patients with megaloblastic anemia may present with symptoms of anemia such as fatigue, pallor, and shortness of breath. Neurological symptoms may occur in vitamin B12 deficiency, including paresthesia, ataxia, and cognitive disturbances.

Diagnosis

Diagnosis is typically made through blood tests showing macrocytic anemia, with a high mean corpuscular volume (MCV). A peripheral blood smear may reveal hypersegmented neutrophils, which are neutrophils with more than five lobes, a classic finding in megaloblastic anemia.

Treatment

Treatment involves addressing the underlying cause of the deficiency. Vitamin B12 deficiency is treated with vitamin B12 supplementation, either orally or via injection. Folate deficiency is treated with oral folic acid supplements.

Related Pages

• Anemia
• Vitamin B12
• Folate
• Pernicious anemia