Folate deficiency - Megaloblastic Anemia - Macrocytic - Hematology Series

Summary

In this video, we dive into folate deficiency and its role in macrocytic anemia. The video explains how folate is essential for DNA synthesis and red blood cell production. It highlights causes of folate deficiency, including poor diet, alcohol, and certain medications, and discusses symptoms such as fatigue, pale skin, and pancytopenia. The script also distinguishes between megaloblastic and non-megaloblastic anemia, emphasizing the importance of diagnosing deficiencies accurately, as folate and vitamin B12 deficiencies share similar symptoms but require different treatments. Viewers will learn the impact of homocysteine levels and the need for proper folate supplementation.

Takeaways

• 😀 **Folate Deficiency Symptoms**: Common symptoms of anemia include tiredness, paleness, angina, murmurs, headache, and exercise intolerance.
• 😀 **Macrocytic Anemia Definition**: Macrocytic anemia is characterized by an MCV >100, and can be categorized into megaloblastic and non-megaloblastic types.
• 😀 **Megaloblastic Anemia Features**: In megaloblastic anemia, hypersegmented neutrophils, pancytopenia, and indirect hyperbilirubinemia are typical.
• 😀 **Folate Absorption**: Folate is absorbed in the jejunum, and the absorption process is inhibited by alcohol, oral contraceptives, and phenytoin.
• 😀 **Folate-B12 Interaction**: Folate provides a methyl group to B12, which is essential for converting homocysteine into methionine, necessary for DNA synthesis.
• 😀 **Folate Deficiency and Homocysteine**: Folate deficiency leads to elevated homocysteine levels and decreased methionine, impairing DNA synthesis.
• 😀 **Causes of Folate Deficiency**: Common causes include malnutrition, alcoholism, malabsorption disorders (e.g., celiac disease), pregnancy, and hemolytic anemia.
• 😀 **Pancytopenia in Folate Deficiency**: Folate deficiency can cause pancytopenia, which involves decreased levels of RBCs, WBCs, and platelets.
• 😀 **Diagnosis of Folate Deficiency**: Lab findings include increased MCV, decreased RBC folic acid levels, and the presence of macrocytic red blood cells and hypersegmented neutrophils on a peripheral smear.
• 😀 **Treatment of Folate Deficiency**: The treatment of choice is daily oral folic acid supplementation (monoglutamate form).
• 😀 **B12 Deficiency vs Folate Deficiency**: Folate supplementation can correct anemia, but neurological symptoms in B12 deficiency will not improve with folate alone. Correct diagnosis is crucial.

Q & A

What is the primary difference between megaloblastic and non-megaloblastic macrocytic anemia?

The main difference is the presence of hypersegmented neutrophils in megaloblastic anemia, which are typically defined as neutrophils with more than five lobes in at least 5% of neutrophils. Non-megaloblastic anemia does not show this feature.

What are some common symptoms of folate deficiency anemia?

Common symptoms of folate deficiency anemia include fatigue, pallor, exercise intolerance, headaches, angina, and murmurs. These symptoms are similar to other types of anemia.

Which part of the small intestine is responsible for the absorption of folate?

Folate is absorbed in the **jejunum** of the small intestine.

What effect do phenytoin and alcohol have on folate absorption?

Phenytoin and alcohol inhibit the absorption of folate by affecting the enzyme **conjugase**, which is required to convert polyglutamate to monoglutamate for absorption.

How does folate participate in DNA synthesis?

Folate, in the form of **tetrahydrofolate**, donates a methyl group to **B12 (cobalamin)**, converting it into **methylcobalamin**. This methyl group is then transferred to **homocysteine** to form **methionine**, which is essential for DNA synthesis.

Why is **B12 deficiency** more likely to cause neurological symptoms than folate deficiency?

B12 deficiency can lead to neurological symptoms because **B12** is required for the proper functioning of the nervous system, while folate primarily affects DNA synthesis. Folate supplementation in B12 deficiency may improve anemia but will not resolve neurological symptoms.

What is the significance of **hypersegmented neutrophils** in diagnosing megaloblastic anemia?

Hypersegmented neutrophils are a hallmark of megaloblastic anemia, indicating a problem with DNA synthesis. This finding supports a diagnosis of macrocytic anemia, especially when seen with **macro-ovalocytes** in a peripheral blood smear.

What are some causes of folate deficiency?

Folate deficiency can be caused by decreased intake (e.g., malnutrition, alcohol), malabsorption (e.g., celiac disease), drug interference (e.g., methotrexate, phenytoin), and increased utilization (e.g., pregnancy, lactation, hemolytic anemia).

What is **pancytopenia**, and how is it related to folate deficiency?

Pancytopenia refers to the simultaneous decrease in red blood cells (RBCs), white blood cells (WBCs), and platelets. In folate deficiency, impaired DNA synthesis leads to inadequate production of all blood cell types, resulting in pancytopenia.

Why is folate supplementation insufficient in the case of **B12 deficiency**?

Folate supplementation alone cannot correct the neurological symptoms of B12 deficiency. While it can improve anemia, it does not address the underlying neurological damage caused by B12 deficiency, which is necessary for proper nerve function.