Macrocytic Anemia - Causes, Types, Symptoms and Management

Introduction

Anemia is caused due to low numbers of functioning red blood cells in the body. Macrocytic anemia is when the body has overly large red blood cells and not enough normal red blood cells. Enlarged red blood cells (macrocytosis) are destroyed before completing their span of 120 days and before new immature red blood cells are formed. Macrocytosis occurs due to various reasons such as nutritional deficiency, DNA or RNA disorder, or drug reaction.

Macrocytic anemia can happen due to specific diets or certain underlying conditions. They develop when they do not get enough nutrients to help their bodies produce healthy red blood cells. Macrocytic anemia is associated with anemia where the hemoglobin is less than 12 g / dL or hematocrit is less than 36 % in non-pregnant women. As a result, the mean corpuscular volume (MCV) exceeds 100 fL. In pregnant women, the hemoglobin reads less than 13 g / dL, or Hct (hematocrit), less than 41 % in men.

What Is Macrocytic Anemia?

Macrocytic anemia is associated with large red blood cells. An average red blood cell ranges from 80 to 100 fL, but macrocytosis occurs when the size increases to more than 100 fL. When the cells grow too large, their total number decreases, and the oxygen and nutrient capacity decrease. As a result, blood oxygen levels reduce, creating numerous health issues.

A single disease does not cause macrocytic anemia but results from several medical conditions and nutritional deficiencies. The most common type of macrocytic anemia is megaloblastic macrocytic anemia, where red blood cells are deficient in producing DNA for division.

What Are the Types of Macrocytic Anemia?

Macrocytic anemia can be divided into two main types: Megaloblastic and non-megaloblastic macrocytic anemias.

• Megaloblastic Macrocytic Anemia: A majority of macrocytic anemias are megaloblastic. Megaloblastic anemia arises due to an error in red blood cell DNA production. This macrocytic anemia occurs when the body does not get enough vitamin B12 and vitamin B6 (folate). Without these nutrients, the bone marrow can not produce viable red blood cells that carry oxygen throughout your body. The unhealthy cells also die sooner and before the formation of new cells.

• Non-Megaloblastic Macrocytic Anemia: It occurs when there is the presence of one or more medical conditions that affect your body’s ability to absorb nutrients. It is mainly seen when there is a liver, spleen, or bone marrow problem.

What Causes Macrocytic Anemia?

Possible causes of megaloblastic macrocytic anemia include:

• Deficiency of Vitamin B-12.

• Folic acid deficiency.

• Some medicines, such as chemotherapeutic (Hydroxyurea), anti-seizure medications, and antiretroviral drugs, are used for people with HIV.

• Rare metabolic disorders.

A variety of factors may cause non-megaloblastic forms of macrocytic anemia. These can include:

• Chronic alcohol use.

• Liver disease.

• Hypothyroidism.

The most common conditions are:

• Myelodysplastic Syndrome- Disorders in this group occur when there is a problem with the bone marrow, and it does not produce healthy blood cells.

• Alcoholic Liver Disease- Drinking too much alcohol can prevent your body from absorbing vitamin B12.

• Hypothyroidism- This condition affects thyroid function.

What Are the Symptoms Seen in Macrocytic Anemia?

Symptoms of macrocytic anemia appear pretty late during the condition after some time has passed. They include:

• Loss of appetite or weight, causing weakness.

• Brittle nails and hair fall due to nutritional deficiency.

• Fast heartbeat.

• Diarrhea.

• Fatigue.

• Pale skin, including lips and eyelids.

• Shortness of breath.

• Poor concentration or confusion due to weakness.

• Memory loss.

More severe symptoms include:

• Increased heart rate even with slight physical movement.

• Confusion of the mind.

• Memory problems such as retention and awareness.

How Is Macrocytic Anemia Diagnosed?

A physical examination and proper history help in diagnosing macrocytic anemia. They generally order the following blood tests:

• Complete Blood Count (CBC) - This test evaluates the red blood cell count and function.

• Peripheral Blood Smear (PBS) - This test is used to examine the blood cells and analyze them by looking at them under a microscope.

• Reticulocyte Count - A reticulocyte count measures the number of immature red blood cells (reticulocytes) in the bone marrow.

How Is Macrocytic Anemia Treated?

Understanding the underlying cause to develop treatment so the bone marrow can create healthy red blood cells can help manage and treat macrocytic anemia. It may be recommended to take supplements until blood tests show your bone marrow is developing healthy red blood cells.

• Treatment of macrocytic anemia focuses on treating the cause of the symptoms and correcting malnutrition.

• Add supplements such as folic acid and vitamins to the diet. Vitamin B-12 injections may also be required if oral vitamin B-12 is not adequately absorbed.

• Foods high in B-12 vitamins include chicken, fortified grains, cereals, eggs, lean meats, crustaceans, and fish.

• High folic acid foods include dark leafy vegetables such as kale, spinach, lentils, fortified cereals, and oranges.

• Eat a healthy balanced diet to ensure enough vitamin B12 and folic acid (vitamin B9) are present.

• If the symptoms of anemia recur, contact your doctor.

How Is Macrocytic Anemia Managed?

Most people can recover from macrocytic anemia after supplementing it with muti-vitamins. However, prognosis, or expected outcome, for people with underlying conditions depends on the underlying disease and their situation.

What Are the Complications Associated With Macrocytic Anemia?

Suppose macrocytic anemia occurs because of Vitamin B12 deficiency. In that case, neural defects can occur in babies, infertility is seen, and there can also be problems such as memory loss and tingling sensation in hands and feet.

If it occurs because of folate deficiency, then cardiovascular health problems risk of colon cancer is increased. Also, there is a risk of rupture of the placenta during or before childbirth.

Conclusion

People develop macrocytic anemia when they do not get enough nutrients to help the body develop healthy red blood cells. Macrocytic anemia can occur when people follow a particular diet or have a specific underlying medical condition. It is not a severe illness but can cause serious medical issues. One can prevent macrocytic anemia by eating well. If you are concerned about macrocytic anemia, ask your healthcare provider for help.