Macrocytosis

What is it about ?

Macrocytosis

We talk about macrocytosis when the red blood cells are too large.

The size of red blood cells is expressed as mean corpuscular volume (MCV), also called mean corpuscular volume (MCV). It is therefore a question of calculating, on average, the size of a red blood cell.

The VGM is between 80 and 100 femtoliter (fl). 1 femtoliter is one millionth of a cubic meter. If the MCV is greater than 100 fl, it is called macrocytosis.

Causes of macrocytosis

The most common causes of macrocytosis are:

• a high production of red blood cells, due to blood loss (haemorrhage) or abnormal destruction of red blood cells (hemolysis);
• liver disease (liver disease);
• a excessive consumption of alcohol ;
• an underactive thyroid (hypothyroidism);
• a lack (deficiency) of vitamin B12 or folic acid. This deficiency can cause megaloblastic anemia. This anemia is characterized by larger than normal red blood cells. It is therefore a macrocytic anemia;
• a disturbance in the production of red blood cells in the bone marrow (myelodysplastic syndrome);
• certain drugs.

How to recognize it?

If you have macrocytosis, you may not have any symptoms.

If you have a megaloblastic anemia, you may have signs of anemia: fatigue, pallor, shortness of breath on exertion, etc.

You may also have symptoms of the condition that causes macrocytosis. For example, symptoms of a “sluggish” thyroid (hypothyroidism).

How does your doctor diagnose macrocytosis?

The blood test is used to determine the size of the red blood cells and to make the diagnosis of macrocytosis.

What can you do ?

Possible causes of macrocytosis include a lack of vitamin B12, folic acid or excessive alcohol consumption.

A balanced diet provides enough vitamin B12 and folic acid. Many foods contain folic acid. On the other hand, foods that contain vitamin B12 are mainly of animal origin (meat, eggs, dairy products). If you are a vegan, it is advisable to take vitamin B12 supplements.

If you difficulties in managing your alcohol consumption, talk to someone you trust. Try to cut down on your alcohol consumption. It takes several months for the red blood cells to return to normal, even if you have completely stopped drinking.

What can your doctor do?

If you have macrocytic anemia, your doctor will look for the cause. The most common causes of macrocytic anemia are a lack of vitamin B12 or folic acid. If you have too little vitamin B12 or folic acid, your doctor will prescribe vitamin B12 or folic acid supplements.

If you do not have anemia, it is very likely that excessive alcohol consumption is the cause of the problem. Your doctor may suggest that you talk about this. This will allow him to confirm the cause of your problem and help you reduce your alcohol consumption.

If you don’t have anemia and your alcohol intake is normal, your doctor will look for other causes of macrocytosis. For example, bleeding or an underactive thyroid (hypothyroidism). Sometimes the cause of macrocytosis cannot be found.

Want to know more?

• The food pyramid – Eat Move – Health Question
• Vitamins – mongeneraliste.be – SSMG – Scientific Society of General Medicine
• Alcohol, the point on your consumption – Stop or else?

Are you looking for more specialized help?

• Find a registered dietitian – Professional Union of French-speaking dieticians
• Alcohol aid – Le Pélican & Le center ALFA
• AA – Alcoholics Anonymous

Sources

• Foreign clinical practice guide ‘Macrocytosis (increased MCV)’ (2000), updated on April 18, 2017 and adapted to the Belgian context on October 19, 2019 – ebpracticenet
• DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 -. Record No. T240897, Anemia in Adults – Approach to the Patient; [updated 2018 Nov 30, cited 29.09.2021]. Available from https://www-dynamed-com.gateway2.cdlh.be/topics/dmp~AN~T240897. Registration and login required.