All about anaemia

By Dr MILTON LUM

While the causes of anaemia may be varied, the condition can be treated easily with proper diagnosis.

BLOOD is made up of fluid (plasma) and cells, that is, red blood cells which transport oxygen; white blood cells which help protect the body against infection; and platelets which help the blood to clot. Most blood cells, including the red blood cells, are produced from the stem cells in the bone marrow which is the red spongy material found in the cavities of the long bones of the body.

Red blood cells contain haemoglobin which is a red, iron-rich protein that gives the red colour to blood. Haemoglobin, which is made up of two proteins called alpha and beta chain globins, enables the red blood cells to transport oxygen from the lungs to all parts of the body and to transport carbon dioxide from other parts of the body to the lungs where it is got rid off during exhalation.

The body uses iron, folate and vitamin B12 found in the food we eat, to produce red blood cells. The number of red blood cells in circulation is maintained through the control of their formation and not their life-span. A feedback mechanism controls the production. It is not until the cells have been removed from the marrow that new cells will develop to replace them.

Erythropoietin, a hormone produced in the kidneys, plays an important role in the development of new red blood cells and the production of haemoglobin.

The red blood cells circulate in the bloodstream for about 120 days before they are broken down in the spleen. If the haemoglobin or number of red blood cells is low, the oxygen-carrying capacity of the blood is reduced and anaemia develops. Anaemia is a general name given to a variety of disorders affecting the red blood cells.

Haemoglobin is measured in grams per 100 millilitres (1 decilitre or dl). The normal level in females is between 11.5 and 15.5gm per dl. A woman is considered to be anaemic if the haemoglobin is below 11.5gm per dl.

Types of anaemia

Iron deficiency anaemia is the most common type of anaemia. It affects about 30% of the world’s population. It is due to a shortage of iron, which is needed by the bone marrow to produce haemoglobin. Without enough iron, the body cannot produce enough haemoglobin for the red blood cells. This results in iron deficiency anaemia. Apart from food, the body can get iron from the red blood cells that die.

The iron in the dead cells is recycled to produce new cells. If blood is lost, iron is also lost. This occurs if women have heavy periods or when there is a chronic blood loss from some part of the body.

Vitamin deficiency anaemia occurs when there is a shortage of folate and/or vitamin B12. The dietary requirements of folate are much more than that of vitamin B12. When the diet is short of these and other important nutrients, there is a decrease in the production of red blood cells. This can also occur if absorption of nutrients is affected by a variety of gut conditions. The bone marrow produces large, abnormal red blood cells called megaloblasts.

Hemolytic anaemia occurs as a result of an inherited or acquired condition in which the red blood cells are destroyed faster than their replacement by the bone marrow. Haemolysis is a term used to describe the breaking up of red blood cells and results in the release of haemoglobin into the plasma.

Aplastic anaemia is a life-threatening condition. It is due to a decrease or failure of the bone marrow to produce sufficient numbers of red blood cells, white blood cells and platelets. Sometimes the cause is unknown but at other times, it could be due to chemotherapy, radiotherapy, toxins and lupus.

Anaemia can also be caused by liver disease, cancer, HIV/AIDS and chronic inflammatory conditions like rheumatoid arthritis which interfere with the production of red blood cells, resulting in chronic anaemia. Kidney failure and chemotherapy can cause a shortage of erythropoietin, resulting in anaemia.

On rare occasions, no cause of anaemia can be identified.

Anaemia in pregnancy

Many women are anaemic during pregnancy. A recent study by the Anaemia Working Group found that about one-third of pregnant Malaysian women are anaemic.

Anaemia occurs because there is increased demand for iron and vitamins in pregnancy. The mother has to produce more red blood cells for herself and the foetus. More plasma is also produced.

The blood volume increases by about 50% during pregnancy with a disproportionate increase in plasma. This leads to a dilution of the blood with the haemoglobin falling. The haemoglobin is at its lowest level between 24 and 30 weeks of pregnancy.

Other causes of anaemia include:

> Poor diet: If the diet is low in iron and vitamins, especially folic acid, there is a risk of anaemia as these are the raw materials needed to produce sufficient numbers of red blood cells.

> Family history: Some women whose family members have anaemia because of inherited genes are at increased risk.

> Alcoholism: Chronic drinking increases the risk because alcohol interferes with the absorption of folic acid.

> Vegetarians who have a strict diet may not get enough iron or vitamin B12 in their food.

> Chronic conditions like kidney or liver failure, and cancer increases the risk. Chronic blood loss from some parts of the body due to ulcers, haemorrhoids, etc, may lead to iron deficiency anaemia.

> Intestinal conditions like Crohn’s disease: Intestinal polyps and even intestinal surgery can result in nutritional deficiencies because of poorer absorption.

> Other conditions: Infections, blood disorders, autoimmune disorders, exposure to toxins, and the use and abuse of certain medicines can affect red blood cell production.

If the anaemia is severe, it may interfere with the ability to carry out daily activities. One may be too tired or even exhausted to work or play. If untreated or inadequately treated, anaemia can lead to rapid or irregular heartbeat. The heart has to pump more blood to compensate for the shortage of oxygen. This can result in a heart attack or stroke.

The rapid loss of a large volume of blood can result in acute anaemia and may be potentially fatal, unless there is blood transfusion. This can happen during childbirth.

If anaemia caused by vitamin B12 deficiency is not treated, it can result in nerve damage and decreased mental function because vitamin B12 is important not only for healthy red blood cells but also optimal nerve and brain function.

The symptoms of anaemia include tiredness, breathlessness, rapid heartbeat (palpitations), dizziness, and headache and chest pain if the anaemia is severe. Apart from these symptoms, anaemia is usually diagnosed during ante-natal blood tests which are usually done at the initial consultation and, if necessary, in the second half of pregnancy. A full blood count measures the haemoglobin level and the levels of the different cells in the blood. Some of the blood may be examined under the microscope to evaluate the size, shape and colour of the red blood cells. This evaluation may indicate a diagnosis.

Blood estimations of iron, folate and vitamin B12 will help confirm deficiencies of these compounds. If inherited conditions are suspected, tests like haemoglobin electrophoresis will be carried out.

Additional tests may be done to determine the underlying cause of the anaemia. For example, iron deficiency can be due to peptic ulcers, benign colon polyps, haemorrhoids or other conditions, in which case, appropriate tests will need to be carried out.

If there is a family history of inherited anaemia, a discussion with the doctor and possibly a medical geneticist would be helpful as they can help advise on your risk and the risk of transmitting the condition to your children.

Management and prevention

The treatment depends on the cause. With adequate treatment, most anaemias can be cured. Iron deficiency anaemia will be gone once the iron stores are replenished and any source of blood loss stopped. Folate and vitamin B12 deficiencies are often successfully treated with supplements. Anaemia caused by chronic conditions, hemolytic anaemia and aplastic anaemia can be managed, if not corrected. Inherited anaemias are not curable but the symptoms can be relieved with treatment.

Many types of anaemia can be prevented. Iron deficiency and vitamin deficiency anaemia can be avoided by eating adequate amounts of a healthy diet.

It is important to eat plenty of iron-rich foods. Adequate iron is also important for vegetarians. Food rich in iron include lamb, beef, pork, beans, peas, whole grain breads, dark green leafy vegetables, dried fruit, nuts and seeds.

Food that contains vitamin C helps increase iron absorption. They include raw vegetables, potatoes, lime and oranges. Foods rich in folic acid includes fresh fruits and vegetables, citrus fruits, meat, dairy products and beans.

Vitamin B12 is found abundantly in meat and diary products.

The diet can be supplemented with iron, vitamins and folic acid.