Anaemia is a condition in which red blood cells or the haemoglobin (a protein) in red blood cells is abnormally low.
What is going on in the body?
Haemoglobin helps red blood cells carry and deliver oxygen to the rest of the body. The amount of haemoglobin and number of red blood cells can be decreased by many different conditions. Anaemia results in a decreased ability of the blood to carry oxygen to the tissues of the body, which often causes symptoms.
What are the signs and symptoms of the condition?
Signs and symptoms depend on the cause of the anaemia. Mild anaemia may cause few or no symptoms. Common signs and symptoms include: What are the causes and risks of the condition?
Because there are different types of anaemia, the causes and risks will vary. Some of the causes of anaemia may include:
What can be done to prevent the condition?
- deficiency of certain minerals or vitamins, such as iron, which is called iron deficiency anaemia. Anaemia due to vitamin B12 deficiency is called pernicious anaemia. Lack of folic acid can also cause anaemia, which is called megaloblastic anaemia.
- inherited conditions, such as sickle cell disease, thalassemia, and glucose-6-phosphate dehydrogenase deficiency
- autoimmune disorders, conditions in which a person's immune system attacks his or her own body. In this case, the immune system attacks and destroys the red blood cells. Examples of these disorders include autoimmune haemolytic anaemia and systemic lupus erythematosus.
- drugs or medications, such as alcohol, the antibiotic penicillin, or the high blood pressure drug methyldopa
- blood loss, which can occur due to menstruation, injury, surgery, bowel cancer, and other conditions
- times of rapid growth, during early childhood, for example
- kidney failure, such as chronic renal failure
- chronic disorders, especially disorders that cause inflammation. Examples are Cancer, the infections tuberculosis and HIV, and rheumatoid arthritis. Hormone imbalances, such as a low thyroid hormone level, called hypothyroidism, are another cause. Anaemia from these causes is called anaemia of chronic disease.
- damage to or other problems in the bone marrow. Bone marrow is a type of tissue in the middle of certain bones that makes red blood cells. cancer, medications, infections, and other conditions can affect the marrow. There are different names for this type of anaemia depending on the exact type. Examples include aplastic anaemia and myelophthisic anaemia.
Many cases cannot be prevented. Eating a well-balanced diet can help prevent some cases caused by low levels of vitamins or minerals. Avoiding alcohol can prevent cases from alcohol abuse.
How is the condition diagnosed?
Diagnosis begins with the history and physical examination. Blood tests are used to confirm the diagnosis. A blood test called a full blood count, or FBC, will show a lower-than-normal amount of haemoglobin in the blood. The number of red blood cells may also be low. Looking at blood cells with a microscope can help figure out the cause in some cases. The size and shape of the blood cells often changes based on the type of anaemia.
Other blood tests may also be done, depending on the suspected cause. For example, the blood level of iron, folate, or vitamin B12 can be checked if these causes are suspected.
The stool may also be tested to check for blood loss. This is known as a faecal occult blood test. Other blood, urine, or imaging tests may also be used.
In some cases, a procedure called bone marrow biopsy may be advised. This involves inserting a special needle through the skin of the buttocks into the back of the hipbone. The needle is pushed into the middle of the bone, which contains bone marrow. A sample of marrow is taken out with the needle. The sample is then sent to the laboratory for examination and other testing.
What are the long-term effects of the condition?
Severe anaemia can make a person too weak to perform normal activities. It can even cause heart attacks, other organ damage, and death. However, most long-term effects of anaemia depend on the cause. For example, cases due to low levels of vitamins or minerals can often be treated. These cases may cause no long-term effects. On the other hand, cases due to cancer may result in death.
What are the risks to others?
Anaemia is not contagious, but it can be inherited. People with inherited forms of anaemia, such as sickle cell disease, may want to seek genetic counselling. This can help people understand the risk of passing anaemia on to their children.
What are the treatments for the condition?
In severe cases, Blood transfusions may be needed. High levels of oxygen can also be given to help the person breathe.
More specific treatments depend on the cause. For example, pills or injections may replace low levels of vitamins or minerals. If anaemia is caused by blood loss, the blood loss needs to be stopped. Sometimes surgery is needed to stop bleeding, such as bleeding from the bowels or heavy menstrual bleeding. Antibiotics may be needed if a long-term infection is the cause. If alcohol or medications caused the anaemia, stopping the drug may be all that is needed. In some cases of anaemia, surgery to remove the spleen is advised. This is known as a splenectomy. Other treatments are also possible.
What are the side effects of the treatments?
Side effects depend on the treatments used. blood transfusions may cause allergic reactions or infections. Surgery may cause heavy bleeding, infection, and allergic reactions to anaesthesia. All medications have possible side effects. For example, antibiotics can cause stomach upset, allergic reactions, or other effects.
What happens after treatment for the condition?
A person's progress after treatment depends on the cause of the anaemia and the response to treatment. For example, cases due to blood loss or certain infections may be "cured" by treatment. In some people with inherited types of anaemia, the anaemia never goes away. These people often need further monitoring and treatment. A person with cancer may die if treatment is not successful.
How is the condition monitored?
If symptoms continue or get worse, the doctor should be notified. It is important to watch for bleeding, weakness, and other unusual symptoms. The haemoglobin level in the blood may be monitored with blood tests.
Author: Adam Brochert, MD
Reviewer: eknowhow Medical Review Panel
Editor: Dr John Hearne
Last Updated: 25/04/2005
Potential conflict of interest information for reviewers available on request