Anaemia: A Closer Look

 



Q1. What is anaemia?
Anaemia occurs when the number of red blood cells or the haemoglobin concentration is lower than normal. It is caused by other conditions and is an indicator of a disease, but not a disease itself. The World Health Organization (WHO) defines anaemia as a haemoglobin level lower than 12 g/dL in women and a level lower than 13 g/dL in men. Anaemia is a serious global health issue that particularly affects pregnant women and children. According to WHO’s estimate, it is so prevalent that globally 40% of pregnant women and children under 5 years old are anaemic. Therefore, anaemia is a very common health condition.
 
Q2. What are the symptoms of anaemia?
Symptoms of anaemia vary depending on its cause and severity. Symptoms are usually mild or even absent at first, but they may appear and worsen as anaemia progresses in severity. Common symptoms include fatigue, weakness, cold hands and feet, pale skin, headache, dizziness, irregular heartbeats, chest pain, etc.
 
Q3. What are the causes of anaemia?
Anaemia is most commonly caused by chronic blood loss leading to iron deficiency anaemia. Chronic blood loss may include excessive menstrual bleeding, stomach ulcer, haemorrhoid, gastrointestinal cancer, etc. Older people, vegetarians and alcoholics may develop megaloblastic anaemia due to deficiency in vitamin B12 and folate. Another common cause of anaemia in Hong Kong is a genetic disease called thalassaemia. It is caused by genetic mutations of the haemoglobin chain genes, which shorten the lifespan of red blood cells. When bone marrow stem cells decrease in number, proliferate abnormally or are replaced by abnormal cells, or when myelofibrosis occurs, the condition of aplastic anaemia may develop. The production of red blood cells can also be affected by insufficient thyroidhormone secretion, kidney failure, or the impact of radiotherapy, chemotherapy, medicines or infection. Anaemia may also be caused by haemolysis where a large number of red blood cells are destroyed by patients’ own antibodies, transfusion of red blood cells with inconsistent blood type or medication, etc.
 
Q4. Do all anaemic patients require blood transfusion?
Not all anaemic patients need blood transfusions, especially if they have no symptoms such as dizziness, pale skin or cold hands and feet. In general, acute anaemic patients with a haemoglobin level below 7 g/dL are indicated for blood transfusion. Older adults at or over 65, or those with heart or lung diseases are more prone to the effects of anaemia. They may require blood transfusions even if the haemoglobin level is over 7g/dL. Chronic anaemic patients may tolerate anaemia better and may not need blood transfusion even if the haemoglobin level drops below 7g/dL.
 
Q5. Apart from blood transfusion, are there other treatment options for anaemia?
Anaemia is a condition caused by other diseases. It is not a disease itself, and therefore it is best treated by targeting the underlying condition. Under certain specific circumstances, certain medications can be given as an alternative to blood transfusion for raising the haemoglobin in a short period of time. These medications include oral or intravenous iron supplement, oral or intramuscular vitamin B12, oral folate, subcutaneous erythropoietin or subcutaneous luspatercept.

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