Polycythaemia
What is polycythaemia?
It can be hard to imagine that health problems might arise from having too much blood. But in polycythaemia this is exactly what happens.
Polycythaemia happens when there are too many red blood cells in the circulating blood. This makes the blood ‘thicker’, which can have the effect of ‘slowing up’ the circulation.
Red blood cells carry oxygen and sometimes the body makes excessive numbers in an attempt to compensate for situations where there is a lack of oxygen. Such situations include living at high altitudes (where there is less oxygen in the air), some heart diseases and lung problems. Many cigarette smokers have a mild degree of this type, known as ‘secondary’ polycythaemia.
But sometimes polycythaemia occurs in the absence of such underlying problems. In these cases, known as polycythaemia vera, there is an abnormality of the JAK 2 gene that helps control production of red blood cells in the bone marrow. This damage is not passed on to children — polycythaemia vera is not an inherited condition.
What are the symptoms of polycythaemia?
Polycythaemia produces a wide variety of symptoms which may arise in almost any part of the body. Among the common symptoms are headache, weakness, itching skin, dizziness, shortness of breath and blurred vision. Bruising and a tendency to bleed are also common. The most significant complication is thrombosis (blood clots).
Some people with polycythaemia have a very distinctive appearance. Their face may have a marked reddish-blue colour. This is particularly obvious on the lips, cheeks, ears and tip of the nose. This can be a very startling appearance and sufferers are often accused of being alcoholics. The body is usually not affected by this appearance, but the hands and feet may have a similar colouration.
What treatment is available?
The treatment of polycythaemia depends upon its severity and the symptoms it produces. Sometimes removing blood will help, although if this is done too often iron deficiency may occur. Special drugs, such as hydroxyurea and immunotherapy medicines, are now available which can suppress the overactivity in the tissues which make red blood cells.
Last Reviewed: 10 November 2008
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