How MPNs affect your body

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Thicker blood and/or higher number of platelets may cause blood clots in the arteries that interfere with the blood and oxygen supply to the brain, and could result in a stroke.

In polycythaemia vera, a lack of oxygen-rich blood reaching the heart, may result in heart failure or angina (chest pain or discomfort).

In polycythaemia vera, extra red blood cells make blood thicker and move more slowly, which may lead to clots. Excess bleeding and bruising are also possible. In essential thrombocythaemia, excess platelets are produced, which may also lead to blood clots. Blood clots may affect the blood and oxygen supply to the heart (heart attacks), brain (stroke), kidney and liver. In myelofibrosis, mutated blood stem cells tend to result in a lack of red blood cells, which may result in anaemia, leaving you feeling tired, weak and short of breath.

Myelofibrosis and polycythaemia vera: Liver enlargement (hepatomegaly) may cause abdominal discomfort. This is caused by the body finding alternative organs to make blood cells.

Myelofibrosis and polycythaemia vera affect the bone marrow, and its ability to make red blood cells. The spleen may take over producing blood, causing it to enlarge (a condition known as splenomegaly). An enlarged spleen may put pressure on the stomach, causing a feeling of fullness, indigestion, abdominal pain or discomfort and loss of appetite (leading to weight loss).

Myelofibrosis: Hardening of bone marrow and inflammation of the connective tissue around bones, may lead to severe bone/joint pain.

Myelofibrosis may cause painful swelling in a single joint (gouty arthritis) – usually the big toe – due to build-up of uric acid, a by-product of extra blood cells.

Polycythaemia vera: High red cell count may cause a red (ruddy) complexion and reddening of palms, soles of feet, ear lobes, mucous membranes and eyes. Excessive sweating, particularly at night (night sweats) and itching (also known as pruritus) can also be symptoms of MPNs.

Polycythaemia vera and essential thrombocythaemia may result in a rare condition known as erythromelalgia. It can cause an intense, burning pain, and an increased skin temperature in the feet (and sometimes the hands).