What Causes Thrombocythemia and
Thrombocytosis?
Primary Thrombocythemia
In this condition, faulty stem cells in the bone
marrow make too many platelets. What causes this to happen usually isn't known.
When this process occurs without affecting other blood cells, it's called
essential thrombocythemia.
A rare form of thrombocythemia is inherited.
("Inherited" means the condition is passed from parents to children.) In some
cases, a genetic mutation may cause the condition.
In primary thrombocythemia, the platelets aren't
normal. They may form blood clots, or, surprisingly, cause bleeding when they
don't work properly.
Bleeding also can occur because of a condition that
develops called
von
Willebrand disease. This condition affects the blood clotting process.
After many years, scarring of the bone marrow can
occur.
Secondary Thrombocytosis
This condition occurs when another disease,
condition, or outside factor causes the platelet count to rise. For example, 35
percent of people who have high platelet counts also have cancermostly
lung, gastrointestinal, breast, ovarian, and lymphoma. Sometimes a high
platelet count is the first sign of cancer.
Unlike primary thrombocythemia, the platelets in
secondary thrombocytosis usually are normal.
Conditions or factors that can cause a high platelet
count are:
Some conditions can lead to a high platelet count
that lasts for only a short time. These include:
- Recovery from serious loss of blood
- Recovery from a very low platelet count caused by
excessive alcohol use and lack of vitamin B12 or folate
- Acute infection or inflammation
- Response to physical activity
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