Essential thrombocythaemia (ET)
Essential thrombocythaemia (ET) symptoms and diagnosis
It’s likely that you won’t have any symptoms at all before or when you’re diagnosed. That’s why so many people with ET are diagnosed after a routine blood test.
Older people and people with very high platelet counts get symptoms more often. Here are some symptoms you may experience:
- persistent or repeated headaches,
- disturbed vision (described by some patients as light shows or silent migraines),
- dizziness or ringing in your ears,
- bruising or bleeding easily (including heavy periods in women or nose bleeds),
- erythromelalgia (pain and redness in some or all of your hands, feet, arms, legs, ears and face), and
- your fingers or toes being blue, or feeling cold.
Thrombosis (blood clots)
People with ET are at an increased risk of thrombosis (blood clots). Thrombosis is a serious condition and may occur in the blood vessels of your:
- brain (causing a stroke or mini-stroke/TIA – transient ischaemic attack),
- eyes (causing blurred vision or loss of vision),
- heart (causing a heart attack),
Blood clots can also form in the veins of your legs. This is known as deep vein thrombosis or DVT. Clots can also form in the vessels in your abdomen (stomach area). If a clot dislodges and travels to the lung it may cause a pulmonary embolism (or PE). This usually results in low oxygen levels, sharp chest pain and shortness of breath. In some cases, this may be fatal.
The risk of clots is higher in older patients who also have other medical conditions such as diabetes or heart problems, or in patients who have had clots in the past. However, the risk of thrombosis is reduced if your ET is treated appropriately.
You’ll have regular blood tests so your healthcare team can monitor your condition and spot any early signs of a blood clot.
Get urgent medical help if you have any of these symptoms:
- sudden chest pain or shortness of breath
- swelling and/or pain in your calf on one side
- slurred or abnormal speech, weakness in your arms or legs, or drooping on one side of your face
- swelling in your abdomen or jaundice (your skin turning a yellow colour)
- sudden loss of vision in one eye.
Tests for ET
Most people are suspected of having ET after a routine blood test or by going to their GP with symptoms. You’d then have a set of tests to confirm the diagnosis of ET.
In ET there’s an abnormally high level of platelets in the blood. A blood test known as a full blood count will detect if your platelet count is higher than normal.
For this test, a small sample of your blood will be taken, then the cells will be studied under a microscope in a laboratory.
DNA from one of your blood samples will be used to test for genetic faults to the JAK2, CALR and MPL genes. Around 60% of ET patients have a fault in the JAK2 gene. However, some people won’t have one of these faults, so a diagnosis can’t always be confirmed after these tests.
Some people need tests on their bone marrow before their doctors can make a diagnosis. This helps to rule out any other bone marrow problems such as myelofibrosis (MF).
A small amount of bone marrow is taken using a needle from the hip bone. You don’t need to stay overnight in hospital for this; you can have it as an outpatient using local anaesthetic or mild sedation. It’s usually quite quick but will be uncomfortable while the sample’s being taken from the marrow; you can take painkillers if you need to. Your doctors will then look at the bone marrow sample under a microscope to assess it and look for any disease which might be in it.
Find out more about bone marrow biopsies.
Other causes of high platelet counts
If tests show that you don’t have any of the genetic faults linked with ET, your doctor will need to rule out other possible causes of a high platelet count before confirming a diagnosis. Other causes of a high platelet count can include:
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