What is ITP?
Immune thrombocytopenia (ITP)
ITP stands for immune thrombocytopenia. The disease was previously known as idiopathic thrombocytopenic purpura, and this term may still be used. If the condition persists for more than a year, it is called chronic immune thrombocytopenia. Thrombocytopenia that is not caused by a previous disease is known as primary ITP. If the disease is caused by another condition affecting the immune system (such as HIV), it is referred to as secondary ITP.
The word thrombocytopenia simply means a deficiency of thrombocytes, or platelets. ITP is a rare autoimmune disease characterised by fatigue and increased risk of bleeding caused by not having enough platelets in the blood. 1,2,3,4
What are platelets?
Platelets are tiny, colourless cell fragments in the blood that form clots which stop or prevent bleeding. They’re called platelets because when viewed through a microscope in their inactive state they resemble plates. A platelet measures about 2 microns (about 0.002 millimetres) in diameter – that’s about one-quarter of the diameter of a red blood cell. Platelets are made in our bone marrow and those that are not used in clotting usually survive for seven to ten days before being destroyed naturally in the body.
Platelets help the body form clots, growing sticky tentacles and adhering to each other
When a blood vessel becomes damaged it sends out a signal. When the platelets receive that signal, they respond by travelling to the area and transforming into their active state, growing sticky tentacles that make the platelets adhere to each other and form a clot.
The blood needs a sufficient platelet count in order to clot normally. A normal platelet count ranges from 150,000 to 450,000 platelets per cubic millimetre of blood. A person who has a platelet count below 150,000 is said to have thrombocytopenia. People with severe ITP may have a platelet count below 10,000.1
What is the difference between ITP and haemophilia?
ITP is not the same as haemophilia, although some of the symptoms are similar. The main differences are:
- Haemophilia is hereditary, while ITP is not believed to be hereditary and often has no clear cause.
- ITP, unlike haemophilia, can go into remission – meaning that the symptoms can go away.
- Haemophilia is a bleeding disorder in which the blood does not clot properly; people with ITP have reduced platelets but the rest of their clotting mechanism works normally.
How common is ITP?
The incidence of new diagnoses is around 3.3 for every 100,000 people each year.2 The prevalence of ITP among adults – how many people have the condition at any one time – is in the order of 9.5 cases per 100,000. Worldwide, this would lead to a total of more than 750,000 people affected by ITP. More women are affected than men.
Treating ITP
When treating ITP, it is important to see the bigger picture and see the patient as a whole person, considering the full range of symptoms can that affect quality of life.
ITP patients in a number of countries around the world have taken the initiative to set up advocacy organisations, running awareness campaigns to increase visibility of the disease and offering practical support to people who live with ITP.
References
2 NORD, National Organization for Rare Disorders
https://rarediseases.org/rare-diseases/immune-thrombocytopenia/
3 Blood Adv 2019 Nov 26;3(22):3780-3817. doi: 10.1182/bloodadvances.2019000812. Updated international consensus report on the investigation and management of primary immune thrombocytopenia. D. Provan et al.
4 Immune Thrombocytopenia (ITP): Current Limitations in Patient Management. Terrell DR, Neunert CE, Cooper N, Heitink-Pollé KM, Kruse C, Imbach P, Kühne T, Ghanima W. Medicina (Kaunas). 2020 Nov 30;56(12):667. doi: 10.3390/medicina56120667. PMID: 33266286