Too few platelets (thrombocytopenia)

What is it about ?

A platelet (thrombocyte) is a blood cell that plays a role in blood clotting. When bleeding, several platelets clump together and form a clot that stops the bleeding. Each cubic millimeter (mm³) blood normally contains between 150,000 and 360,000 platelets.

A lack of platelets (thrombocytopenia) is associated with an increased risk of bleeding. We speak of lack when the number of platelets in the blood is less than 150,000 per cubic millimeter (mm³).

The causes can be subdivided into 3 main groups:

• A reduced production of platelets in the bone marrow. This condition can be congenital or acquired (non-congenital).
• A congenital lack of platelets is very rare.
• In the case of an acquired deficiency, the cause comes from a disease or an external factor:
• Destruction of the bone marrow (leukemia, cancer, infection …);
• Inhibition of platelet production (radiotherapy or chemotherapy);
• Adverse drug reactions (eg certain diuretics, certain antibiotics, etc.);
• Deficiency of vitamins and other trace elements or essential nutrients (vitamin B12 or folic acid);
• Viral infection ;
• Excessive consumption of alcohol ;
• Pregnancy.
• A increased platelet consumption may also be congenital or acquired, and may or may not be due to a dysfunction of the immune system.
• The congenital causes are for example a high consumption of platelets in premature babies or in the event of arterial hypertension in the pregnant woman of pre-eclampsia;
• Acquired causes include a number of blood diseases, side effects of drugs and a reaction to a blood transfusion.
• Increased storage and destruction of platelets following an increase in the size of the spleen (enlarged spleen).

In addition, loss of platelets can also occur with severe bleeding. This lack of platelets is temporary and the situation spontaneously returns to normal.

It also happens sometimes that the measurements taken in the laboratory are falsely reduced because the platelets have stuck to each other in the blood sample.

How to recognize it?

The main characteristic of a lack of platelets is an increased risk of bleeding. This does not mean that there is necessarily bleeding somewhere in the body, but that the risk of spontaneous bleeding is greatly increased. The lower the platelet count, the greater the risk of bleeding, especially when the platelet count is less than 50,000 cubic millimeter (mm³).

Usually, bleeding begins in the gums and lining of the nose. Women may notice that their period is unusually heavy. You may also bleed from the digestive tract, which is manifested by vomiting blood or having blood in the stool. On the skin, bruises and small red or purple dots may appear.

Sometimes it is difficult to stop the bleeding.

How is the diagnosis made?

The doctor will consider a lack of platelets based on your complaints. Blood tests will confirm the diagnosis and show other possible abnormalities. Physical examination may show an enlarged spleen. If necessary, a bone marrow exam will be done.

What can your doctor do?

Follow-up and treatment depend on the cause, the total number of platelets, and whether or not symptoms are present. A lack of platelets can be caused by many medications. Your doctor will take this into account when prescribing medication. Paracetamol is harmless. But beware of anti-inflammatory drugs and aspirin!

If the number of platelets is between 100,000 and 150,000 per cubic millimeter (mm3) , that the remainder of the blood test is normal and that there are no symptoms, no treatment is necessary. The doctor will do a blood test every two to three months. Follow-up stops when the platelet count stops decreasing and no underlying disease can be demonstrated. If possible, drugs that cause platelet deficiency are avoided.

If the number of platelets is less than 100,000 per cubic millimeter (mm3) and there are no symptoms, the doctor will review the list of medications. A blood test will be taken automatically and supplemented, if necessary, by an examination of the bone marrow. In the absence of sufficient improvement, you will be referred to a specialist in blood diseases (hematologist).

In case of bleeding, you will be sent to hospital immediately to find and treat the possible cause.

Cortisone is used to treat bleeding skin in adults. This treatment is initiated and monitored by a specialist. In one third to one half of cases, the response to treatment is good (the platelet count rises above 100,000 cubic millimeter (mm³)). The drug is then gradually reduced to the lowest effective dose.
Medicines that prevent blood clots from breaking down (fibrinolysis inhibitors) reduce excessive bleeding from the mucous membranes and abnormal vaginal bleeding.

Blood transfusions can be helpful if the body does not make antibodies against the platelets. Transfusions of red blood cells, fresh frozen plasma and platelets are used to treat massive bleeding. Sometimes drugs are given that work on the immune system.

Consideration may be given to removing the spleen by surgery.

Want to know more?

• The spinal and lumbar punctures, here, Where to find on this page of Cliniques St Luc UCL

Source

Foreign clinical practice guide ‘Thrombocytopenia’ (2000), updated on 25.04.2017 and adapted to the Belgian context on 01.07.2017 – ebpracticenet