In the human body system, especially in blood, there are key elements that are normally checked by medical professionals.One of the key blood components is platelets that control bleeding. The scientific term for platelets is thrombocytosis. The platelets make sure blood does not flow or leak outside the vascular system. This role makes them key components of blood and, therefore, vital for our body function.When blood has lower than normal number of platelets, it is known as thrombocytopenia. The platelets are made in the bone marrow as other blood cells. They circulate in blood vessel searching for damaged vascular components to be repaired.In situation when there is body injury, you notice bleeding that comes and stop after a while followed by a clot or drying of the bleeding site. This is mainly done by aggregation of platelets.Individuals with low level of platelets tend to suffer prolonged bleeding. However, bleeding can occur inside the body (internal bleeding), underneath the skin, and from the surface of the skin (external bleeding).Thrombocytopenia or low platelets can be fatal, especially if the bleeding is severe or occurs in the brain. In most cases the overall appearance for people with low platelets is good. I have seen people who are able to carry out their daily duties with platelets of 10 per micro liter yet the normal count ranges 150,000 to 450,000 per micro liter of blood. Platelets below 150,000 per micro liter are usually lower than normal. The risk is usually noticed the count becomes very low and in most cases less than or equal to 20,000 platelets per micro liter. Minor bleeding sometimes occurs when the count is less than 50,000 platelets per micro liter.There are factors that usually prompt a decrease in the number of platelets in the body. Since the platelets like other blood cells are produced in the bone marrow, the bone marrow might not be able to make enough platelets.There are also circumstances where the bone marrow makes enough platelets, but the body destroys them or uses them up. The spleen holds on to too many platelets. The spleen usually stores one-third of the body’s platelets. This is the reason why in cases of the spleen problems, there is marked thrombocytopenia.There are other causes that might lead to thrombocytopenia. For example, cancers like leukemia or lymphoma can damage the bone marrow and destroy blood stem cells. Cancer treatments, such as radiation and chemotherapy, also destroy the stem cells. Genetics can also play role in thrombocytopenia recurrence especially in some families.A plastic anemia is also another blood condition that lowers level of platelets in blood due to its destructive effect in the bone marrow.Viruses such as chickenpox, mumps, rubella, Epstein-Barr virus, or parvovirus can decrease the platelet count. Thrombocytopenia has also been seen in people exposed to HIV virus especially in poorly controlled cases.Heavy alcoholic takers have also been found to suffer episodes of low platelets especially those who do not feed well after drinking. They always need food supplements with iron, vitamin B12 and folates.A low platelet count can occur after blood poisoning from a widespread bacterial infection.Reactions to some drugs can make the body to destroy its platelets. It is now days seen in a few patients’ especially young children treated with quinine and antibiotics that contain sulfate compounds. Heparin is a medicine commonly used to prevent blood clots. But an immune reaction may trigger the medicine to cause blood clots and thrombocytopenia. This condition is called heparin-induced thrombocytopenia. This is a problem that is commonly seen in hospitals.Dr Joseph Kamugisha is a resident oncologist in Jerusalem, Israel