Thrombocytopenia: Nursing

Thrombocytopenia is when there’s a low number of platelets, also known as thrombocytes, in the blood. Normally, there are between 150,000 and 450,000 thrombocytes per microliter of blood; while in thrombocytopenia, this number goes below 150,000 cells per microliter. Remember that platelets are involved in blood clotting, so with thrombocytopenia, clients have an increased risk of bleeding.

But let’s start with some basic physiology of platelets, which form in the bone marrow. Although often called cells, platelets are actually small fragments of megakaryocytes, which themselves derive from hematopoietic stem cells, that give rise to all types of blood cells. After they’re formed, platelets leave the bone marrow to enter the bloodstream, and almost 50% of them are stored in the spleen, while the remaining keep circulating through the vascular system.

Now, when there’s any kind of damage to a blood vessel, circulating platelets aggregate to form a platelet plug at the site of the injury. This process is also known as primary hemostasis, and it’s followed by secondary hemostasis. During secondary hemostasis, clotting factors come into play one after another, eventually cleaving the fibrinogen into fibrin, which forms a protein mesh. This protein mesh is like a giant net that wraps around the platelet plug and reinforces it, stopping the bleeding.

Now, based on the cause, thrombocytopenia can be subdivided into three main groups. The first group covers conditions associated with impaired platelet production, such as inherited thrombocytopenia; viral infections, like HIV and HCV infections; folate and vitamin B12 deficiencies; and aplastic anemia. Aplastic anemia is typically associated with bone marrow suppression, and it’s characterized by decreased production of platelets as well as red and white blood cells.

The second group covers thrombocytopenias caused by increased platelet destruction or consumption, which are further subdivided into non-immune and immune-mediated. Non-immune thrombocytopenias include thrombotic thrombocytopenic purpura or TTP, hemolytic-uremic syndrome, or HUS for short, and disseminated intravascular coagulation, or DIC. Moreover, these thrombocytopenias occur because of increased consumption of platelets during the formation of abnormal clots. As a result, there are fewer platelets left in circulation.