Thrombocytopenia (low platelet count)
- Thrombocytopenia is generally defined as a platelet count of less than 150,000/µL.
- Mucosal bleeding. Epistaxis, gingival bleeding, rash or bruising on the skin, menorrhagia or abnormal vaginal bleeding in women, rectal bleeding (hematochezia or melena), hematuria, bleeding after surgeries, or dental procedures are common sign and symptoms.
Thrombocytopenia (low platelet count) is caused by a number of different factors that either reduce the production of platelets or increase the destruction of platelets.
The normal platelet count is usually between 150,000 to 400,000/µL. The number represents the balance between platelet production, storage/pooling, and degradation. Thrombocytopenia is generally defined as a platelet count of less than 150,000/µL. Platelets generally have a lifespan of about 7-10 days in peripheral blood and can be lower in cases of thrombocytopenia.
Platelets below 100,000. bleeding mucous membranes. bleeding internal organs.
Platelets below 20,000. serious bleeding risks.
Platelet counts are regulated by thrombopoietin, a hormone produced by the liver. This hormone acts on bone marrow stem cells to differentiate and mature into megakaryocytes(platelets precursors), contributing to the production of platelets. Thrombopoietin generally binds to c-Mpl receptor on platelets. In cases of low platelet counts, free thrombopoietin is more prevalent, and the free hormone increases megakaryocyte and platelet production. Conversely, free thrombopoietin levels decrease with higher platelet counts due to increased binding of thrombopoietin with platelet receptors, with subsequent clearance from circulation. Hence, platelet production decreases.
Broadly speaking, these can be divided into immune and non-immune causes.
Non-immune causes include:
- inherited causes of abnormalities of megakaryocyte development,
- infiltration of the bone marrow,
- liver disease,
Immunes causes include:
- Immune thrombocytopenia (ITP) is caused by antibody- or cell-mediated destruction and can be primary (where a cause is not identified) or secondary to infections,
- Autoimmunity or lymphoproliferative disorders.
Some oncologist divide thrombocytopenia into three broad mechanisms:
Decreased platelet production
Myeloproliferative or lymphoproliferative disorders (acute or chronic leukemias, myelofibrosis).
- Aplasia or hypoplasia (idiopathic, radiation, alcohol, or drugs – for example, chemotherapy, thiazide diuretics, and certain antibiotics).
- Ineffective hematopoiesis (MDS, severe megaloblastic anemia in the setting of B12 or folate deficiency).
Increased platelet destruction or utilization
- Immune Destruction: Idiopathic thrombocytopenic purpura (ITP), medication-induced (caused by dozens, if not hundreds of medications; for example, heparin, quinidine, sulfonamides), infection (HIV, hepatitis, CMV, EBV), Evans syndrome.
- Non-immune destruction: Thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), disseminated intravascular coagulation (DIC), preeclampsia/HELLP syndrome, IABP, hemangiomas, infection (bacterial, viral, malarial, tick-borne illnesses), sepsis.
Abnormal pooling or distribution
- Splenomegaly, massive transfusion.
What are the symptoms of thrombocytopenia?
Thrombocytopenia signs and symptoms may include:
- Easy or excessive bruising (purpura)
- Superficial bleeding into the skin that appears as a rash of pinpoint-sized reddish-purple spots (petechiae), usually on the lower legs
- Prolonged bleeding from cuts
- Bleeding from your gums or nose
- Blood in urine or stools
- Unusually heavy menstrual flows
- Enlarged spleen
How is thrombocytopenia diagnosed?
Detailed history and physical examination to help assess for possible causes, as well as manifestations of bleeding.
History of mucocutaneous bleeding – Since platelets are very important in hemostasis, a decrease in platelet count will predispose to mucosal bleeding. Epistaxis, gingival bleeding, rash or bruising on the skin, menorrhagia or abnormal vaginal bleeding in women, rectal bleeding (hematochezia or melena), hematuria, bleeding after surgeries, or dental procedures.
A Blood test or complete blood cell count determines the number of blood cells, including platelets, in a sample of your blood. In adults, normal platelet count is 150,000 to 450,000 platelets per microliter of blood. If the complete blood count finds you have fewer than 150,000 platelets, you have thrombocytopenia.
How is thrombocytopenia treated?
Patient with mild thrombocytopenia may not need treatment; they may not have symptoms or the condition clears up on its own.
Some Patients develop severe or long-term (chronic) thrombocytopenia. Depending on what’s causing your low platelet count, treatments may include:
- Treating the underlying cause of thrombocytopenia.
- Blood or platelet transfusions.
- If your condition is related to an immune system problem, your doctor may prescribe drugs to boost your platelet count. The first-choice drug may be a corticosteroid. If that doesn’t work, he or she may try stronger medications to suppress your immune system.
- Surgery to remove your spleen (splenectomy).
- Plasma exchange. Thrombotic thrombocytopenic purpura can result in a medical emergency requiring plasma exchange.
The information in this document does not replace a medical consultation. It is for personal guidance use only. We recommend that patients ask their doctors about what tests or types of treatments are needed for their type and stage of the disease.
- American Cancer Society
- The National Cancer Institute
- National Comprehensive Cancer Network
- American Academy of Gastroenterology
- National Institute of Health
- MD Anderson Cancer Center
- Memorial Sloan Kettering Cancer Center
- American Academy of Hematology