thrombocytopenie

Thrombocytopenie, or thrombocytopenia, is a condition characterized by a lower than normal platelet count in the blood. In adults, platelets normally range from about 150 to 450 x 10^9/L. Thrombocytopenie is defined as a platelet count below 150 x 10^9/L. The main clinical consequence is an increased risk of bleeding, especially mucocutaneous bleeding. Symptoms may include petechiae, easy bruising, nosebleeds or gum bleeding, and in severe cases gastrointestinal or intracranial hemorrhage. Bleeding risk rises as the platelet count falls, particularly below 50 x 10^9/L and more markedly below 20 x 10^9/L.

Causes and classification are typically described as decreased production, increased destruction or consumption, and sequestration. Decreased production can occur with bone marrow disorders (aplastic anemia, leukemia, myelodysplastic syndromes), nutritional deficiencies (vitamin B12, folate), or cytotoxic chemotherapy. Increased destruction includes immune thrombocytopenia (ITP), drug-induced immune thrombocytopenia, infections, and autoimmune diseases. Consumption occurs in disseminated intravascular coagulation or heavy bleeding. Splenomegaly can cause sequestration of platelets. Pregnancy-related thrombocytopenia is common and usually mild.

Diagnosis starts with a complete blood count confirming low platelets and a peripheral smear to exclude pseudothrombocytopenia. Additional tests are guided by suspected causes and may include coagulation studies, reticulocyte count, infection screening, iron studies, and bone marrow examination if marrow disease is suspected or the cause remains unclear.

Management depends on the underlying cause and the severity of thrombocytopenia. Many individuals with mild or asymptomatic thrombocytopenia require no specific treatment, along with avoidance of NSAIDs and other agents that impair platelets. Treatments for significant thrombocytopenia or active bleeding may include platelet transfusions, corticosteroids, intravenous immunoglobulin, rituximab, or thrombopoietin receptor agonists, and addressing the underlying condition. Prognosis varies with etiology; many cases related to reversible factors resolve, while chronic IT P may require ongoing management.