What causes thrombocytopenia (low platelet count)?

From the Guidelines

Low platelets, or thrombocytopenia, can be caused by several factors, with hypersplenism being a common cause in patients with advanced cirrhosis, leading to thrombopenia due to portal hypertension, intra-splenic sequestration, myeloid toxicity, anti-platelet antibody, and/or low levels of thrombopoietin, as noted in the 2024 study 1.

Causes of Thrombocytopenia

• Bone marrow disorders that decrease platelet production, such as leukemia, aplastic anemia, or vitamin B12 deficiency
• Increased destruction of platelets by the immune system, such as immune thrombocytopenia or ITP
• Medications, like heparin, quinine, sulfonamides, and certain antibiotics, which can cause thrombocytopenia, as seen in heparin-induced thrombocytopenia (HIT) 1
• Infections, particularly viral infections like HIV, hepatitis C, or COVID-19
• Consumption of platelets during conditions like disseminated intravascular coagulation (DIC)
• Pregnancy complications, alcohol abuse, cirrhosis of the liver, and certain genetic disorders

Management of Thrombocytopenia

• Treatment depends on the underlying cause and may include stopping problematic medications, treating infections, using corticosteroids like prednisone, immune globulin infusions, or medications that stimulate platelet production like avatrombopag and lusutrombopag, as recommended in the 2024 study 1
• In severe cases with bleeding, platelet transfusions may be necessary, and rotational thromboelastometry may be superior to routine coagulation laboratory tests in predicting the risk of bleeding 1
• The management of platelets should integrate correction of coagulation factors, and blood products should be used sparingly to avoid side effects, including fluid overload 1

From the FDA Drug Label

Heparin-induced thrombocytopenia (HIT) is a serious antibody-mediated reaction. HIT occurs in patients treated with heparin and is due to the development of antibodies to a platelet Factor 4­ heparin complex that induce in vivo platelet aggregation Thrombocytopenia in patients receiving heparin has been reported at frequencies up to 30%. It can occur 2 to 20 days (average 5 to 9) following the onset of heparin therapy.

Low platelets (thrombocytopenia) can be caused by:

• Heparin-induced thrombocytopenia (HIT), a serious antibody-mediated reaction
• Heparin therapy, with reported frequencies up to 30% 2

From the Research

Causes of Low Platelets

Low platelets, also known as thrombocytopenia, can be caused by various factors. Some of the possible causes include:

• Autoimmune disorders, such as immune thrombocytopenic purpura (ITP), where the immune system produces antibodies that destroy platelets 3, 4, 5
• Iron deficiency, which can affect thrombopoiesis and lead to thrombocytopenia 6
• Other conditions, such as thrombotic thrombocytopenia purpura (TTP), heparin-induced thrombocytopenia (HIT), and antiphospholipid syndrome (APS), which are associated with immune-mediated pathogenesis and thrombocytopenia 7

Mechanisms of Thrombocytopenia

Thrombocytopenia can result from:

• Reduced life span of thrombocytes 3
• Decreased production of platelets in the bone marrow 3
• Increased destruction of platelets due to autoantibodies 3, 4, 5
• Impaired platelet production due to iron deficiency 6

Associated Conditions

Thrombocytopenia can be associated with other conditions, such as:

• Autoimmune disorders, such as ITP 3, 4, 5
• Hypercoagulability, which can increase the risk of thrombosis 7
• Other thrombocytopenic conditions, such as TTP, HIT, and APS 7