From the Guidelines
Low platelet count (thrombocytopenia) is primarily caused by decreased production, increased destruction, or sequestration of platelets, with common causes including bone marrow disorders, viral infections, medications, autoimmune conditions, and alcohol abuse, as noted in the 2019 American Society of Hematology guidelines for immune thrombocytopenia 1.
Causes of Thrombocytopenia
The causes of thrombocytopenia can be categorized into:
- Decreased production: bone marrow disorders such as leukemia, aplastic anemia, and myelodysplastic syndromes
- Increased destruction: autoimmune conditions like immune thrombocytopenic purpura (ITP) and lupus, as well as viral infections like HIV and hepatitis C
- Sequestration: hypersplenism and splenic sequestration Other causes include:
- Medications: heparin, quinine, certain antibiotics, and chemotherapy drugs
- Alcohol abuse
- Vitamin B12 or folate deficiency
- Pregnancy complications like HELLP syndrome and disseminated intravascular coagulation (DIC)
- Severe infections leading to sepsis
Management and Treatment
Management of thrombocytopenia depends on identifying and treating the underlying cause, which may involve:
- Stopping offending medications
- Treating infections
- Using medications like corticosteroids or immunoglobulins for immune-mediated causes
- Platelet transfusions for severe thrombocytopenia with active bleeding or before invasive procedures Regular monitoring of platelet counts is essential during treatment to assess response and adjust management accordingly, as recommended in the international consensus report on the investigation and management of primary immune thrombocytopenia 1.
From the FDA Drug Label
- 3 Heparin-Induced Thrombocytopenia and Heparin-Induced Thrombocytopenia and Thrombosis Heparin-induced thrombocytopenia (HIT) is a serious antibody-mediated reaction.
- 5 Thrombocytopenia Thrombocytopenia in patients receiving heparin has been reported at frequencies up to 30%.
Heparin can cause low platelet count (thrombocytopenia), with reported frequencies up to 30%. This can occur due to heparin-induced thrombocytopenia (HIT), a serious antibody-mediated reaction. Platelet counts should be obtained before and periodically during heparin therapy, and the medication should be discontinued if the count falls below 100,000/mm3 or if recurrent thrombosis develops 2.
From the Research
Causes of Low Platelet Count
- Heparin-induced thrombocytopenia (HIT) is an immune-mediated disorder caused by the development of antibodies to platelet factor 4 (PF4) and heparin, leading to a low platelet count 3, 4
- Immune thrombocytopenia (ITP) is a rare cause of thrombocytopenia, resulting from antibody-mediated platelet destruction combined with impaired platelet production 5, 6, 7
- Other factors that may contribute to a low platelet count include:
- Recent exposure to heparin, which can cause a rapid drop in platelet count due to preformed anti-heparin/PF4 antibodies 3
- Delayed onset of HIT, which can occur days or weeks after heparin has been discontinued 3
- Underlying medical conditions, such as autoimmune disorders or bone marrow disorders, which can increase the risk of thrombocytopenia 6, 7
Characteristics of Low Platelet Count
- Thrombocytopenia is typically moderate, with a median platelet count nadir of approximately 50 to 60 x 10(9) platelets/L in patients with HIT 3
- Severe thrombocytopenia can occur in patients with HIT, with high antibody levels and severe clinical outcomes, including disseminated intravascular coagulation with microvascular thrombosis 3
- ITP can present with isolated thrombocytopenia, with bleeding as the most common clinical manifestation 6, 7