What are the causes of thrombocytopenia (low platelet count)?

From the Guidelines

Thrombocytopenia should be managed based on its severity, cause, and symptoms, with a focus on addressing the underlying cause and preventing bleeding complications, as recommended by the most recent guidelines 1.

Diagnosis and Classification

Thrombocytopenia is characterized by a platelet count below 150,000 platelets per microliter, and its diagnosis involves distinguishing between true thrombocytopenia and pseudothrombocytopenia, which can occur due to laboratory errors or conditions such as EDTA-induced platelet agglutination 1. The classification of thrombocytopenia into mild, moderate, or severe is crucial for determining the appropriate management strategy.

Management Strategies

For mild cases of thrombocytopenia (platelet count >50,000/μL) without bleeding, observation may be sufficient, while for moderate to severe cases, addressing the underlying cause is essential, such as discontinuing offending medications or treating underlying infections 1. For immune thrombocytopenia (ITP), first-line treatment includes corticosteroids such as prednisone or intravenous immunoglobulin (IVIG) for rapid response in severe cases, with second-line options including thrombopoietin receptor agonists, rituximab, or splenectomy 1.

Prevention of Bleeding Complications

Patients with thrombocytopenia should avoid aspirin and NSAIDs, which can exacerbate bleeding, and seek immediate medical attention for signs of bleeding such as petechiae, bruising, or blood in urine or stool 1. Platelet transfusions are generally reserved for active bleeding or counts below 10,000/μL, and the management of cancer-associated thrombosis in patients with thrombocytopenia requires careful consideration of the competing risks of bleeding and recurrent VTE, as outlined in recent guidance from the SSC of the ISTH 1.

Key Considerations

The management of thrombocytopenia should be individualized based on the patient's specific circumstances, including their underlying medical conditions, lifestyle, and risk factors for bleeding or thrombosis, as emphasized in the international consensus report on the investigation and management of primary immune thrombocytopenia 1. By prioritizing the prevention of bleeding complications and addressing the underlying cause of thrombocytopenia, healthcare providers can improve patient outcomes and reduce the risk of morbidity and mortality associated with this condition.

From the Research

Definition and Causes of Thrombocytopenia

• Thrombocytopenia is a platelet count of less than 150 × 10^3 per μL and can occur from decreased platelet production, increased destruction, splenic sequestration, or dilution or clumping 2.
• Patients with isolated thrombocytopenia in the absence of systemic illness most likely have immune thrombocytopenia or drug-induced thrombocytopenia 2.

Symptoms and Risk of Bleeding

• Patients with a platelet count greater than 50 × 10^3 per μL are generally asymptomatic 2.
• Patients with platelet counts between 20 and 50 × 10^3 per μL may have mild skin manifestations such as petechiae, purpura, or ecchymosis 2.
• Patients with platelet counts of less than 10 × 10^3 per μL have a high risk of serious bleeding 2.

Diagnosis and Management

• The first step in evaluating thrombocytopenia is to exclude pseudothrombocytopenia by collecting blood in a tube containing heparin or sodium citrate and repeating the platelet count 2.
• Examination of the blood film is essential in the investigation of any patient with thrombocytopenia 3.
• Transfusion of platelets is recommended when patients have active hemorrhage or when platelet counts are less than 10 × 10^3 per μL, in addition to treatment (when possible) of underlying causative conditions 2.
• Antithrombotic therapy should not be withheld because of thrombocytopenia alone, as thrombocytopenia does not protect against thrombosis 3.

Specific Conditions

• Immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by isolated thrombocytopenia caused by increased platelet destruction and impaired platelet production 4.
• First-line therapies for ITP include corticosteroids, intravenous immunoglobulin, and anti-D immunoglobulin, while second-line therapies include splenectomy, rituximab, and thrombopoietin-receptor agonists 4.
• Acute thrombocytopenia can present with a wide variety of conditions, ranging from relatively benign and self-limiting to those that require urgent therapeutic intervention 5.