What is the approach for evaluating thrombocytopenia?

From the Guidelines

The evaluation of thrombocytopenia should begin with confirming the low platelet count through repeat testing to rule out pseudothrombocytopenia, followed by a thorough history and physical examination, as recommended by the most recent guidelines 1. The approach to evaluating thrombocytopenia involves several key steps, including:

• Confirming the low platelet count through repeat testing to rule out pseudothrombocytopenia
• Conducting a thorough history and physical examination to identify potential causes of thrombocytopenia, such as medication use, recent infections, bleeding symptoms, family history, and alcohol use
• Laboratory testing, including a complete blood count with peripheral smear examination to assess platelet morphology and other cell lines
• Additional first-line tests, such as liver function tests, renal function tests, coagulation studies (PT/INR, PTT), and consideration of HIV testing
• If the cause remains unclear, second-line investigations may include bone marrow examination, testing for specific antibodies (anti-platelet antibodies), and specialized tests based on clinical suspicion, such as ADAMTS13 activity for TTP or heparin-induced antibodies if relevant The pattern of thrombocytopenia can help distinguish between decreased production (associated with abnormalities in other cell lines) versus increased destruction (isolated thrombocytopenia with normal bone marrow) 1. Management depends on the underlying cause, severity of thrombocytopenia, and presence of bleeding, with urgent evaluation warranted for platelet counts below 20,000/μL or in patients with active bleeding, as these situations may require immediate intervention 1. It is also important to consider the patient's lifestyle and individual risk factors when determining the need for platelet transfusion, as some patients may be at higher risk of bleeding due to their occupation or activities 1.

From the FDA Drug Label

Use the lowest dose of Nplate to achieve and maintain a platelet count ≥ 50 × 10^9/L as necessary to reduce the risk for bleeding. Obtain complete blood counts (CBCs), including platelet counts, weekly during the dose adjustment phase of Nplate therapy and then monthly following establishment of a stable Nplate dose. For Adult Patients with ITP The initial dose of Nplate is 1 mcg/kg For Pediatric Patients with ITP The initial dose of Nplate is 1 mcg/kg

The approach for evaluating thrombocytopenia involves:

• Using the lowest dose of Nplate to achieve and maintain a platelet count ≥ 50 × 10^9/L
• Obtaining complete blood counts (CBCs), including platelet counts, weekly during the dose adjustment phase of Nplate therapy
• Adjusting the dose based on changes in platelet counts
• Monitoring for thrombotic/thromboembolic complications and loss of response to Nplate 2

From the Research

Evaluation Approach

The approach to evaluating thrombocytopenia involves several steps, including:

• Excluding pseudothrombocytopenia by collecting blood in a tube containing heparin or sodium citrate and repeating the platelet count 3
• Distinguishing acute from chronic thrombocytopenia by obtaining or reviewing previous platelet counts 3
• Identifying the underlying cause of thrombocytopenia, which can be due to decreased platelet production, increased destruction, splenic sequestration, or dilution or clumping 3

Common Causes

Common causes of thrombocytopenia include:

• Immune thrombocytopenia (ITP) 4
• Drug-induced thrombocytopenia 3, 5
• Hepatic disease 3
• Heparin-induced thrombocytopenia 3, 5
• Thrombotic microangiopathies 3, 5

Management

Management of thrombocytopenia depends on the underlying cause and severity of the condition, and may include:

• Platelet transfusions for patients with active hemorrhage or platelet counts less than 10 × 10^3 per μL 3
• Corticosteroids as initial treatment for newly diagnosed ITP 4
• Thrombopoietin receptor agonists (TPO-RAs), rituximab, and fostamatinib as subsequent medical therapies for ITP 4
• Splenectomy for patients failing medical therapy 4

Patient Care

Patients with thrombocytopenia should:

• Adhere to activity restrictions to avoid trauma-associated bleeding if platelet counts are less than 50 × 10^3 per μL 3
• Ensure adequate platelet counts to decrease bleeding risk before invasive procedures, which may require a platelet transfusion 3