What is the diagnosis and management of thrombocytopenia (low platelet count)?

From the Guidelines

Thrombocytopenia, or low platelet count, should be managed based on the underlying cause and severity, with prophylactic platelet transfusions recommended for patients with therapy-induced hypoproliferative thrombocytopenia and a morning platelet count of 10 × 10^9 cells/L or less, as per the most recent guidelines 1.

Diagnosis of Thrombocytopenia

Thrombocytopenia is a condition characterized by a low platelet count, typically less than 150,000 platelets per microliter. The severity of thrombocytopenia varies, with mild cases (100,000-150,000 platelets) often requiring monitoring only, while severe cases (below 50,000) necessitate prompt treatment. Common causes of thrombocytopenia include:

• Medications (like heparin, quinine, sulfa antibiotics)
• Infections (viral, bacterial)
• Immune disorders (ITP, lupus)
• Bone marrow problems (leukemia, aplastic anemia)
• Pregnancy complications
• Alcohol abuse
• Vitamin deficiencies

Management of Thrombocytopenia

Treatment of thrombocytopenia depends on the underlying cause and severity. It may involve:

• Stopping certain medications
• Treating underlying infections
• Using corticosteroids like prednisone to reduce immune response
• Administering immune globulin
• Platelet transfusions in severe cases
• Medications like eltrombopag (Promacta) or romiplostim (Nplate) to boost platelet production
• Avoiding aspirin and NSAIDs, which affect platelet function
• Using soft toothbrushes, avoiding contact sports, and being careful with activities that could cause injury

Prophylactic Platelet Transfusions

Prophylactic platelet transfusions are recommended for patients with therapy-induced hypoproliferative thrombocytopenia and a morning platelet count of 10 × 10^9 cells/L or less, as per the American Society of Clinical Oncology clinical practice guideline update 1. The AABB also suggests prophylactic platelet transfusion for patients having elective central venous catheter placement with a platelet count less than 20 × 10^9 cells/L, and for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 10^9 cells/L 1. However, the quality of evidence for these recommendations is low to very low, and the strength of recommendation is weak.

Key Considerations

When managing thrombocytopenia, it is essential to consider the individual patient's risk factors for bleeding and the potential benefits and risks of platelet transfusions. The decision to transfuse platelets should be based on the patient's clinical condition, treatment modality, and the threshold platelet count, as recommended by the most recent guidelines 1.

From the FDA Drug Label

The efficacy and safety of eltrombopag in adult patients with persistent or chronic ITP were evaluated in three randomized, double-blind, placebo-controlled trials and in an open-label extension trial Nplate is indicated for the treatment of thrombocytopenia in: Adult patients with immune thrombocytopenia (ITP) who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy 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

The diagnosis of thrombocytopenia (low platelet count) is not directly addressed in the provided drug labels. The management of thrombocytopenia includes the use of:

• Eltrombopag for adult patients with persistent or chronic ITP who have had an insufficient response to other treatments
• Romiplostim for adult and pediatric patients with ITP who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy The dose of romiplostim should be adjusted to achieve and maintain a platelet count ≥ 50 × 10^9/L, with a maximum weekly dose of 10 mcg/kg 2. The dose of eltrombopag can be adjusted based on individual platelet counts, with a starting dose of 50 mg daily 3. Key points for management include:
• Using the lowest effective dose to reduce the risk of bleeding
• Monitoring platelet counts regularly to adjust the dose as needed
• Discontinuing treatment if the platelet count does not increase to a level sufficient to avoid clinically important bleeding 2

From the Research

Diagnosis of Thrombocytopenia

• Thrombocytopenia is defined as a platelet count of less than 150 × 10^3 per μL 4, 5, 6.
• The diagnosis of thrombocytopenia involves excluding pseudothrombocytopenia by collecting blood in a tube containing heparin or sodium citrate and repeating the platelet count 4.
• A history, physical examination, and laboratory studies can help differentiate patients who require immediate intervention from those who can be treated in the outpatient setting 4, 5.

Clinical Presentation of Thrombocytopenia

• Patients with a platelet count greater than 50 × 10^3 per μL are generally asymptomatic 4, 5.
• Patients with platelet counts between 20 and 50 × 10^3 per μL may have mild skin manifestations such as petechiae, purpura, or ecchymosis 4.
• Patients with platelet counts of less than 10 × 10^3 per μL have a high risk of serious bleeding 4, 5.
• A low platelet count is a strong and independent predictor of an adverse outcome in critically ill patients 7.

Management of Thrombocytopenia

• Treatment is based on the etiology and, in some cases, treating the secondary cause results in normalization of platelet counts 4, 5, 6.
• 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 of underlying causative conditions 4.
• Patients with platelet counts of less than 50 × 10^3 per μL should adhere to activity restrictions to avoid trauma-associated bleeding 4.
• Consultation with a hematologist should be considered if patients require hospitalization, if there is evidence of systemic disease, or if thrombocytopenia worsens despite initial treatment 5.

Causes of Thrombocytopenia

• Thrombocytopenia can occur from decreased platelet production, increased destruction, splenic sequestration, or dilution or clumping 4.
• Common causes of thrombocytopenia include infections, malignancy, liver disease, autoimmune disorders, disseminated intravascular coagulation, pregnancy, medications, and coagulation disorders 8, 5, 6.
• Patients with isolated thrombocytopenia in the absence of systemic illness most likely have immune thrombocytopenia or drug-induced thrombocytopenia 4.