From the Guidelines
Low platelets, or thrombocytopenia, can cause increased bleeding risk and bruising, and the most recent and highest quality study recommends prophylactic platelet transfusion for a morning platelet count of 10 × 10^9 cells/L or less in patients with therapy-induced hypoproliferative thrombocytopenia. This condition occurs when platelet count falls below 150,000 platelets per microliter of blood. Common symptoms include easy or excessive bruising, prolonged bleeding from cuts, spontaneous bleeding from gums or nose, blood in urine or stool, and unusually heavy menstrual flows. Low platelets can result from decreased production in bone marrow (due to leukemia, certain medications, alcohol abuse, vitamin deficiencies), increased destruction (immune thrombocytopenia, medications, infections), or increased consumption (during severe infections or DIC) 1. Other causes include pregnancy complications, certain autoimmune disorders, and enlarged spleen.
Causes and Symptoms
- Decreased production in bone marrow: leukemia, certain medications, alcohol abuse, vitamin deficiencies
- Increased destruction: immune thrombocytopenia, medications, infections
- Increased consumption: severe infections or DIC
- Pregnancy complications, certain autoimmune disorders, and enlarged spleen
Treatment
Treatment depends on the underlying cause and may include:
- Stopping problematic medications
- Treating infections
- Immune suppressants for autoimmune causes
- Platelet transfusions in severe cases, with a threshold of 10 × 10^9 cells/L or less for prophylactic transfusion in patients with therapy-induced hypoproliferative thrombocytopenia 1
Platelet Transfusion Thresholds
- 10 × 10^9 cells/L or less for prophylactic transfusion in patients with therapy-induced hypoproliferative thrombocytopenia 1
- 20 × 10^9 cells/L for central venous catheter placement 1
- 50 × 10^9 cells/L for lumbar puncture or major elective nonneuraxial surgery 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. 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 HIT may progress to the development of venous and arterial thromboses, a condition referred to as heparin-induced thrombocytopenia with thrombosis (HITT).
Low platelet count causes include heparin-induced thrombocytopenia (HIT) which is a serious antibody-mediated reaction that occurs in patients treated with heparin 2.
- Key points:
- HIT is due to the development of antibodies to a platelet Factor 4 heparin complex
- HIT may progress to the development of venous and arterial thromboses
- Low platelet count can also be caused by other factors, but in the context of heparin use, HIT is a significant concern.
From the Research
Causes of Low Platelet Count
- Low platelet count, also known as thrombocytopenia, can occur due to decreased platelet production, increased destruction, splenic sequestration, or dilution or clumping 3
- Common causes of thrombocytopenia include infections, malignancy, liver disease, autoimmune disorders, disseminated intravascular coagulation, pregnancy, medications, and coagulation disorders 4
- Heparin-induced thrombocytopenia (HIT) is a relatively infrequent complication of heparin administration that can cause devastating thrombosis 5
- Immune thrombocytopenia (ITP) is an autoimmune disease characterized by platelet destruction and reduced platelet production resulting in decreased platelet level and an increased risk of bleeding 6
Risk Factors for Bleeding
- Platelet count thresholds associated with bleeding are < 20 × 10^9 L^-1 and < 10 × 10^9 L^-1 7
- Exposure to anticoagulants is a major risk factor for severe bleeding 7
- Female sex and exposure to non-steroidal anti-inflammatory drugs (NSAIDs) are also risk factors for bleeding 7
- A low platelet count is the main risk factor for mucosal bleeding 7
Treatment Options
- Treatment for thrombocytopenia is determined by the underlying cause of the condition 4
- 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 3
- Intravenous immunoglobulin (IVIG) may be an optimal treatment for patients with heparin-induced thrombocytopenia 5
- Novel drugs, such as rituximab, thrombopoietin receptor agonists, and cytotoxic drugs, may be used to treat refractory immune thrombocytopenia 6