What is the relationship between thrombocytopenia and infection?

From the Guidelines

Thrombocytopenia during infection requires prompt medical attention, as infections can worsen thrombocytopenia and low platelets can increase bleeding risk, and treatment should focus on addressing the underlying infection while monitoring platelet levels 1. The relationship between thrombocytopenia and infection is complex, with many infections triggering immune responses that can destroy platelets, while some pathogens directly damage platelets or suppress bone marrow production. Certain infections like dengue, malaria, and sepsis are particularly associated with thrombocytopenia. Some key points to consider in the management of thrombocytopenia during infection include:

• Monitoring platelet levels closely, especially in patients with severe infections or those at high risk of bleeding
• Avoiding medications that can worsen bleeding risk, such as aspirin and NSAIDs
• Considering platelet transfusions for severe thrombocytopenia (platelets below 10,000-20,000/μL) with active bleeding
• Using specific antibiotics for the underlying infection and occasionally corticosteroids like prednisone to reduce immune-mediated platelet destruction Recovery of platelet counts typically follows successful treatment of the underlying infection, though this may take 1-2 weeks after the infection resolves. It's worth noting that thrombocytopenia can be an indicator of sepsis mortality, but this is not always the case, especially in COVID-19 patients, where thrombocytopenia at admission may not be a consistent prognosticator 1. In terms of specific guidelines, the American Society of Clinical Oncology recommends considering platelet transfusions for patients with solid tumors at a threshold of 10,000/mL platelets or less, although this may vary depending on the individual patient's risk factors and clinical situation 1. Overall, the management of thrombocytopenia during infection requires a careful and individualized approach, taking into account the underlying cause of the infection, the severity of the thrombocytopenia, and the patient's overall clinical condition.

From the FDA Drug Label

In patients with renal impairment, thrombocytopenia has been observed but no clinical bleeding reported [ see Dosage and Administration (2.2), Adverse Reactions (6.1), Use in Specific Populations (8.5) and (8.6), and Clinical Pharmacology (12.3)].

The relationship between thrombocytopenia and infection is that thrombocytopenia has been observed in patients with renal impairment, which can be a complication of severe infection. However, there is no direct information in the drug label that supports a causal relationship between thrombocytopenia and infection.

• Key points:
  • Thrombocytopenia has been observed in patients with renal impairment.
  • Renal impairment can be a complication of severe infection.
  • No clinical bleeding has been reported in patients with thrombocytopenia 2.

From the Research

Relationship Between Thrombocytopenia and Infection

• Thrombocytopenia can be caused by various factors, including infections, and is characterized by a low platelet count of less than 150 × 10^3 per μL 3.
• Infections such as HIV, hepatitis C virus, dengue, malaria, scrub typhus, and other rickettsial infections can cause thrombocytopenia with or without disseminated intravascular coagulation 4, 5.
• Thrombocytopenia in bacterial infections can occur as a part of sepsis with disseminated intravascular coagulation, and patients with sepsis may also develop hemophagocytic histiocytosis with phagocytosis of platelets and leucocytes in the bone marrow histiocytes 5.
• Recombinant human thrombopoietin (rhTPO) has been shown to improve platelet counts and reduce platelet transfusion possibility among patients with severe sepsis and thrombocytopenia 6.
• Certain viral infections, such as herpes simplex virus-2 (HSV-2), can also cause thrombocytopenia, and treatment with antiviral medications like acyclovir can lead to improvement in platelet counts 7.

Mechanisms of Thrombocytopenia in Infections

• Infections can cause a decrease in platelet count due to effects on platelet production and platelet survival 5.
• Elevated platelet-associated IgG has been implicated in thrombocytopenia caused by bacterial infections 5.
• Platelets tend to adhere to damaged vascular surfaces in meningococcemia, contributing to thrombocytopenia 5.

Clinical Implications

• Thrombocytopenia can increase the risk of bleeding, and patients with severe thrombocytopenia may require platelet transfusions or other treatments to manage bleeding risk 3, 6.
• Identifying the underlying cause of thrombocytopenia is crucial for appropriate management, and treatment of the underlying infection can lead to improvement in platelet counts 4, 5, 7.