Mononucleosis Can Cause Thrombocytopenia
Yes, infectious mononucleosis (mono) can cause thrombocytopenia (decreased platelet count), which is a rare but recognized complication of Epstein-Barr virus infection. 1, 2, 3
Epidemiology and Mechanism
- Severe thrombocytopenia is an uncommon complication of infectious mononucleosis, with an incidence of less than 1% of cases 1
- The mechanism appears to be immunologic or consumptive in nature, as evidenced by increased bone marrow megakaryocytes despite peripheral thrombocytopenia 1
- Platelet autoantibodies have been detected in some patients with mono-associated thrombocytopenia, suggesting an immune-mediated process similar to immune thrombocytopenia (ITP) 3, 4
Clinical Presentation
- Thrombocytopenia in mono can range from mild to severe, with platelet counts as low as 3-25 × 10⁹/L in severe cases 3
- Some patients may present primarily with thrombocytopenia and bleeding symptoms without the classic signs of infectious mononucleosis 2
- The condition can be mistaken for primary immune thrombocytopenia (ITP) or even acute leukemia before the diagnosis of EBV infection is confirmed 3
Diagnosis
- Diagnosis requires confirmation of both thrombocytopenia and acute EBV infection through serological testing 2
- Bone marrow examination typically shows normal or increased megakaryocytes, consistent with peripheral destruction rather than production failure 1
- Testing for platelet autoantibodies may be positive in some cases but is not required for diagnosis 3, 4
Treatment
- For severe thrombocytopenia associated with mono (platelet count <20,000/μL) or in patients with bleeding symptoms, treatment is often required 1, 2
- Corticosteroids (prednisone 1 mg/kg/day or methylprednisolone) are typically used as first-line therapy 1, 2, 5
- Intravenous immunoglobulin (IVIG) at 400 mg/kg/day for 2-5 days has shown effectiveness in cases refractory to corticosteroid therapy 1, 4
- Platelet transfusions may be considered in cases of severe bleeding but are generally not required 3
Prognosis
- The prognosis for mono-associated thrombocytopenia is generally good, with most patients recovering completely without serious hemorrhagic complications 3
- Some patients may experience relapse of thrombocytopenia after initial improvement, requiring additional treatment courses 1
- Fatal outcomes are extremely rare but have been reported in cases of severe hemorrhage 4
Clinical Pearls and Pitfalls
- Consider EBV infection in any patient presenting with acute thrombocytopenia, especially adolescents and young adults 2, 5
- Initial presentation may mimic primary ITP, and the diagnosis of mono may be missed if specific EBV serology is not performed 3
- Response to treatment with IVIG appears to be independent of whether platelet autoantibodies are detectable 4
- Thrombocytopenia may persist or recur even after other symptoms of mono have resolved, requiring continued monitoring of platelet counts 1