A pediatric case of anti-PF4 antibody-induced cerebral venous sinus thrombosis and thrombocytopenia following adenovirus infection: a literature review

Abstract

Introduction

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a rare disorder caused by antibodies against platelet factor 4 (PF4) triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines using non-replicable adenoviral vectors. It emerged during the pandemic, with patients typically presenting with thrombosis at uncommon sites, thrombocytopenia, and elevated D-dimer levels. VITT antibodies and heparin-dependent antibodies bind to distinct PF4 epitopes. Recently, VITT-like clinical, laboratory, and anti-PF4 antibody features have also been observed in patients with adenoviral infections. Only four pediatric cases of cerebral venous sinus thrombosis (CVST) have been reported.

Case report

The patient was a previously healthy 2-year-old girl with no history of heparin exposure or SARS-CoV-2 vaccination. She presented with fever and was diagnosed with adenovirus infection. The fever resolved by day 4, but by day 6 she became increasingly lethargic and experienced vomiting. On day 12, Laboratory data showed severe thrombocytopenia and elevated D-dimer levels. Computed tomography revealed CVST along with a secondary hemorrhage in the right temporal lobe. She underwent hematoma removal with external/internal decompression and was started on continuous intravenous unfractionated heparin, and she was switched to warfarin. The thrombus decreased, platelet count spontaneously increased. Platelet activation assays using acute-phase serum identified a PF4-dependent platelet-activating antibody.

Conclusion

We report a case of CVST in a 2-year-old girl following adenovirus infection. Unlike heparin-induced thrombocytopenia, where heparin exacerbates the condition, it is effective here by competitively inhibiting anti-PF4 antibody binding. In patients with prior adenovirus infection presenting with CVST and thrombocytopenia, anti-PF4 disorders should be considered.