Omicron and Thrombosis in Children: Cause for Concern?

To the Editors:

We have recently diagnosed 2 cases of cerebral venous sinus thrombosis in children with a positive severe acute respiratory syndrome (SARS)-CoV-2 reverse transcription polymerase chain reaction during the emergence of the Omicron variant in our country.

Large studies have proven that coronavirus disease 2019 (COVID-19) can cause, in severe cases, thrombotic complications in adults.[1] However, these hematologic disorders have been so far exceptional in children with the last predominant virus variants.[2,3] Since the beginning of the pandemic, only 4 cases of venous thrombosis have been reported in Spain in children with SARS-CoV-2 infection.[2] Two of these children associated several significant thrombotic risk factors, and the other 2 were female teenagers, one of whom had lupus anticoagulants. Nevertheless, since the emergence of the Omicron variant, 2 new cases of thrombosis, in a 7- and 11-year-old healthy boys were recorded in our country in December 2021.

In these 2 new cases, severe cerebral venous sinus thrombosis occurred in relation with a concomitant complicated sinusitis, requiring both of them intensive care unit admission at diagnosis. In the case of the 7-year-old patient, cavernous sinus and both internal jugular veins were affected (Fig. 1). The oldest patient presented a superior sagittal sinus thrombosis (Fig. 2). Both patients had a close contact with a COVID-19 case and a positive SARS-CoV-2 reverse transcription polymerase chain reaction when the hematologic disorders were diagnosed. The Omicron variant was confirmed by genomic sequencing in the first case. In the other patient, the virus could not be sequenced but infection by the Omicron variant is highly likely, as this variant represented during the week (December 20–26) around the 80% of cases of COVID-19.[4]

FIGURE 1.

Axial enhanced computed tomography (CT) show cavernous sinus and both internal jugular veins thrombosis. (A) Thrombosis of bilateral internal jugular veins evidenced by intraluminal nonocclusive filling defects and (B) filling defects in both cavernous sinuses and irregularity of the intracavernous internal carotid arteries (arrowheads).

FIGURE 2.

Subacute thrombus of the superior sagittal sinus. A, Sagittal T1-weighted magnetic resonance (MR) image and multiplanar reconstructions (right), (B) coronal T2-weighted, and (C) axial fluid-attenuated inversion recovery MR images show an area of abnormal increased signal intensity in the anterior part of the superior sagittal sinus (arrows).

Both cases were treated with endoscopic sinus surgery, intravenous broad-spectrum antibiotics, and anticoagulation therapy. The evolution was favorable, and they were discharged after 2 weeks of admission with oral antibiotics and anticoagulation treatment, which will be continued for at least three months. Thrombophilia workup was performed in both patients with normal results.

These 2 new cases of thrombosis in such a short period of time coinciding with the emergence of the Omicron variant, make us wonder whether this is just a coincidence or whether this new variant is associated with an increased risk of thrombus formation. More studies are needed to analyze this possible association, but meanwhile pediatricians must be aware of similar cases in children with no comorbidities during the Omicron outbreak.