COVID-19 vaccine (Ad26.COV2.S), an unlikely culprit of portal vein thrombosis in a middle-aged man

While vaccination is the single most effective intervention to prevent spread of COVID-19, rare thromboembolic events have been reported following vaccination with COVID-19 vaccines ChAdOx1 nCOV-19 (AstraZeneca) and Ad26.COV2·S (Johnson & Johnson/Janssen). We present here a case of one such patient who received Ad26.COV2–S (recombinant) JanssenCOVID_19 vaccine. A 55-year-old male presented with a two week history of abdominal pain, nausea, vomiting, and distention. He received the Ad26.COV2–S (recombinant) JanssenCOVID_19 vaccine, one month before onset of symptoms. On presentation, lab results revealed hyponatremia, lactic acidosis, and leukocytosis. CT abdomen and pelvis with contrast revealed moderate circumferential bowel wall thickening, prominent mesenteric vessels present, and a portal vein thrombus extending to the superior mesenteric and splenic veins. An extensive hypercoagulable workup was negative. Patient's history revealed he was a frequent airline passenger but was otherwise negative. Additional etiologies were examined before associating the COVID-19 vaccine with thrombosis and the penultimate diagnosis was only reached by exclusion of other causes after initial evaluation and further outpatient follow up.