ABSTRACT
We present the case of a 39-year-old female who presented to University Hospitals of Leicester 14 days after the second dose of ChAdOx1 nCov-19 vaccine. Her presenting symptoms included skin rash, nausea, intermittent abdominal pain and occasional episodes of dizziness. Her past medical history included Type 2 Diabetes Mellitus and hidradenitis suppurativa. The first dose of ChAdOx1 nCov-19 vaccine had been administered on 27th February 2021, following which the patient reported flu like symptoms that resolved after four days and did not require further medical input. Following this, a preplanned surgical procedure to incise and drain a vulval abscess was performed on 17th May 2021. Preoperative testing performed on 13th May 2021 showed a normal platelet count of 219 × 10 9 /l. The second dose of ChAdOx1 nCov-19 vaccine was subsequently administered on 23rd May 2021. On presentation, examination revealed mild epigastric tenderness and features of classical thrombocytopenic rash affecting all limbs with no other associated bleeding. Initial blood results confirmed thrombocytopenia of 11 × 10 9 /l, with D-Dimer 14.26 μg/ml and fibrinogen 2.1 g/l. Blood film microscopy revealed an occasional schistocyte and microangiopathic haemolysis was considered. Treatment with plasmapheresis of 1.5 x plasma volume using Octaplas was administered. Subsequent abdominal computed topography imaging identified extensive thrombotic events. This included bilateral pulmonary embolism, superior mesenteric vein non-occlusive thrombus and multiple soft atheromas lining the abdominal aorta causing moderate infrarenal stenosis. In view of the recent history, vaccine associated thrombosis and thrombocytopenia (VITT) was considered. Subsequent testing showed a normal ADAMTS13 level. Treatment for VITT with intravenous immunoglobulin along with oral steroids and anticoagulation using Argatroban was commenced in line with national guidance. Anti-PF4 antibody, tested using the Asserachrom HPIA ELISA assay, was positive at a level of 1.298 OD units confirming the diagnosis of VITT;the first case we are aware of in the UK following second dose administration. Given high-risk presentation, Rituximab therapy was given as an inpatient with good clinical response. Prior to discharge, anticoagulation was switched to oral apixaban with a platelet count on discharge of 170 × 10 9 /l. Subsequent follow-up has shown ongoing clinical remission with consistently negative Anti-PF4 antibody titres. This report outlines the first known definite case of VITT identified following administration of the second dose of ChAdOx1 nCov-19 vaccine in the United Kingdom. The subsequent clinical course was similar to those of patients presenting after their first dose but the atypical presentation mimicking that of Thrombotic Thrombocytopenia is noted..