A Rare Case of Acute Ischemic Stroke in 17-Year-Old Renal Transplant Recipient: The Role of Protein S Deficiency

Abstract

Acute ischaemic stroke is an uncommon but potentially severe complication after renal transplantation, particularly in adolescents without conventional cerebrovascular risk factors. We report a 17-year-old male who underwent live-donor renal transplantation for rapidly progressive renal failure of uncertain aetiology. On postoperative day 4, he developed sudden right-sided hemiplegia, aphasia, and altered sensorium. Neuroimaging demonstrated acute infarcts in the left middle cerebral artery territory, absent flow distal to the M1 segment, a marked cervical internal carotid artery loop, and a substantial diffusion-perfusion mismatch. Emergency mechanical thrombectomy achieved clot retrieval and revascularisation, followed by progressive neurological recovery. A thrombophilia evaluation identified reduced free Protein S, while autoimmune testing, including ANA, p-ANCA, and c-ANCA, was negative. The patient was discharged on postoperative day 10 with improvement of motor power to MRC grade 4/5 and was prescribed apixaban for secondary stroke prevention. This case highlights the diagnostic complexity of acute ischaemic stroke occurring soon after renal transplantation in a young patient. The findings suggest that thrombophilic states may warrant consideration when conventional vascular risk factors are absent. However, confirmation of hereditary Protein S deficiency requires appropriate repeat assessment after exclusion of acquired causes. Careful neurological surveillance, timely vascular imaging, prompt reperfusion therapy when indicated, and individualised evaluation of thrombophilic abnormalities may assist management of similar post-transplant thrombotic events.