Cortical necrosis with urticarial rash revealing a thyrotoxic crisis: A case report

Introduction: Acute cortical necrosis (ACN) is a rare and often irreversible cause of anuric acute kidney injury (AKI), typically associated with shock or vasculitis. We report an exceptional case of ACN occurring in the context of severe thyrotoxicosis with an urticarial rash. Case Observation: A 30-year-old female, previously diagnosed with hyperthyroidism and treated with carbimazole, was admitted for prolonged oligo-anuria with gastrointestinal symptoms, a recent urticarial rash, and moderate pancytopenia. Hemodialysis was required. Renal ultrasound showed normal-sized kidneys. Renal biopsy revealed extensive bilateral cortical necrosis. The immunological and infectious workup was negative. The pancytopenia was considered medication-induced. The progression was marked by the onset of end-stage chronic kidney disease. Discussion: ACN is exceptionally associated with thyrotoxicosis. Potential pathophysiological mechanisms include hemodynamic dysregulation, endothelial activation, and a prothrombotic state promoted by thyrotoxicosis. The urticarial rash may represent a hypersensitivity vasculitis. The combination of pancytopenia, rash, and thyrotoxicosis suggests a systemic immunoallergic syndrome. Conclusion: This case highlights a rare and severe complication of thyrotoxicosis, associated with an immunoallergic context. It underscores the importance of a broad etiological approach in unexplained anuric AKI.