Diazoxide toxicity in congenital hyperinsulinism: A case report.

Background: Diazoxide is the sole approved drug for congenital hyperinsulinism; however, diuretic administration and vigilant monitoring are crucial to prevent and promptly identify potentially life-threatening adverse effects. This report aims to highlight a seldom-considered rare side effect of diazoxide. We believe that this brief report is of general interest to readership and increase the physicians' awareness of the guideline importance. Moreover, it underlines the importance of stopping immediately the drug if suspected side effects.

Case Summary: The manuscript describes a patient diagnosed with congenital hyperinsulinism (CHI) treated with diazoxide not overlapping with diuretic. He resulted in sudden respiratory distress and therefore was transferred to the Neonatal Intensive Care Unit. The cardiological evaluation showed pericardial effusion and left ventricular myocardial hypertrophy, absent before. In suspicion of an iatrogenic effect of diazoxide it was progressively reduced until stop while introducing diuretic treatment, with resolution of symptoms. Once clinically stabilized, an 18 fluoro-diydroxy-phenylalanine positron emission tomography/computed tomography (PET/CT) was performed to differentiate between a focal or diffuse form of CHI. The PET/CT highlighted the presence of a single focal accumulation of the tracer located in the pancreatic tail, consistent with a focal form of hyperinsulinism. At the age of four months, the patient underwent a distal pancreatectomy with histological confirmation of a focal form of nesidioblastosis, resulting in a curative operation.

Conclusion: Diuretic administration and vigilant monitoring of diazoxide therapy are crucial to prevent and promptly identify potentially life-threatening adverse effects.