A REVERSIBLE CASE OF COMPLETE HEART BLOCK DUE TO HYPERKALEMIA FOLLOWING GASTROENTERITIS AND PRE-RENAL AKI: A RARE PRESENTATION WITH SUCCESSFUL REVERSAL

Abstract

Background: Hyperkalaemia is a frequent electrolyte disturbance encountered in emergency and critical care settings, often associated with high morbidity and mortality due to its cardiac effects. While classical electrocardiographic changes progress in a predictable sequence from peaked T waves to sine-wave morphology, the occurrence of complete heart block (CHB) is rarely reported.

Case Presentation: We report the case of a middle-aged male who presented with vomiting, diarrhea, dehydration, and acute onset dyspnea with presyncope. He was found to have hyperkalaemia in the setting of pre-renal acute kidney injury, with electrocardiography revealing CHB and a ventricular escape rhythm. The patient was managed with intravenous calcium gluconate, insulin-dextrose infusion, β-agonist nebulization, oral potassium binders, antiemetics, intravenous hydration, and supportive therapy. Owing to hemodynamic instability, a temporary pacemaker was placed via the transfemoral approach. Within 36 hours, his serum potassium normalized, and sinus rhythm was restored, allowing safe removal of the pacemaker. At discharge and two-week follow-up, ECG and electrolytes were normal, with no conduction abnormalities.

Conclusion: This case highlights the importance of recognizing hyperkalaemia as a potentially reversible cause of CHB, even at modest potassium elevations, and underscores the role of timely electrolyte correction and temporary pacing in management.