Bradycardia, Renal Failure, Atrioventricular Nodal Blockade, Shock, and Hyperkalemia (BRASH) Syndrome: A Deadly Pentad of Symptoms.

Bradycardia, renal failure, atrioventricular (AV) nodal blockade, shock, and hyperkalemia (BRASH) syndrome is an underrecognized clinical entity characterized by a synergistic interplay among hyperkalemia, renal dysfunction, and AV nodal blockade. This self-perpetuating cycle can lead to profound bradycardia and hemodynamic instability if not promptly identified and managed. We report the case of a man in his 70s who presented to the emergency department (ED) with acute-onset watery diarrhea followed by a syncopal episode. On evaluation, he was bradycardic and hypotensive, with laboratory findings notable for hyperkalemia and acute kidney injury. His home medications included amiloride, carvedilol, and losartan. The electrocardiogram (ECG) demonstrated complete heart block. The patient was treated medically for hyperkalemia, with subsequent spontaneous resolution of the bradyarrhythmia. He was diagnosed with BRASH syndrome and admitted to the intensive care unit for further monitoring. In the setting of hyperkalemia and concurrent use of AV nodal blockers, there is a risk of worsening bradycardia and cardiovascular collapse if not recognized early. This case highlights the importance of early identification of BRASH syndrome in patients presenting with bradycardia, particularly those receiving AV nodal blockers. Prompt correction of hyperkalemia and supportive care may reverse the cycle and prevent progression to cardiovascular collapse.