Hypokalemia is among the most common electrolyte abnormalities, often well tolerated, but sometimes responsible for an increase in morbidity and mortality due to cardiovascular causes. The kidneys play a key role in potassium homeostasis, making the nephrologist the professional directly involved in the diagnosis and treatment of this condition. We present the clinical case of a 24-year-old man who came in with multiple episodes of emesis and hyperpyrexia. The patient rapidly developed severe hypokalemia with ascending flaccid paralysis. Despite early treatment with potassium chloride, intensive therapy was necessary to manage the complications. The clinical case illustrates the diagnostic and therapeutic challenges encountered and demonstrates how a multidisciplinary approach and a thorough diagnostic process, including genetic testing, identified a heterozygous mutation in the CACNA1S gene, confirming the diagnosis of hypokalemic periodic paralysis type I. The importance of early recognition and appropriate management of hypokalemia is emphasized to prevent potentially fatal complications.