Navigating a Complex Presentation: Management of Hypernatremic Dehydration, Acute Kidney Injury, Hyperkalemia, and Metabolic Acidosis in a Patient With Down Syndrome: A Case Report

Worldwide, gastroenteritis is a well-known cause of dehydration in pediatric patients and can be life-threatening due to subsequent electrolyte disturbance or dehydration itself. In this case, we present an infant with Down syndrome (karyotype: 21 trisomy) who presented to us with moderate hypernatremic dehydration associated with severe hyperkalemia, moderate metabolic acidosis (pH: 7.1, random blood glucose: 80-110 mg/dL), and elevated kidney function tests secondary to the gastroenteritis caused by Entamoeba histolytica infection. The patient is being followed up by the pediatrics genetics clinic for growth and development, with regular screening for thyroid and celiac diseases, and he has no major heart, gastrointestinal, or renal anomalies. This unique and complex presentation of electrolyte disturbance and dehydration associated with a susceptible condition of Down syndrome deserves special attention with precise management which can be challenging. We managed the patient as a case of hypernatremic dehydration with gradual correction of serum sodium and dehydration, while concurrently managing hyperkalemia by routine methods (beta agonist inhalers, insulin, dextrose 10%) with close laboratory and clinical monitoring at the pediatric intensive care unit. The pediatric nephrology team was also consulted while delineating the management plan. As the patient’s condition eventually resolved with normal kidney function and electrolytes, metabolic acidosis also resolved, with good oral intake and urine output, stable vitals, and was discharged after 72 hours. In conclusion, this case showed that pediatric patients with susceptible conditions such as Down syndrome with gastroenteritis can present with a lethal combination of dehydration and/or electrolyte disturbance, making close monitoring and prompt management paramount in such cases.