ABSTRACT
INTRODUCTION: Hypernatremic dehydration is an uncommon condition, whose main treatment is fluid administration. In cases of extreme hypernatremia, that treatment paradoxically poses a real danger to the patient's morbidity and mortality. In very rare cases, restrictive type anorexia nervosa causes extreme dehydration that can result in elevated sodium levels. In this case study we present a teenage girl who suffers from restrictive anorexia nervosa and was admitted to the pediatric intensive care unit (PICU) with an acute confusional state, with extremely severe hypernatremia up to 203 mEq/L, combined with hyperglycemia up to 700 mg/dL. Under hypotonic electrolyte solution treatment, a gradual sodium level decrease of 8 mEq/L per day was achieved with complete normalization of sodium without any neurological damage. Moreover, glucose levels were normalized rapidly and spontaneously without additional treatment with insulin.