A loss of consciousness in a teenage girl with anorexia nervosa, due to polydipsia: case report and a minireview.

Purpose: Anorexia nervosa is a chronic disease which may result in various complications. In pediatric clinical practice, it is common to observe complications related to progressive cachexia caused by malnutrition; however, cases of severe complications, like electrolyte disorders, which represent a direct threat to life, due to polydipsia, are rarely observed. The purpose of this study is to highlight that excessive drinking is of primary importance in anorexia nervosa patients, as it can result in severe medical complications, including increased risk of death.

Methods: We report the case of a 13-year-old girl with anorexia nervosa, who was referred to hospital with seizures, disorders of consciousness, and cardiorespiratory failure.

Results: The unstable condition of the patient was attributed to hyponatremia (119 mmol/l), decreased serum osmolality (248 mmol/kg), and decreased urine osmolality (95 mmol/kg) caused by polydipsia (water intoxication) and persistent vomiting. The presented girl was drinking large amounts of water prior to a weigh-in to falsify her low body weight.

Conclusions: Polydipsia is a common problem reported by patients with eating disorders, but one which rarely leads to serious clinical complications, due to severe hyponatremia. This case underscores the importance of careful evaluation of fluid intake and the need for regular monitoring of serum electrolytes in patients with anorexia nervosa. All clinicians treating patients with such disease, as well as the parents of sick children, should be familiar with this life-threatening condition.

Level Iv: Evidence obtained from multiple time series with or without the intervention, such as case studies.