Pseudo Bartter Syndrome in anorexia nervosa.

Introduction: Anorexia nervosa is a psychiatric disorder with various non-psychiatric manifestations that arise from the self-imposed malnourishment and possible purging behaviors. These medical manifestations or complications may mimic non psychiatric disorders and difficult the diagnosis of an eating disorder.
Case Report: We report the case of a patient with a binge-eating/purging subtype of anorexia nervosa, whose purges consisted in diuretic abuse. She kept her purges secret and during more than 1 year she was admitted several times in the emergency room for, sometimes life-threatening, hypokalemia. Furthermore, she consulted practitioners from different specialties and was hospitalized in a nephrology service to investigate chronic hypokalemia and other metabolic and hydroelectrolytic disturbances. A Bartter Syndrome was suspected, and she underwent genetic testing. Eventually she started psychiatric follow up and was admitted as an inpatient under the care of a specialized eating disorders unit.
Conclusion: This patient presented a series of metabolic disturbances secondary to the diuretic abuse, that mimicked the manifestations of hereditary tubulopathies like Bartter Syndrome. Coincidentally it was found that the patient had a mutation in a gene linked to Bartter Syndrome, that wasn't enough to justify this diagnosis. So, a Pseudo Bartter Syndrome secondary to the diuretic abuse was evident. The focus on medical manifestations delayed the recognition of the anorexia nervosa and the associated diuretic abuse as the main cause of the electrolyte and metabolic disturbances. This case emphasizes the importance of being familiarized with the non-psychiatric manifestations of eating disorders, so they may be rapidly recognized and managed.
Level of Evidence: Level V, Case Report.
(© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)