Endocrine Abstracts

Introduction: Psychogenic polydipsia occurs in both psychiatric and somatic contexts. Clinically, it presents with a wide range of symptoms, both neurological and psychiatric, and can evolve into acute somatic complications, of which water intoxication is the most severe, with a high mortality rate.

Case report: A 35 years-old male patient, treated for mental retardation since the age of 9 following a tonsillectomy, the post-op effects of which were marked by a coma lasting one month, also treated for epilepsy since the age of 18 on levetiracetam. The patient had presented 5years ago with behavioral problems such as psychomotor agitation, self-aggressivity and suicide attempts, and was put on amisulpride and risperidone. He was referred to us to investigate a Polyuria-polydipsia syndrome that had been evolving for 4 months, with abundant drinking (7l/pd) and abundant polyuria (5l/pd) with a single nocturnal awakening. Clinical examination revealed a conscious patient; normal blood pressure and cardiac rate, eupneic, moderate obesity BMI 33.2 kg /m². Input/output fluide balance was 3.9L/4L per day. Paraclinical tests showed: Natremia 137.93mmol/l, Kalemia 3.96mmol/l, renal function normal, urinary osmolarity: On admission (1pm urine): 225.99mosmol/l, Morning urine (1st micturition): Concentrated appearance, Osmolarity: 378.46mosmol/l. Hypothalamo-pituitary MRI: diffuse supratentorial and subtentorial cortico-subcortical atrophy associated with sequellar gliosis lesions, pituitary gland of normal size and morphology, presence of physiological hypersignal of the postpituitary gland. Water deprivation test was not performed, given the context of epilepsy and the appearance of concentrated urine and urinary osmolarity greater than 300mosmol/l. Psychogenic polydipsia was considered, given the psychiatric involvement, the concentrated appearance of urine, urinary osmolarity >300mosmol/l and normal MRI. Polyuria secondary to the use of levetiracetam was discussed, but the patient had been on this treatment for at least 5 years.

Conclusions: Psychogenic polydipsia is characterized by a disturbance in the control of thirst that is not due to a disorder of antidiuretic hormone production. Although most often seen in patients with chronic schizophrenia, psychogenic polydipsia is also associated with other mental illnesses such as affective disorders, childhood-onset psychoses, mental retardation, personality disorders and anxiety. Treatment options are limited, if, for psychiatric reasons, a choice of antipsychotic medication has to be made, preference will be given to risperidone, olanzapine and clozapine. Short-term cognitive-behavioral therapies have produced interesting results, based on self-monitoring of fluid intake, behavioral control of stimuli through the use of reduced-capacity bottles, learning coping strategies and the use of reinforcement and gratification mechanisms.