Endocrine Abstracts

Introduction: Central diabetes insipidus is a rare disorder, characterized by a failure of the posterior pituitary to produce vasopressin that lead to hypotonic polyuria and polydipsia. Diabetes insipidus may be due to post-pituitary surgery, where sometimes the posterior lobe also has to be removed or damaged; other injury as fractures of the skull, trauma, infiltrative lesions, tumors/metastases, idiopathic or rare genetic causes. As the sensation of thirst is the key homeostatic mechanism that prevents hypernatraemic dehydration in patients with untreated diabetes insipidus (DI), adipsia leads to failure to respond with appropriate fluid intake. Marked hypernatremia can occur if a central lesion impairs both ADH release and thirst centre, this being the typical biochemical manifestation of adipsic DI. It poses a significant challenge to manage due to an absent thirst response and the co-existence of cognitive impairment in some patients.

Case presentation: A 50-year-old, normal weight male patient, known for 5-months with postoperative panhipopituitarism after craniopharyngioma removal and diabetes insipidus, probably adipsic, is transferred to our institute from a rural hospital for evaluation and treatment of severe hypernatremia (serum sodium 159 mmol/l). He was in substitution treatment, but in the past 2 months it was interrupted by the patient. The clinical exam revealed a confused, dehydrated, tachycardic, afebril patient with increased dimension and low pulse of the calf. Head and abdominal CT scans were performed and revealed pituitary tissue debris, minimal hydrocephalus and space-replacement processes in the pulmonary arteries that raised the suspicion of lung thromboembolism. The diagnose was confirmed in a cardiology service and anticoagulant therapy was initied. After the admission, hormonal tests confirmed the panhipopituitarism. The biochemical test revealed a severe hypernatremia which was corrected during his hospitalization, but his mental status degraded showing psychomotor agitation, agressive behaviour, both verbal and pysical, being diagnosed with organic behaviour disorder.

Particularities: Craniopharyngioma was probably clinical latent congenital form since endocrine features were lacking during chilhood. The psychiatric complications that occurs in around 11–57%, either transient or permanent, started late after the sugery, despite the literature data. Also is known that women, not men, are an independent predictor of increased cardiovascular, neurological and psyhosocial morbidity.

Conclusions: Management of DI with cognitive impairment is complex and requires a multidisciplinary approach. The majority experience morbidity (severe hypernatremia, sleep apnea, venous thromboembolism and obesity) and an increased mortality risk. Recovery from it is very rare, but the prognosis is variable.

Keywords: Craniopharyngioma, hypernatremia, behavioral disorders