Endocrine Abstracts

Background: Arginine Vasopressin Deficiency [AVP-D] can occur as consequence of any abnormality or injury at one or more of the sites involved in the Antidiuretic hormone [ADH] secretion. AVP-D is one of the presenting features of suprasellar lesions with panhypopituitrism. The natural course of the disease differs based on the underlying aetiology. It is likely to be transient post-operatively. Idiopathic DI is usually permanent however DI can be reversible with infiltrative diseases.

Case Presentation: A 29-year-old gentleman who was diagnosed with suprasellar germinoma affecting the optic pathway. He presented initially with change in his vision. Further investigations confirmed a suprasellar mass with panhypopituitarism. He Underwent frontotemporal craniotomy for open biopsy. Histology reported germ cell tumour in keeping with germinoma. Diuresis came to the medical attention within 24 hrs postoperatively that was associated with hypernatremia. The patient reported that he used to drink around 5 Liters of water daily even before the procedure. He was started on regular Desmopressin 100 mg PO twice per day because of persistent polyuria. Oncology review concluded Suprasellar Germinoma, with no metastasis. The patient was started on chemotherapy and received Radiotherapy as well. Six weeks postoperatively and while on chemotherapy the dose of desmopressin was reduced down to 50 mg PO nightly then switched to desmopressin nasal spray 10 mg/inh 1 puff at night.

Discussion: Clinical assessment is always the key during the long-term management of central DI. The dose of desmopressin should be reviewed and changed based on the degree of polyuria The need for clinical indicators to help define the course of the disease is crucial. As the case with other pituitary hormones deficiency, it is important to reassess the recovery of the AVP axis after treating the underlying cause using a valid clinical tool.