Background: Diabetes insipidus (DI) is a well-recognized post neuro surgical complication arising after hypothalamic-pituitary surgery. DI occurring in the post-operative period can be transient happening within 2448 hour of surgery, secondary to trauma to the connections between the magnocellular bodies and the nerve terminals in the posterior pituitary, or to axonal shock from disturbances in the vascular supply to the pituitary stalk and posterior pituitary.
Objective and hypotheses: We report primary thirst defect, a previously unreported rare complication following surgery for hypothalamic hamartoma in an adolescent girl.
Method: An eighteen-year-old girl with intractable epilepsy, secondary to hypothalamic hamartoma was admitted for the resection of her hypothalamic lesion. She developed hypernatremia with hyper-osmolality but without thirst or polyuria 24 hours after surgery. She had normal plasma cortisol reserve (plasma cortisol: 679 nmol/l), thyroid and renal function tests.
Results: A hypertonic saline test was performed. The results are shown in Table 1. A targeted fluid intake of 2.6 litres/day after appropriate rehydration subsequently led to the improvement of plasma osmolality (298 mosmol/kg) and normalisation of plasma sodium(144 mmol/l).
|Plasma Osmolality (mosm/kg)||306||305||307||311||312|
|Plasma sodium (mmol/l)||148||149||150||151||152|
|Urine Osmolality (mosm/kg)||614||643|
|Plasma AVP (pmol/l)||0.9||0.9||1.6||32.6||38.7|
|Thirst (visual analogue scale 110)||0||0||2||7||9|
Conclusion: Primary thirst defect, is a rare and dangerous complication that can occur after epilepsy surgery for hypothalamic hamartoma. This can cause a confusing picture with DI and vigilance is required to identify and recognise the problem early to initiate the most appropriate management.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology