ESPE Abstracts (2016) 86 P-P2-773

Primary Thirst Defect is a Rare But Important Complication Following Surgery for Hypothalamic Hamartoma and Intractable Epilepsy

Dinesh Giri, Jo Blair, Urmi Das, Poonam Dharmaraj, Senthil Senniappan, Connor Malluci, Pettorini Benedetta, Barry Pizer, Sasha Burns & Mohammed Didi


Alder Hey Children’s Hospital, Liverpool, UK


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 24–48 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).

Table 1.
Time (hours)15:5716:1116:2917:3018:00
Plasma Osmolality (mosm/kg)306305307311312
Plasma sodium (mmol/l)148149150151152
Urine Osmolality (mosm/kg)614643
Plasma AVP (pmol/l)0.90.91.6 32.638.7
Thirst (visual analogue scale 1–10)00279

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.