Endocrine Abstracts

Background: Weight gain is underrecognised in patients with hypothalamic damage and the prevalence and mechanisms are poorly defined. The aim of this study was to define the diagnoses and endocrine characteristics associated with weight gain.

Subjects and methods: A retrospective study of 48 patients (25 female) mean (SD) age 45.3yrs (9.8).They included 22 patients with primary hypothalamic lesions (craniopharyngiomas, Rathke's cysts and other tumours)[group 1]; 16 with pituitary adenomas and hypothalamic extension and 10 with brain tumours who had received hypothalamic radiotherapy [group 2].

Results: Mean (SD) BMI at diagnosis was 27.2 (4.7) kilograms per m² and at follow up 30.7 (6.1) ,after 10.4 (9.8) years. Overall, 52% of patients were obese (BMI>30) at follow up (59% group1,46% group 2). BMI increased more in Group 1 than group 2 (plus4.8(4.1) vs 2.1(3.7) (p=0.05). Irrespective of group, individuals with most weight gain were more likely to require DDAVP (p=0.004), but not thyroxine, hydrocortisone, sex steroids or growth hormone replacement.

Conclusions: In this survey the majority of patients with damage to the hypothalamic region were obese. Weight gain following diagnosis was more frequent with primary hypothalamic tumours. Requirement for DDAVP is associated with weight gain but not other hormone replacements. Weight gain probably results from damage to nuclei controlling ingestive behaviour and energy expenditure.