Endocrine Abstracts

Introduction: The debate surrounding the most suitable pituitary provocation test in children is controversial. There is a perception that the gold standard insulin tolerance test (ITT) is ‘dangerous’ and that the glucagon stimulation test (GST) is ‘safer’ and a more tolerable alternative, particularly in younger children. There have been no reports in the literature comparing patient experiences of these tests.

Aim: To examine the tolerability of the GST compared to the ITT in children aged 8 or more years.

Methods: A prospective, qualitative cohort study was carried out over 3 months. The occurrence of adverse symptoms and children’s level of distress following glucagon or insulin was ascertained using semi-structured interviews and structured questionnaires.

Results: 16 children aged 8–17 years were studied (ITT n=8; GST n=8). 100% of children undergoing an ITT reported a fall in their distress score post-test, however 63% undergoing a GST reported a rise. With age and pre-test scores taken into account this difference was significant by linear regression. The duration of nonspecific (abdominal pain (P=0.007), hunger (P=0.001)) and neuroglycopenic (headache (P=0.007)) symptoms was significantly greater after GST, whereas autonomic and non-specific symptoms were more common, and of greater severity, after ITT but of shorter duration. Glucagon caused a delayed hypoglycaemia in 37% of cases, which occurred 90–120 min post injection.

Conclusion: The ITT, as performed at our centre (following a strict protocol including breakfast with oral glucose 20–30 min post injection), is surprisingly well tolerated in children over 8 years of age. By contrast the GST is poorly tolerated and does not necessarily avoid a delayed, unpredictable, and hence potentially more risky, hypoglycaemia. These novel findings in a small cohort highlight the need for reappraisal of the comparative risk-benefit and predictive values of these tests in a larger randomised biochemical and qualitative crossover study.