Diabetes Care, Vol 22, Issue 7 1144-1150, Copyright © 1999 by American Diabetes Association
Counterregulation during spontaneous nocturnal hypoglycemia in prepubertal children with type 1 diabetes
KA Matyka, EC Crowne, PJ Havel, IA Macdonald, D Matthews and DB Dunger
Department of Paediatrics, John Radcliffe Hospital, Oxford, U.K.
OBJECTIVE: To examine counterregulatory responses during spontaneous
nocturnal hypoglycemia in prepubertal children with type 1 diabetes.
RESEARCH DESIGN AND METHODS: A total of 29 prepubertal patients with type 1
diabetes underwent two overnight profiles. Data were analyzed from 16
children (median [range] 8.7 [5.9-12.9] years of age) with a night of
hypoglycemia and a nonhypoglycemic night. Children hypoglycemic (< 3.5
mmol/l) on night 1 were given 25% extra carbohydrate as uncooked cornstarch
with their usual evening snack on night 2 to avoid hypoglycemia. Glucose,
growth hormone, and cortisol were measured every 15 min, catecholamines
every 30 min, and glucagon, pancreatic polypeptide, insulin, and ketones
every 60 min. A group of 15 healthy control subjects, aged 9.5 (5.6-12.1)
years, underwent one overnight profile. RESULTS: Median duration of
hypoglycemia was 225 (30-630) min, and glucose nadir was 2.0 (1.2-3.3)
mmol/l. Insulin levels were not different on the two nights (P = 0.9,
analysis of variance), but children with diabetes had higher insulin levels
than normal control subjects between 2300 and 0300, maximal at 0200 (mean
+/- SEM 57.4 +/- 5.7 vs. 31.6 +/- 5.0 pmol/l, P = 0.002). Peak epinephrine
was higher on the night of hypoglycemia (0.98 [0.52-2.09] nmol/l) versus
nonhypoglycemia (0.32 [0.21-0.62] nmol/l), P = 0.001, but norepinephrine
(1.29 [1.07-2.64] vs. 1.26 [1.04-1.88] nmol/l, P = 0.5), glucagon (93
[64.2-125.6] vs. 100.5 [54.6-158] ng/l, P = 0.6), pancreatic polypeptide
(410.2 [191-643.2] vs. 270.8 [158.2-777.8] ng/l, P = 0.5), and cortisol
(513 [300-679] vs. 475 [235-739] nmol/l, P = 0.6) were not different.
Glucose threshold for epinephrine release was very low, 1.9 +/- 0.2 mmol/l.
There was a short-lived rise in growth hormone from 75-105 min after onset
of hypoglycemia, maximal at 90 min (7.8 +/- 1.2 vs. 3.5 +/- 0.9 ng/ml, P =
0.02). CONCLUSIONS: The prolonged nature of nocturnal hypoglycemic episodes
may be explained in part by defective counterregulation. The risk of
nocturnal hypoglycemia needs to be reduced before intensification of
insulin therapy can be contemplated in this age-group.