Hypoglycemia during acute illness in children with classic congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) describes a group of genetic, autosomal recessive conditions, where there is a block in cortisol biosynthesis. Approximately 95 percent of cases are due to 21-hydroxylase deficiency, which is discussed in this article. Patients with the severe or classic form of CAH have epinephrine deficiency in addition to cortisol deficiency. Both epinephrine and cortisol are important counterregulatory hormones and help prevent hypoglycemia during physical stress. This is the first prospective study to evaluate the incidence of hypoglycemia during acute illness in children with classic CAH. Our objective was to examine blood glucose levels and symptoms of these children during the physical stressor of a typical acute illness managed at home. Twenty patients, ages 3 to 10 years with classic CAH participated. Parents were instructed regarding management of illnesses, home blood glucose monitoring and questionnaire completion. Over 29 months, 20 patients completed questionnaires and 6 patients performed home blood glucose monitoring. A blood glucose of <60 mg/dL was documented in 3 out of 8 monitored acute illness episodes, and in 2 out of 6 of monitored children. The acute illness episodes with documented blood glucose <60 mg/dL were not associated with vomiting. Our data suggest that children with classic CAH may experience lowering of blood glucose during illnesses, and patient education regarding the management of common childhood illness should include glucose supplementation.