Clinical communication
Presenting features of idiopathic ketotic hypoglycemia

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Abstract

Idiopathic ketotic hypoglycemia (IKH) is an important cause of emergent hypoglycemia among children. We present a case series of 24 patients with IKH in an effort to provide a current clinical description of this disorder. Secondly, we provide a crude lower-bound estimate of the incidence of IKH in an Emergency Department (ED) setting. The charts of 94 non-diabetic patients presenting to an ED during a period of 64 months with a diagnosis of hypoglycemia as identified via ICD-9 codes were reviewed. Eleven patients, accounting for 24.4% of all significant hypoglycemic episodes unrelated to diabetes in children over 6 months of age, were diagnosed with IKH. These patients accounted for 31.4% of hypoglycemic episodes among previously heathy children older than 6 months. A further review of 13 individuals with IKH identified from an endocrinology specialty clinic was also performed. Among all 24 individuals identified with IKH, the mean age of presentation was 30.8 months. We have found IKH to be the most common cause of hypoglycemia among previously healthy ED patients during childhood. In our series, patients with IKH presented initially before 5 years of age with symptomatic hypoglycemia during the morning hours after a moderate fast. These patients were found to have ketonuria with symptoms resolving after glucose administration. Patients with IKH were more likely to be Caucasian, male gender, and have a low body weight.

Introduction

Among non-diabetic children presenting to hospitals for treatment, idiopathic ketotic hypoglycemia (IKH) is considered the most common cause of hypoglycemia beyond infancy 1, 2. Originally described by Colle and Ulstrom in 1964, IKH is defined by periodic episodes of hypoglycemia, associated with ketonuria, in an otherwise healthy child, usually occurring after food deprivation (1). The original authors reported that the first attack rarely occurred before the age of 18 months and that the children were less than 50th percentile for height and weight. Later reports described affected children as young as 12 months old with normal growth parameters 3, 4. The diagnosis of IKH can be difficult in an emergency setting. Protracted vomiting, obtundation, and new onset seizures are frequently encountered problems in the ED. As these symptoms all may be manifestations of profound hypoglycemia, serum glucose determination is an important component of the emergency evaluation of these concerns (5). Hypoglycemia due to IKH recovers after glucose administration, and the disorder typically remits by the age of 8–9 years.

We present a case series of hypoglycemic children diagnosed with IKH in an effort to provide a modern clinical description of the entity. Furthermore, we present data offering a crude lower-bound estimate of the incidence of IKH among children presenting to a tertiary care children’s hospital for emergency treatment. We also estimate the incidence of IKH among patients treated for hypoglycemia in the same ED setting. As the management of IKH is relatively simple, an accurate and early diagnosis could save the patient from unnecessary testing and future hypoglycemic episodes.

Section snippets

Materials and methods

We conducted a retrospective chart review of all non-diabetic children presenting to the ED of an urban, tertiary care children’s hospital between September 1994 and December 1999 with a discharge diagnosis of hypoglycemia; and of children evaluated for IKH at the endocrinology clinic of the same institution. Eligible ED patients were identified through computerized search of the International Classification of Diseases, 9th revision, (ICD-9) codes 251.0, 251.2, and 775.6; and patients with

Results

Our ED cared for 276,313 patients during the study period. Over the slightly more than 5-year period, 128 children were identified with ICD-9 codes for non-diabetic hypoglycemia. Eighteen of these patients were found to have been misclassified, and were excluded. Sixteen medical records were unable to be completely recovered for review. The 94 remaining records of non-diabetic children who presented to the ED with hypoglycemia were analyzed. The lower-bound limit of the incidence of

Discussion

IKH is a physiologic process in which children experience an unusual degree of episodic hypoglycemia after a relatively brief period of caloric deprivation. Pathophysiologic investigations into the etiology of IKH have searched for disturbances in gluconeogenesis, glycolysis, regulation of insulin response to fasting states, and brain glucose utilization. In the first few hours of fasting, glucose demand is met via glycogenolysis. Because children with IKH tend not to experience symptoms until

Conclusions

IKH was responsible for 11.7% of cases of non-diabetic hypoglycemia, as identified through ED discharge diagnoses, presenting to our tertiary care children’s hospital ED; and IKH accounted for 31.4% of hypoglycemic diagnoses among previously healthy children above 6 months of age. The incidence of IKH in this setting was found to be at least 4.0 cases per 100,000 patient visits. Our study found the typical demographic profile for IKH to be a child aged 7 months to 5 years, presenting with

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Clinical Communications (Pediatrics) is coordinated by Roger Barkin, md, of HealthONE, Denver, Colorado and Ghazala Q. Sharieff, md, the University of Florida, Jacksonville, Florida

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