Method comparison of beta-hydroxybutyrate point-of-care testing to serum in healthy children

Approach to the Patient: Investigation of Pediatric Hypoglycemia in the Emergency Department-A Practical Algorithm

Hypoglycemia in the pediatric population tends to present in the newborn period or during metabolic crisis triggered by prolonged fasting and intercurrent illness. Current recommendations to investigate all children presenting with hypoglycemia for the first time are cumbersome and costly but necessary to identify those with serious conditions who predispose to hypoglycemia. We describe a practical and cost-effective method of evaluating children who present to the emergency department with previously undiagnosed hypoglycemia. Glucose and point-of-care (POC) beta-hydroxybutyrate levels should be measured on all children with a low screening POC glucose level, and a full history and physical examination will identify those requiring further investigation. This approach is suggested to identify patients with serious and life-threatening disease with the same fidelity as the currently recommended approach of performing a critical sample on all children with hypoglycemia. Our streamlined approach will reduce the cost to approximately 10% of the current approach per patient diagnosed with a serious underlying disease. Further, children without underlying hypoglycemia-predisposing disorders will be identified and discharged without unnecessary intervention.

Fasting ketone levels vary by age: implications for differentiating physiologic from pathologic ketotic hypoglycemia

OBJECTIVES

Ketone production is a physiological phenomenon that occurs during beta-oxidation of free fatty acids. Distinguishing physiologic ketosis from pathologic over-production/underutilization of ketones is critical as part of the diagnostic evaluation of disorders of carbohydrate metabolism, but there is limited literature on normal ketone production with fasting. Our aim is to measure fasting serum beta-hydroxybutyrate (BHB) concentrations in healthy children after an overnight fast.

METHODS

Children ≤18 years of age were prospectively recruited from elective procedures through our surgery centers. Exclusion criteria included a history of diabetes, hypopituitarism, adrenal, metabolic or inflammatory disorders, dietary restrictions, trauma, or use of medications that might affect blood glucose. Serum glucose, cortisol, and BHB were assessed after an overnight fast.

RESULTS

Data from 94 participants (mean 8.3 ± 5.7 years, 54 % male, 46 % female, were analyzed. Children ≤3 years of age (19) have significantly higher mean (0.40 ± 0.06 mmol/L) and median (0.4, IQR 0.2-0.6 mmol/L) BHB concentrations compared to children >3 years of age (75) with mean (0.21 ± 0.02 mmol/L) and median BHB (0.1, IQR 0.1-0.2 mmol/L) (p<0.0001). Fasting BHB levels of >1.0 mmol/L was rare (2 %, N=2) and 74 % (N=70) of participants had BHB levels <0.3 mmol/L.

CONCLUSIONS

BHB concentrations are significantly higher in young children (≤3 years of age) compared to older children. Fasting BHB levels >1.0 mmol/L are rare within our population and therefore may identify a value above which there may a greater concern for pathologic ketotic hypoglycemia. It is imperative to establish the normative range in children to differentiate physiological from pathological ketotic hypoglycemia.

Dynamic Methods for Childhood Hypoglycemia Phenotyping: A Narrative Review

Hypoglycemia results from an imbalance between glucose entering the blood compartment and glucose demand, caused by a defect in the mechanisms regulating postprandial glucose homeostasis. Hypoglycemia represents one of the most common metabolic emergencies in childhood, potentially leading to serious neurologic sequelae, including death. Therefore, appropriate investigation of its specific etiology is paramount to provide adequate diagnosis, specific therapy and prevent its recurrence. In the absence of critical samples for biochemical studies, etiological assessment of children with hypoglycemia may include dynamic methods, such as in vivo functional tests, and continuous glucose monitoring. By providing detailed information on actual glucose fluxes in vivo, proof-of-concept studies have illustrated the potential (clinical) application of dynamic stable isotope techniques to define biochemical and clinical phenotypes of inherited metabolic diseases associated with hypoglycemia. According to the textbooks, individuals with glycogen storage disease type I (GSD I) display the most severe hypoglycemia/fasting intolerance. In this review, three dynamic methods are discussed which may be considered during both diagnostic work-up and monitoring of children with hypoglycemia: 1) functional in vivo tests; 2) in vivo metabolic profiling by continuous glucose monitoring (CGM); 3) stable isotope techniques. Future applications and benefits of dynamic methods in children with hypoglycemia are also discussed.