Hypoglycemia in infants and children

A serious and unusual presentation of congenital isolated ACTH deficiency due to TBX19 mutation, beyond the neonatal period

Summary

Congenital isolated adrenocorticotrophic hormone (ACTH) deficiency due to T-box transcription factor-19 (TBX19 mutation) (MIM 201400; ORPHA 199296) usually presents in the neonatal period with severe hypoglycemia, seizures, and sometimes prolonged cholestatic jaundice. We report a case with an unusual presentation that delayed the diagnosis. A 9-month-old female patient with no relevant personal history was admitted to the emergency department due to a hypoglycemic seizure in the context of acute gastroenteritis. There was rapid recovery after glucose administration. At age 4, she presented with tonic-clonic seizures, fever, and gastrointestinal symptoms and came to need support in an intensive care unit. Low serum cortisol was documented and hydrocortisone was initiated. After normalization of inflammatory parameters, the patient was discharged with hydrocortisone. The genetic investigation was requested and compound heterozygous mutations in TBX19 were detected. This is a rare case of presentation of TBX19 mutation outside the neonatal period and in the setting of acute disease, which presented a diagnostic challenge.

Learning points

Congenital isolated adrenocorticotrophic hormone deficiency due to TBX19 mutation usually presents with neonatal hypoglycemia and prolonged cholestatic jaundice. An uneventful neonatal period, however, does not exclude the diagnosis as the disease may be asymptomatic at this stage. In the context of idiopathic hypoglycemia, even in the context of acute disease, hypocortisolism must always be excluded. Genetic evaluation should be performed in cases of congenital central hypocortisolism to allow proper counselling.

Management and Appropriate Use of Diazoxide in Infants and Children with Hyperinsulinism

BACKGROUND

The diagnosis of hypoglycemia and the use of diazoxide have risen in the last decade. Diazoxide is the only Food and Drug Agency-approved pharmacologic treatment for neonatal hypoglycemia caused by hyperinsulinism (HI). Recent publications have highlighted that diazoxide has serious adverse effects (AEs) such as pulmonary hypertension (2-3%) and neutropenia (15%). Despite its increasing use, there is little information regarding dosing of diazoxide and/or monitoring for AEs.

METHODS

We convened a working group of pediatric endocrinologists who were members of the Drug and Therapeutics Committee of the Pediatric Endocrine Society (PES) to review the available literature. Our committee sent a survey to its PES members regarding the use of diazoxide in their endocrine practices. Our review of the results concluded that there was substantial heterogeneity in usage and monitoring for AEs for diazoxide among pediatric endocrinologists.

CONCLUSIONS

Based on our extensive literature review and on the lack of consensus regarding use of diazoxide noted in our PES survey, our group graded the evidence using the framework of the Grading of Recommendations, Assessment, Development and Evaluation Working Group, and has proposed expert consensus practice guidelines for the appropriate use of diazoxide in infants and children with HI. We summarized the information on AEs reported to date and have provided practical ideas for dosing and monitoring for AEs in infants treated with diazoxide.

Characterization of the duration of treatment with diazoxide in infants with prolonged hyperinsulinism (PHI)

Background Prolonged neonatal hyperinsulinism (PHI) causes hypoglycemia in the neonatal period and is associated with perinatal stress. Even though diazoxide is an effective treatment option for PHI, it has serious adverse effects making an argument for safe yet expeditious wean off of diazoxide while ensuring normoglycemia. The objective of this study was to characterize clinical course, dose requirement and duration of treatment with diazoxide in our cohort of infants diagnosed with PHI. Methods A retrospective chart review of infants diagnosed with PHI during a 6-year period was done documenting the diagnostic workup and the duration of treatment with diazoxide. Results PHI was diagnosed (n = 20; mean ± standard deviation [SD]) at 14.3 ± 22.4 days. Elevated insulin (8.3 ± 8.4 mIU/L), normal cortisol (15.5 ± 6.6 μg/dL [6-21]), normal growth hormone (18.8 ± 15.7 ng/mL [0.1-6.2]) and inappropriate low serum free fatty acids (0.3 ± 0.2 mmol/L [>1.5]) levels were measured during hypoglycemia (plasma glucose <50 mg/dL). Detectable insulin at the time of hypoglycemia was measured in 17 of 20 infants while the same number (17/20) of infants had a positive glucagon stimulation test (GST). The dose of diazoxide was 10 ± 3.7 mg/kg/day and duration of treatment was 44.9 ± 27.9 days. Conclusions This study illustrates that the duration of treatment with diazoxide in infants with PHI can be shorter than previously reported in the literature. We speculate that active tapering of diazoxide started within a week after discharge from hospital as well an outpatient tapering of diazoxide based on glucose monitoring were possible reasons for this outcome.

Inborn Errors of Metabolism in the Emergency Department (Undiagnosed and Management of the Known)

An inborn error of metabolism should be considered in any neonate who presents to the emergency department in extremis and in any young child who presents with altered mental status and vomiting. In children with unknown diagnoses, it is crucial to draw the appropriate laboratory studies before the institution of therapy, although treatment needs rapid institution to mitigate neurologic damage and avoid worsening metabolic crisis. Although there are hundreds of individual genetic disorders, they are roughly placed into groups that present similarly. This article reviews the approach to the patient with unknown metabolic diagnosis and up-to-date management pearls for children with known disorders.

A Short-Term Fasting in Neonates Induces Breathing Instability and Epigenetic Modification in the Carotid Body

The respiratory control system is not fully developed in newborn, and data suggest that adequate nutrition is important for the development of the respiratory control system. Infants need to be fed every 2-4 h to maintain appropriate energy levels, but a skip of feeding can occur due to social economical reasons or mild sickness of infants. Here, we asked questions if a short-term fasting (1) alters carotid body (CB) chemoreceptor activity and integrated function of the respiratory control system; (2) causes epigenetic modification within the respiratory control system. Mouse pups ( Collapse

Key Words

• carotid body
• epigenetics
• fasting
• hypoxia
• mouse
• respiratory control

Collapse

MESH Headings

• Animals
• Animals, Newborn
• Carotid Body/physiology
• Epigenesis, Genetic
• Fasting/physiology
• Mice
• Respiration

Collapse

Grants

• ES016817 NIEHS NIH HHS
• HL081345 NHLBI NIH HHS
• R00 ES016817 NIEHS NIH HHS
• R01 HL081345 NHLBI NIH HHS
• K99 ES016817 NIEHS NIH HHS

Collapse

Affiliation(s)

Machiko Shirahata Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MD, USA
Wan-Yee Tang Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MD, USA
Eric W. Kostuk Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MD, USA

Collapse

Septo-optic dysplasia: fitting the pieces together

A 7-year-old boy was admitted for a general tonic-clonic seizure with severe hypoglycaemia (1.39 mmol/l). His medical history was remarkable for a congenital left eye strabismus, unilateral cryptorchidism and three previous episodes of hypoglycaemic seizures with inconclusive metabolical and neurological investigations. Physical examination revealed a hoarse tone voice, dry skin, cold extremities and height in the third percentile (target height between 50th and 85th percentile). Left wrist radiography revealed a bone age of 4.5 years ±6 months Laboratory studies confirmed growth hormone deficiency and central hypothyroidism. The brain MRI showed an ectopic neurohypophysis. Neuroophthalmology investigation revealed left optic nerve hypoplasia and septo-optic dysplasia was then diagnosed. Thyroid and recombinant growth hormone replacement were started showing clinical improvement. A detailed clinical history and a careful physical examination in children presenting with multiple clinical signs of hypopituitarism may lead to a timely diagnosis, avoiding clinical morbidity associated to untreated hormonal abnormalities.