Hypoglycaemia due to inherited metabolic disease — branching viva

Branching viva on hypoglycaemia due to inherited metabolic disease: recognising hypoketotic hypoglycaemia as a metabolic emergency, capturing the critical sample, classifying the cause into insulin-driven, glucose-production failure, and fuel-oxidation block, and delivering disease-specific therapy with diazoxide, carnitine and cornstarch.

branching clinical structured oral3 min readVerification in progress

Prompt

Emergency department: a 16-month-old previously well boy, found unresponsive in the morning after 36 hours of a viral illness with poor intake, seizing on arrival with a glucose of 1.0 mmol/L and mild hepatomegaly. The examiner asks: what is the emergency principle and why is the critical sample drawn before treatment, how does the insulin–ketone–free-fatty-acid pattern localise the cause, what is the fasting-tolerance and glucagon-response logic, and what is the disease-specific long-term management — then branches to a neonate with persistent high-glucose-requirement hypoglycaemia and a positive glucagon response, and asks you to discuss congenital hyperinsulinism genetics, the diazoxide–sirolimus–surgery ladder, and the diffuse-versus-focal surgical decision.

Opening framework

My framework has three layers. First, the recognition — a child with neuroglycopenia after a fast or illness is a metabolic emergency until proven otherwise, and the critical sample drawn while the child is hypoglycaemic is the single most important diagnostic act. Second, the physiology — glucose homeostasis is a balance between supply and utilisation, and ketones are the brain's alternate fuel, so a child who cannot make ketones is doubly exposed. Third, the classification — three physiological failures (insulin-driven, glucose-production, fuel-oxidation) are localised by the insulin, beta-hydroxybutyrate, free-fatty-acid and lactate pattern, and each carries its own therapy. [1] [9]

Paediatrics Fellowship Pro

You have read the opening of this viva. The complete unit — every section and its primary-source references — is part of the Paediatrics Fellowship fellowship atlas.

References4Show ledger

[1]Thornton PS, Stanley CA, De Leon DD, et al. Recommendations from the Pediatric Endocrine Society for Evaluation and Management of Persistent Hypoglycemia in Neonates, Infants, and Children. J Pediatr, 2015.PMID 25957977
[9]Saudubray JM, Garcia-Cazorla À. Inborn Errors of Metabolism Overview: Pathophysiology, Manifestations, Evaluation, and Management. Pediatr Clin North Am, 2018.PMID 29502909
[2]Kapoor RR, Flanagan SE, Arya VB, et al. Clinical and molecular characterisation of 300 patients with congenital hyperinsulinism. Eur J Endocrinol, 2013.PMID 23345197
[6]Spiekerkoetter U, Bastin J, Gillingham M, et al. Current issues regarding treatment of mitochondrial fatty acid oxidation disorders. J Inherit Metab Dis, 2010.PMID 20830526