CLINICAL
THE MANAGEMENT OF CONGENITAL HYPERINSULINISM
Annaruby Cunjamalay Paediatric Dietitian Great Ormond Street Hospital for Children Annaruby is a highly specialised Paediatric Dietitian who has been working in paediatrics for 14 years. She has a keen interest in swimming and enjoys cooking and travelling the world.
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Congenital hyperinsulinism (CHI) is a rare but potentially serious condition that presents soon after birth. The estimated incidence is 1:40,000 births, with the highest incidence rate of 1:2500 births found in consanguineous parents.1 CHI is characterised by the over production of insulin secretion from pancreatic β-cells. The risk of brain injury results from insulin action stopping the body from using alternative fuels for the brain to use instead of glucose. It is, therefore, essential to make a rapid diagnosis and commence immediate management in order to prevent severe hypoglycaemic brain injury associated complications, such as epilepsy, cerebral palsy and other neurological damage, or even death.2 The aim of treatment is to avoid any episodes of hypoglycaemia. For the purpose of CHI, hypoglycaemia is less than 3.5mmol/litre. In the absence of ketone bodies, infants with CHI are constantly reliant on the circulating blood glucose as the fuel for normal neurological functioning, hence the importance of maintaining the blood glucose concentration above 3.5mmol/ litre. CHI is often missed, as it is difficult to identify, with non-specific symptoms such as abnormal feeding, irritability, jitteriness and lethargy. Despite advanced treatment, the evidence suggests that approximately a third of children with CHI have some degree of brain injury.3 Some of the neurodevelopmental problems are often only evident at school age when higher-order cognitive functions have developed; these children present with problems such as attention-deficit/hyperactivity disorders, plus learning problems.4
www.NHDmag.com March 2019 - Issue 142
Hypoglycaemic brain injury has a lifelong devastating effect on the child and the family, which consequently has a long-term socioeconomic impact on the NHS. WHAT ARE THE SYMPTOMS OF CHI?
A child usually starts to show symptoms within the first few days of life, although very occasionally symptoms may appear later in infancy. Symptoms of hypoglycaemia can include floppiness, shakiness, poor feeding and sleepiness, all of which are due to the low blood glucose levels. Seizures can also occur due to low blood glucose levels. If the child’s blood glucose level is not corrected, it can lead to loss of consciousness and potential brain injury. SECONDARY CAUSES OF HYPERINSULINISM
This can be subdivided into several categories and often distinguished by the length of treatment required and the infant’s response to medical management. Transient hyperinsulinaemic hypoglycaemia means that the increased insulin production is only present for a short duration and often resolves in the first few weeks or months of life and is found in conditions such as: • intrauterine growth retardation • infants of diabetic mothers • infants with perinatal asphyxia