NEONATAL HYPOGLYCEMIA

By: Huzaifa Hamid

Introduction

the most common metabolic problem in newborns Fetal glucose level maintained at 2/3 of maternal Blood

glucose through the placenta. Blood glucose in newborns are generally lower than

older children & adult

Whipple’s triad:

1. low blood glucose level

2. symptoms of hypoglycemia at the time of the low glucose level

3. symptom relief with treatment of hypoglycemia

Definition

is a serum glucose concentration < 40 mg/dL in term neonates or < 30 mg/dL in preterm neonates.

Or a plasma glucose level of < 30 mg/dL in the first 24 hours of life and < 45 mg/dL thereafter.

The overall incidence of symptomatic hypoglycemia in newborns varies from 1.3-3 per 1000 live births.

During pregnancy, glucose is passed to the baby from the mother through the placenta. Some of the glucose is stored as glycogen in the placenta, and later in the baby's liver, heart and muscles. These stores of sugar are important for supplying the baby's brain with energy during delivery and for nutrition after the baby is born. 

Reasons for concern

It is a common, readily diagnosed and readily treated problem.

The brain depends on blood glucose as its main source of energy. The brain will not function normally if there is not enough glucose. Severe or long-drawn-out low blood sugar may result in seizures and permanent brain damage.

Risk factors:

Premature infants Small for gestational age infants Macrosomic infants Infants with CNS depression at birth or encephalopathy Infants with sepsis Infants with respiratory distress Infants with rhesus isoimmunisation Infants of mothers with gestational diabetes Infants who are nil orally

Etiology

PHHI (persistent hyperinsulinemic hypoglycemia of infancy)

Limited glycogen stores (eg, prematurity, intrauterine growth retardation)

Increased glucose use (eg, hyperthermia, polycythemia, sepsis, growth hormone deficiency)

Decreased glycogenolysis, gluconeogenesis, or use of alternate fuels (eg, inborn errors of metabolism, adrenal insufficiency)

Depleted glycogen stores (eg, asphyxia-perinatal stress, starvation)

Sign and Symptoms

Most neonates with hypoglycaemia are initially asymptomatic.

Those who are symptomatic may present with the following: Apnoea Cyanosis Jitteriness Hypotonia Poor feeding Seizures Irritability Lethargy High pitched cry

All signs are nonspecific and also occur in neonates who have asphyxia, sepsis or hypocalcemia, or opioid withdrawal. Therefore, at-risk neonates with or without these signs require an immediate bedside serum glucose check.

Screening

consider hypoglycemia screening in infants with significant hypoxia, perinatal distress, 5-minute Apgar scores of less than 5, isolated hepatomegaly (possible glycogen-storage disease), microcephaly, anterior midline defects, gigantism, macroglossia or hemihypertrophy (possible Beckwith-Wiedemann Syndrome), or any possibility of an inborn error of metabolism or whose mother is on terbutaline, beta blockers, or oral hypoglycemic agents

Diagnosis

A simple blood test:

for blood glucose levels can diagnose hypoglycemia. Blood may be drawn from a heel stick, from the baby's arm, or through an umbilical catheter. Generally, a baby with low blood glucose levels will need treatment.

Critical Sampling

While the list of causes of hypoglycemia is long and complex, establishing the etiology in a particular patient is important. Frequently, it is difficult to make an accurate diagnosis until one can obtain a critical sample of blood and urine at the time of the hypoglycemic episode. In a child with unexplained hypoglycemia, a serum sample should be obtained before treatment for the measurement of glucose and insulin, GH, cortisol, FFAs, and b-hydroxybutyrate and aceto-acetate. Measurement of serum lactate levels also should be considered. A urine specimen should be obtained for measuring ketones and reducing substances. Hypoglycemia without ketonuria suggests hyperinsulinism or a defect in fatty acid oxidation. The results of this initial testing can establish whether endocrine causes are responsible and, if not, provide initial information regarding which types of metabolic disorders are most likely. Whenever possible, additional samples of blood and urine should be frozen for further analysis if necessary.

Emergency department care Supportive therapy includes oxygen, establishing

an intravenous (IV) line, and monitoring. Seizures unresponsive to correction of hypoglycemia should be managed with appropriate anticonvulsants. Marked acidosis (pH < 7.1) suggests shock or serious underlying disease and should be treated appropriately.

Treatment

Blood sugar <40 mg/dL without symptoms—feed and repeat glucose.

Blood sugar <40 mg/dL with symptoms—start IV within 10 minutes and give 2 mL/kg of 10% dextrose bolus followed by3.6 mL/kg/h constant infusion. Monitor glucose within 30 minutes.

Blood sugar <20 mg/dL with/without symptoms—start IV within10 minutes and give 2 mL/kg 10% dextrose bolus followed by3.6 mL/kg/h constant infusion. Monitor glucose within 30 minutes

Other modes of treatment of neonatal hypoglycemia (as a result of hyperinsulinemia) by Diazoxide, glucagons, steroids, & in persistent hypoglycemia as result of islet cell hyperplasia may be treated by subtotal pancreatectomy.

Complications

neurologic damage resulting in mental retardation recurrent seizure activity developmental delay personality disorders Some evidence suggests that severe hypoglycemia

may impair cardiovascular function.

The principal causes of morbidity from neonatal hypoglycemia are failure to anticipate, failure to treat

promptly and effectively, and failure to make sure hypoglycemia does not recur when treatment is stopped.

References

Medscape Merck Manual Illstrated Textbook of Pediatrics, 4e Nelson Essentials of Pediatrics, 6e Step-up to pediatrics Current Essentials Pediatrics Wikipedia

Thank you