Low blood sugar (hypoglycemia) in children is a potentially serious condition, especially during early childhood when the brain is rapidly developing and relies heavily on glucose for energy. It is defined as a blood sugar level below 45 mg/dL in newborns and below 54 mg/dL in older children. Since the brain’s main fuels are glucose, fatty acids, and ketones, a drop in these can significantly impact brain function. Prolonged or repeated episodes of low blood sugar can cause long-term complications like delayed development, seizures, vision problems, and learning difficulties. Unlike other organs, the developing brain doesn’t recover easily from injury, which makes early recognition and treatment essential.

There are many possible causes of hypoglycemia in children. Hormonal issues such as excessive insulin production, low thyroid or adrenal hormone levels, and multiple pituitary hormone deficiencies are common endocrine causes. Metabolic and genetic disorders—like glycogen storage diseases, galactosemia, fatty acid oxidation defects, and certain liver diseases—can also interfere with the body’s ability to maintain normal blood sugar levels. To find the exact cause, doctors usually perform “critical sampling,” which involves taking blood samples when sugar is below 50 mg/dL. These tests help identify which body systems are malfunctioning. If a low-sugar sample isn’t captured, a controlled fasting test under close medical supervision may be needed to safely recreate and study the hypoglycemic state.

In cases where hypoglycemia is caused by genetic conditions like Congenital Hyperinsulinism (CHI), symptoms often start in the newborn period. These children typically need genetic testing and close monitoring. Many can be treated effectively with medications, avoiding the need for surgery such as partial or full removal of the pancreas, which can lead to lifelong diabetes and digestive issues. Management should always be guided by a pediatric endocrinologist to ensure accurate diagnosis and the best possible outcome. With early intervention and specialized care, most children with hypoglycemia can grow and develop normally.