Glucose is the simple sugar needed for basic energy in muscles, organs and the brain. It may be stored in the liver and muscles in other forms. Excess glucose is stored in the body as fat. Neural tissue does not store glucose, but requires a constant stream to function correctly. In children, chronic low blood sugar (hypoglycemia) can cause neurological impairments during development.
Normal levels of blood glucose in children are between 70 and 150 mg/dL. In children, levels below 55 mg/dL and, in neonates, levels below 35 mg/dL are considered as hypoglycemic.
Those children with either type 1 or type 2 diabetes mellitus are highly susceptible to hypoglycemia, although the reason for their susceptibility differs. Type 1 diabetics must also be concerned with high levels of blood glucose (hyperglycemia), as their bodies produce little to no insulin, the hormone which lowers blood glucose. Type 1 diabetics have β-cell dysfunction. Beta-cells are those cells in the pancreas which produce and secrete insulin. These children require regular injections of exogenous insulin to maintain regular glucose levels; as such, they may experience what is referred to as relative hyperinsulinemia. If they receive a regular dosage, but do not eat or eat enough, or become overly active, they may develop hypoglycemia. Also patients with diabetes tend to have problems coping with hypoglycemia because they often do not have normal responses in glucagon, the hormone which raises blood sugar levels, opposite to the actions of insulin.
Children with type 2 diabetes generally display hyperinsulinism, though that would not cause hypoglycemia, as insulin does not function normally in their bodies. However, other oral medications, such as sulphonylureas (Sus) and meglitinides, both of which stimulate β-cell function, can lower glucose levels. Also missing meals can result in hypoglycemia. The symptoms of low blood sugar in children fall into two categories.
In either type of diabetes, the most common causes of hypoglycemia include:
- Insuffient food or carbohydrate intake
- Physical or emotional stress
- Prolonged strenuous activity or exercise
- Excessive amounts of diabetic medications
Although rare, congenital hyperinsulinism strikes newborns and very young children. A defective gene passed on by one or both of the parents causes the pancreas to secrete excessive amounts of insulin resulting in prolonged and chronic bouts of hypoglycemia.
Hypoglycemia places stress upon the body. When this occurs, the body reacts with normal stress responses by releasing norepinephrine and epinephrine, the “fight or flight” hormones. As a result of this, the normal signals take hold that would happen under other stresses. Shakiness, sweating, pallor and pupil dilation are usually observable, though each child will react differently. Some chidren may appear giddy while others may show signs of irritability or frustration and others may become very quiet and withdrawn. Less obvious symptoms may include anxiety, nervousness, heart palpitations and dry mouth.
After the initial burst of stress hormones subsides, other symptoms appear, especially as hypoglycemia continues to affect the child. These symptoms may include bluish-hues in the skin of extremities (cyanosis), excessive sweating, extreme hunger and strange sensations in the extremities, like tingling or itching (paresthesias). These symptoms occur secondarily because during the stress of hypoglycemia, the body is reserving blood for essential tissues, such as muscle, heart and neural.
As the friends and family of diabetic children, it is pertinent that you keep an eye out for the symptoms that indicate neural tissues are not receiving the appropriate amount of glucose (neuroglycopenia). These will be the most easily recognizable signs that hypoglycemia may be occurring. Irritability, confusion, difficulty speaking, headaches and loss of coordination (ataxia) are often the first noticeable signs. Should they continue untreated, seizures and coma may occur. Following these, hypoglycemia is fatal for diabetic patients of any age.
The University of Chicago Comer Children’s Hospital: Hypoglycemia
Lucile Packard Children’s Hospital at Stanford: Hypoglycemia (Low Blood Sugar)
Children’s Hospital of The King’s Daughters: Hypoglycemia-Diabetes and Other Endocrine and Metabolic Disorders
The University of Chicago Pritzker School of Medicine: Hypoglycemia <55 mg/dL In Children
PubMed: Hypoglycaemia in Type 2 Diabetes
Amiel, SA, et al.
Briscoe, Vanessa J., PhD and Stephen N. Davis, MD