Causes There are several ways to classify hypoglycemia. The following is a list of
the more common causes and factors which may contribute to hypoglycemia grouped
by age, followed by some causes that are relatively age-independent. See
causes of hypoglycemia for a more complete list grouped by etiology.
Hypoglycemia in newborn infants
Hypoglycemia is a common problem in critically ill or extremely low
birthweight infants. If not due to maternal hyperglycemia, in most cases it is
multifactorial, transient and easily supported. In a minority of cases
hypoglycemia turns out to be due to significant hyperinsulinism, hypopituitarism
or an inborn error of metabolism and presents more of a management challenge.
- Transient neonatal hypoglycemia
-
Prematurity,
intrauterine growth retardation,
perinatal asphyxia
- Maternal hyperglycemia due to
diabetes or iatrogenic glucose administration
- Sepsis
- Prolonged fasting (e.g., due to inadequate breast milk or condition
interfering with feeding)
- Congenital hypopituitarism
-
Congenital hyperinsulinism, several types, both transient and persistent
-
Inborn errors of carbohydrate metabolism such as glycogen storage
disease
Hypoglycemia in young children
Single episodes of hypoglycemia may occur due to
gastroenteritis or fasting, but recurrent episodes nearly always indicate
either an inborn error of metabolism, congenital hypopituitarism, or congenital
hyperinsulinism. A list of common causes:
- Prolonged fasting
-
Diarrheal illness in young children, especially
rotavirus gastroenteritis
- Idiopathic
ketotic hypoglycemia
- Isolated
growth hormone deficiency, hypopituitarism
-
Insulin excess
- Hyperinsulinism due to several congenital disorders of insulin
secretion
- Insulin injected for type 1 diabetes
-
Gastric dumping syndrome (after gastrointestinal surgery)
- Other congenital metabolic diseases; some of the common include
-
Maple syrup urine disease and other organic acidurias
-
Type 1 glycogen storage disease
-
Disorders of fatty acid oxidation
-
Medium chain acylCoA dehydrogenase deficiency (CAD)
- Accidental ingestions
-
Sulfonylureas,
propranolol and others
- Ethanol (mouthwash, "leftover morning-after-the-party drinks")
Hypoglycemia in older children and young adults
By far the most common cause of severe hypoglycemia in this age range is
insulin injected for
type 1 diabetes. Circumstances should provide clues fairly quickly for the
new diseases causing severe hypoglycemia. All of the congenital metabolic
defects, congenital forms of hyperinsulinism, and congenital hypopituitarism are
likely to have already been diagnosed or are unlikely to start causing new
hypoglycemia at this age. Body mass is large enough to make starvation
hypoglycemia and idiopathic ketotic hypoglycemia quite uncommon. Recurrent mild
hypoglycemia may fit a
reactive hypoglycemia pattern, but this is also the peak age for
idiopathic postprandial syndrome, and recurrent "spells" in this age group
can be traced to
orthostatic hypotension or
hyperventilation as often as demonstrable hypoglycemia.
- Insulin-induced hypoglycemia
- Insulin injected for type 1 diabetes
- Factitious insulin injection (unchausen
syndrome)
- Insulin-secreting pancreatic tumor
- Reactive hypoglycemia and idiopathic postprandial syndrome
- Addison's disease
- Sepsis
Hypoglycemia in older adults
The incidence of hypoglycemia due to complex drug interactions, especially
involving oral hypoglycemic agents and insulin for diabetes rises with age.
Though much rarer, the incidence of insulin-producing tumors also rises with
advancing age. Most tumors causing hypoglycemia by mechanisms other than insulin
excess occur in adults.
- Insulin-induced hypoglycemia
- Insulin injected for diabetes
- Factitious insulin injection (Munchausen syndrome)
- Excessive effects of oral diabetes drugs, beta-blockers, or drug
interactions
- Insulin-secreting pancreatic tumor
- Alimentary (rapid jejunal emptying with exaggerated insulin
response)
- After gastrectomy
dumping syndrome or bowel bypass surgery or resection
- Reactive hypoglycemia and idiopathic postprandial syndrome
-
Tumor hypoglycemia,
Doege-Potter syndrome
- Acquired
adrenal insufficiency
- Acquired hypopituitarism
- Immunopathologic hypoglycemia
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