User:Baflyer2/Ketotic hypoglycemia

Ketotic hypoglycemia refers to a state of low blood glucose that is accompanied by ketosis, the presence of ketone bodies in the blood or urine. This state can be either physiologic or pathologic; physiologic ketotic hypoglycemia is a common cause of hypoglycemia in children, often in response to stressors such as infection or fasting. Pathologic ketotic hypoglycemia is typically caused by metabolic defects, such as glycogen storage disorders.

Physiologic ketotic hypoglycemia
The body's physiologic response to falling glucose levels is a suppression of insulin secretion from the pancreas, which decreases the amount of glucose available to most tissue but instead prioritizes the remaining amount for the brain. Hormones such as glucagon, cortisol, and adrenaline are then released to stimulate glycogenolysis and gluconeogenesis in the liver, in addition to lipolysis in adipose tissue. As glycogen stores start to be depleted, the liver begins oxidizing fatty acids to ultimately yield ketone bodies, which can serve as an alternative fuel source for the brain in the absence of glucose. Therefore, the combination of low glucose (hypoglycemia) and the presence of ketone bodies yields the state known as ketotic hypoglycemia. Such a physiologic response is common in adults during periods of fasting, and is particularly common in ill younger children who cannot tolerate long periods of fasting. Episodes of physiologic ketotic hypoglycemia in children decrease with increasing age, presumably because fasting tolerance improves with increasing body mass. Such episodes are rare after the age of nine; persisting episodes past this age should raise suspicion for an underlying pathologic cause.

Pathologic ketotic hypoglycemia
Pathologic causes of ketotic hypoglycemia, in which episodes persist in children despite increasing age, include glycogen storage defects, disorders of fatty acid metabolism, and disorders of gluconeogenesis, among several others. In essence, any metabolic defect that interferes with the body's ability to maintain glucose homeostasis can trigger ketotic hypoglycemia.

Diagnosis
Ketotic hypoglycemia is a diagnosis of exclusion.

The advocacy organization Ketotic Hypoglycemia International defines pathologic ketotic hypoglycemia as recurrent, symptomatic episodes in which patients have beta-hydroxybutyrate levels ≥ 1.0 mmol/L and blood glucose levels < 70 mg/dL in the absence of triggers that would otherwise explain ketotic hypoglycemia.

Treatment
The mainstay of physiologic ketotic hypoglycemia treatment typically includes management of the underlying cause, fluid resuscitation, and dietary supplementation of sugars and carbohydrates. In children, alanine — a precursor in gluconeogenesis — can be infused to rapidly increase plasma glucose levels.