Congenital hyperinsulinism  is a medical term referring to a variety of congenital disorders in which hypoglycemia is caused by excessive insulin secretion. Congenital forms of hyperinsulinemic hypoglycemia can be transient or persistent, mild or severe. These conditions are present at birth and most become apparent in early infancy. Mild cases can be treated by frequent feedings, more severe cases can be controlled by medications that reduce insulin secretion or effects. Signs and symptoms
Hypoglycemia in early infancy can cause jitteriness, lethargy, unresponsiveness, or seizures. The most severe forms may cause macrosomia in utero, producing a large birth weight, often accompanied by abnormality of the pancreas. Milder hypoglycemia in infancy causes hunger every few hours, with increasing jitteriness or lethargy. Milder forms have occasionally been detected by investigation of family members of infants with severe forms, adults with the mildest degrees of congenital hyperinsulinism have a decreased tolerance for prolonged fasting.Other presentations are:
Dizziness
Intellectual disability
Hypoglycemic coma
CardiomegalyThe variable ages of presentations and courses suggest that some forms of congenital hyperinsulinism, especially those involving abnormalities of KATP channel function, can worsen or improve with time. The potential harm from hyperinsulinemic hypoglycemia depends on the severity, and duration. Children who have recurrent hyperinsulinemic hypoglycemia in infancy can suffer harm to the brain. Cause
The cause of congenital hyperinsulinism has been linked to anomalies in nine genes. The diffuse form of this condition is inherited via the autosomal recessive manner (though sometimes in autosomal dominant).
A variety of pre-operative diagnostic procedures have been investigated but none has been established as infallibly reliable. Positron emission tomography is becoming the most useful imaging technique. Differential diagnosis
The differential diagnosis of congenital hyperinsulinism is consistent with PMM2-CDG, as well as several syndromes. Among other diagnoses, the following are listed:
MPI-CDG
Beckwith-Wiedemann syndrome
Sotos syndrome
Usher 1 syndromes

Types
Congenital hyperinsulinism has two types, diffuse and focal, as indicated below:

Treatment
In terms of treatment, acute hypoglycemia is reversed by raising the blood glucose, but in most forms of congenital hyperinsulinism hypoglycemia recurs and the therapeutic effort is directed toward preventing falls and maintaining a certain glucose level. Some of the following measures are often tried:

Corn starch can be used in feeding; unexpected interruptions of continuous feeding regimens can result in sudden hypoglycemia, gastrostomy tube insertion (requires a minor surgical procedure) is used for such feeding. Prolonged glucocorticoid use incurs the many unpleasant side effects of Cushings syndrome, while diazoxide can cause fluid retention requiring concomitant use of a diuretic, and prolonged use causes hypertrichosis. Diazoxide works by opening the KATP channels of the beta cells. Octreotide must be given by injection several times a day or a subcutaneous pump must be inserted every few days, octreotide can cause abdominal discomfort and responsiveness to octreotide often wanes over time. Glucagon requires continuous intravenous infusion, and has a very short half-life.Nifedipine is effective only in a minority, and dose is often limited by hypotension.