CONGENITAL ADRENAL HYPERPLASIA

 

Congenital adrenal hyperplasia is a genetic condition that results from an abnormality of the adrenal glands. The adrenal glands are a pair of small glands situated above the kidneys. This gland has 2 parts, an outer cortex, and an inner medulla. The medulla of the adrenal gland makes adrenaline. This part is not affected in CAH and remains normal. The outer portion produces three hormones:

1. Cortisol (Hydrocortisone)

Cortisol helps to maintain blood sugar in our body. It is also called the “stress hormone” of our body since it’s production increases during physical stress such as infection and emotional stress, to protect our body. This hormone is essential for life.


2. Aldosterone (salt retaining hormone)

Aldosterone is a salt-retaining hormone. It works on the kidney to help the body maintain normal levels of the salt minerals, sodium and potassium. Normal levels of sodium and potassium are necessary for all cells to work normally. If the adrenal gland cannot make this hormone too much salt and water is lost in the urine, leading to salt deficiency and dehydration.

3. Androgen (male sex hormone)

The adrenals of both girls and boys make several types of male-like hormones. These are normally present in very small amounts in children.

What is the abnormality in CAH?

The hormones produced by the adrenal gland are made in a series of steps or chemical reactions.

If one enzyme in this series of chemical reactions is missing, the commonest being 21 hydroxylase, there is a decrease in the end product cortisol and increase in adrenal androgens, which form a part of the series of chemical reactions. The androgens that are increased are 17a(OH) progesterone, Androstenedione, DHEA, and testosterone.

Effects of deficiency of 21 hydroxylase

Deficiency of 21 hydroxylase results in

  • Deficiency of the end product, cortisol, which is the stress hormone in our body, and this can be life threatening. It also results in darkening of the skin.
  • Increase in the adrenal androgens: These androgens have a masculinizing effect in females. These girls may look like males at birth because the clitoris is enlarged and looks like the penis. The internal structures like the uterus and ovaries are normal in these girls.
    Excessive male hormone in boys results in early sexual hair, acne and increase in the penile size.
    Due to increase in these androgens, boys and girls have a growth rate that is too rapid. They look much taller than their peers. These androgens also affect the growth plates of children. The bone age is advanced and there is early fusion of the growth plates resulting in short adult height.
  • Decrease of aldosterone is present in 75% children with CAH. These are called “salt losers”. This results in increased loss of sodium in the urine. They develop low sodium and high potassium levels in the blood. These babies do not gain weight, and develop vomiting in the first few days of life. If treatment is not started immediately, it may result in death.

Treatment of CAH

Treatment for CAH should be instituted as early as possible. Treatment consists of replacing the missing hormone cortisol. There are various preparations available in the market, but hydrocortisone is the most preferable. This is available in tablet form in India. The dose of the medication changes with age and regular monitoring by your pediatrician/ endocrinologist with certain lab tests is important. The dose needs to be increased during stress such as infections, fever etc. to cope with the stress.

This medication also decreases the adrenal androgens and prevents further increase in the size of the clitoris in females, early appearance of sexual hair and rapid advancement of growth and bone age. The clitoris may not return completely to normal size, however, and the vaginal opening may remain closed because of the joined labial folds. Surgery may be needed in girls who have a marked male-like appearance of their external genitals. The age at which surgery is done is determined on an individual basis, depending on the severity of the problem.
In salt losers, a substitute of aldosterone called fludrocortisone is given to prevent loss of sodium from the kidneys. This results in normalization of the sodium and potassium levels. This medication is available in India. Extra salt needs to be given in babies who are “salt losers”.

REMEMBER

  • With regular medication, your child with CAH can lead a normal life.
  • The life expectancy is normal in CAH.
  • Girls with CAH (if they take their medications regularly) have no difficulties becoming pregnant or carrying a baby.
  • Men who take their medications appropriately have normal fertility.
  • There are no know mental deficiencies associated with CAH

Frequently asked questions

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