Congenital adrenal hyperplasia (abbreviated CAH) is a disease caused by a deficiency in an enzyme in the adrenal glands – bilateral organs that are located right above the kidneys.
They normally function to produce steroid hormones that are involved in salt, sugar, water, and sexual development regulation. The production of these steroid hormones is controlled by the brain and are involved in a negative feedback loop that regulates the levels of these substances in the bloodstream.
The brain stimulates the production of these hormones by producing a molecule known as ACTH, which is in turn inhibited by the very hormones it stimulates the creation of in the adrenal glands.
In congenital adrenal hyperplasia the absence of an enzyme (most commonly 21-apha hydroxylase, the enzyme involved in the creation of cortisol and aldosterone) leads to lower levels of these steroid hormones in the blood. This causes the brain to produce more ACTH, which eventually leads to enlargement (also known as hyperplasia) of the adrenal glands in an attempt to bring the blood levels back to normal.
The signs and symptoms of congenital adrenal hyperplasia are related to the deficiency of the particular enzyme involved. By far the most common deficiency is the enzyme 21-alpha hydroxylase.
This enzyme is involved in the production of aldosterone (a steroid the promotes salt and water retention in the kidney causing more concentrated urine) and cortisol (a steroid that regulates many bodily functions including sugar and blood pressure). A deficiency in the enzyme thus leads reduced levels of cortisol and aldosterone, which can cause life threatening complications in infancy.
Furthermore, because the body attempts to compensate for low levels of cortisol and aldosterone by overproducing ACTH, the other substance stimulated by ACTH (sex hormones) is overproduced.
This causes female infants to have malformed genitalia, an image of which is shown below. Because this is immediately apparent at birth these babies receive prompt treatment. Male infants are usually diagnosed 2-3 weeks later as the effects of aldosterone and cortisol deficiency become apparent.
Congenital Adrenal Hyperplasia has a spectrum of presentation – ranging from the classic severe presentation the occurs in infancy to a more mild presentation that causes early puberty in males and acne an irregular menstrual periods in females.
Fortunately treatment is available and fairly straightforward – using synthetic version of cortisol and sometimes aldosterone. Cortisol replacement is accomplished with the use of dexamethasone.
Fludrocortisone is also considered as it may be used to replace aldosterone. In female patients anti-androgen therapy may also be used to combat the excessive male hormones produced. However, these medications must be taken for life.
Mild forms of congenital adrenal hyperplasia often go undiagnosed in females as the symptoms can be limited to acne and/or abnormal hair growth.
If you or your child suffer from symptoms of congenital adrenal hyperplasia contact your physician for evaluation and treatment.