Congenital Adrenal Hyperplasia

What is congenital adrenal hyperplasia?

Summary

Congenital Adrenal Hyperplasia (CAH) is an inherited (genetic) disorder that causes the adrenal glands to make too much or too little of important hormones that are critical for life.

CAH is an autosomal recessive trait, meaning that a child can get the disease only if both parents carry a mutation for it. Carriers of the mutation typically do not have any CAH symptoms.

There are two types of CAH: Classical and Non-Classic. Classic CAH is the more common type, affecting about 1 in 15,000 individuals in the U.S. and Europe. All newborns in the U.S. are tested for the classical form of CAH when given the standard genetic test after birth. Various forms of CAH are more common among certain ethnic groups, including Ashkenazi Jews, Hispanics, Yupik Eskimos, and Yugoslavians.

Signs of CAH are evident at birth, such as in an infant's genitalia, and are again evident during puberty, which tends to start early. Symptoms associated with a low cortisol level continue throughout life.

Treatment consists of hormone replacement therapy and possibly supplementation with certain salts. Surgery may be chosen to improve appearance of genitalia in females.

Recommended care

You should see your primary care physician (PCP) tomorrow for a sick visit.

Congenital adrenal hyperplasia symptoms

Symptoms differ between the various forms and vary by age and sex.

Symptoms of classic CAH

Symptoms of classic CAH evolve throughout life.

• At birth: Masculinized development in the womb results in an enlarged clitoris and ambiguous genitals in females. Generally, males have normal-appearing genitals, but sometimes have small testes.
• During the first month of life: Children with severe forms of the disorder may experience symptoms including poor feeding and vomiting, dehydration, and abnormal salt levels, which can lead to abnormal heart rhythms.
• During childhood: Early puberty, such as pubic or armpit hair before age 8, may occur. Despite rapid growth initially, ultimately children have shorter-than-average height.
• During the reproductive years: Males and females with CAH may experience fertility difficulties; however, most people with CAH can reproduce.
• Throughout life: Low cortisol levels can lead to episodes of fatigue or low blood pressure, which can be associated with lightheadedness. Low blood sugar (glucose) can lead to lightheadedness, shakiness, and sweating. The body may also have an inability to normally respond to stress. An adrenal crisis may occur, resulting in critically low levels of cortisol, leading to extremely low blood pressure, diarrhea, vomiting, low blood sugar, and shock, which can be deadly if not treated promptly.

Symptoms of non-classic CAH

Typically no symptoms are present at birth. In puberty and adulthood, early puberty may be seen. Initially growth is rapid, but ultimately the child has shorter-than-average height. Females may have:

• Irregular menstrual periods
• Masculine characteristics: Such as a deeper voice, and excess body hair and facial hair
• Acne

Congenital adrenal hyperplasia causes

Your adrenal glands, which sit on top of your kidneys, make three types of steroid hormones: those that regulate salts and blood pressure, those that regulate metabolism and immunity, and those that are involved in male sex characteristics.

To be produced, all the hormones require enzymes. When one of the enzymes does not work properly, it causes the adrenal glands to overproduce or underproduce some hormones, affecting regulation of the body's functions.

21-hydroxylase deficiency

Defects in the gene for this enzyme are responsible for 95% of cases of CAH, including the classic and non-classic forms.

Classic CAH

Classic CAH is the most common form of CAH and has two subforms.

• Salt-losing form: This accounts for 75% of classical CAH cases and is the most severe form, resulting in cortisol and mineralocorticoid deficiency as well as an excess of sex hormones.
• Simple-virilizing form: This accounts for 25% of classical CAH cases and is moderately severe, resulting in cortisol deficiency and an excess of sex hormones.

Non-classic CAH

Non-classic CAH is aless common and less severe form of CAH. People with this form experience milder symptoms than people who have classical CAH. The enzymes work but they function at only 20% to 50% of their typical capacity.

Rare forms of CAH

Rare forms of CAH can occur if other adrenal enzymes are deficient. These include:

• 11-beta hydroxylase deficiency
• 17-alpha hydroxylase deficiency
• 3-beta hydroxysteroid dehydrogenase deficiency
• Congenital lipoid adrenal hyperplasia

Treatment options and prevention

Although CAH cannot currently be cured, with careful treatment most people with CAH can live relatively normal lives.

Hormone replacement

Fortunately, the hormones affected by CAH can be supplemented in medication form. Dosages of medications need to be carefully monitored and adjusted throughout the patient's life.

• A medicine called hydrocortisone can replace cortisol.
• Fludrocortisone can replace mineralocorticoids to regulate salt and blood pressure.
• Stress dosing. Normally, the body produces cortisol to help the body overcome stressors, such as illness or surgery. If the body is unable to make cortisol on its own, additional doses are necessary during stressors or the patient may get sicker.

Salt

Certain forms of CAH cause excessive loss of certain salts, which can be carefully supplemented to avoid complications.

Surgery

Cosmetic surgery can alter the appearance of masculinized female genitalia. This can be done early in life when the child is 2 to 6 months old, but some parents prefer to wait until later, so the girl can participate in joint decision-making. Counseling and psychological care are often recommended to support patients undergoing cosmetic genital surgery.

When to seek further consultation

If you have concerns that your child has early puberty

Classic CAH is typically detected on newborn genetic testing, but non-classic CAH typically is not tested. The American Academy of Pediatrics currently defines puberty as typically occurring between 8 and 12 years in females and 9 and 14 years in males. If you have concerns that your child is showing signs of puberty, such as pubic and armpit hair, rapid growth, or early or severe acne before these ages, it is important to discuss this concern with your child's physician.

If you have a family history of CAH and are pregnant or considering becoming pregnant

If you or your partner has a personal or family history of CAH, consider asking your physician about genetic testing to determine if your child has CAH. If so, you may consider prenatal treatments, although these are still experimental. Research experiments are trying to mitigate the effects of CAH during development by giving mothers of affected fetuses a medication that helps stabilize the hormone levels in the womb. If you or your partner has CAH and you are having difficulty becoming pregnant, ask your physician about fertility treatment options for people with CAH.