Congenital adrenal hyperplasia
Congenital adrenal hyperplasia (CAH) is a group of inherited genetic disorders that affect the adrenal glands, a pair of walnut-sized organs above your kidneys. A person with CAH lacks one of the enzymes the adrenal glands use to produce hormones that help regulate metabolism, the immune system, blood pressure and other essential functions.
CAH affects the production of one or more of three steroid hormones: cortisol, which regulates your body's response to illness or stress; mineralocorticoids, such as aldosterone, which regulate sodium and potassium levels; or androgens, such as testosterone, which are sex hormones. In many cases, CAH results in lack of cortisol and overproduction of androgen.
The milder and more common form of CAH is called nonclassic. The classic form, which is more severe, can be detected in newborn screening programs. Some forms of CAH can cause problems with normal growth and development in children and even be life-threatening.
Although there is no cure, with proper treatment, most people with congenital adrenal hyperplasia can lead normal lives.
Signs and symptoms of congenital adrenal hyperplasia vary, depending on which gene is defective and the level of enzyme deficiency.
There are two major types of congenital adrenal hyperplasia:
- Classic CAH. This more-severe form of the disease is usually detected in infancy.
- Nonclassic CAH. This milder and more common form may not become evident until childhood or early adulthood.
Approximately two-thirds of people with classic CAH are classified as having the salt-losing form, while one-third have the simple-virilizing form. In both forms, affected females have genital ambiguity.
A child with classic CAH may experience:
- A lack in the production of cortisol in both the salt-losing and simple-virilizing forms. Most of the problems caused by classic CAH are related to a lack of cortisol, which plays an important role in regulating your blood pressure, maintaining blood sugar and energy levels, and protecting your body against stress.
- A lack in the production of aldosterone in the salt-losing form. This can lead to low blood pressure, a lower sodium level and a higher potassium level. Sodium and potassium normally work together to help maintain the right balance of fluids in your body.
- Excess production of the male sex hormones (androgens such as testosterone). This can result in short height, early puberty and in females, abnormal genital development while in the womb.
Signs and symptoms of classic CAH in infants include:
- In females, enlarged clitoris or genitals that look more male than female (ambiguous genitalia) at birth, but males have normal appearing genitals
- Significant illness related to a lack of cortisol, aldosterone or both (adrenal crisis), which can be life-threatening
Signs and symptoms of classic CAH in children and adults include:
- Very early appearance of pubic hair
- Rapid growth during childhood, but shorter than average final height
This form of CAH is milder than classic CAH. Often there are no symptoms at birth. The condition is not identified on routine infant blood screening and often only becomes evident in late childhood or early adulthood. Hormone deficiency may only involve cortisol levels.
Although teenage and adult females may have normal appearing genitals at birth, later signs and symptoms often include:
- Irregular or absent menstrual periods
- Masculine characteristics such as facial hair, excessive body hair and a deepening voice
- Severe acne
In both females and males, signs and symptoms of nonclassic CAH also may include:
- Early appearance of pubic hair
- Rapid growth during childhood, but shorter than average final height
When to see a doctor
Classic CAH is usually detected at birth through required newborn screening or when female babies show ambiguous genitalia. CAH may also be identified when male or female babies show signs of severe illness due to low levels of cortisol, aldosterone or both.
In nonclassic CAH, you may notice signs and symptoms of early puberty in your toddler or child. In this case, or if you have concerns about your child's growth or development, make an appointment with your child's pediatrician.
If you're pregnant and may be at risk of CAH because of your own medical history or your ethnicity, ask your doctor about genetic counseling.
In 95 percent of cases, the enzyme lacking in congenital adrenal hyperplasia is 21-hydroxylase. CAH may sometimes be called 21-hydroxylase deficiency. There are other much rarer enzyme deficiencies that also cause CAH.
CAH is passed along in an inheritance pattern called autosomal recessive. Children who have the condition have two parents who either have CAH themselves or who are both carriers of the genetic mutation that causes the condition.
Factors that increase the risk of having congenital adrenal hyperplasia include:
- Parents who both have CAH or are both carriers of the genetic defect for the disorder
- People in certain ethnic groups, particularly Ashkenazi Jews, but also Hispanics, Italians, Yugoslavians and Yupik Inuits
Complications depend on the type of congenital adrenal hyperplasia and its severity.
People with classic CAH are at risk of experiencing adrenal crisis. This is caused by severely low levels of cortisol in the blood, resulting in diarrhea, vomiting, dehydration, low blood sugar levels and shock. It's a life-threatening medical emergency that requires immediate treatment. Impaired production of aldosterone may occur as well, leading to dehydration with low sodium and high potassium levels. Adrenal crisis does not occur in the nonclassic form of CAH.
In classic and nonclassic CAH, males and females may eventually experience fertility problems.
There is no known way to prevent congenital adrenal hyperplasia. Your doctors may recommend genetic counseling if you're thinking of starting a family and you're at risk of having a child with CAH.
Diagnosis of congenital adrenal hyperplasia may include the following tests.
Tests to diagnose CAH in fetuses can be done when siblings have the disease or family members are known to carry the gene defect. One of these tests may be done:
- Amniocentesis. This procedure involves using a needle to withdraw a sample of amniotic fluid from the womb, and then examining the cells.
- Chorionic villus sampling. This test involves withdrawing cells from the placenta for examination.
Newborns, infants and children
All newborns in the United States are screened for classic CAH caused by genetic 21-hydroxylase deficiency during the first few days of life. This test does not identify nonclassic CAH.
Diagnosis of CAH includes:
- Physical exam. The doctor examines your child and evaluates symptoms. If, based on these findings, the doctor suspects CAH, the next step is to confirm the diagnosis with blood and urine tests.
- Blood and urine tests. Tests used to diagnose CAH measure levels of hormones produced by the adrenal glands. A diagnosis can be made when there are abnormal levels of these hormones.
- Gene testing. In older children and young adults, genetic testing may be needed to diagnose CAH.
- Testing to determine a child's sex. In female infants who have severe ambiguous genitalia, tests can be done to analyze chromosomes to identify genetic sex. Also, pelvic ultrasound can be used to identify the presence of female reproductive structures such as the uterus and ovaries.
Your doctor will likely refer your child to a specialist in childhood hormonal issues (pediatric endocrinologist) for treatment of congenital adrenal hyperplasia. The health care team may also include other specialists, such as urologists, psychologists and geneticists, as needed.
Treatment will depend on the type of CAH and the severity of symptoms and is aimed at reducing excess androgen production and replacing deficient hormones. People with nonclassical CAH may not require treatment or may need only small doses of corticosteroids.
Your child's doctor may prescribe replacement hormone medication taken on a daily basis to restore normal levels of deficient hormones. Additional medications or higher doses may be needed during periods of illness or significant stress such as surgery.
Medications may include:
- Corticosteroids to replace cortisol ? this is the main treatment
- Mineralocorticoids to replace aldosterone to help retain salt and get rid of excess potassium
- Salt supplements to help retain salt
Monitoring the effectiveness of medication includes regularly scheduled:
- Physical exams. The doctor can check your child's growth and development, including monitoring changes in height, weight, blood pressure and bone growth.
- Monitoring for side effects. The doctor can also monitor your child for side effects, such as the loss of bone mass and impaired growth, particularly if steroid-type replacement medication doses are high and used long term.
- Blood tests to check hormone levels. It's critical to have regular blood tests that indicate whether medications need adjusting. Adequate cortisone replacement is needed to suppress androgens, allowing for normal height in growing children and minimizing masculine characteristics in females. However, too much cortisone may cause Cushing's syndrome.
As adults, some men and women with nonclassic CAH are able to stop taking their replacement hormone medications. But others, particularly people with symptoms or with the classic form of CAH, may need to take replacement hormone medications indefinitely.
Possible reconstructive surgery for females
In some female infants with severe ambiguous genitalia as a result of classic CAH, reconstructive surgery to normalize the appearance and function of the genitals may be recommended.
This procedure may involve reducing the size of the clitoris and reconstructing the vaginal opening. The surgery is typically performed between 2 and 6 months of age. Females who have corrective genital surgery may need more cosmetic surgery later in life.
Some parents choose to wait for surgery until their child is old enough to understand the risks and choose his or her own gender assignment. However, performing corrective genital surgery when females are very young is technically easier than it is in later years.
Before making decisions about the best treatment approach for your child, talk with your doctor about these issues. Working together, you and your doctor can make informed choices that will help your child thrive.
Psychological support can be important to the emotional health and social adjustment of females with genital abnormalities.
When identified before birth, treatment for CAH can begin while the fetus is still in the womb. A synthetic corticosteroid that crosses the placenta to the infant can be taken by the mother during pregnancy. This may reduce the secretion of male hormones (androgens), allowing female genitals to develop normally.
This treatment is still considered experimental. There's no clear evidence yet about the long-term safety of this drug. Because of the side effects and how the treatment might affect brain development, this remains a controversial treatment.
Many children with CAH can successfully manage the condition by staying on their replacement hormone medications. They grow up to lead healthy lives with a normal life expectancy.
Coping and support
Early and steady support from family and health care professionals can help your child grow up to have normal self-esteem and a satisfying social life. These approaches may help:
- Include psychological counseling in your child's treatment plan as needed
- Seek help from a mental health professional if you're having trouble coping and to help you develop healthy parenting strategies
Preparing for an appointment
You may start by seeing your family doctor or your child's pediatrician. He or she may refer you to a doctor who specializes in the diagnosis and treatment of conditions related to the adrenal glands (pediatric endocrinologist).
Here's some information to help you prepare for your appointment. Consider taking a family member or friend along for support and to help you remember information.
What you can do
To prepare for your appointment:
- Find out if your child needs to follow any pre-appointment restrictions, such as changing food or liquid intake to get ready for blood and urine tests.
- Make a list of any signs and symptoms your child has been experiencing, and for how long.
- Make a list of your child's key medical information, including recent illnesses, any medical conditions, and the names and dosages of any medications, vitamins, herbs or other supplements.
- Prepare questions you want to ask your doctor.
Some basic questions to ask your doctor may include:
- What is likely causing my child's signs and symptoms?
- Are there any other possible causes for these symptoms?
- What kinds of tests does my child need?
- What treatment approach do you recommend?
- What are the expected results of treatment?
- What are the possible side effects of treatment?
- How will you monitor my child's health over time?
- What is my child's risk of long-term complications?
- Do you recommend that my child receive psychological counseling?
- Do you recommend that our family meet with a genetic counselor?
Don't hesitate to ask any other questions during your appointment.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Be ready to answer them to reserve time to go over points you want to focus on. For example, your doctor may ask:
- What are your child's symptoms?
- When did you first begin noticing these symptoms?
- Has anyone in your family been diagnosed with congenital adrenal hyperplasia? If so, do you know how it was treated?
- Are you planning to have more children?