Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) is a group of inherited genetic conditions that affect your adrenal glands, which are small glands located above your kidneys. These conditions prevent your body from making enough of certain hormones, like cortisol and aldosterone, and can sometimes lead to producing too many male sex hormones (androgens). CAH requires lifelong management with medication.

What is Congenital Adrenal Hyperplasia?

Congenital adrenal hyperplasia (CAH) is an inherited condition present from birth that affects the adrenal glands, which are small organs above your kidneys. Your adrenal glands usually produce essential hormones like cortisol, which helps your body respond to stress, and aldosterone, which balances salt and water. In CAH, your body has trouble making enough of these hormones and may produce too many androgens (male sex hormones).

CAH is a genetic disorder, meaning it is passed down through families. The most common form, accounting for about 95% of cases, is 21-hydroxylase deficiency. This deficiency means your body lacks a specific enzyme needed to make cortisol and aldosterone. There are two main types of CAH: classic and nonclassic. Classic CAH is more severe and is usually found at birth or in early childhood. It can be further divided into salt-wasting CAH, which is life-threatening, and simple virilizing CAH. Nonclassic CAH is a milder form that may not be diagnosed until later in childhood or adulthood.

Symptoms

The symptoms of congenital adrenal hyperplasia (CAH) can vary greatly depending on the type and severity of the condition. Classic CAH symptoms often appear early in life and can include ambiguous genitalia in girls or signs of early puberty in both sexes. Nonclassic CAH symptoms are typically milder and may emerge later, such as early puberty, acne, or irregular periods.

In classic CAH, symptoms are usually noticeable at birth or shortly after. Girls with classic CAH may have ambiguous genitalia, meaning their genitals don't look clearly male or female. Boys with classic CAH may appear normal at birth but can show signs of early puberty, such as an enlarged penis, within the first few years of life. Salt-wasting CAH, a severe form of classic CAH, can lead to a life-threatening adrenal crisis, usually within the first few weeks of life. Symptoms include severe vomiting, dehydration, poor feeding, lethargy, low blood pressure, and problems with heart rhythm due to low sodium and high potassium levels. This is a medical emergency. Nonclassic CAH often has milder symptoms that may not appear until childhood or adulthood. These can include early or rapid growth spurts, early puberty, severe acne, excess body hair (hirsutism) in girls and women, irregular menstrual periods, and fertility problems.

Causes & risk factors

Congenital adrenal hyperplasia (CAH) is caused by a genetic mutation, most commonly in the CYP21A2 gene, which is inherited from both parents. This means that for a child to develop CAH, they must receive a copy of the mutated gene from each parent. CAH is an autosomal recessive condition, meaning it is not linked to sex and requires two copies of the faulty gene.

The most common cause of CAH is a deficiency of the enzyme 21-hydroxylase. This enzyme is crucial for the adrenal glands to produce cortisol and aldosterone. Without enough of this enzyme, the body produces too many androgens instead. CAH is an inherited condition, meaning it is passed down through families. It follows an autosomal recessive inheritance pattern. This means that a child must inherit a copy of the mutated gene from both parents to develop the condition. If a child inherits only one copy of the mutated gene, they are a carrier but usually do not show symptoms. Having parents who are carriers of the mutated gene is the primary risk factor for CAH. The condition affects about 1 in 15,000 children for classic CAH. Nonclassic CAH is more common, affecting about 1 in 100 to 1 in 200 people in certain ethnic groups.

How it's diagnosed

Congenital adrenal hyperplasia (CAH) is often diagnosed through newborn screening programs, which test for elevated levels of a hormone precursor called 17-hydroxyprogesterone (17-OHP). If screening results are abnormal, further blood tests are conducted to measure hormone levels and electrolytes. A physical exam and genetic testing can confirm the diagnosis and identify the specific type of CAH.

Newborn screening is a crucial tool for diagnosing classic CAH early, often before symptoms appear. This involves a heel prick to collect a blood sample, which is then tested for high levels of 17-hydroxyprogesterone (17-OHP). Elevated 17-OHP levels suggest the adrenal glands are struggling to produce cortisol. If newborn screening results are abnormal, or if symptoms appear later, a doctor will order additional tests. These include blood tests to measure levels of various hormones, such as cortisol, aldosterone, and androgens, as well as electrolytes like sodium and potassium. These tests help determine the severity and type of CAH. Genetic testing can confirm the diagnosis by identifying mutations in the genes responsible for CAH, most commonly the CYP21A2 gene. This can also help determine if a person is a carrier. A physical exam, including an assessment of genitalia in newborns, also plays a role in diagnosis.

Treatment options

Treatment for congenital adrenal hyperplasia (CAH) focuses on replacing the hormones your body cannot produce enough of and managing excess hormone levels. This typically involves lifelong hormone replacement therapy with medications like glucocorticoids and mineralocorticoids. The goal is to balance hormone levels, prevent adrenal crises, and support normal growth and development.

The primary treatment for CAH is hormone replacement therapy. You will likely take medications called glucocorticoids, such as hydrocortisone, to replace the cortisol your body isn't making. This helps reduce the production of excess androgens and prevents adrenal crises. If you have salt-wasting CAH, you will also need to take a mineralocorticoid, such as fludrocortisone. This medication helps your body retain salt and water, preventing dehydration and maintaining healthy blood pressure. Your doctor will carefully adjust the doses of these medications based on your age, growth, and hormone levels. During times of stress, such as illness, injury, or surgery, you may need higher doses of glucocorticoids, known as "stress dosing." This is because your body naturally produces more cortisol during stress, and your medication needs to compensate. For girls with ambiguous genitalia, surgery may be an option to reconstruct the genitals, often performed in infancy or early childhood. Regular monitoring by an endocrinologist is essential to adjust treatment as needed.

Recovery & outlook

With proper diagnosis and consistent lifelong treatment, individuals with congenital adrenal hyperplasia (CAH) can lead full and healthy lives. Adhering to medication schedules and regular medical follow-ups are crucial for managing the condition effectively. The outlook is generally good, but careful management helps prevent complications like adrenal crises and long-term health issues.

Managing CAH is a lifelong commitment, but with consistent treatment, most people can maintain a good quality of life. It's important to take your medications exactly as prescribed and to never stop them suddenly, as this can lead to a life-threatening adrenal crisis. Regular check-ups with an endocrinologist are essential. Your doctor will monitor your hormone levels, growth, and overall health to ensure your treatment plan is effective and to make any necessary adjustments. They will also educate you on stress dosing and how to recognize signs of an adrenal crisis. While treatment helps manage the condition, some individuals with CAH may still experience challenges. These can include issues with growth, bone density, fertility, or psychological well-being. However, ongoing medical care and support can help address these concerns and improve long-term outcomes.

When to see a doctor

It is crucial to seek immediate medical attention if you or your child with congenital adrenal hyperplasia (CAH) show signs of an adrenal crisis, which is a life-threatening emergency. These signs include severe vomiting, extreme weakness, lethargy, poor feeding, or signs of dehydration. You should also contact your doctor if you experience new or worsening symptoms or have concerns about your medication.

An adrenal crisis is a medical emergency that can occur in people with CAH, especially those with the salt-wasting form. If you notice any of the following symptoms, seek emergency medical care right away: * Severe vomiting or diarrhea * Extreme weakness or fatigue * Lethargy or unresponsiveness * Poor feeding in infants * Signs of dehydration, such as dry mouth, decreased urination, or sunken eyes * Low blood pressure or rapid heart rate Always contact your doctor if you or your child with CAH become ill with a fever, severe infection, or injury, as these situations may require an increase in medication (stress dosing). Also, reach out to your healthcare provider if you have any concerns about your treatment, experience new or worsening symptoms, or have questions about managing your condition.

Frequently asked questions

Can congenital adrenal hyperplasia be cured?

No, congenital adrenal hyperplasia (CAH) is a lifelong genetic condition that cannot be cured. However, it can be effectively managed with lifelong hormone replacement therapy. This treatment helps replace the hormones your body cannot produce and controls the overproduction of other hormones, allowing individuals to lead healthy lives.

Is congenital adrenal hyperplasia contagious?

No, congenital adrenal hyperplasia (CAH) is not contagious. It is a genetic condition, meaning it is caused by changes in your genes that are inherited from your parents. You cannot catch CAH from another person, nor can you pass it to others through contact.

How common is congenital adrenal hyperplasia?

The most common form of congenital adrenal hyperplasia (classic CAH) affects about 1 in 15,000 children. A milder form, nonclassic CAH, is more common, affecting about 1 in 100 to 1 in 200 people in certain ethnic groups. The prevalence can vary among different populations.

What happens if congenital adrenal hyperplasia is left untreated?

If congenital adrenal hyperplasia (CAH) is left untreated, especially the classic salt-wasting form, it can lead to life-threatening adrenal crises. These crises can cause severe dehydration, low blood pressure, and dangerous electrolyte imbalances. Untreated CAH can also cause problems with growth, early puberty, and fertility issues.

Do people with CAH need to take medication for their entire lives?

Yes, individuals with congenital adrenal hyperplasia (CAH) typically need to take hormone replacement medication for their entire lives. This is because their adrenal glands cannot produce enough essential hormones on their own. Lifelong treatment is crucial for managing symptoms, preventing complications, and maintaining overall health.

Can people with congenital adrenal hyperplasia have children?

Many individuals with congenital adrenal hyperplasia (CAH) can have children, but fertility can sometimes be affected, especially in women with classic CAH. With proper management and treatment, many women with CAH can conceive and carry a pregnancy to term. Men with CAH generally have normal fertility, though some may experience issues.

Sources

• MedlinePlus — Congenital Adrenal Hyperplasia
• Mayo Clinic — Congenital Adrenal Hyperplasia
• Cochrane Library — Congenital Adrenal Hyperplasia