Question

What are the clinical features and treatment of congenital adrenal hyperplasia (CAH) in the newborn baby?

Hint:

Early diagnosis and treatment of CAH are essential to prevent life-threatening conditions such as adrenal crisis. Lifelong management is needed to maintain normal growth and prevent complications.

Answer 1

Congenital adrenal hyperplasia (CAH) is a group of inherited disorders that lead to deficiencies in enzymes required for adrenal steroidogenesis. The most common form is 21-hydroxylase deficiency, which causes decreased cortisol and aldosterone production, and an increase in androgen production.
Step 1: Clinical Features of CAH in Newborns:
1. Salt Wasting (Classic CAH): - This is the most severe form of CAH. Affected newborns cannot produce aldosterone, leading to salt wasting, dehydration, and hyperkalemia. This results in symptoms such as vomiting, poor feeding, weight loss, lethargy, and hypovolemic shock. If not treated, this condition can lead to death in the first weeks of life. 2. Ambiguous Genitalia (Classic CAH): - In female infants, excessive androgen production leads to virilization of the external genitalia, causing clitoromegaly and labial fusion, which can be mistaken for male genitalia. In male infants, virilization is typically less noticeable at birth, but early signs of puberty may develop. 3. Non-Salt Wasting (Simple Virilizing CAH): - In this less severe form of CAH, there is sufficient aldosterone production, so salt-wasting is not a concern. However, excessive androgen production still leads to virilization of female genitalia. These infants may also develop early signs of puberty. 4. Cortisol Deficiency: - Infants with CAH may present with cortisol deficiency, resulting in hypoglycemia, lethargy, and poor feeding. This deficiency can further contribute to dehydration and weight loss.
Step 2: Treatment of CAH in Newborns:
1. Glucocorticoid Replacement: - The cornerstone of treatment for CAH is the replacement of cortisol with glucocorticoids such as hydrocortisone. The dose is carefully adjusted to both suppress the excessive androgen production and ensure normal growth and development. 2. Mineralocorticoid Replacement (for Salt-Wasting CAH): - For salt-wasting forms of CAH, fludrocortisone is administered to replace aldosterone and help the body retain sodium, thus preventing dehydration and hypovolemia. This is essential in the early life of the infant. 3. Surgical Management (for Ambiguous Genitalia): - Female infants with ambiguous genitalia may require reconstructive surgery to normalize the appearance of the external genitalia. This is usually done later in infancy or early childhood, depending on the severity of the genital virilization. 4. Monitoring and Support: - Regular monitoring of electrolytes, growth, and development is crucial. In the early days of life, close monitoring of fluid and electrolyte balance is required, especially in salt-wasting forms.
- Lifelong glucocorticoid therapy is required, and the dosage may need to be adjusted during times of stress (e.g., infections or surgeries). Salt and fluid intake should be monitored, particularly in the first few months.