Congenital Adrenal Hyperplasia
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Introduction
Congenital adrenal hyperplasia (CAH) is the most common cause of ambiguous genitalia.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis. To get students thinking.
Causes and Risk Factors
CAH is an autosomal-dominant condition leading to partial or total enzyme defect.
In over 95% of cases, 21-hydroxylase deficiency leads to decreased cortisol and aldosterone, leading to androgen overproduction.
Pathophysiology
Cortisol deficiency increases ACTH production, leading to adrenal hyperplasia.
Different types include:
Late-onset 21-hydroxylase deficiency
Salt-wasting 21-hydroxylase deficiency
Salt-wasting accounts for over half of cases. It leads to low [Na], high [K], low [Cl], low glucose, and high ACTH.
It is a medical emergency, as infants can die of dehydration and shock at 2-4 weeks of age.
Treat with fluid and electrolytes, restore glucose, and start lifetime regimen of hydrocortisone.
Simple virilizing 21-hydroxylase deficiency
11-hydroxylase deficiency
17-hydroxylase deficiency
Signs and Symptoms
Clinical presentation depends on specific deficieincy.
- history
- physical exam
History
Physical Exam
Salt-wasting 21-hydroxylase deficiency can lead to hyperpigmentation of genitals and areola.
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
electrolytes
Increased ACTH leads to increased:
- 17-OH progesterone
- testosterone, DHEAS
- urinary 17-ketosteroids
Diagnostic Imaging
Advanced bone age results.
Differential Diagnosis
Treatments
Stress dosing of cortisol
Consequences and Course
The Case of...
Case #2 - a small story wrapping it all up and asking about esp management.
Additional Resources
Topic Development
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