Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ Key Features +++ Essentials of Diagnosis ++ Adrenal hyperplasia: 21-OHase deficiency Genital virilization in females, with labial fusion, urogenital sinus, enlargement of the clitoris, or other evidence of androgen action Salt-losing crises in infant males or isosexual precocity in older males with infantile testes Increased linear growth and advanced skeletal maturation Elevation of plasma 17-hydroxyprogesterone concentrations in the most common form; may be associated with hyponatremia, hyperkalemia, and metabolic acidosis, particularly in newborns +++ General Considerations ++ CAH is most commonly (> 90% of patients) the result of homozygous or compound heterozygous mutations in the cytochrome P-450 C21 (CYP21A2) gene causing 21-hydroxylase deficiency The defective gene is present in 1:250–1:100 people and the worldwide incidence of the disorder is 1:15,000, with increased incidence in certain ethnic groups In its severe form, excess adrenal androgen production starting in the first trimester of fetal development causes virilization of the female fetus and life-threatening hypovolemic, hyponatremic shock (adrenal crisis) in the newborn, if untreated +++ Clinical Findings ++ In females Abnormality of the external genitalia varies from mild enlargement of the clitoris to complete fusion of the labioscrotal folds, forming an empty scrotum, a penile urethra, a penile shaft, and clitoral enlargement sufficient to form a normal-sized glans Signs of adrenal insufficiency (salt loss) typically appear 5–14 days after birth With milder enzyme defects, clinically apparent salt loss may not occur and virilization predominates with accelerated growth and skeletal maturation Pubic hair appears early, acne may be excessive, and voice may deepen Excessive pigmentation may develop Isosexual central precocious puberty may occur if treatment is not initiated before the bone age is significantly advanced In males Infant usually appears normal at birth but may present with salt-losing crisis in the first weeks of life In milder forms, salt-losing crises may not occur and virilization predominates, with enlargement of the penis and increased pigmentation, as well as other symptoms and signs similar to those of affected females Testes are not enlarged unless there are rare adrenal rests in the testes producing asymmetric enlargement In some rare enzyme defects, ambiguous genitalia may be present due to impaired androgen production +++ Diagnosis +++ Laboratory Findings ++ Hormonal studies are essential for accurate diagnosis Rapid assessment of genetic sex should be obtained in any newborn with ambiguous genitalia since 21-hydroxylase deficiency is the most common cause of ambiguity in females Assessment of urinary steroid metabolites is no longer routine but is reserved for rare forms of CAH +++ Imaging ++ Generally not required Ultrasonography, CT scanning, and MRI may be useful in defining pelvic anatomy or to exclude an adrenal tumor +++ Treatment +++ Pharmacologic ++ Hydrocortisone Initially, 30–50 mg/m2/d is given parenterally or orally until suppression ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.