Review the following clinical scenarios of patients with suspected congenital adrenal hyperplasia. Match each patient's clinical presentation and laboratory profile to the most likely specific deficient adrenal enzyme.
- A 2-week-old genotypic female (46,XX) presents with virilized ambiguous genitalia, lethargy, blood pressure of 60/40 mmHg, serum sodium of 126 mEq/L, and serum potassium of 6.4 mEq/L.21-hydroxylase
- A 2-week-old genotypic female (46,XX) presents with virilized ambiguous genitalia, blood pressure of 105/65 mmHg (>95th percentile for age), serum sodium of 146 mEq/L, and serum potassium of 3.1 mEq/L.11-beta-hydroxylase
- A 16-year-old genotypic male (46,XY) presents with phenotypic female external genitalia, primary amenorrhea, absent secondary sexual characteristics, blood pressure of 142/92 mmHg, and serum potassium of 3.0 mEq/L.17-alpha-hydroxylase
Cevap
The hypotensive, hyperkalemic virilized infant has 21-hydroxylase deficiency. The hypertensive, hypokalemic virilized infant has 11-beta-hydroxylase deficiency. The hypertensive, hypokalemic under-virilized adolescent has 17-alpha-hydroxylase deficiency.
The adrenal steroidogenesis pathway branches into mineralocorticoids, glucocorticoids, and androgens. A block at 21-hydroxylase eliminates mineralocorticoids and glucocorticoids, causing salt wasting and androgen excess. A block at 11-beta-hydroxylase eliminates terminal mineralocorticoids and glucocorticoids but traps 11-deoxycorticosterone (a potent mineralocorticoid), causing hypertension, hypokalemia, and androgen excess. A block at 17-alpha-hydroxylase eliminates glucocorticoids and androgens, forcing all production down the mineralocorticoid pathway, resulting in hypertension, hypokalemia, and phenotypic female genitalia regardless of genotypic sex.
Adım Adım Çözüm
Anahtar Kavram
Clinical and laboratory differentiation of Congenital Adrenal Hyperplasia (CAH) enzyme deficiencies