Review the following hormonal and clinical profiles of pediatric and adolescent patients p… — USMLE Step 2 CK

Review the following hormonal and clinical profiles of pediatric and adolescent patients presenting with disorders of steroidogenesis. Correlate each specific laboratory and physical presentation with the most accurate underlying enzyme deficiency or clinical syndrome.

A $2$ -week-old newborn presents with lethargy, vomiting, ambiguous genitalia ( $46,\text{XX}$ ), hyponatremia, hyperkalemia, and markedly elevated serum $17$ -hydroxyprogesterone levels.Classic $21$ -hydroxylase deficiency
A $3$ -week-old infant is evaluated for ambiguous genitalia ( $46,\text{XX}$ ). Laboratory testing reveals hypokalemia, severe hypertension, and elevated serum $11$ -deoxycorticosterone and $11$ -deoxycortisol levels. $11\beta$ -hydroxylase deficiency
A $15$ -year-old phenotypic female ( $46,\text{XY}$ ) presents with primary amenorrhea and lack of secondary sexual characteristics. Examination reveals hypertension and hypokalemia. Serum testosterone and estradiol are low, while corticosterone is elevated. $17\alpha$ -hydroxylase deficiency
A $16$ -year-old female presents with severe acne, hirsutism, and oligomenorrhea. Blood pressure and basic metabolic panel are normal. An ACTH stimulation test demonstrates an exaggerated increase in $17$ -hydroxyprogesterone.Non-classic $21$ -hydroxylase deficiency

Answer

The clinical profiles correspond to Classic 21-hydroxylase deficiency, 11-beta-hydroxylase deficiency, 17-alpha-hydroxylase deficiency, and Non-classic 21-hydroxylase deficiency, respectively.

Each congenital adrenal hyperplasia variant presents with a distinct pattern of mineralocorticoid, glucocorticoid, and sex steroid derangements based on the specific enzymatic block in the adrenal steroidogenesis pathway.

Step-by-Step Solution

Analyze the first profile for electrolyte abnormalities and signs of virilization.

The combination of hyponatremia, hyperkalemia, virilization, and high 17-hydroxyprogesterone indicates a complete lack of mineralocorticoids and glucocorticoids with a shunt toward androgen production.

This is the hallmark pattern of Classic 21-hydroxylase deficiency.

Evaluate the second profile, focusing on blood pressure, electrolytes, and physical appearance.

The presence of hypertension and hypokalemia (mineralocorticoid excess) along with virilization (androgen excess) points to an accumulation of 11-deoxycorticosterone.

This specific combination identifies 11-beta-hydroxylase deficiency.

Assess the third profile by noting the chromosomal sex versus phenotypic presentation alongside vital signs.

A 46,XY individual appearing as a phenotypic female with hypertension and hypokalemia indicates a lack of sex steroids coupled with excessive mineralocorticoid production.

This pathway blockage is characteristic of 17-alpha-hydroxylase deficiency.

Examine the fourth profile for late-onset symptoms without baseline metabolic derangements.

Late-onset signs of hyperandrogenism with normal blood pressure and electrolytes, unmasked fully by an ACTH stimulation test, point to partial enzyme activity.

This matches the clinical picture of Non-classic 21-hydroxylase deficiency.

Key Concept

Pathophysiology and clinical differentiation of congenital adrenal hyperplasia (CAH) enzyme deficiencies.

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