A 6-week infant with ambiguous genitalia (as shown below) presents with an episode of dehydration & shock requiring hospitalization. What is the electrolyte abnormality that you expect in this baby?
**Core Concept**
The question is testing the understanding of the electrolyte imbalance associated with Congenital Adrenal Hyperplasia (CAH), a condition that affects the adrenal glands' ability to produce hormones, particularly cortisol and aldosterone. This condition can lead to an overproduction of androgens, causing ambiguous genitalia in infants.
**Why the Correct Answer is Right**
In CAH, the enzyme 21-hydroxylase deficiency leads to a decrease in aldosterone production. Aldosterone plays a crucial role in regulating electrolyte balance by promoting sodium retention and potassium excretion in the kidneys. With decreased aldosterone levels, the kidneys retain less sodium and excrete more potassium, resulting in hyponatremia (low sodium levels) and hyperkalemia (high potassium levels).
**Why Each Wrong Option is Incorrect**
* **Option B:** This option is incorrect because CAH is associated with an overproduction of androgens, not an underproduction. Additionally, the electrolyte imbalance in CAH is primarily related to aldosterone deficiency, not an overproduction.
* **Option C:** This option is incorrect because the electrolyte imbalance in CAH is not primarily related to an overproduction of cortisol. While cortisol levels may be decreased in CAH, the primary electrolyte abnormality is related to aldosterone deficiency.
* **Option D:** This option is incorrect because the electrolyte imbalance in CAH is related to aldosterone deficiency, not an overproduction of aldosterone.
**Clinical Pearl / High-Yield Fact**
In cases of ambiguous genitalia, it's essential to consider CAH as a possible diagnosis, especially if the infant presents with electrolyte imbalances or signs of androgen excess.
**Correct Answer: C. Hyperkalemia**