Question

An 8 days old male infant was brought in a state of dehydration and shock. Examination revealed hyperpigmentation over the body with normal external genitalia. Blood tests revealed hypoglycemia, Na = 124 mEq/L and K = 7 mEq/L. What is the probable diagnosis?

• A. Congenital adrenal hyperplasia
• B. Adrenal haemorrhage and shock
• C. Acute gastroenteritis with dehydration
• D. Hyperaldosteronism

Hint:

Neonate with low sodium, high potassium, low sugar and hyperpigmentation equals salt-wasting adrenal failure.

Answer 1

The Correct Option is A

Step 1: List the biochemical findings. The infant has hyponatremia (Na 124, low), hyperkalemia (K 7, high) and hypoglycemia, together with dehydration and shock. This is the classic salt-wasting crisis picture.
Step 2: Note the hyperpigmentation. Excess ACTH (driven by low cortisol) raises melanocyte stimulation, causing generalised hyperpigmentation, which is a strong clue to primary adrenal insufficiency from birth.
Step 3: Recognise the diagnosis. Salt-wasting congenital adrenal hyperplasia (most often 21-hydroxylase deficiency) causes deficient cortisol and aldosterone, leading to hyponatremia, hyperkalemia, hypoglycemia, dehydration and shock in the second week of life, with compensatory ACTH excess and hyperpigmentation.
Step 4: Address the normal genitalia. In a male infant, salt-wasting CAH typically presents with normal-looking external genitalia, so a crisis without genital ambiguity in a boy still strongly suggests CAH.
Step 5: Eliminate the others. Adrenal haemorrhage is usually acute and not associated with chronic hyperpigmentation, gastroenteritis would not characteristically cause hyperkalemia with this pattern plus pigmentation, and hyperaldosteronism causes hypokalemia and hypertension (the opposite of this picture).
Step 6: The correct answer is congenital adrenal hyperplasia (option 1).