Question: Labs

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Match the classic serum electrolyte / acid-base findings with the pediatric condition:

1) hypochloremic hypokalemic metabolic alkalosis

2) hyponatremic hyperkalemic metabolic acidosis

3) hyponatremic normokalemic metabolic acidosis

4) hypercalcemic metabolic alkalosis

A) DKA

B) pyloric stenosis

C) milk alkali syndrome

D) congenital adrenal hyperplasia

Kelly September 11, 2018 - 6:39 pm Reply

B. In pyloric stenosis after vomiting a lot (think of it as vomiting up H+ and Cl- from stomach acid), patients have a hypochloremic hypokalemic metabolic alkalosis. This pattern is seen less often now with earlier diagnosis due to ubiquitous use of ultrasound to rule out pyloric stenosis. In classic salt-losing congenital adrenal hyperplasia patients have low sodium and high potassium and may present in shock with metabolic acidosis. Diabetic ketoacidosis typically results in metabolic acidosis with a pseudohyponatremia due to the high glucose, and although the patient is total body potassium depleted, often a normal serum potassium due to cellular shifts with the acidosis. Milk alkali syndrome results from ingestion of too much calcium in conjunction with absorbable alkali, previously seen in kids taking milk and sodium bicarbonate, now seen more in women taking too much calcium carbonate supplementation; patients have a hypercalcemic metabolic alkalosis.