GERD and Peptic Ulcer Disease USMLE Step 1 Practice Question
A 4-week-old boy presents with progressive nonbilious projectile vomiting after feeds for 3 days. He appears hungry immediately after vomiting. Vital signs show HR 145/min, RR 32/min, BP 70/45 mmHg, and normal temperature. Physical examination reveals visible peristaltic waves and a palpable olive-shaped epigastric mass. Serum electrolytes show hypochloremia and hypokalemia. Upper abdominal ultrasound confirms the clinical suspicion. Which acid-base disturbance is most likely present?
Answer choices
- AHypochloremic metabolic alkalosisCorrect answer
- BRespiratory alkalosis
- CHigh anion gap metabolic acidosis
- DNormal anion gap metabolic acidosis
- EHyperkalemic metabolic acidosis
- FHypochloremic metabolic acidosis
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