Callum is a four-month-old who has been brought in by his parents after 12 hours of vomiting and lethargy.

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<p>Callum is a four-month-old who has been brought in by his parents after 12 hours of vomiting and lethargy.</p><p>He has passed stool in the last 24 hours, with no blood or mucus.</p><p>Callum was seen at the practice two days ago for his routine vaccinations and was noted to be a thriving, fully breastfed infant with normal examination findings.</p><p>He was delivered vaginally at term after an uncomplicated pregnancy. His mother received influenza and pertussis vaccines antenatally and was vaccinated against COVID-19 post-partum.</p><p>On examination, Callum is afebrile but looks pale, with capillary refill of over three seconds and abdominal distension. He has a bilious vomit during the assessment.</p><p>He is referred to ED, where an X-ray is performed (pictured).</p>

Dr Kate Kelso is a GP and medical editor at Australian Doctor.