Vomiting, at four ages

3 weeks

Bilious vomiting is malrotation with volvulus until proven otherwise; projectile non-bilious vomiting is pyloric stenosis.

Differential

1. Malrotation with midgut volvulus (bilious)
2. Pyloric stenosis (projectile, non-bilious, hungry after)
3. Gastro-esophageal reflux (effortless, thriving)
4. Sepsis or urinary tract infection
5. Inborn error of metabolism

What changes

Green vomit is a surgical emergency; do not wait for a scan to call the surgeon. Check the weight trend, electrolytes and glucose. Feel for the olive; an ultrasound confirms pyloric stenosis.

9 months

Intussusception, dehydration from gastroenteritis, and the infection hiding behind the vomiting.

Differential

1. Viral gastroenteritis
2. Intussusception (intermittent pain, drawing up legs, lethargy between episodes)
3. Urinary tract infection
4. Otitis media or pneumonia presenting with vomiting
5. Raised intracranial pressure (bulging fontanelle, head growth)

What changes

Ask about the pattern between episodes: a floppy or lethargic infant between bouts of screaming is intussusception until ultrasound says otherwise. Assess hydration first.

4 years

Appendicitis, diabetic ketoacidosis, and the head.

Differential

1. Gastroenteritis
2. Appendicitis (pain before vomiting, migrating)
3. Diabetic ketoacidosis (polyuria, polydipsia, weight loss, Kussmaul breathing)
4. Streptococcal pharyngitis or other infection
5. Raised intracranial pressure (morning vomiting, headache, ataxia)

What changes

Ask which came first, the pain or the vomiting: pain first points to a surgical abdomen. Check a glucose in any vomiting child with polyuria or weight loss. Early-morning vomiting with headache is imaging.

15 years

Diabetic ketoacidosis, pregnancy, ingestion, eating disorder, and the adult surgical abdomen.

Differential

1. Gastroenteritis or food-borne illness
2. Diabetic ketoacidosis
3. Pregnancy
4. Intentional or unintentional ingestion
5. Appendicitis, pancreatitis, cholecystitis
6. Eating disorder with purging

What changes

Interview privately. A pregnancy test in anyone who could be pregnant. A glucose and ketones. Ask about substances and about eating without judgement.