Verifying vomiting

Ask any clinician in the paediatric emergency department, and they’ll tell you that a shift doesn’t go by without at least one vomiting child. Vomiting babies with reflux and vomiting children with gastroenteritis they’re easy to manage and (as long as you don’t get vomited on) pretty satisfying. You either wave them goodbye with a diagnosis and management plan or watch them get better with some fluids and improving blood gas. But, it’s very easy to fall into the pitfall of cognitive bias – in reality, the list of differentials goes far beyond reflux and gastroenteritis.

There are two questions I always ask myself when I see a vomiting child in the ED.

What is the most likely thing this could be?

What do I not want to miss?

Let’s explore the non-reflux, non-gastroenteritis causes of vomiting from head to toe.

The Head

It’s easy to forget that raised intracranial pressure is a significant cause of vomiting. The classic is the vomiting infant, so it is easy to diagnose with reflux. It is so tragic when the diagnosis is wrong. There’ll be clues in the history:

• Fever and irritability in an infant, or fever, headache and photophobia in an older child? Think meningitis.
• Recent head injury? This could be an intracranial bleed or concussion.

You probably won’t miss these, but what about a more subtle cerebral cause of vomiting?

Early morning or night-time vomiting suggests raised intracranial pressure, especially if the child also has headaches. But – and this is a big but – not all children can tell us they have headaches. Children with speech and language delays can’t, toddlers can’t, and infants can’t. And to make it even harder in infants who spend much of their time lying down, the pressure effects won’t have such an obvious night-time pattern.  

A cognitive bias trap is assuming an infant who cries and vomits when they lie flat has reflux. So how do I ensure I don’t miss raised ICP in these kids? They need a full neurological examination, including cranial nerve and cerebellar function. A 6th nerve palsy is a giveaway for raised ICP, but you won’t always find a focal neurological deficit. In infants, the head circumference will be hugely helpful. The baby with a disproportionately large head to their weight is very worrying.

Behaviour change is another clue. An infant crying all the time, a child who’s no longer doing so well in school, an adolescent who’s always moody – another diagnostic trap would be to assume this is hormonal; they could have raised ICP.

Headsmart is an incredible resource and is my go-to for any symptom that could be due to a brain tumour. In 2006, a national survey showed that the UK time from symptom onset to diagnosis of paediatric brain tumours was, on average, 14 ½ weeks, much longer than other similar countries. So, in 2008, the RCPCH published a NICE-accredited, evidence-based referral guideline called The Brain Pathways Guideline and in 2011, launched the Headsmart: Be Brain Tumour Aware campaign.

By May 2013, the time-to-diagnosis dropped to 6 ½ weeks. This change was most pronounced from the first medical contact to cranial imaging.

(Watch Shaarna’s DFTB19 talk to hear more on this.)

Rob Delaney’s Tribute to My Beautiful Henry, recorded for BBC 4, is an incredibly moving description of Henry’s diagnosis with a brain tumour at age 1.

Sadly, I have to include intracranial bleeds due to non-accidental injury in neonates and infants in this group. The tragic fact is, for many children and infants with abusive head trauma, this isn’t their first presentation to an ED, and sadly, the opportunity to intervene was missed. We need to be on high alert for the possibility every time we see a child in the ED.

Ears, Nose or Throat

Otitis media and tonsillitis both commonly cause vomiting. Not all children can give you a history of ear pain or sore throat, so make sure you’re always armed with an otoscope cover and tongue depressor to look for infection here in kids who are vomiting.

If I diagnose otitis media, the mainstay of treatment is not antibiotics. It’s analgesia – otitis media is sore. I don’t prescribe antibiotics routinely unless the child is under two with bilateral otitis media or unless there is otorrhoea – discharge after a perforated tympanic membrane. The evidence shows that antibiotics don’t reduce the duration of infection enough to justify their side effects and the risk of resistance.

However, if the child is systemically unwell with mastoid tenderness, they are referred to ENT and started on IV antibiotics to minimise the risk of intracranial spread.

Not all tonsillitis is bacterial. I use a FEVER-PAIN score ≥ four to decide whether to prescribe penicillin, although neither scoring system is perfect. Check your local guidelines, as some hospitals prefer a throat swab and antibiotics only if it’s positive for streptococcus, while others suggest treating it clinically.

The Chest

Vomiting after coughing is common in asthma and infections such as bronchiolitis and pneumonia.

A recent mild fever, runny nose, and a lot of coughing in a child who hasn’t yet had their primary immunisations? Think pertussis. Do a rnasal swab and start a macrolide. And if that baby’s very young, they’re at risk of apnoeas—they’re coming in.

Although there might be a history of choking on some food, there’s not always a clear history of foreign body aspiration, especially in preverbal toddlers who put everything in their mouths.

Your examination will give you more clues: wheeze might point towards asthma, bronchiolitis, or inhaled foreign body; crepitations could suggest infection.

A note about pneumonia: if I diagnose pneumonia in a child with no oxygen requirement, who can take oral antibiotics and is well enough to go home, then I save the kid some radiation and don’t do a chest x-ray; I diagnose clinically and treat with oral antibiotics. I reserve chest X-rays for the much sicker children with severe respiratory distress to ensure I’m not missing an effusion or empyema.

And which antibiotic? The first line in most of the UK is amoxicillin, but the jury’s out as to what dose and for how long. I’m eagerly awaiting the results of the CAP-IT trial to see if low-dose, short-duration amoxicillin is a possible treatment for community-acquired pneumonia. Watch this space.

The Abdomen

We’ve already covered many differentials of vomiting in neonates, infants and children and have only just reached the abdomen. The causes so far are seen in most ages. When considering abdominal causes, it’s easiest to split them into age categories.

Neonates

As Tim Horeczko says, “Green vomit is surgical. Green vomit and abdominal distention is surgical. Vomiting and shock is surgical.”

Most children with intestinal malrotation and volvulus present within the first month of life, with the majority in the first week after birth. These neonates are sick. Fluid resuscitate, put down an NG tube on free drainage and call a surgeon.

Always check the inguinal orifices. Handily, these are just about where you’d feel for a femoral pulse as part of your cardiac exam. Strangulated inguinal hernias can cause obstruction and vomiting. You must look for them; otherwise, they’re easy to miss.

Pyloric stenosis is a non-bilious surgical cause of vomiting. It typically occurs between 2 and 12 weeks of age and is around four to six times more common in boys, particularly if they are first-born. A family history is often present. The pyloric muscle becomes hypertrophied, obstructing the outflow from the stomach. These babies vomit forcefully immediately after feeds – not just down their top but hitting the wall – and they’re always hungry.

The vomit is not bilious because the obstruction is proximal to the ampulla of Vater. The textbook says you can feel a palpable olive-sized pylorus, but this is difficult. A test feed might reveal visible waves of peristalsis across the abdomen.

Although the blood gas classically shows a hypokalaemic, hypochloraemic metabolic alkalosis, studies suggest hypokalaemia often doesn’t occur until three weeks’ worth of vomiting, so don’t be reassured by normal potassium. Use ultrasound when the diagnosis is in doubt. The initial treatment is medical (although don’t tell the surgeons that). Metabolic disturbances must be corrected before surgery, as this dramatically reduces the risk of intra- and post-operative complications.

Urinary tract infections are easy to rule out. A fever is not always present. It’s worth checking the urine in a vomiting neonate – if it’s an infection, that baby’s coming in for IV antibiotics.

Infants

There’s quite a lot of overlap in causes of vomiting between neonates and infants, but the presentation you don’t want to miss in this age group is intussusception.

Intussusception is the most common cause of obstruction in children ages 6 to 36 months old. Part of the intestine telescopes into the section immediately ahead of it, often at the ileocaecal junction, as the smaller ileum can fit snugly inside the bigger caecum. A recent viral infection often occurs, and the mesenteric lymph nodes act as a lead point.

Don’t be fooled by the toddler with a runny nose and intermittent vomiting. Intussusception is the great mimicker – infants and toddlers may present with crying, lethargy, or a syncopal-like event. The classic redcurrant jelly stool in the nappy is a late sign – don’t wait for it to make your diagnosis. Ultrasound will make the diagnosis, showing a classic doughnut with end-on bowel-inside-bowel. Most cases can be reduced with an air enema, but have a surgeon on standby – perforation is a risk, and if this happens, the child will need to go straight to theatre.

Children

The two main non-gastroenteritis abdominal causes of vomiting are appendicitis and torted testicles or ovaries, particularly in pre-adolescents and adolescents.

Appendicitis can be difficult to diagnose in young children. Maintain a high index of suspicion in a child who presents with vomiting and fever and looks unwell. I love the hop test – if a child can hop three times in a row with a smile, it’s not appendicitis. But if they limp over to the bed and grimace when you palpate their abdomen, this could be appendicitis. Bloods can help, but inflammatory markers don’t have to be raised for this to be appendicitis – and don’t let the surgeon tell you otherwise.

In adolescent girls, don’t forget – pregnancy makes you vomit. Do a HEEADSSS assessment and seek consent to do a pregnancy test.

Outside the box

But it doesn’t all end at the abdomen. Sometimes, you need to think outside the box too. Endocrine problems are not always so obvious. Always check the blood sugar in a vomiting neonate – could this be galactosaemia or another inherited metabolic condition?

And, if a neonate is hypoglycaemic or sick, check their electrolytes. Could this be an adrenal crisis secondary to a UTI or a crashing presentation of congenital adrenal hyperplasia? Have a low threshold to check an older child’s blood sugar, too – their vomiting could be due to DKA.

This is where our cognitive bias comes into play – in the middle of winter or a COVID pandemic, when it seems like almost every child we see has viral-induced wheeze, asthma or pneumonia, it’s easy to think the tachypnoeic child in front of you could have a respiratory tract infection. If they don’t have chest signs, think outside the box. Don’t miss the kid presenting in DKA who’s become tachypnoeic in an attempt to correct their ketotic acidosis.

And finally, consider toxins. Could the child have ingested something they shouldn’t have? Simply asking if there are any medications or toxins in the house the child could have gotten their hands on may be enough for the penny to drop.

This blog post was based on a DFTB Essentials Illness course talk. If you like it, look at https://www.dftbdigial.com for some other paediatric pearls.

Selected references

As well as the DFTB blog posts linked above, I also used these resources in preparing the DFTB Essentials talk.

https://www.headsmart.org.uk

brain_pathways_guidelines_final.pdf (headsmart.org.uk)

The Playbook | Pediatric Emergency Playbook (pemplaybook.org)