Cyclical Vomiting Syndrome in Children: Break the Cycle

It is the middle of the night, and your child has woken you again with that look you have come to dread, and within minutes you are kneeling on the bathroom floor with a bowl and a flannel, holding back their hair and watching helplessly as another round of sickness takes hold. This is the reality of life with Cyclical Vomiting Syndrome (CVS) which kicks in every two or four weeks with exhausting predictability.

Most of the families who come to see us with a child who has CVS have had a long and exhausting road including multiple A&E trips, drips and anti-sickness medication; and yet their tests have come back ‘normal’. The good news is that there is so much more to investigate and digging deep into their gut health, nutrition, cellular health and nervous system can help them to break this cycle.

In this blog I explain what CVS really is, the conditions that we have found at NatureDoc that can hide behind a CVS label as well as the tests worth asking for if your child is vomiting every two to four weeks for no obvious reason. More importantly, I share the nutrients with the best clinical evidence to help support recovery.

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What is Cyclical Vomiting Syndrome?

Cyclical Vomiting Syndrome is defined by sudden and repeated episodes of severe vomiting separated by stretches of feeling totally well in between. These episodes often start in the early hours of the morning and can last from a few hours to several days, and tend to follow a predictable pattern in each child, meaning that every episode looks much like the last one. In between, your child is themselves again, often completely full of beans and feeling great.

The average age of CVS onset is around five years old, but it can start earlier on in babies and young toddlers or appear for the first time during the teenage years.

CVS belongs to a family of conditions known as disorders of the gut-brain axis, and shares similar metabolic reasons to migraine. Many children with CVS go on to develop migraine headaches in adolescence, and most have a parent or grandparent with migraine. The genetic and biochemical overlap with migraine is something to always consider when a child is having repeated episodes of vomiting.

The classic episode pattern

Vomiting comes on suddenly, often in the night between 1am and 7am.
They experience intense nausea, retching and forceful vomiting (sometimes 20 times an hour at its peak).
They look very pale and can sweat and drool.
They are lethargic and sensitive to light or noise.
They experience tummy pain, headache and sometimes a low-grade temperature.
Episodes can last hours to days, then stop as suddenly as they started.
They are symptom-free in between, with each episode resembling the last.

Common episode triggers

Episodes rarely come out of nowhere and most families spot patterns for CVS once they start looking. Keeping a careful diary is one of the most useful things you can do when being your child’s health detective. The big triggers in children include:

Emotional stress and anxiety. This includes anticipatory anxiety just before school, exams or parties.
Overexcitement, even positive excitement, such as ahead of their birthday or a special holiday.
Infections, including viral and bacterial illnesses.
Not enough sleep or disrupted daily routines.
Skipped meals or not eating for long periods of time.
Specific food triggers such as chocolate, cheese, MSG, food colourings and additives which are common offenders.
Travel and time zone changes.
Hot weather and dehydration.
At specific times during the menstrual cycle in older girls.

What is actually driving CVS?

CVS is technically a diagnosis of exclusion, meaning that the doctors have ruled out any other significant medical reasons for the vomiting, such as cancer, allergy or coeliac disease.

When we work with kids experiencing CVS in our NatureDoc clinics, we look at three layers. These are the underlying drivers (the things that prime a child for the vomiting episodes), the triggers (what tips them into one), and the conditions that can mimic CVS and need ruling out.

Mitochondria and energy

Mitochondria are the tiny energy factories living inside every cell in your child’s body. Think of them as little batteries that turn the food your child eats into the energy their brain, gut, muscles and immune system need to run smoothly. Every time they think, digest, run around or fight off a bug, their mitochondria are doing the hard work keeping their energy levels on an even keel in the background.

When their mitochondria are not working as well as they should, their body struggles to convert their food into useable energy. The cells most affected tend to be the ones that need the most energy (and have the most mitochondria), which is why the brain and gut so often bear the brunt of this.

This is why CVS can feel like a whole-body experience rather than just a tummy problem. It is why kids often feel wiped out, foggy or wobbly in the run-up to an episode, and then exhausted for days afterwards, as if their internal batteries have been completely drained.

A subset of children with CVS carries inherited mitochondrial genetic variants that affect how efficiently these little batteries charge. And this is one of the reasons why CVS tends to run in families and overlaps so much with migraine, which also has similar mitochondrial features. The good news is that mitochondrial function can be supported nutritionally, which is why the supplements covered later on in this blog tend to work so well.

Autonomic nervous system imbalance

The autonomic nervous system (ANS) is the part of your child’s nervous system that runs in the background, without them having to think about it. It controls a child’s heart rate, blood pressure, breathing, digestion, sweating, body temperature, pupil size and the stress response. And it has two main settings: a fight-or-flight mode that revs everything up, and a rest-and-digest mode that calms everything down. Ideally, these two modes keep in balance like the in-and-out of breath.

In children with CVS, this balance is often out of kilter. The fight-or-flight mode dominates, and their rest-and-digest mode fades into the background. The vagus nerve, which is the main communication superhighway between the gut and the brain and the most important nerve in the rest-and-digest system, tends to misfire. This feeds directly into the nausea pathway and explains all those autonomic symptoms that happen during an episode, like the pallor, drooling, sweating, rapid heartbeat and that floppy, washed-out look.

Even between episodes, a child with autonomic imbalance might seem jumpy or anxious or often experience racing thoughts. They might feel dizzy or become light-headed easily when they stand up quickly, they might struggle to regulate their body temperature (running hot one minute and freezing the next), have cold hands and feet, get a pounding heart for no obvious reason, feel exhausted after eating, or need the loo at unpredictable times. Many of these children also have disturbed sleep and a heightened sensitivity to noise, light or strong smells.

A child whose ANS is out of sync will need more input with nutrition and lifestyle support to help regulate their nervous system better. Simple things like learning to breathe optimally, laughing more and spending time in nature can really help over time.

The gut-brain axis

The gut and the brain are constantly chatting to each other through nerves (especially the vagus nerve), hormones and immune messengers. This two-way conversation is called the gut-brain axis, and it explains why butterflies in the tummy, anxious poos before a school exam or losing your appetite when worried are all real, physical responses.

With CVS, this conversation between the gut and the brain has become noisy and confused. The signals coming up from the gut to the brain are exaggerated, and the brain has become hypersensitive to them, which is a phenomenon called visceral hypersensitivity. Things that would normally pass unnoticed, like a slightly overfull tummy, a bit of trapped wind or a touch of indigestion, can be interpreted by the brain as a major alarm and trigger the nausea or vomiting.

A big part of this conversation is shaped by the gut microbiome, which is the trillions of bacteria, yeasts and other microbes living in your child’s tummy. A healthy, diverse microbiome produces calming compounds like short-chain fatty acids and helps make neurotransmitters such as serotonin and GABA. An unbalanced microbiome can do the opposite and drive nausea, anxiety, low mood and visceral pain.

This is why supporting the microbiome with whole foods, brightly coloured fruits and vegetables, fibre, fermented foods and (where appropriate) specific probiotic strains can be such an important piece of the CVS picture. A gut microbiome and function test can be your guide to know precisely which aspects of your child’s gut health and microbiome need support.

The hidden conditions that can look like CVS

Before a CVS diagnosis is made by a doctor, several conditions need ruling out because they can cause very similar symptoms and respond to completely different treatment. Many of these get missed when families are only ever seen in A&E during an episode and this is why it is important to push for more investigations. The conditions below are the ones we most often see sitting underneath a CVS label which has been given too soon and should ideally be assessed thoroughly by a gastroenterologist.

Helicobacter pylori

H. pylori is a bacterial infection that lives in the stomach lining and can cause gastritis, nausea and regular vomiting episodes. It is a spiral-shaped bacteria that can screw into the stomach lining and hide dormant for weeks and then rear its head again. This can mimic a cyclical pattern and may be dubbed an H pylori flare. H pylori is straightforward to test for through a stool antigen test or a breath test via your GP and then eradication treatment using a combination of antibiotics and proton pump inhibitors is usually offered. We offer herbal protocols to help the stomach lining to recover from the damage from this nasty bacterial infection.

Coeliac disease

Coeliac disease can present atypically in children, with out of the blue vomiting rather than the classic gut symptoms (yellow, fatty stools and weight loss), and it absolutely must be excluded before settling on a CVS label.

Testing for coeliac disease is through a Transglutaminase (TTG) blood test together alongside a total IgA level which can be done through your GP. The total IgA is essential on top of the TTG, especially in very young children as an IgA deficiency would give a false negative result for coeliac disease.

Children must still be eating gluten when the TTG test is done, otherwise the result will not be reliable. However, NatureDoc do offer advanced gluten sensitivity testing options if eating gluten again really is not an option.

SIBO and gut dysbiosis

When there is bacterial overgrowth in the small intestine, these microbes produce symptoms of gas, bloating, nausea and post-meal vomiting that can overlap a lot with CVS. Children with slower stomach emptying (gastroparesis) or sluggish gut motility (known as a slow migrating-motor complex), which often accompanies CVS, are at higher risk of developing small intestinal bacterial overgrowth (SIBO), so the two can feed each other and become a vicious circle. If your gastroenterologist does not offer SIBO testing, then this is something we can offer at NatureDoc and is part of our broader gut microbiome and gut function panels.

Eosinophilic conditions

Eosinophilic conditions involve allergy-type immune cells building up along the throat and gut wall and this is an increasingly recognised cause of recurrent vomiting in children. It can also look like extremely painful reflux in babies and food refusal in young children. It does need an endoscopy with biopsies to diagnose it properly through a gastroenterologist, because blood tests alone will not pick it up. And, if eosinophils are found in the biopsy, then a trial elimination diet such as cutting out gluten, dairy, eggs and soya as well as taking mast cell stabilising medications and supplements can often help.

Pancreatic insufficiency

When the pancreas does not produce enough digestive enzymes, then food is poorly broken down and nausea, bloating and vomiting can follow meals. This is not a classic CVS trigger, but it is worth screening for if your child has weight loss, fatty stools or is found to have low levels of fat-soluble vitamins such as vitamin A, D and E in their blood tests. A simple stool pancreatic elastase test will pick this issue up and then digestive enzymes must be given every time they eat.

Inflammatory bowel disease

Even though there are usually much more significant symptoms, Crohn’s and ulcerative colitis can present with vomiting alongside tummy pain and weight loss. This is where a faecal calprotectin test can show if there is inflammation in the gut and if so, this warrants further investigations for inflammatory bowel disease through a gastroenterologist.

Well-established nutrients

There are now consensus guidelines that specifically recommend a ‘mitochondrial cocktail’ of coQ10, carnitine, vitamin B2 and magnesium as a prophylactic strategy in CVS, meaning these are supplements taken together between episodes to reduce the chance of new episodes. This approach is particularly important if mitochondrial dysfunction appears to be part of the picture and there is migraine in the family. Dosing for children is weight-based, and it is important to get proper guidance from a practitioner.

Coenzyme Q10

Coenzyme Q10 is probably the single nutrient that has the strongest evidence for helping CVS specifically. It plays a central role in mitochondrial energy production and is essentially helping to recharge those tiny cellular batteries. CoQ10 blood levels can be measured or tracked through organic acid testing and then the dose adjusted accordingly.

L-carnitine

L-carnitine helps to shuttle fatty acids into the mitochondria where they can be burned for energy. It is the second leg of the standard mitochondrial cocktail and is usually used alongside CoQ10 rather than instead of it. Children with CVS often have low or borderline carnitine on testing and the child rallies and is full of beans once this is optimised. One thing to know is that at higher doses L-carnitine can cause a fishy body odour, which usually resolves when the dose is adjusted.

Riboflavin (vitamin B2)

Riboflavin supports mitochondrial energy production and has strong evidence behind it for preventing migraine, which is why it has translated over into the CVS space. The migraine evidence is solid enough that riboflavin now appears in mainstream paediatric neurology recommendations and it is hard to overdose as we urinate out any excess. One harmless side effect to be aware of is that it turns the urine a bright yellow colour (think the colour of a highlighter pen!).

Magnesium

Magnesium is a mighty mineral which calms the nervous system, supports mitochondrial function and has good evidence for reducing the frequency and intensity of migraines. The form matters when supplementing. Ideally you would give your child magnesium bisglycinate and for older teens and young people then use magnesium l-threonate, which is able to reach through the blood-brain barrier and helps to reset the nervous system.

Probiotics and microbiome support

If you remember, the gut-brain axis really matters in CVS and this means that supporting the microbiome is sensible and important groundwork. As well as feeding them yoghurt, kefir and other cultured foods, you can also consider topping their gut up with some live bacterial strains to help ease the nausea, anxiety and gut-brain communication. But it must be noted that if SIBO is in the picture, then probiotics need handling carefully and are best given alongside or after a round of antimicrobials.

Round Up

If your child has been vomiting in consistent cycles for months or even years without a clear answer, then the most important step you can make is moving from ‘managing the episodes’ to ‘finding the root cause’. CVS is a real condition, and for some children, it is the right label, but only once conditions that mimic it have been thoroughly excluded and the underlying drivers are being addressed. And it is worth trialling the mitochondrial cocktail, especially if there is migraine in the family.

If you would like personalised lab testing and support for your child, do get in touch with our NatureDoc clinical team. We can work alongside your gastroenterologist and GP to dig into the root causes of recurring vomiting episodes, and we put together a tailored nutritional and lifestyle plan to help your child feel better and stay better.

Ask me what supplements can help… or anything else!

Being violently sick every two weeks? The reasons for Cyclical Vomiting Syndrome