Cyclical vomiting syndrome

Also called CVS, Abdominal migraine

Severe vomiting attacks with complete recovery in between. Closely related to migraine, and in adults, heavy cannabis use is a common cause.

What it is

Recurrent episodes of severe nausea and vomiting lasting hours to days, separated by periods of complete normality.

It affects both children and adults and is closely related to migraine: many people have migraine themselves or a strong family history, and the same preventive medicines often work.

The episodes are stereotyped, meaning each one follows the same pattern for that person, often starting at the same time of day, frequently in the early morning. Between episodes the person is entirely well, which is the feature that distinguishes it from most digestive conditions.

Diagnosis takes years on average, and people typically undergo repeated investigations and repeated emergency admissions before anybody names it.

**In adults, a specific and increasingly common cause is cannabinoid hyperemesis syndrome**, from regular heavy cannabis use. The distinctive feature is compulsive hot bathing or showering, which relieves the nausea. It resolves completely on stopping cannabis, and continues indefinitely if not, and asking about it without judgement is essential because people rarely volunteer it.

Attacks cause dehydration and electrolyte disturbance, and repeated vomiting damages tooth enamel and can tear the oesophagus.

Treatment is a written plan: triggers, early abortive treatment, and preventive medication.

Signs you might notice

Sudden severe nausea and repeated vomiting, often starting in the early hours.

Episodes lasting hours to several days, then stopping.

Complete wellness between episodes.

The same pattern each time.

Pallor, exhaustion, abdominal pain, headache, and sensitivity to light and noise during attacks.

Triggers: stress, excitement, infection, missed meals, poor sleep, menstruation, certain foods.

Urgent: signs of dehydration, inability to keep fluids down, drowsiness, confusion, or vomiting blood.

Not this, and needing investigation: weight loss, vomiting that is not episodic, blood in the vomit, severe abdominal pain, or a change in the established pattern.

Ask about cannabis use and about hot bathing behaviour in any adult with this picture.

How it can affect day-to-day life

The exhaustion after an attack lasts a day or two and is often not accounted for in school or work absence.

Repeated emergency attendances lead to people being labelled and treated with suspicion, particularly where opioids have been given previously. A written care plan agreed with the local emergency department transforms that, and is worth pushing for.

Dental damage from repeated acid exposure is significant and preventable: rinsing with water rather than brushing immediately after vomiting protects enamel.

For children, school needs to understand that attacks are sudden and unpredictable and that the child is completely well in between.

Preventive treatment, often amitriptyline, propranolol or topiramate, works for many people and requires weeks to take effect.

Early treatment at the first warning symptom, with anti-sickness medication and sometimes a triptan, can abort an attack, which is why having medicines at home matters.

Supporting someone well

Keep a diary of attacks: timing, duration, triggers, what helped.

Ask for the diagnosis by name if the pattern fits, and ask about the link to migraine.

Ask for a written emergency care plan agreed with the local hospital.

Treat early, at the first warning sign, rather than waiting.

Ask about preventive medication and give it several weeks.

Keep fluids going and use rehydration salts; seek help if nothing stays down.

Rinse the mouth with water after vomiting and do not brush immediately.

In an adult, ask about cannabis directly and without judgement, including hot bathing behaviour.

Address sleep, meals and stress, which are the commonest triggers.

Where to get help

A GP practice for diagnosis and preventive treatment; gastroenterology or neurology for difficult cases.

The emergency department for dehydration, with a care plan if one exists.

Guts UK and Migraine Trust both publish relevant information.

Talk to Frank or a local drug service for cannabis-related cases.