What Is Cyclic Vomiting Syndrome (CVS)?
Cyclic vomiting syndrome is a complex disorder characterised by recurrent episodes of severe vomiting, separated by asymptomatic periods.
This condition affects individuals of all ages, though it typically begins in childhood. The average onset age is around five years in children and 21-35 years in adults. The prevalence of CVS in children is estimated to be around 2%, but the prevalence in adults remains unknown.
Typically, the diagnosis remains elusive, with an average delay of 2 years in children and 8 years in adults. Cyclic vomiting episodes normally last almost 30 hours in children and up to 3-6 days in adults, occurring every four weeks in children and around three months in adults. Abdominal pain occurs in 80% of children and 60% of adults. Inter-episodic symptoms occur in 50-60% of adults but are uncommon in children.
The prognosis?
CVS is not fatal and does not shorten life expectancy. The condition is not typically progressive, and many patients, especially children, experience improvement or resolution of symptoms over time. Approximately 60% of children have resolution of vomiting episodes, often within weeks or months after diagnosis. Some children outgrow CVS completely, particularly as they enter adolescence.
About 40-42% of patients continue to have somatic complaints like headaches and abdominal pain, even after vomiting episodes resolve. In some cases, CVS in childhood may transition to migraine headaches in adulthood.
What causes it?
The pathophysiology is unknown.
However, CVS shares clinical features with central nervous system disorders like migraine; CVS has been associated with autonomic symptoms similar to those observed in migraine.
Treatment
Because CVS is a migraine variant and can lead to migraine as an adult, treatment is modelled on migraine treatment, i.e. primarily pharmaceutical.
These include antidepressants for serotonin, a biochemical thought to be involved in migraine but not proven (antidepressants increase serotonin). Other medication to help manage nausea and vomiting may be prescribed along with triptan medication, which was explicitly developed to abort migraine. Importantly, triptan medication aborts migraine by desensitising the brainstem.
Other approaches are identifying and avoiding triggers and lifestyle modifications, such as regular sleep, meals, hydration, and exercise. While stress is considered by some to be involved, psychological counselling is sometimes recommended.
Triggers are not a cause. Furthermore, they are often difficult to recognise and, therefore, avoid.
Evidence supports that (painless) musculoskeletal misbehaviour in the upper neck can sensitise the brainstem in migraine. My research has shown that manual (not ‘cracking’ of the joints) therapy can desensitise the brainstem.
The Watson Headache® Approach, a specific manual therapy protocol, has been shown to decrease the brainstem’s sensitivity.
Conclusion
While CVS is harmless, as with adults, it can significantly impact the quality of a child’s (a critical phase of) life and whole families. This needs to be managed appropriately. All possibilities must be considered, and the current medical recommendations, i.e. tolerating medication and its effects on a child’s body, identifying triggers, modifying lifestyle, etc., must be approached empathetically and realistically.
Assessing and treating the upper neck in those with CVS over the past 25 years has changed my perspective. Along with Abdominal Migraine, Cyclic Vomiting Syndrome is one of the most rewarding conditions to manage.
Summary
Abdominal migraine and cyclic vomiting syndrome (CVS) are closely related conditions, often considered variants of migraine. These episodic disorders share clinical features and are more common in children. Both conditions are associated with a higher prevalence of migraine in patients and their families compared to controls. Whilst the pathophysiology remains unknown, autonomic dysfunction, i.e. disturbance of the automatic nervous system, is influenced by nerve signals from structures in the upper neck. Abdominal migraine and CVS are considered paediatric precursors of migraine.
