What causes Cyclic Vomiting Syndrome (CVS)?

From the Guidelines

Cyclic Vomiting Syndrome (CVS) is likely caused by a combination of psychological and physiological factors, including stress, which is confirmed as a trigger in approximately 70%–80% of patients 1. The exact cause of CVS remains unknown, but several factors likely contribute to its development.

• Psychological factors, such as stress, anxiety, and panic, are common triggers for episodes, with stress being the most prevalent trigger, affecting 70%–80% of patients 1.
• Physiological factors, including hormonal fluctuations, sleep deprivation, and physiological stressors like acute infections or surgery, can also trigger episodes 1.
• Other potential triggers include travel, motion sickness, prolonged fasting, and intense periods of exercise 1.
• The pathophysiology underlying CVS is complex and not fully understood, but it is thought to involve abnormal regulation of gut motility and vomiting reflexes, possibly related to autonomic nervous system dysfunction.
• Understanding these potential causes is crucial in guiding treatment approaches, which typically involve preventive medications, lifestyle modifications to avoid triggers, and acute interventions during episodes.
• It is essential to note that CVS often runs in families, suggesting a possible genetic predisposition, and that certain foods, food allergies, and gastrointestinal disorders like gastroesophageal reflux may also precipitate attacks, although the evidence for these factors is not as strong as for stress and other psychological and physiological factors 1.

From the Research

Causes of Cyclic Vomiting Syndrome (CVS)

The exact etiology of CVS remains unknown, but several factors are postulated as possible triggers, including:

• Genetic factors (polymorphisms) 2
• Nervous system alterations and autonomic dysregulation 2, 3
• Environmental factors, such as the use and abuse of cannabinoids 2, 4
• A combination of genetic, environmental, autonomic, and neurohormonal factors 4
• A possible shared pathophysiology with migraine headaches 5, 4

Associated Conditions

CVS is frequently associated with:

• Anxiety and depression 6, 4
• Autonomic dysfunction 4
• Migraine headaches 5, 4
• Cannabinoid hyperemesis syndrome, a subset of CVS with chronic heavy cannabis use leading to hyperemesis 4

Pathophysiology

The pathophysiology of CVS is believed to involve a complex interplay of factors, including:

• Gut-brain interaction 4
• Neurohormonal factors 4
• Autonomic dysregulation 2, 3
• Central nervous system (CNS) origin, suggested by the role of pain and the response to tricyclic antidepressants and lorazepam 3