What are the symptoms? Most people affected can identify experiences or conditions which may bring on attacks, the most common being heightened emotional states and infections. Before the attacks some patients experience early signs of an attack consisting usually of malaise (a feeling of general discomfort or uneasiness), anxiety and mild nausea. The onset of the attack is more frequently seen during the night or on awakening in the morning. The main feature is recurrent episodes of vomiting lasting hours or days with frequent retching. Nausea is constant throughout the episode and is frequently intense. There is a high frequency of vomiting at the peak of the attack with vomiting which can occur up to every 10 to 15 minutes. The average attack duration is 24 hours, but some patients have considerably longer attacks. Other associated problems include headache, abdominal pain, photophobia (sensitivity to light) and dizziness. At the end of the attack there is rapid resolution to normality (they are said to be self-limiting). Between attacks the patient is completely well and free of nausea and vomiting. The frequency of attacks ranges from 1 to 70 per year with an average of 12 attacks per year. They occur at regular intervals in about half of patients and sporadically (not in a regular pattern) in others. Children with CVS have a strong chance of developing migraine headache. This most commonly occurs around puberty, but about one third of children with CVS will continue to suffer from cyclical vomiting attacks well into their teens. In many, but not all patients, the cyclical vomiting attacks will subside as migraine headaches develop. What are the causes? It has been suggested that the genetic cause of CVS is inherited on the DNA from the mitochondria (a small body in our cells). How is it diagnosed? Individual attacks of CVS are often diagnosed as gastroenteritis (infection of the stomach and bowel caused by bacteria or viruses) and it is only when a pattern emerges over time that they can be identified as CVS. Many patients with milder symptoms have not sought medical attention or the condition has not been recognised. How is it treated? There is no good evidence-based treatment for CVS based on research. Attack frequency may be reduced by the use of drugs such as Propranolol and Pizotifen. Acute attacks are usually treated with intravenous fluids (usually 10% Dextrose) and Ondansetron. Sedation with Lorazepam may be required. Inheritance patterns and prenatal diagnosis Inheritance patternsA family history of migraine is frequency seen in CVS and, as with other forms of migraine, the condition appears more commonly to be inherited from the mother. Prenatal diagnosisNone. Is there support? Cyclical Vomiting Syndrome Association UK Helpline: 0151 342 1660Email: email@example.comWebsite: cvsa.org.uk The Association is a Registered Charity in England and Wales No. 1045723. It provides information and support to anyone affected by Cyclical Vomiting Syndrome. The Association holds an annual family day. Group details last updated October 2015.