Medicines for Cyclical vomiting syndrome

What it is

Cyclical vomiting syndrome (CVS) is a condition characterised by recurrent episodes (attacks) of severe nausea and vomiting, separated by periods of feeling well with no symptoms. It affects both children and adults, though it is more commonly recognised in children. The hallmark of CVS is the pattern: episodes of intense, repeated vomiting that come on (often suddenly, sometimes at a similar time, such as during the night or early morning), last from hours to a few days, and then settle, with the person returning to normal in between; the episodes tend to be similar (stereotyped) for that individual. During an attack, a person may vomit repeatedly and forcefully, feel very nauseated, be pale, tired, and unwell, and may have other symptoms such as tummy pain, headache, sensitivity to light, or aversion to food; the attacks can be exhausting and distressing, and repeated vomiting risks dehydration. Between attacks, the person is usually completely well. The exact cause of CVS is not fully understood, but it is thought to be related to the way the brain and gut interact, and it has links with migraine (people with CVS, or their families, often have migraine, and CVS is sometimes considered related to migraine). Episodes can be triggered by certain factors, which vary between individuals but can include stress or excitement, infections, lack of sleep, certain foods, menstruation, or other triggers. Because the symptoms overlap with other conditions, CVS is often diagnosed after other causes of recurrent vomiting have been considered and excluded, along with recognising the characteristic pattern. While CVS can be distressing and disruptive, it can be managed: this involves identifying and avoiding triggers where possible, treating and shortening attacks (including preventing dehydration and using medicines to help), and, for frequent or severe cases, preventive treatment. Many children improve or grow out of CVS over time. The key messages are that CVS causes recurrent episodes of severe vomiting with well periods in between, that it is linked with migraine, and that managing triggers, treating attacks (and preventing dehydration), and, where needed, preventive treatment help.

How it is treated

Cyclical vomiting syndrome is managed by recognising the pattern and diagnosis, identifying and avoiding triggers, treating and shortening attacks (including preventing dehydration), and, for frequent or severe cases, preventive treatment; specialist input often helps. Reaching the diagnosis usually involves recognising the characteristic pattern of recurrent, similar episodes of severe vomiting with well periods in between, along with considering and, where appropriate, excluding other causes of recurrent vomiting (which may involve tests, guided by the doctor). Once CVS is diagnosed, management has several strands. Identifying and avoiding triggers where possible can reduce attacks — keeping a diary can help spot individual triggers (such as stress, excitement, lack of sleep, infections, certain foods, or menstruation), and managing these (for example managing stress, keeping regular routines and sleep, and avoiding known dietary triggers) helps. Managing attacks is important: at the onset, resting in a quiet, dark room can help; treatments can be used to control the nausea and vomiting and to help settle or shorten an attack (a doctor can advise on medicines, which may include anti-sickness medicines and, given the migraine link, sometimes migraine-type treatments); and preventing and treating dehydration is crucial, as repeated vomiting can cause dehydration — this means trying to take small sips of fluids if possible, and seeking medical help if the person cannot keep fluids down, is becoming dehydrated, or is very unwell, as fluids given into a vein (in hospital) may be needed for a severe attack. For people with frequent or severe attacks, preventive (prophylactic) treatment taken regularly between episodes may be recommended to reduce how often attacks occur, and, given the link with migraine, some of the treatments used are similar to those used for migraine prevention; this is guided by a doctor or specialist. Specialist input (such as a gastroenterologist, or paediatrician for children) is often helpful for diagnosis and management, particularly for frequent, severe, or difficult cases. Support and reassurance are important, as CVS can be distressing and disruptive. Many children improve or grow out of CVS over time, though some continue to have it or it may evolve (for example into migraine). The reassuring messages are that CVS, though distressing, can be managed — through identifying and avoiding triggers, treating and shortening attacks, and preventing dehydration, with preventive treatment for frequent cases — that it is linked with migraine, and that many children improve over time; and that seeking medical help for the diagnosis, for management, and for severe attacks (particularly dehydration) is important.