Vomiting, also known as emesis, is the process where the upper gastrointestinal contents are expelled through the mouth often with force. It is a coordinated process that starts from the small intestine or stomach. Since peristaltic waves pushes food from the mouth downwards into the esophagus and through the rest of the gut, the waves during vomiting “work” in the opposite direction. This is known as antiperistalsis. It is coordinated by the vomiting center in the brain, often with input from another area known as the chemoreceptor trigger zone (CTZ).
Vomiting is not always a sign of an illness. It is actually a protective mechanism whereby the gut quickly expels noxious substances before it travels further down the gastrointestinal tract. Vomiting may be caused by overdistention of the gut or irritation of the gut lining which is not related to any disease. Upon expelling the causative agent, vomiting may cease. It is often preceded by nausea which may persist for a short while after vomiting but no other symptoms are usually present. However, when vomiting is persistent or recurrent, for just a few days or even weeks and months, it needs to be investigated further. It may be accompanied by other symptoms which would indicate a possible cause – for example, fever may be an indication of an infection.
Most cases of vomiting are acute in nature. This means that it often comes on suddenly, may or may not be intense, and resolves in a short period of time. It is almost always preceded by nausea and there is often a clear etiology. In most instances, this is due to infectious agents as is the case with gastroenteritis or food poisoning. It is usually accompanied by diarrhea in these instances.
Pregnancy, excessive alcohol consumption, motion sickness and certain medication are other fairly common causes of acute vomiting. There are various other causes as discussed under sudden vomiting. Many of the same causes of acute vomiting may persist for long periods of time and account for chronic vomiting, either persistent or recurrent. In the absence of known chronic ailments or other concurrent symptoms, apart from dehydration associated with the vomiting, the diagnosis can be difficult and require extensive investigation.
Chronic vomiting may be persistent where it occurs frequently throughout the day and is often triggered by even small meals. In these instances, hydration has to be maintained with an IV drip and feeding may only be possible through a nasogastric tube. These are severe cases and in the elderly, a person with a serious chronic ailment or after severe trauma, this may not bode well for the prognosis if it does not resolve within a few days.
More often, chronic vomiting presents as recurrent episodes. A person may have periods of no vomiting that may last anywhere from a few hours, days or even weeks and then episodes of vomiting return. The term cyclic vomiting syndrome is often used synonymously with recurrent vomiting. However it is a separate condition, with no known cause although there may be various triggers. It should therefore be considered as a condition on its own. Recurrent vomiting is at least three episodes of vomiting within a 3 month period that cannot be linked to common causes of acute vomiting, like food poisoning, gastroenteritis and so on. Nevertheless there is usually an underlying cause.
Causes of Chronic Vomiting
There are many causes of chronic vomiting but some of the more common of these have been discussed below. Vomiting, whether acute or chronic, should be assessed by a doctor. Further tests ad investigations may be necessary to reach a final diagnosis.
Chronic vomiting is most frequently seen in pregnancy as ‘morning sickness’ although it may occur anytime in the day or in the very severe form known as hyperemesis gravidarum. Vomiting can persist beyond the first trimester and is discussed further under vomiting during pregnancy. It should always be investigated when severe or persistent as it could be related to many non-obstetric causes.
Food Intolerance and Malabsorption
Intolerance to certain foods typically causes intestinal cramps and diarrhea although vomiting may occur in many cases. It arises a short while after consuming the causative foods and therefore in most cases the patient is able to clearly identify the trigger. Malabsorption is less likely to cause vomiting and diarrhea is a more common presentation but it should be considered as a possible cause.
Medication and Other Substance
Chronic medication or regular use of certain medication may cause nausea with or without vomiting. These adverse effects may be associated with the dosage, interactions with other drugs, taking medication without eating (‘empty stomach’) or the concurrent intake of certain foods and beverages. Drug hypersensitivity may also be a contributing factor. It is more likely to occur in a person with gastritis, peptic ulcers, acid reflux and underlying gastrointestinal diseases. Medication may be missed as a possible cause as a person may not associate the vomiting with drug intake and may therefore fail to disclose this to the doctor.
Although many different types of medication can cause vomiting, it is chemotherapeutic agents that are known for these adverse effects. Most patients undergoing cancer therapy are informed accordingly and may experience nausea and vomiting along with other symptoms for periods of time after administration of the relevant agent.
Poisoning, either intentional or accidental, may also cause regular bouts of vomiting particularly when there is exposure to small amounts of the toxin over a long period of time. The small dose may not cause other symptoms and also be insufficient to cause any severe biochemical disturbance to warrant medical attention. The only feature of poisoning may therefore be vomiting.
Alcohol is another substance that may cause recurrent vomiting if ingested on a regular basis. This is more likely to occur with excessive consumption but may even arise with low intake in a person with underling gastrointestinal, pancreatic, kidney or liver disease. Episodes of vomiting usually occur a short time after alcohol ingestion and can last for a few hours to days. Alcoholics may experience vomiting as a withdrawal symptom upon discontinuing alcohol intake. In most cases it is limited to within the first few days of alcohol cessation.
Caffeine and other stimulants that may be found in certain energy drinks may also trigger nausea and/or vomiting. This is more likely to occur with underlying gastrointestinal conditions such as gastritis and peptic ulcer disease (PUD) since these substances may increase gastric acid secretion.
Cyclic Vomiting Syndrome
Cyclic vomiting syndrome (CVS) are cycles of symptomatic episodes marked by severe nausea and vomiting interspersed with asymptomatic periods. It more often occurs in children but may also affect adolescents and adults. The bouts of nausea and vomiting typically last a few days and can be severe enough to warrant hospitalization. Despite no clear underlying causes, CVS is often triggered by :
- Emotional stress
- Motion sickness
- Hot weather
- Certain foods
- Colds, allergies or sinusitis
The term cyclic vomiting syndrome and abdominal migraines are often used interachangably. However, cyclic vomiting syndrome is characterized by nausea and vomiting although abdominal pain may be present in some cases whereas with abdominal migraines, pain in the abdomen is the characteristic feature although nausea and vomiting may also be present. Abdominal migraines is more often seen in children and there is usually a family history of migraine headaches.
Any obstruction in the alimentary tract may present with vomiting. Usually if the obstruction is within the esophagus or higher, regurgitation will be present. Obstruction from the stomach downwards is more likely to present with vomiting. A blockage in the stomach or small intestine tends to present as forceful violent vomiting. This is discussed in detail along with causes in adults in children under projectile vomiting. An obstruction in the large intestine is less likely to present with vomiting unless the intestinal contents are significantly backed up and there is subsequent irritation of the small intestine.
Chronic pancreatitis may present with vomiting over the long term along with other symptoms like weight loss, diarrhea and pale fatty stools. It is usually preceded by recurrent bouts of acute pancreatitis which presents with severe abdominal pain, nausea and vomiting. Read more on acute and chronic pancreatitis. Pancreatic cancer may also present with several of the features seen in chronic pancreatitis including vomiting.
Although many liver diseases may present with vomiting, the more common of these is hepatitis (inflammation of the liver). It is more frequently caused by a viral infection (viral hepatitis) although other systemic infections and autoimmune disorders may cause hepatitis. Jaundice and diarrhea is often present with the nausea ad vomiting.
Vomiting is more often seen with chronic kidney failure although nausea and vomiting may also occur with acute kidney failure. Hypertension and diabetes mellitus are the more common causes of kidney failure. Other features may include swelling, shortness of breath, decreased urine output, itchy skin and mental confusion.