Vomiting (also known as emesis, puking, barfing, and throwing up) is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like Food-poisoning, gastroenteritis, pregnancy, motion sickness, or hangover; or it can be an after effect of diseases such as , elevated intracranial pressure, or overexposure to ionizing radiation.
Complications
Aspiration
Vomiting is dangerous if gastric content enters the respiratory tract. Under normal circumstances, the
gag reflex and
coughing prevent this from occurring; however, these protective reflexes are compromised in persons who are under the influence of certain substances (including
ethanol) or even mildly
anesthesia. The individual may choke and
asphyxiation or develop aspiration pneumonia.
Dehydration and electrolyte imbalance
Prolonged and excessive vomiting depletes the body of
water (
dehydration), and may alter the
electrolyte status. Gastric vomiting leads to the loss of acid and chloride directly. Combined with the resulting
alkaline tide, this leads to
hypochloremia metabolic alkalosis (low
chloride levels together with high and and increased blood pH) and often
hypokalemia (
potassium depletion). The hypokalemia is an indirect result of the
kidney compensating for the loss of acid. With the loss of intake of food the individual may eventually become
cachexia. A less frequent occurrence results from a vomiting of intestinal contents, including bile acids and .
Mallory–Weiss tear
Repeated or profuse vomiting may cause erosions to the
esophagus or small tears in the esophageal mucosa (Mallory–Weiss tear). This may become apparent if fresh red blood is mixed with vomit after several episodes.
Dentistry
Recurrent vomiting, such as observed in
bulimia nervosa or more rarely
anorexia nervosa, may lead to the destruction of the
tooth enamel due to the acidity of the vomit.
can also have a negative effect on oral health, by degrading the tissue of the
gums.
Pathophysiology
Receptors on the floor of the
fourth ventricle of the brain represent a chemoreceptor trigger zone, known as the
area postrema, stimulation of which can lead to vomiting.
[ The area postrema is a circumventricular organ and as such lies outside the blood–brain barrier; it can therefore be stimulated by blood-borne drugs that can Emetic or Antiemetics.][ ]
There are various sources of input to the vomiting center:
-
The chemoreceptor trigger zone at the base of the fourth ventricle has numerous dopamine D2 receptors, serotonin 5-HT3 receptors, , acetylcholine receptors, and receptors for substance P. Stimulation of different receptors are involved in different pathways leading to emesis, in the final common pathway substance P appears involved.
-
The vestibular system, which sends information to the brain via cranial nerve VIII (vestibulocochlear nerve), plays a major role in motion sickness, and is rich in muscarinic receptors and histamine H1 receptors.
-
The vagus nerve (vagus nerve) is activated when the pharynx is irritated, leading to a gag reflex.
-
The vagal and enteric nervous system inputs transmit information regarding the state of the gastrointestinal system. Irritation of the GI mucosa by chemotherapy, radiation, distention, or acute infectious gastroenteritis activates the 5-HT3 receptors of these inputs.
-
The CNS mediates vomiting that arises from psychiatric disorders and stress from higher brain centers.
-
The medulla plays an important role for triggering the vomiting act.
The vomiting act encompasses three types of outputs initiated by the chemoreceptor trigger zone: Motor, parasympathetic nervous system (PNS), and sympathetic nervous system (SNS). They are as follows:
-
Increased to protect tooth enamel from stomach acids.
-
The body takes a deep breath to avoid aspirating vomit.
-
Retroperistalsis starts from the middle of the small intestine and sweeps up digestive tract contents into the stomach, through the relaxed pylorus.
-
Intrathoracic pressure lowers (by Inhalation against a closed glottis), coupled with an increase in abdominal pressure as the abdomen contract, propels stomach contents into the esophagus as the cardia relaxes.
-
Vomiting is ordinarily preceded by retching.
-
Vomiting also initiates an SNS response causing both sweating and increased heart rate.
Phases
The vomiting act has two phases. In the retching phase, the abdominal muscles undergo a few rounds of coordinated contractions together with the diaphragm and the muscles used in respiratory inspiration. For this reason, an individual may confuse this phase with an episode of violent hiccups. In this retching phase, nothing has yet been expelled. In the next phase, also termed the expulsive phase, intense pressure is formed in the stomach brought about by enormous shifts in both the diaphragm and the abdomen. These shifts are, in essence, vigorous contractions of these muscles that last for extended periods of time—much longer than a normal period of muscular contraction. The pressure is then suddenly released when the upper esophageal sphincter relaxes resulting in the expulsion of gastric contents. As the mouth and nasal cavity are connected via the back of the throat, particularly forceful vomiting, or producing large quantities of vomit may result in material being ejected through the in addition to the mouth. Individuals who do not regularly exercise their abdominal muscles may experience pain in those muscles for a few days. The decrease in pressure and the release of endorphins into the bloodstream after the expulsion causes the vomiter to feel relief almost immediately after vomiting.
Contents
Gastric acid and likewise vomit are highly . Recent food intake appears in the gastric vomit. Irrespective of the content, vomit tends to be odor.
The content of the vomitus (vomit) may be of medical interest. Fresh blood in the vomit is termed hematemesis ("blood vomiting"). Altered blood bears resemblance to coffee grounds (as the iron in the blood is oxidation) and, when this matter is identified, the term coffee-ground vomiting is used. Bile can enter the vomit during subsequent heaves due to duodenum contraction if the vomiting is severe. Fecal vomiting is often a consequence of intestinal obstruction or a gastrocolic fistula and is treated as a warning sign of this potentially serious problem ( signum mali ominis).
If the vomiting reflex continues for an extended period with no appreciable vomitus, the condition is known as non-productive emesis or "dry heaves", which can be painful and debilitating.
- Color of vomit
-
Bright red in the vomit suggests bleeding from the esophagus
-
Dark red vomit with liver-like clots suggests profuse bleeding in the stomach, such as from a perforated ulcer
-
Coffee-ground-like vomit suggests less severe bleeding in the stomach because the gastric acid has had time to change the composition of the blood
-
Yellow or green vomit suggests bile, indicating that the pyloric valve is open and bile is flowing into the stomach from the duodenum. This may occur during successive episodes of vomiting after the stomach contents have been completely expelled.
Causes
Vomiting may be due to a large number of causes, and vomiting has a long differential diagnosis.
Digestive tract
Causes in the digestive tract
Sensory system and brain
Causes in the sensory system:
Causes in the brain:
-
Concussion
-
Cerebral hemorrhage
-
Cerebral aneurysm
-
Migraine
-
, which can cause the chemoreceptors to malfunction
-
Benign intracranial hypertension and hydrocephalus
Metabolic disturbances (these may irritate both the stomach and the parts of the brain that coordinate vomiting):
Pregnancy:
Drug reaction (vomiting may occur as an acute somatic response to):
-
Alcohol, which can be partially oxidized into acetaldehyde that causes the symptoms of hangover, including nausea, vomiting, shortness of breath, and fast heart rate.
-
-
Selective serotonin reuptake inhibitors
-
Many chemotherapy drugs
-
Some (such as peyote or ayahuasca)
High altitude:
Illness (sometimes colloquially known as "stomach flu"—a broad name that refers to gastric inflammation caused by a range of viruses and bacteria):
Psychiatric/behavioral:
Emetics
An emetic, such as syrup of ipecac, is a substance that induces vomiting when administered orally or by injection. An emetic is used medically when a substance has been ingested and must be expelled from the body immediately. For this reason, many toxic and easily digestible products such as rat poison contain an emetic.
Salt water and Mustard seed water, which act directly on the stomach, have been used since ancient times as emetics.
Hydrogen peroxide is used as an emetic in veterinary practice.
Self-induced
-
(anorexia nervosa or bulimia nervosa)
-
To eliminate an ingested poison (some poisons should not be vomited as they may be more toxic when inhaled or aspirated; it is better to ask for help before inducing vomiting)
-
Some people who engage in binge drinking induce vomiting to make room in their stomachs for more alcohol consumption.
-
Participants in milk chugging typically end up vomiting most of the milk they consume, as proteins in the ingested milk (such as casein) rapidly denature and unravel on contact with gastric acid and protease enzymes, rapidly filling the stomach. Once the stomach becomes full, in the stomach wall trigger signals to vomit to expel any further liquid the participant ingests.
-
People suffering from nausea may induce vomiting in hopes of feeling better.
Miscellaneous
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After surgery (postoperative nausea and vomiting)
-
Disagreeable sights or disgust, smells, tastes, sounds or thoughts (such as decayed matter, others' vomit, thinking of vomiting), etc.
-
Extreme pain, such as an intense headache or myocardial infarction (heart attack)
-
Extreme emotions
-
Cyclic vomiting syndrome (a poorly understood condition with attacks of vomiting)
-
Cannabinoid hyperemesis syndrome (similar to cyclic vomiting syndrome, but has cannabis use as its underlying cause).
-
High doses of ionizing radiation sometimes trigger a vomit reflex.
-
Violent fits of coughing, hiccups, or asthma
-
Anxiety
-
Depression
-
Overexertion (doing too much strenuous exercise can lead to vomiting shortly afterwards).
Other types
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Projectile vomiting is vomiting that ejects the gastric contents with great force.
Treatment
An antiemetic is a medication that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of medications such as and chemotherapy.
Antiemetics act by inhibiting the receptor sites associated with emesis. Hence, anticholinergics, antihistamines, dopamine antagonists, serotonin antagonists, and cannabinoids are used as antiemetics.
Evidence to support the use of for nausea and vomiting among adults in the emergency department is poor.[ It is unclear if any medication is better than another or better than no active treatment.]
Epidemiology
Nausea and/or vomiting are the main complaints in 1.6% of visits to family physicians in Australia.
Society and culture
Herodotus, writing on the culture of the ancient Persians and highlighting the differences with those of the Ancient Greece, notes that to vomit in the presence of others is prohibited among Persians.
Social cues
It is quite common that, when one person vomits, others nearby become nauseated, particularly when smelling the vomit of others, and often to the point of vomiting themselves. This tendency in human populations has been observed at drinking parties, where excessive consumption of alcoholic beverages may cause a number of party members to vomit nearly simultaneously, triggered by the initial vomiting of a single member of the party.
Intense vomiting in ayahuasca ceremony is a common phenomenon. However, people who experience "la purga" after drinking ayahuasca, in general, regard the practise as both a physical and spiritual cleanse and often come to welcome it.[Shanon, B. (2002). The antipodes of the mind: Charting the phenomenology of the ayahuasca experience. Oxford: Oxford University Press.] It has been suggested that the consistent emetic effects of ayahuasca—in addition to its many other therapeutic properties—was of medicinal benefit to indigenous peoples of the Amazon Basin, in helping to clear from the gastrointestinal system.
There have also been documented cases of a single ill and vomiting individual inadvertently causing others to vomit, when they are especially fearful of also becoming ill, through a form of mass hysteria.
Most people try to contain their vomit by vomiting into a sink, toilet, or trash can, as vomit is difficult and unpleasant to clean. On airplanes and boats, Sickness bag are supplied for sick passengers to vomit into. A special disposable bag (leakproof, puncture-resistant, odorless) containing absorbent material that solidifies the vomit quickly is also available, making it convenient and safe to store until there is an opportunity to dispose of it conveniently.
People who vomit chronically (e.g., as part of an eating disorder such as bulimia nervosa) may devise various ways to hide this disorder.
An online study of people's responses to "horrible sounds" found vomiting "the most disgusting". Professor Trevor Cox of the University of Salford's Acoustic Research Centre said, "We are pre-programmed to be repulsed by horrible things such as vomiting, as it is fundamental to staying alive to avoid nasty stuff." It is thought that disgust is triggered by the sound of vomiting to protect those nearby from possibly diseased food.[ "Sickening sounds - research to make your ears cringe". University of Salford. January 28, 2007. ]
Psychology
Emetophilia is sexual arousal from vomiting, or watching others vomit.
See also
Notes
External links
