Nausea, the unpleasant feeling of needing to vomit, represents awareness of afferent stimuli (including increased parasympathetic tone) to the medullary vomiting center. Vomiting is the forceful expulsion of gastric contents caused by involuntary contraction of the abdominal musculature when the gastric fundus and lower esophageal sphincter are relaxed.
Vomiting should be distinguished from regurgitation, the spitting up of gastric contents without associated nausea or forceful abdominal muscular contractions. Patients with achalasia or rumination syndrome or a Zenker diverticulum may regurgitate undigested food without nausea.
Nausea and vomiting in infants and children is discussed elsewhere.
Complications
Severe vomiting can lead to symptomatic dehydration and electrolyte abnormalities (typically a metabolic alkalosis with hypokalemia) or rarely to an esophageal tear, either partial (Mallory-Weiss) or complete (Boerhaave syndrome).
If a patient is unconscious or only partly conscious, the vomitus may be inhaled (aspirated). The acid in the vomitus can severely irritate the lungs, causing aspiration pneumonia.
Chronic vomiting can result in undernutrition, weight loss, and metabolic abnormalities.
Etiology
Nausea and vomiting occur in response to conditions that affect the vomiting center. Causes may originate in the gastrointestinal (GI) tract or central nervous system (CNS) or may result from a number of systemic conditions (see Table: Some Causes of Nausea and Vomiting).
The most common causes of nausea and vomiting are the following:
Cyclic vomiting syndrome (CVS) is an uncommon disorder characterized by severe, discrete attacks of vomiting or sometimes only nausea that occur at varying intervals, with normal health between episodes and no demonstrable structural abnormalities. It is most common in childhood (mean age of onset 5 years) and tends to remit with adulthood. Cyclic vomiting in adults can occur with chronic marijuana (cannabis) use (cannabis hyperemesis syndrome); the vomiting can be relieved by a hot bath and resolves after cessation of marijuana use.
Chronic nausea and vomiting syndrome is a functional disorder characterized by the occurrence of symptoms for at least 6 months including the last 3 months. Bothersome nausea and/or vomiting occur at least once a week. This disorder should be considered in patients who, after routine investigation (including upper endoscopy), have no evidence of organic, systemic, or metabolic disease that is likely to explain the symptoms and in who self-induced vomiting, eating disorders, regurgitation, and rumination have been excluded (1).
Some Causes of Nausea and Vomiting
Cause |
Suggestive Findings* |
Diagnostic Approach |
Gastrointestinal disorders |
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Obstipation, distention, tympany Often bilious vomiting, abdominal surgical scars, or hernia |
Flat and upright abdominal x-rays |
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Vomiting, diarrhea Benign abdominal examination |
Clinical evaluation |
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Gastroparesis or ileus |
Vomiting of partially digested food a few hours after ingestion Often in diabetics with elevated blood glucose or after abdominal surgery |
Flat and upright abdominal x-rays Sometimes gastric emptying scan |
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Mild to moderate nausea for many days, sometimes vomiting Jaundice, anorexia, malaise Sometimes slight tenderness over the liver |
Serum aminotransferases, bilirubin, viral hepatitis titers |
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Perforated viscus or other acute abdomen (eg, appendicitis, cholecystitis, pancreatitis) |
Significant abdominal pain Usually peritoneal signs |
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Toxic ingestion (numerous) |
Usually apparent based on history |
Varies with substance |
Central nervous system (CNS) disorders |
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Closed head injury |
Apparent based on history |
Head CT |
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CNS hemorrhage |
Sudden-onset headache, mental status change Often meningeal signs |
Head CT Lumbar puncture if CT is normal |
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CNS infection |
Gradual-onset headache Often meningeal signs, mental status change Sometimes petechial rash* due to meningococcemia |
Head CT Lumbar puncture |
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Increased intracranial pressure (eg, caused by hematoma or tumor) |
Headache, mental status change Sometimes focal neurologic deficits |
Head CT |
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Vertigo, nystagmus, symptoms worsened by motion Sometimes tinnitus |
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Headache sometimes preceded or accompanied by a neurologic aura or photophobia Often a history of recurrent similar attacks In patients with known migraine, possible development of other CNS disorders |
Clinical evaluation Head CT and lumbar puncture considered if evaluation is unclear |
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Apparent based on history |
Clinical evaluation |
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Psychogenic disorders (eg, anorexia and bulimia nervosa) |
Occurring with stress Eating food considered repulsive |
Clinical evaluation |
Systemic conditions |
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Advanced cancer (independent of chemotherapy or bowel obstruction) |
Apparent based on history |
Clinical evaluation |
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Polyuria, polydipsia Often significant dehydration With or without history of diabetes |
Serum glucose, electrolytes, ketones |
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Drug adverse effect or toxicity |
Apparent based on history |
Varies with substance |
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Liver failure or renal failure |
Often apparent based on history Asterixis Often jaundice in advanced liver disease, uremic odor in renal failure |
Laboratory tests of liver and renal function Blood ammonia level |
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Pregnancy |
Often occurring in morning or triggered by food Benign examination (possibly dehydration) |
Pregnancy test |
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Apparent based on history |
Clinical evaluation |
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Severe pain (eg, due to a kidney stone) |
Varies with cause |
Clinical evaluation |
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* Sometimes forceful vomiting (caused by any disorder or condition) causes petechiae on the upper torso and face, which may resemble those of meningococcemia. Patients with meningococcemia are usually very ill, whereas those with petechiae caused by vomiting often appear otherwise quite well. |
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Etiology reference
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1. Stanghellini V, Chan FK, Hasler WL, et al: Gastroduodenal disorders. Gastroenterology 150(6):1380–1392, 2016. doi: 10.1053/j.gastro.2016.02.011.
Evaluation
History
History of present illness should elicit frequency and duration of vomiting; its relation to possible precipitants such as drug or toxin ingestion, head injury, and motion (eg, car, plane, boat, amusement rides); and whether vomitus contained bile (bitter, yellow-green) or blood (red or “coffee ground” material). Important associated symptoms include presence of abdominal pain and diarrhea, the last passage of stool and flatus, and presence of headache, vertigo, or both.
Review of systems seeks symptoms of causative disorders such as amenorrhea and breast swelling (pregnancy), polyuria and polydipsia (diabetes), and hematuria and flank pain (kidney stones).
Past medical history should ascertain known causes such as pregnancy, diabetes, migraine, hepatic or renal disease, cancer (including timing of any chemotherapy or radiation therapy), and previous abdominal surgery (which may cause bowel obstruction due to adhesions). All drugs and substances ingested recently should be ascertained; certain substances may not manifest toxicity until several days after ingestion (eg, acetaminophen, some mushrooms).
Family history of recurrent vomiting should be noted.
Physical examination
Vital signs should particularly note presence of fever and signs of hypovolemia (eg, tachycardia, hypotension, or both).
General examination should seek presence of jaundice and rash.
On abdominal examination, the clinician should look for distention and surgical scars; listen for presence and quality of bowel sounds (eg, normal, high-pitched); percuss for tympany; and palpate for tenderness, peritoneal findings (eg, guarding, rigidity, rebound), and any masses, organomegaly, or hernias. Rectal examination and (in women) pelvic examination to locate tenderness, masses, and blood are essential.
Neurologic examination should particularly note mental status, nystagmus, meningismus (eg, stiff neck, Kernig sign or Brudzinski sign), and ocular signs of increased intracranial pressure (eg, papilledema, absence of venous pulsations, 3rd cranial nerve palsy) or subarachnoid hemorrhage (retinal hemorrhage).
Red flags
Interpretation of findings
Many findings are suggestive of a cause or group of causes (see Table: Some Causes of Nausea and Vomiting).
Vomiting occurring shortly after drug or toxin ingestion or exposure to motion in a patient with an unremarkable neurologic and abdominal examination can confidently be ascribed to those causes, as may vomiting in a woman with a known pregnancy and a benign examination. Acute vomiting accompanied by diarrhea in an otherwise healthy patient with a benign examination is highly likely to be infectious gastroenteritis; further assessment may be deferred.
Vomiting that occurs at the thought of food or that is not temporally related to eating suggests a psychogenic cause, as does personal or family history of functional nausea and vomiting. Patients should be questioned about the relationship between vomiting and stressful events because they may not recognize the association or even admit to feeling distress at those times.
Testing
All females of childbearing age should have a urine pregnancy test. Patients with severe vomiting, vomiting lasting over 1 day, or signs of dehydration on examination should have other laboratory tests (eg, electrolytes, blood urea nitrogen, creatinine, glucose, urinalysis, sometimes liver tests). Patients with red flag findings should have testing appropriate to the symptoms (see Table: Some Causes of Nausea and Vomiting).
The assessment of chronic vomiting usually includes the previously listed laboratory tests plus upper GI endoscopy, small-bowel x-rays, and tests to assess gastric emptying and antral-duodenal motility.
Treatment
Specific conditions, including dehydration, are treated. Even without significant dehydration, IV fluid therapy (0.9% saline 1 L, or 20 mL/kg in children) often leads to reduction of symptoms. In adults, various antiemetics are effective (see Table: Some Drugs for Vomiting). Choice of agent varies somewhat with the cause and severity of symptoms. Typical use is the following:
Only parenteral or sublingual agents should be used in actively vomiting patients.
For psychogenic vomiting, reassurance indicates awareness of the patient’s discomfort and a desire to work toward relief of symptoms, regardless of cause. Comments such as “nothing is wrong” or “the problem is emotional” should be avoided. Brief symptomatic treatment with antiemetics can be tried. If long-term management is necessary, supportive, regular office visits may help resolve the underlying problem.
