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 Achalasia Achalasia is a neurogenic esophageal motility disorder characterized by impaired esophageal peristalsis and a lack of lower esophageal sphincter relaxation during swallowing. Symptoms are slowly... read more or rumination syndrome Rumination Rumination is the (usually involuntary) regurgitation of small amounts of food from the stomach (most often 15 to 30 minutes after eating) that are rechewed and, in most cases, again swallowed... read more or a Zenker diverticulum Esophageal Diverticula An esophageal diverticulum is an outpouching of mucosa through the muscular layer of the esophagus. It can be asymptomatic or cause dysphagia and regurgitation. Diagnosis is made by barium swallow... read more may regurgitate undigested food without nausea.
Nausea and vomiting in infants and children Nausea and Vomiting in Infants and Children Nausea is the sensation of impending emesis and is frequently accompanied by autonomic changes, such as increased heart rate and salivation. Nausea and vomiting typically occur in sequence;... read more is discussed elsewhere.
Severe vomiting can lead to symptomatic dehydration and electrolyte abnormalities (typically a metabolic alkalosis Metabolic Alkalosis Metabolic alkalosis is primary increase in bicarbonate (HCO3−) with or without compensatory increase in carbon dioxide partial pressure (Pco2); pH may be high or nearly normal. Common causes... read more with hypokalemia Hypokalemia Hypokalemia is serum potassium concentration 3.5 mEq/L ( 3.5 mmol/L) caused by a deficit in total body potassium stores or abnormal movement of potassium into cells. The most common cause is... read more ) or rarely to an esophageal tear, either partial (Mallory-Weiss Mallory-Weiss Syndrome Mallory-Weiss syndrome is a nonpenetrating mucosal laceration of the distal esophagus and proximal stomach caused by vomiting, retching, or hiccuping. (See also Overview of Esophageal and Swallowing... read more ) or complete (Boerhaave syndrome Esophageal Rupture Esophageal rupture may be iatrogenic during endoscopic procedures or other instrumentation or may be spontaneous (Boerhaave syndrome). Patients are seriously ill, with symptoms of mediastinitis... read more ).
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 of Nausea and Vomiting
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 Some Causes of Nausea and Vomiting 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... read more ).
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 Etiology reference 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... read more ).
Evaluation of Nausea and Vomiting
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.
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).
The following findings are of particular concern:
Signs of hypovolemia
Headache, stiff neck, or mental status change
Distended, tympanitic abdomen
Interpretation of findings
Many findings are suggestive of a cause or group of causes (see Table: Some Causes of Nausea and Vomiting Some Causes of Nausea and Vomiting 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... read more ).
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 Overview of Gastroenteritis Gastroenteritis is inflammation of the lining of the stomach and small and large intestines. Most cases are infectious, although gastroenteritis may occur after ingestion of drugs and chemical... read more ; 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.
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 Some Causes of Nausea and Vomiting 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... read more ).
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 of Nausea and Vomiting
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 Some Drugs for Vomiting 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... read more ). Choice of agent varies somewhat with the cause and severity of symptoms. Typical use is the following:
Motion sickness: Antihistamines, scopolamine patches, or both
Mild to moderate symptoms: Prochlorperazine or metoclopramide
Severe or refractory vomiting and vomiting caused by chemotherapy: 5-HT3 antagonists, neurokinin-1 receptor antagonists (eg, aprepitant)
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.
Many episodes of nausea and vomiting have an obvious cause and benign examination and require only symptomatic treatment.
Be alert for signs of an acute abdomen or significant intracranial disorder.
Always consider pregnancy in females of childbearing age.