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(For nausea and vomiting in infants and children, see Approach to the Care of Normal Infants and Children: Spitting Up 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 expulsion of gastric contents produced 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 a Zenker's diverticulum may regurgitate undigested food without nausea.

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's syndrome). Chronic vomiting can result in malnutrition, weight loss, and metabolic abnormalities.

Etiology

Nausea and vomiting occur in response to conditions that affect the vomiting center. Causes may originate in the GI tract or CNS or may result from a number of systemic conditions (see Table 5: Approach to the Patient with Upper GI Complaints: Some Causes of Nausea and Vomiting).

The most common causes are the following:

• Gastroenteritis
• Drugs
• Toxins

Cyclic vomiting syndrome 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. It is most common in childhood (mean age of onset 5 yr) and tends to remit with adulthood. The condition may be associated with migraine headaches, possibly representing a migraine variant.

Table 5
Some Causes of Nausea and Vomiting Cause Suggestive Findings* Diagnostic Approach GI disorders Bowel obstruction Obstipation, distention, tympany Often with bilious vomiting, abdominal surgical scars, or hernia Flat and upright abdominal x-ray Gastroenteritis Vomiting and diarrhea, benign abdominal examination Clinical evaluation Gastroparesis or ileus Vomiting partially digested food a few hours after ingestion Often in diabetics or after abdominal surgery Flat and upright abdominal x-rays Hepatitis Jaundice, anorexia, sometimes slight tenderness over liver Serum aminotransferases, bilirubin, viral hepatitis titers Perforated viscus or other acute abdomen (eg, appendicitis, cholecystitis, pancreatitis) Significant abdominal pain, usually peritoneal signs See Acute Abdomen and Surgical Gastroenterology: Acute Abdominal Pain Toxic ingestion (numerous) Usually apparent by history Varies with substance CNS disorders Closed head injury Apparent by history Head CT CNS hemorrhage Sudden onset headache, mental status change, often meningeal signs Head CT Lumbar puncture if CT normal CNS infection Gradual onset headache Often meningeal signs, mental status change Meningococcemia may cause petechial rash* Head CT head Lumbar puncture Increased intracranial pressure (eg, caused by hematoma, tumor) Headache, mental status change, sometimes focal neurologic deficit Head CT Labyrinthitis Vertigo, nystagmus, symptoms worsened by motion Sometimes with tinnitus See Approach to the Patient With Ear Problems: Vertigo Migraine Headache sometimes preceded or accompanied by a neurologic aura, photophobia Often a history of recurrent similar attacks Patients with known migraine may develop other CNS disorders Clinical evaluation Head CT and lumbar puncture considered if evaluation unclear Motion sickness Apparent by history Clinical evaluation Psychogenic disorders Occur with stress, eating food considered repulsive Clinical evaluation Systemic conditions Advanced cancer (independent of chemotherapy or bowel obstruction) Apparent by history Clinical evaluation Diabetic ketoacidosis Polyuria, polydipsia, often significant dehydration May or may not have history of diabetes Serum glucose, electrolytes, and ketones Drug adverse effect or toxicity Apparent by history Varies with substance Liver failure or renal failure Often apparent by history Often jaundice in advanced liver disease, uremic odor in renal failure Laboratory tests of liver and renal function Pregnancy Often in morning or triggered by food Benign examination (may be dehydrated) Pregnancy test Radiation exposure Apparent by history Clinical evaluation Severe pain (eg, kidney stone) Varies with cause Clinical evaluation *Sometimes forceful vomiting (caused by any disorder or condition) causes petechiae on the upper torso and face, which may resemble those of meningococcemia. Those with meningococcemia are usually very ill, whereas those with petechiae caused by vomiting often appear otherwise quite well.

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, breast swelling (pregnancy); polyuria, polydipsia (diabetes); and hematuria, 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 Trade Names
GENAPAP
TYLENOL
VALORIN
Click for Drug Monograph
, 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 skin 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's or Brudzinski's signs), and ocular signs of increased intracranial pressure (eg, papilledema, absence of venous pulsations, 3rd cranial nerve palsy) or subarachnoid hemorrhage (retinal hemorrhage).

Red flags: The following findings are of particular concern:

• Signs of hypovolemia
• Headache, stiff neck, or mental status change
• Peritoneal signs
• Distended, tympanitic abdomen

Interpretation of findings: Many findings are suggestive of a cause or group of causes (see Table 5: Approach to the Patient with Upper GI Complaints: 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, BUN, creatinine, glucose, urinalysis, and sometimes liver tests). Patients with red flag findings should have testing appropriate to the symptoms (see Table 5: Approach to the Patient with Upper GI Complaints: 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 6: Approach to the Patient with Upper GI Complaints: Some Drugs for Vomiting). Choice of agent varies somewhat with the cause and severity of symptoms. Typical use is the following:

• Motion sickness: Antihistamines, scopolamine Some Trade Names
  TRANSDERM SCOP
  Click for Drug Monograph
  patches or both
• Mild to moderate symptoms: Prochlorperazine Some Trade Names
  COMPAZINE
  Click for Drug Monograph
  or metoclopramide Some Trade Names
  REGLAN
  Click for Drug Monograph
  
• Severe or refractory vomiting and vomiting caused by chemotherapy: 5-HT₃ antagonists

Obviously, only parenteral 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.

Table 6
Some Drugs for Vomiting Drug Usual Dose* Comments Antihistamines Dimenhydrinate Some Trade Names DRAMAMINE TRIPTONE Click for Drug Monograph 50 mg po q 4–6 h Vomiting of labyrinthine etiology (eg, motion sickness, labyrinthitis) Meclizine Some Trade Names ANTIVERT BONINE Click for Drug Monograph 25 mg po q 8 h 5-HT3 Antagonists Dolasetron Some Trade Names ANZEMET Click for Drug Monograph 12.5 mg IV at onset of nausea and vomiting Severe or refractory vomiting; vomiting caused by chemotherapy; may cause constipation, diarrhea, abdominal pain Granisetron Some Trade Names KYTRIL Click for Drug Monograph 1 mg po or IV tid Ondansetron Some Trade Names ZOFRAN Click for Drug Monograph 4–8 mg po or IV q 8 h Palonosetron Prophylaxis: 0.25 mg IV as a single dose 30 min before chemotherapy Other drugs Aprepitant Some Trade Names EMEND Click for Drug Monograph 125 mg po 1 h before chemotherapy on day 1, then 80 mg po daily in the morning on days 2 and 3 In combination with ondansetron Some Trade Names ZOFRAN Click for Drug Monograph , 32 mg IV 30 min before chemotherapy on day 1 only; dexamethasone Some Trade Names DECADRON DEXASONE HEXADROL Click for Drug Monograph 12 mg po 30 min before chemotherapy on day 1; and 8 mg po daily in the morning on days 2, 3, and 4 For highly emetogenic chemotherapy regimens; somnolence, fatigue, hiccups Metoclopramide Some Trade Names REGLAN Click for Drug Monograph 5–20 mg po or IV tid to qid Initial treatment of mild vomiting Perphenazine Some Trade Names TRILAFON Click for Drug Monograph 5–10 mg IM or 8–16 mg po daily in divided doses; maximum dose 24 mg/day   Prochlorperazine Some Trade Names COMPAZINE Click for Drug Monograph 5–10 mg IV or 25 mg per rectum   Scopolamine Some Trade Names TRANSDERM SCOP Click for Drug Monograph 1-mg patch worn for up to 72 h Motion sickness, diminished sweating, dry skin

Key Points

• Many episodes have an obvious cause and benign examination and require only symptomatic treatment.
• Physicians should be alert for signs of an acute abdomen or significant intracranial disorder.
• Pregnancy should always be considered in females of childbearing age.

Last full review/revision March 2008 by Norton J. Greenberger, MD

Content last modified March 2008