Nausea and Vomiting in Adults: A Merck Manual of Patient Symptoms podcast

(For nausea and vomiting in infants and children, see Approach to the Care of Normal Infants and Children: Nausea and Vomiting in Infants and Children.)

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 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 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 GI tract or CNS or may result from a number of systemic conditions (see Table 5: Symptoms of GI Disorders: Some Causes of Nausea and Vomiting).

The most common causes are the following:

• Gastroenteritis
• Drugs
• Toxins

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 yr) and tends to remit with adulthood. CVS in adults is often due to chronic marijuana (cannabis) use.

Table 5
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Some Causes of Nausea and Vomiting Cause Suggestive Findings* Diagnostic Approach GI disorders Bowel obstruction Obstipation, distention, tympany Often bilious vomiting, abdominal surgical scars, or hernia Flat and upright abdominal x-rays Gastroenteritis Vomiting, diarrhea Benign abdominal examination Clinical evaluation Gastroparesis or ileus Vomiting of partially digested food a few hours after ingestion Often in diabetics or after abdominal surgery Flat and upright abdominal x-rays Hepatitis Mild to moderate nausea for many days, sometimes vomiting Jaundice, anorexia, malaise Sometimes slight tenderness over the 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 based on history Varies with substance CNS disorders Closed head injury Apparent based on history Head CT CNS hemorrhage Sudden-onset headache, mental status change Often meningeal signs Head CT Lumbar puncture if CT is normal CNS infection Gradual-onset headache Often meningeal signs, mental status change Sometimes petechial rash*due to meningococcemia Head CT Lumbar puncture Increased intracranial pressure (eg, caused by hematoma or tumor) Headache, mental status change Sometimes focal neurologic deficits Head CT Labyrinthitis Vertigo, nystagmus, symptoms worsened by motion Sometimes tinnitus See Approach to the Patient With Ear Problems: Dizziness and Vertigo Migraine 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 Motion sickness Apparent based on history Clinical evaluation Psychogenic disorders Occurring with stress Eating food considered repulsive Clinical evaluation Systemic conditions Advanced cancer (independent of chemotherapy or bowel obstruction) Apparent based on history Clinical evaluation Diabetic ketoacidosis Polyuria, polydipsia Often significant dehydration With or without history of diabetes Serum glucose, electrolytes, ketones Drug adverse effect or toxicity Apparent based on history Varies with substance Liver failure or renal failure Often apparent based on history Often jaundice in advanced liver disease, uremic odor in renal failure Laboratory tests of liver and renal function Pregnancy Often occurring in morning or triggered by food Benign examination (possibly dehydration) Pregnancy test Radiation exposure Apparent based on history Clinical evaluation Severe pain (eg, due to a 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. Patients with meningococcemia are usually very ill, whereas those with petechiae caused by vomiting often appear otherwise quite well. Some Causes of Nausea and Vomiting Cause Suggestive Findings* Diagnostic Approach GI disorders Bowel obstruction Obstipation, distention, tympany Often bilious vomiting, abdominal surgical scars, or hernia Flat and upright abdominal x-rays Gastroenteritis Vomiting, diarrhea Benign abdominal examination Clinical evaluation Gastroparesis or ileus Vomiting of partially digested food a few hours after ingestion Often in diabetics or after abdominal surgery Flat and upright abdominal x-rays Hepatitis Mild to moderate nausea for many days, sometimes vomiting Jaundice, anorexia, malaise Sometimes slight tenderness over the 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 based on history Varies with substance CNS disorders Closed head injury Apparent based on history Head CT CNS hemorrhage Sudden-onset headache, mental status change Often meningeal signs Head CT Lumbar puncture if CT is normal CNS infection Gradual-onset headache Often meningeal signs, mental status change Sometimes petechial rash*due to meningococcemia Head CT Lumbar puncture Increased intracranial pressure (eg, caused by hematoma or tumor) Headache, mental status change Sometimes focal neurologic deficits Head CT Labyrinthitis Vertigo, nystagmus, symptoms worsened by motion Sometimes tinnitus See Approach to the Patient With Ear Problems: Dizziness and Vertigo Migraine 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 Motion sickness Apparent based on history Clinical evaluation Psychogenic disorders Occurring with stress Eating food considered repulsive Clinical evaluation Systemic conditions Advanced cancer (independent of chemotherapy or bowel obstruction) Apparent based on history Clinical evaluation Diabetic ketoacidosis Polyuria, polydipsia Often significant dehydration With or without history of diabetes Serum glucose, electrolytes, ketones Drug adverse effect or toxicity Apparent based on history Varies with substance Liver failure or renal failure Often apparent based on history Often jaundice in advanced liver disease, uremic odor in renal failure Laboratory tests of liver and renal function Pregnancy Often occurring in morning or triggered by food Benign examination (possibly dehydration) Pregnancy test Radiation exposure Apparent based on history Clinical evaluation Severe pain (eg, due to a 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. Patients 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 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 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: Symptoms of GI Disorders: 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, sometimes liver tests). Patients with red flag findings should have testing appropriate to the symptoms (see Table 5: Symptoms of GI Disorders: 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: Symptoms of GI Disorders: 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 patches, or both
• Mild to moderate symptoms: Prochlorperazine or metoclopramide
• 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
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Some Drugs for Vomiting Drug Usual Dose Comments Antihistamines Dimenhydrinate 50 mg po q 4–6 h Used to treat vomiting of labyrinthine etiology (eg, motion sickness, labyrinthitis) Meclizine 25 mg po q 8 h 5-HT3 antagonists Dolasetron 12.5 mg IV at onset of nausea and vomiting Used to treat severe or refractory vomiting, or vomiting caused by chemotherapy Possible adverse effects: Constipation, diarrhea, abdominal pain Granisetron 1 mg po or IV tid Ondansetron 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 125 mg po 1 h before chemotherapy on day 1, then 80 mg po daily in the morning on days 2 and 3 When used with ondansetron, 32 mg IV 30 min before chemotherapy on day 1 only When used with dexamethasone 12 mg po 30 min before chemotherapy on day 1 and 8 mg po daily in the morning on days 2, 3, and 4 Used with highly emetogenic chemotherapy regimens Possible adverse effects: Somnolence, fatigue, hiccups Metoclopramide 5–20 mg po or IV tid to qid Used to treat initial treatment of mild vomiting Perphenazine 5–10 mg IM or 8–16 mg po daily in divided doses; maximum dose 24 mg/day — Prochlorperazine 5–10 mg IV or 25 mg per rectum — Scopolamine 1-mg patch worn for up to 72 h Used to treat motion sickness Possible adverse effects: Diminished sweating, dry skin Some Drugs for Vomiting Drug Usual Dose Comments Antihistamines Dimenhydrinate 50 mg po q 4–6 h Used to treat vomiting of labyrinthine etiology (eg, motion sickness, labyrinthitis) Meclizine 25 mg po q 8 h 5-HT3 antagonists Dolasetron 12.5 mg IV at onset of nausea and vomiting Used to treat severe or refractory vomiting, or vomiting caused by chemotherapy Possible adverse effects: Constipation, diarrhea, abdominal pain Granisetron 1 mg po or IV tid Ondansetron 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 125 mg po 1 h before chemotherapy on day 1, then 80 mg po daily in the morning on days 2 and 3 When used with ondansetron, 32 mg IV 30 min before chemotherapy on day 1 only When used with dexamethasone 12 mg po 30 min before chemotherapy on day 1 and 8 mg po daily in the morning on days 2, 3, and 4 Used with highly emetogenic chemotherapy regimens Possible adverse effects: Somnolence, fatigue, hiccups Metoclopramide 5–20 mg po or IV tid to qid Used to treat initial treatment of mild vomiting Perphenazine 5–10 mg IM or 8–16 mg po daily in divided doses; maximum dose 24 mg/day — Prochlorperazine 5–10 mg IV or 25 mg per rectum — Scopolamine 1-mg patch worn for up to 72 h Used to treat motion sickness Possible adverse effects: Diminished sweating, dry skin

Key Points

• Many episodes 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.

Last full review/revision July 2012 by Norton J. Greenberger, MD