Nausea is the sensation felt immediately before vomiting.
Vomiting is a partially voluntary act of forceful expelling of stomach contents up to and out of the mouth that may or may not be preceded by nausea.
Retching or repetitive active contraction of the abdominal muscles occurs between nausea and vomiting.
Management includes correction of clinically relevant metabolic complications, pharmacological therapy and treatment of underlying cause.

Nausea%20-and-%20vomiting Diagnosis


  • A detailed history and physical exam are crucial in evaluating patients with nausea and vomiting and in determining the underlying cause of nausea and vomiting


  • Determine the duration, frequency and severity of nausea and vomiting
    • Nausea and vomiting is considered chronic when it lasts >1 month
  • Determine when vomiting occurs during the day (timing) and the characteristic of the vomiting process itself
    • Eg projectile vomiting may suggest an increased intracranial pressure (ICP) resulting from an intracranial problem 
  • Elicit information about the onset of vomiting ie relation to meals
  • Investigate the quantity and quality of the vomitus
    • Ask if vomitus consists of undigested, partially digested or bilious material
    • Ask about a possible fecaloid character of the vomitus or a putrid odor which is characteristic of intestinal obstruction
  • Ask about associated symptoms as these may assist in localizing the underlying disease process:
    • Fever, weight loss
    • CNS symptoms: Headache, focal neurologic deficits, neck stiffness, vertigo
    • Abdominal pain, diarrhea
    • Presence of a similar illness in the patient’s family and/or friends
  • Ask about concomitant illnesses
    • Patient may be suffering from nausea and vomiting related to treatment ie chemotherapy-related nausea and vomiting

Physical Examination

  • Search for signs of dehydration or weight loss
    • Orthostatic hypotension
    • Postural increase in pulse rate
  • Search for findings that may suggest autonomic neuropathy
    • Postural decrease in blood pressure (BP) without a concomitant increase in pulse rate
  • Conduct a careful abdominal examination
    • Ascertain if there is abdominal tenderness, together with its specific location
    • Listen for decreased bowel sounds
    • Palpate for abdominal masses
  • Conduct a detailed neurologic and psychiatric exam
    • Check for cranial nerve abnormalities, gait problems, funduscopic changes and other relevant information
  • The rest of the systemic physical exam may also provide other helpful information with regard to the etiology of nausea and vomiting
    • Findings suggestive of autonomic neuropathy may be found
    • Exam may reveal signs of systemic diseases causing nausea and vomiting
    • Evidence of self-induced vomiting may be apparent

Laboratory Tests

  • Diagnostic tests are done to aid in determining the underlying cause of nausea and vomiting and to assess the effects of nausea and vomiting on a patient
  • Basic tests include a complete blood count (CBC), erythrocyte sedimentation rate (ESR), standard blood chemistry
  • Other tests to be done would depend on the diseases being considered, eg:
    • Serum drug levels for possible drug toxicities
    • Pregnancy test
    • Thyroid-stimulating hormone (TSH) levels for possible thyrotoxicosis or Addison’s disease
    • Fecal occult blood

Tests of Gastric Motor Function

  • Gastric emptying time
    • Relatively accurate, easy and noninvasive
    • May reveal presence of gastroparesis
  • Electrogastrography (EGG)
    • A decrease in or the absence of the expected postprandial increase in the EGG amplitude has been shown to correlate with prolonged gastric emptying time and antral hypomotility
  • Antroduodenal manometry
    • May be useful in identifying patients with primary or diffuse motor abnormalities
    • A normal study may be useful in ruling out dysmotility and pointing the clinical investigation into another direction


  • Imaging tests are usually focused on the abdominal area and are done depending on the etiologies of nausea and vomiting being considered eg mechanical gut obstruction
  • Abdominal x-rays, barium studies
  • Small bowel enema, small bowel follow-through exam
  • Endoscopic investigations
  • Computed tomography (CT) scan of the abdomen

Disorders of Gut Motility


  • Functional disorders of gut motility give rise to nausea because of inability to clear food and secretions
  • Gastroparesis may be part of the following conditions:
    • Postvagotomy and postgastric drainage surgery patients
    • Pancreatic malignancy
    • Systemic diseases eg diabetes mellitus (DM), systemic lupus erythematous (SLE) and other connective tissue diseases
    • Idiopathic gastroparesis
  • The dysfunction is documented by tests of gastric motor function
    • Clinicians should be careful not to quickly assume that confirmed gastroparesis is the primary cause in itself of a patient’s symptoms

Other Conditions Associated with Disorders of Gut Motility

  • Other conditions that may result in gut dysmotility are chronic intestinal pseudo-obstruction, Roux-en-Y syndrome, functional dyspepsia

Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum

Nausea and Vomiting of Pregnancy

  • A common condition that affects about ¾ of pregnant women
    • 25% of women may have nausea only
  • May occur at all times of the day (not just in the morning)
  • Symptoms usually begin 4-7 weeks after the last menstrual period and cease by 12 weeks in most women
    • Symptoms that begin after the 9th week of gestation are not typical of nausea and vomiting of pregnancy
  • Increased incidence is noted in the following situations:
    • Previous pregnancy with nausea and vomiting
    • Nulliparity
    • Younger age of the mother
    • Obesity
    • Family history of hyperemesis gravidarum
    • Increased placental mass (eg molar or multiple pregnancies)
    • History of motion sickness or migraine
  • Nausea and vomiting of pregnancy is self-limiting in most patients and it usually resolves without complications as pregnancy proceeds

Hyperemesis Gravidarum

  • Represents the most severe form of nausea and vomiting of pregnancy
  • Most common reason for hospital admission during the 1st part of pregnancy
  • A diagnosis of exclusion based on typical signs and symptoms and the absence of other causes that may explain the clinical presentation
  • Criteria for diagnosis are as follows:
    • Persistent vomiting not related to other causes
    • Evidence of weight loss, usually ≥5% of prepregnancy weight
    • Evidence of starvation ie ketonuria
    • Abnormalities of electrolyte levels, thyroid and liver may also be present
  • Hyperemesis gravidarum may lead to significant complications, eg the following:
    • Rupture of the esophagus
    • Wernicke’s encephalopathy secondary to Thiamine deficiency
    • Hyperthyroxinemia with low thyroid-stimulating (TSH) levels
    • Depression

Differential Diagnoses for Nausea and Vomiting of Pregnancy

  • Nausea and vomiting that begins after the 9th week of gestation is not characteristic of nausea and vomiting of pregnancy and should be investigated further
  • Headache, fever, abdominal pain or tenderness are not typical in nausea and vomiting of pregnancy
  • Diseases that may present as nausea and vomiting in pregnant patients include the following:
    • Pregnancy-related conditions: Preeclampsia, acute fatty liver of pregnancy
    • GI diseases: Gastroenteritis, biliary tract disease, hepatitis, peptic ulcer disease, appendicitis, etc
    • Neurologic diseases: Migraines, CNS tumors
    • Genitourinary tract diseases: Pyelonephritis, kidney stones, uremia
    • Other conditions: Hydatidiform mole, diabetic ketoacidosis, drug-related toxicity, eating disorders, labyrinthitis, motion sickness

Postoperative Nausea and Vomiting (PONV)

Risk Factors for PONV

The presence of certain risk factors is predictive of a patient’s likelihood of experiencing post operative nausea and vomiting (PONV)

  • Patient Factors
    • Female gender
    • Nonsmoker
    • Postoperative opioid use
    • Previous episode of PONV
    • History of motion sickness
  • Surgical Factors
    •  Craniotomy
    • Laparoscopy
    • Laparotomy
    • Major breast surgery
    • Otolaryngological procedures
    • Plastic surgery
    • Strabismus surgery
PONV Risk Stratification

Very High Risk

  • >4 factors present
  • Emesis potential >80%
Moderate-High Risk
  • 3-4 risk factors present
  • Emesis potential 40-80%
Mild-Moderate Risk
  • 1-2 risk factors present
  • Emesis potential 20-40%
Other Issues Affecting PONV Risk
  • PONV is seen more often in patients who have undergone general anesthesia compared to those who have received regional anesthesia
    • Propofol use decreases the risk of PONV
  • Dehydration, pain and anxiety can increase the incidence of PONV

Chemotherapy- and Radiation-Related Nausea and Vomiting

Incidence of Chemotherapy-Related Nausea and Vomiting
  • About 70-80% of cancer patients receiving chemotherapy experience nausea and vomiting
  • The incidence and severity of nausea and vomiting following chemotherapy are influenced by the following factors:
    • Chemotherapeutic agents used
    • Dosage of chemotherapeutic agents
    • Schedule and route of administration
    • Radiation therapy target
    • Individual patient propensities eg gender, age, previous chemotherapy, history of alcohol use
Effects of Chemotherapy-Related Nausea and Vomiting
  • Poor compliance or withdrawal from chemotherapy
  • Malnutrition, anorexia, metabolic imbalances
  • Decreased level of functioning
  • Esophageal tears
Classification of Chemotherapy-Related Nausea and Vomiting

Acute-onset Nausea and Vomiting

  • Occurs within a few minutes to several hours after chemotherapy administration
  • Usually peaks after 5-6 hours and resolves within 24 hours
Delayed-onset Nausea and Vomiting
  • Arises >24 hours after chemotherapy administration
Anticipatory Nausea and Vomiting
  • A conditioned response which occurs before patients receive their next chemotherapy treatment
  •  Anticipatory nausea and vomiting usually occurs when patients have had a previous unpleasant experience with chemotherapy
  • Younger patients are more prone to anticipatory nausea and vomiting because they have poorer emesis control and they usually receive more aggressive chemotherapy regimens
Breakthrough Nausea and Vomiting
  • Nausea and Vomiting that arises in spite of preventive treatment
Refractory Nausea and Vomiting
  • Symptoms that occur during subsequent chemotherapy sessions when antiemetic prophylaxis has failed during previous treatment sessions
Classification of Chemotherapeutic Agents According to Emetogenic Potential1
  • The type of antiemetic treatment regimen that a patient needs depends on the emetogenic potential of the chemotherapeutic agents that a patient is receiving
    • The risk of nausea and vomiting for chemotherapeutic agents with high emetic risk lasts for about 3 days and with moderate emetic risk 2 days after the final dose of chemotherapy
High (Emetic Risk >90%)
  • IV agents: Anthracycline/cyclophosphamide combination, Carmustine (>0.25 g/m2), Cisplatin, Cyclophosphamide (>1.5 g/m2), Dacarbazine, Doxorubicin (≥0.06 g/m2), Epirubicin (>0.09 g/m2), Ifosfamide (≥2 g/m2 per dose), Mechlorethamine, Streptozocin
Moderate (Emetic Risk Between 30-90%)
  • IV agents: Azacitadine, Bendamustine, Busulfan, Carboplatin, Carmustine (≤0.25 g/m2), Clofarabine, Cyclophosphamide (≤1.5 g/m2), Cytarabine (>0.2 g/m2), Daunorubicin, Doxorubicin (<0.06 g/m2), Epirubicin (<0.09 g/m2), Idarubicin, Ifosfamide (<2 g/m2 per dose), Irinotecan, Melphalan, Methotrexate (≥0.25 g/m2), Oxaliplatin, Temozolomide, Trabectedin
Oral Antineoplastic Agents with Moderate to High Emetic Risk
  • Busulfan (≥0.004 g/day), Cyclophosphamide (≥0.1 g/m2/day), Etoposide, Niraparib, Olaparib, Procarbazine, Rucaparib, Temozolomide (>0.075 g/m2/day)
Low (Emetic Risk Between 10-30%)
  • IV agents: Cytarabine (0.1-0.2 g/m2), Docetaxel, Etoposide, Fluorouracil, Gemcitabine, Liposomal Doxorubicin, Methotrexate (<0.25-0.05 g/m2), Mitomycin, Mitoxantrone, Paclitaxel, Pemetrexed, Topotecan
Minimal (Emetic Risk <10%)
  • IV agents: Bevacizumab, Bleomycin, Cladribine, Cytarabine (<0.1 g/m2), Fludarabine, Ipilimumab, Methotrexate (≤0.05 g/m2), Peginterferon, Pertuzumab, Pembrolizumab, Rituximab, Trastuzumab, Vincristine, Vinblastine, Vinorelbine
Oral Antineoplastic Agents with Minimal to Low Emetic Risk
  • Abemaciclib, Capecitabine, Chlorambucil, Erlotinib, Everolimus, Fludarabine, Hydroxyurea, Imatinib, Melphalan, Methotrexate, Neratinib, Regorafenib, Ribociclib, Sunitinib, Thalidomide, Topotecan, Vemurafenib

1List of chemotherapeutic agents shown above is not exhaustive. Please refer to available guidelines from health authorities for the complete list.

Radiation-Induced Nausea and Vomiting
  • Patients receiving whole body or upper abdominal radiation therapy have the greatest chance of developing nausea and vomiting after the procedure
    • The rapidly dividing cells of the intestinal tract are especially sensitive to radiation
  • The potential for postradiation nausea and vomiting is increased by a higher total and daily fractional dose of radiation and a larger amount of irradiated tissue

Classification of Radiotherapy Emetogenic Potential According to Irradiated Site 

High (Emetic Risk >90%)  

  • Total body irradiation

Moderate (Emetic Risk Between 30-90%)   

  • Craniospinal irradiation, upper abdomen

Low (Emetic Risk Between 10-30%)   

  • Cranium, head and neck, thorax, pelvis

Minimal (Emetic Risk <10%)   

  • Breast, extremities

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