Definition

• Forceful, neurologically mediated reflex expulsion of gastric contents from the oral cavity.
• Acute vomiting is defined as vomiting of short duration (<5–7 days) and variable frequency.

Pathophysiology

• A complex set of reflex activities under central neurologic and hormonal control involving the coordination of GI, abdominal, and respiratory musculature.
• Often preceded by prodromal signs of nausea.
• In the first stage there is increased saliva production with bicarbonate to lubricate the esophagus and neutralize gastric acid.
• This is followed by decreased gastric and esophageal motility and increased retrograde motility of the proximal small intestine.
• Stage 2 consists of retching, which is forceful contractions of the abdominal muscles and diaphragm with a resultant negative intrathoracic pressure and positive intra-abdominal pressure to facilitate moving gastric contents orally.
• In stage 3 the gastric contents are expelled. There is a change in the intrathoracic pressure from negative to positive via the force generated by the abdominal and diaphragm muscles. Concurrently, respiration is inhibited and the nasopharynx and glottis close to prevent aspiration.
• Stimulation of stretch receptors, chemoreceptors, and osmoreceptors located throughout the GI tract, hepatobiliary system, genitourinary system, peritoneum, and pancreas are examples of neural activation. (Duodenum has the most receptors.)
• The humoral stimuli are mediated through the chemoreceptor trigger zone; with a more permeable blood-brain barrier.
• Cats have poorly developed CTZ dopaminergic receptors and therefore respond poorly to apomorphine or D2 dopaminergic receptor antagonists such as metoclopramide.
• Higher centers can lead to psychogenic vomiting, and input from the vestibular apparatus (e.g. motion sickness, vestibular disease) can stimulate the emetic center.

Systems Affected

• Cardiovascular-hypovolemia, causing tachycardia, pale mucous membranes, and weak pulses; hypokalemia can cause arrhythmias.
• Gastrointestinal-reflux esophagitis.
• Metabolic-electrolyte and acid–base abnormalities (e.g. hypokalemia, hyponatremia, hypochloremia, metabolic alkalosis), prerenal azotemia, and dehydration.
• Nervous-lethargy.
• Respiratory-aspiration pneumonia, rhinitis from vomitus refluxed into the nasopharynx.

Genetics

No genetic basis

Incidence/Prevalence

Increased incidence in younger animals with dietary indiscretion

Geographic Distribution

None

Signalment

No age, breed, or sex predisposition

Signs

Causes

• Adverse food reactions-most frequent cause of acute vomiting; indiscretions (eating rapidly, ingestion of foreign material); intolerances (e.g. sudden diet change, allergies).
• Drugs-antibiotics, anti-inflammatory drugs (corticosteroids, NSAIDs), chemotherapeutics, digitalis, narcotics, xylazine.
• GI inflammation-infectious enteritis: viruses (parvo, distemper, corona virus), bacteria (Salmonella, Campylobacter, Helicobacter spp.); hemorrhagic gastroenteritis.
• Gastroduodenal ulcers.
• GI obstruction-foreign bodies, intussusception, neoplasia, volvulus, ileus, constipation, mucosal hypertrophy.
• Systemic disease-uremia, hepatic failure, sepsis, acidosis, electrolyte imbalance (hypokalemia, hypocalcemia, hypercalcemia).
• Abdominal disorders-pancreatitis, peritonitis, pyometra.
• Endocrine disease-hypoadrenocorticism, diabetic ketoacidosis.
• Neurologic disease-vestibular disturbances, meningitis, encephalitis, CNS trauma.
• Parasitism-ascarids, Giardia, Physaloptera, Ollulanus tricuspis (cats), salmon poisoning (dogs).
• Toxins-lead, ethylene glycol, zinc, mycotoxins, household plants.
• Miscellaneous-anaphylaxis, heat stroke, motion sickness, pain, fear.

Risk Factors

• Dietary indiscretion
• Sudden changes to diet

Differential Diagnosis

CBC/Biochemistry/Urinalysis

• In non-severe vomiting, the hemogram, biochemical profile, and urinalysis are typically unremarkable unless the animal is dehydrated.
• Anemia with panhypoproteinemia seen with severe gastric ulceration and bleeding.
• Dehydration-may see hemoconcentration (high PCV and total protein).
• May see a stress leukogram.
• Infectious or inflammatory causes-may see an inflammatory leukogram.
• Acute hepatopathies-may see elevated liver enzymes and serum bilirubin.
• Pancreatitis-may see elevated lipase, amylase, and liver enzymes.
• Hyponatremia, hyperkalemia, hypoglycemia, and azotemia suggest hypoadrenocorticism.
• Hyperglycemia with glucosuria and ketonuria indicates ketoacidotic diabetic mellitus.

Other Laboratory Tests

Additional blood tests for specific diseases when indicated (e.g., blood lead level, ethylene glycol assay, ACTH stimulation testing for hypoadrenocorticism, and canine pancreatic lipase immunoreactivity (cPL) or feline pancreatic lipase immunoreactivity (fPL) testing for pancreatitis.

Imaging

• Survey abdominal radiographs are often unremarkable, but radiodense foreign bodies, segmental ileus, or gastric distension indicating volvulus or outflow obstruction may be observed; serosal detail may be lost (“ground glass” appearance) with pancreatitis or peritonitis; a mass effect or haziness in the right cranial quadrant or persistent gas in the descending duodenum may indicate pancreatitis.
• Can use contrast radiography to evaluate for radiolucent foreign bodies, obstruction, intussusception, or volvulus.
• Can use abdominal ultrasonography to visualize an obstruction, an intussusception, or pancreatitis.

Diagnostic Procedures

Endoscopy may be useful to assess for gastroduodenal ulceration and gastric and proximal duodenal foreign bodies.

Pathologic Findings

Dependent on etiology

Appropriate Health Care

• Outpatient if vomiting non-serious
• Hospitalize if severe vomiting

Nursing Care

• Fasting the animal is not warranted unless the vomiting is intractable and the risk of aspiration pneumonia is increased.
• Patients with frequent episodes of vomiting should be treated initially by keeping the animal NPO and administering intravenous crystalloid fluids.

Activity

Animals should have limited activity until the vomiting has stopped.

Diet

• If vomiting resolves, initially offer small amounts of water or ice cubes, and if vomiting does not recur, follow with an easily digestible, low-fat, intestinal diet or single-protein and single-carbohydrate-source diet such as non-fat cottage cheese or skinless white chicken and rice in a 1:3 ratio.
• If vomiting does not recur, wean the patient back onto the normal diet over 4–5 days.

Client Education

Owners should be educated on the risks of giving their pet table scraps and to refrain from feeding high-fat treats. They should limit the pet's access to the trash and monitor the pet while it plays with toys to prevent ingestion of foreign bodies.

Surgical Considerations

Surgery should be considered for obstructions of any kind as well as for peritonitis or volvulus.

Drug(s) Of Choice

• May use antiemetics in patients with severe vomiting causing electrolyte and/or acid-base disturbances or reflux esophagitis.

• Several antiemetics are available for both dogs and cats-phenothiazine derivatives that act at the CTZ and emetic center include chlorpromazine (0.5 mg/kg SC q8h) and metoclopramide, a dopamine antagonist and motility modifier that acts at the CTZ and on local receptors in the gut (0.2–0.5 mg/kg PO or SC q6–8h, or 1–2 mg/kg/day as a CRI); H₁-receptor antagonists acting on the CTZ can be used in motion sickness (e.g., diphenhydramine 2–4 mg/kg PO, IM q6–8h) for dogs only; maropitant, a neurokinin-1 antagonist (1 mg/kg SC q24h or 2 mg/kg PO q24h).

• Patients with ulceration-can use H₂-receptor antagonists such as ranitidine (1–2 mg/kg PO, SC, IV q12h) and famotidine (0.5–1 mg/kg PO, SC, IV q12h), proton pump inhibitors such as omeprazole (0.7–1 mg/kg PO q12–24h), and/or gastric mucosal protectants such as sucralfate (250 mg/cat PO q6–12h, 250–1,000 mg/dog PO q6–12h) as a slurry.
• Fever or mucosal injury (hematemesis, melena)-antibiotics may be indicated (e.g., ampicillin, enrofloxacin).

Contraindications

• Use phenothiazines with caution in dehydrated patients because of possible hypotension from their alpha-receptor antagonist effect; they also may lower the seizure threshold and should be avoided in epileptics.
• Do not use anticholinergics; they can cause gastric atony and intestinal ileus, which could exacerbate vomiting.
• Do not use prokinetics such as metoclopramide and cisapride in patients with GI obstruction
• Maropitant should be used with caution in patients with hepatic disease and preferably for a maximum of 5 days.

Precautions

Use antiemetics cautiously; they may suppress vomiting and mask progressive disease or hamper an important means of monitoring response to primary therapy.

Possible Interactions

Anticholinergics and opoids may negate the effect of metoclopramide.

Alternative Drug(s)

• Cisapride
• Famotidine
• Dolasetron
• Pantoprazole

Patient Monitoring

• If frequency of vomiting increases or the animal has systemic evidence of disease: hospitalize for treatment and obtain appropriate diagnostics.
• If vomiting persists beyond 7 days despite conservative therapy, pursue appropriate testing for chronic vomiting.

Prevention/Avoidance

• Animals should be fed a highly digestible fat-restricted diet.
• Owners should attempt to control indiscriminant eating and monitor for foreign body ingestion.

Possible Complications

• Aspiration pneumonia
• Esophagitis
• Dehydration
• See “Systems Affected”

Expected Course and Prognosis

• Recovery from non-serious vomiting is usually rapid and spontaneous.
• Feeding of a highly digestible, fat-restricted diet will frequently control non-serious vomiting.
• GI foreign bodies have a good prognosis after endoscopic retrieval or surgical removal.

Associated Conditions

See “Systems Affected”

Age-Related Factors

Young animals are more likely to ingest foreign objects and acquire viral, bacterial, and parasitic disease.

Zoonotic Potential

Some species of Giardia, Salmonella, and Campylobacter are zoonotic.

Pregnancy/Fertility/Breeding

Misoprostol, a synthetic prostaglandin E1 analogue used most often in treatment or prevention of gastric ulceration associated with nonsteroidal anti-inflammatory drugs, is contraindicated in pregnant animals.

Synonym

Emesis

See Also

• Diarrhea, Acute
• Gastroduodenal Ulceration/Erosion

Abbreviations

• ACTH = adrenocorticotropic hormone
• CNS = central nervous system
• CTZ = chemoreceptor trigger zone
• GI = gastrointestinal
• NSAID = nonsteroidal anti-inflammatory drug
• PCV = packed cell volume

Client Education Handout Available Online