Introduction

• Clinical sign NOT a diagnosis therefore try to identify cause.
• Differentiate between regurgitation, retching and true vomiting.
• Cause: primary gastrointestinal or other abdominal conditions, secondary to systemic or metabolic disease or drug toxicity, secondary to neurological disease (cerebral or vestibular).
• Diagnosis: biochemistry, urinalysis, radiography and ultrasonography, endoscopy all useful aids.
• Treatment: depends on cause.

Pathogenesis

Etiology

• Visceral stimulation of vomiting center.
• Central stimulation of vomiting center.
• Vestibular stimulation of vomiting center.
• Stimulation of chemoreceptor trigger zone (CRTZ).

Predisposing factors

• Most often acute vomiting of uncertain cause; the majority of acute presentations are self-limiting.
• A routine fecal exam for parasites Fecal analysis: parasites should be performed in all animals with GI signs.

Pathophysiology

• The act of vomiting can be divided into three components: nausea, retching and vomiting.

• Distension of visceral organ/inflammation of visceral mucosa → neural stimulation (via sympathetic and vagal nerves) of vomiting center, located in the medulla oblongata of the brain.

• Inflammation in CNS → increased intracranial pressure → stimulate chemoreceptor trigger zone (CRTZ) in brain → dopamine release from neurones → stimulation of vomiting center.
• Toxins, toxic substances - uremia, ketoacidosis, drugs such as xylazine, morphine.

• Irregular motion → disturbance in semi-circular canals → stimulation of vomiting center.
• Labyrinthitis.

• Dehydration.
• Potassium depletion:
  • Minor loss in vomitus.
  • Urinary losses as kidney tries to maintain blood volume in face of dehydration and loss of gastric acid.
• Acid base imbalances Acid base imbalance - usually metabolic acidosis. (Alkalosis suggests pyloric outflow obstruction with predominant loss of gastric acid.)

Timecourse

• See specific conditions.

Diagnosis

Treatment

Outcomes