The diagnostic approach to vomiting, regurgitation dysphagia

• Physiology of vomiting

  Vomiting is an active reflex mediated via the emetic centre that can be stimulated via the chemoreceptor trigger zone (CRTZ) or GI tract, cerebral cortex or vestibular syndrom.
• Causes of acute vomiting - GI tract


  Obstructive (foreign body, neoplasia, parasitic, constipation, intussusception, volvulus)

  Inflammatory (gastritis, gastroenteritis, colitis).

  Mucosal insult (dietary indescretion, intolerance, sudden change in diet, toxins).

  Infectious (bacterial/viral/parasitic).

  Gastric stretch (eating to much).

  Visceral pain.
• Causes of acute vomiting - cerebral cortex

  Head trauma

  Sudden changes in intracranial pressure.
• Causes of acute vomiting - vestibular

  Motion sickness

  Idiopathic vestibular disease

  Otitis interna
• Causes of acute vomiting - CRTZ

  Endogenous: any systemic metabolic or endocrine disease resulting in acute changes e.g. DKA, Addisones, AKI, pancreatitis, acute hepatitis, peritonitis, prostatitis, pyometra, electrolyte disturbances, acid-base disturbances.

  Exogenous: toxins/drugs
• Causes of chronic vomiting - GI tract

  Chronic inflammatory: gastritis, gastroenteritis, colitis, chronic enteropathy.

  Mucosal insult: dietary intolerance

  Infectious: bacterial, viral, parasitic.

  Obstructive: pyloric foreign body, neoplasia, parasitic, constipation.

  Cerebral cortex: neoplasia/SOL, CNS disease.

  Vestibular system: chronic vestibular damage, otitis interna, neoplasia, cerebellar disease.
• Physiology of regurgitation

  Passive expulsion of food from the pharynx or oesophagus. This is a failure of swallowing (Dysphagia) and/or subsequent movement of food down the oesophagus to the stomach.
• Causes of dysphagia

  Failure to prehend/bite (mouth) and initially swallow (pharynx):

  • Pain - on closing (e.g. dental disease, stomatitis) or on opening (e.g. retrobulbar abscess) or both (fracture jaw, TMJ disease).
  • Failure of neuromuscular control - cranial nerves disease (V, VII, IX, X, XII), CNS disease, masticatory myositis, Botulism, myasthenia gravis.
  • Obstruction - pharyngeal FB, polyp, neoplasia, abscessation, lymphadenopathy.
• Causes of regurgitation

  Failure to pass the oesophagus.

  Dilation (megaoesophagus) - may be congenital or occurring via wither being active stretch (e.g. chronic obstruction) or passive stretch (weak muscular wall, dysmotility) or idiopathic.

  Obstruction - intraluminal (internal), mural (wall) or extramural (external).

  • Intraluminal - foreign body, stricture (e.g. secondary to oesophagitis).
  • Mural - neoplasia, inflammation.
  • Extramural - vascular ring anomaly, Hiatal hernia, SOL (neoplasia).

  Nueromuscular disorders - Myasthenia gravis, botulism, tetanus
• How to approach diagnosis of vomiting?

  Differentiate vomiting (active) from regurgitation/dysphagia - speak to the owner.

  Vomiting is usually associated with retching, abdominal effort and lots of noise. Regurgitation is passive, the food just ‘plops’ out, no retching, less noise.
• History and examination clues with vomiting

  Importantly in the vomiting patient determine if they are an emergency - i.e. collapsed, poorly responsive, signs of hypovolaemia, etc and proceed to triage if the case.

  Consider possible causes and therefore questions. Recent medical history, GI disease, neurological abnormalities, pain.
• Signalment clues for vomiting

  Congenital megaoesophagus - Labrador, Newfoundland, Shar-Pei.

  Congenital and acquired - Great Dane, GSD, Irish setter.

  Vascular ring anomaly - persistent right aortic arch GSD, Irish setter, Great Dane.

  Intussesception - Juvenile, puppies with recent diarrhoea.
• Diagnostic testing for vomiting

  Imaging - primarily looking for obstructive/ anatomical.

  Radiography

  Ultrasound - operator dependant.

  Direct visualisation - examination under GA, Endoscopy - upper GI foreign bodies, inflammatory disease - biopsy opportunity.

  Look for systemic/ metabolic disease - Haemotology/ Biochemistry.

  Specific blood tests - e.g. cPLI (pancreatitis).
• Maropitant

  NK1 antagonist -> helps with centrally mediated vomiting e.g. metabolic, CRTZ, vestibular.
• Metoclopramil

  D2 receptor antagonist and 5-HT3 receptor antagonist -> dual effect, CRTZ and lower oesophageal sphincter, but prokinetics so if FB present could rupture the GI tract.
• Gastroprotectants - omeprazole

  Proton pump inhibit or, reduced H+ secretion -> useful for gastric ulceration (and reducing CSF production e.g. Syringomyelia)

  Long term use -> Dysbiosis. <3-4 weeks.
• Gastroprotectants - Misoprostol

  Prostaglandin analogue - increases mucosal blood flow and therefor healing e.g ulcers - don’t use in pregnancy - primarily used for NSAID tox.
• Vomiting due to neoplasia - diagnosis

  Diagnosis requires biopsy.

  • Full thickness is the most reliable.
  • Endoscopic biopsies are superficial and may miss lesions.
  • Ultrasound is not as sensitive as endoscopy at identifying abnormal tissue for FNA/biopsy.
  • Surgical biopsy is the most sensitive.
  • Always do a met check (3 view CXR or CT), although intestinal neoplasms less commonly spread to the lungs.
• Vomiting due to neoplasia in dogs - adenocarcinoma

  Adenocarcinoma is the most common tumour of the stomach and large intestine, found in small intestine also. Locally invasive and progressive neoplasm, reducing the luminal diameter. Therefore, additional clinical signs include:

  • Gastric - haematemesis (coffee granules).
  • SI and colonic - ribbon like faeces.

  At the time of diagnosis ~95% of gastric carcinoma has metastasised and up to 58% of intestinal. Treatment is surgical excision +/- draining lymph nodes.

  Prognosis - Gastric (6 months), SI (4-18 months), Colorectal (2-4y)
• Vomiting due to neoplasia in dogs - Leiomyosarcoma and gastro-intestinal stromal tumour

  A diffuse neoplasm mean local excision is often not an option. However, responsive to chemotherapy depending on the degree of differentiation. Chemotherapy protocols include Wisconsin-Madison, Prednisolone +/- chlorambucil +/- cyclophosphamide.

  Prognosis:

  • Poorly differentiated, high grade lymphoma - <3 months.
  • Well differentiated, low grade, small cell - 1.5-2years.
  • Large intestinal lymphoma - 5.5-6years.
• Vomiting due to neoplasia in dogs - adenocarcinoma

  Adenocarcinoma is less common in cats and prognosis is poorer compared to dogs.

  Prognosis - upper GI (5-15 months). Colonic (4-9 months).
• Vomiting due to neoplasia in cats - lymphoma

  The most common GI neoplasm in cats.

  As with dogs, diffuse, meaning chemotherapy is the main treatment.

  Prognosis:

  • Poorly differentiated, high grade lymphoma - <3 months.
  • Well differentiated, low grade, small cell - 2-3 years.
• Vomiting due to gastroduodenal ulceration

  In dogs more than cats.

  Anything that disrupts mucosal barrier -> HCl, Bile acid and proteolytic enzymes can now degrade epithelial cells. Leads to damage and inflammation, local histamine release from mast cells promotes further HCl production, reduced blood flow inhibits cellular repair, necrosis and perforation.
• Vomiting due to gastroduodenal ulceration - common causes

  Steroids and NSAIDs.

  Neoplasia

  Hepatic disease
• Vomiting due to gastroduodenal ulceration - diagnosis

  Endoscopy.

  Ultrasound is less sensitive, but will detect free fluid/ gas if perforation has occurred.
• Vomiting due to gastroduodenal ulceration - treatment

  Evidence is poor for all of these:

  • H2 receptor antagonist (e.g. Cimetidine) OR proton inhibitor (e.g. omeprazole).
  • Sucralfate
  • Misoprostol - primarily consider in NSAID toxicity.

  Prognosis - completely depends on the underlying disease process.
• Vomiting due to Helicobacter

  Curved, gram-negative, and motile.

  Implicated in gastritis, ulcers and neoplasia in humans.

  Very commonly isolated in normal and unwell dogs and cats - therefore their significance is unknown.

  Diagnosis - endoscopic brush samples or biopsy of the stomach.

  Because they exist, some will argue the use of antibiotics e.g. amoxicillin in cases of gastritis or ulcers.
• Vomiting due to chronic gastritis

  Lymphatic-plasmacytic gastritis and eosinophillic gastritis.

  These are histopath diagnoses - i.e. it’s simply a description of the predominant inflammatory cell present.

  Realistically - they both represent and abnormal, over-reaction of the local immune system. Dietary allergens (usually proteins) or antigens are probably the cause.

  Treatment is either to remove the allergen/antigen or suppress the immune response or birth.