Approach to vomiting & regurgitation

Question 1

What are acute causes of vomiting?

Answer 1

• GI Tract – obstructive (FB, Neoplasia, parasitic, constipation, intussusception, volvulus), inflammatory (gastritis, gastroenteritis, colitis), mucosal insult (Dietary indiscretion, intolerance, sudden change in diet, toxins), infectious (bacterial/viral/parasitic), gastric stretch (you ate too much!) and visceral pain.
• Cerebral cortex – head trauma, sudden changes in ICP
• Vestibular system – motion sickness, idiopathic vestibular disease, otitis interna
• CRTZ - chemo receptor trigger zone
  ◦ Endogenous: any systemic metabolic or endocrine disease resulting in acute changes e.g. DKA, Addisons, AKI, pancreatitis, acute hepatitis, peritonitis, prostatitis, pyometra, electrolyte disturbances, acid-base disturbances.
  ◦ Exogenous: Toxins/Drugs

Question 2

What are chronic causes of vomiting?

Answer 2

• GI Tract – Chronic inflammatory (gastritis, gastroenteritis, colitis, chronic enteropathy), mucosal insult (Dietary intolerance), infectious (bacterial/viral/parasitic) obstructive (pyloric FB, Neoplasia, parasitic, constipation)
• Cerebral cortex – Neoplasia/SOL, CNS disease
• Vestibular system – chronic vestibular damage, otitis interna, neoplasia, cerebellar disease
• CRTZ
  ◦ Endogenous: any systemic metabolic or endocrine disease resulting in chronic changes e.g. diabetes mellitus, Addisons, chronic renal failure, liver failure, chronic pancreatitis, electrolyte disturbances, acid-base disturbances, hyperT4 (cats)
  ◦ Exogenous: Toxins/Drugs less likely

Question 3

What is the difference between dysphagia and regurgitation?

Answer 3

Dysphagia - Failure to prehend/bite (mouth) and initially swallow (pharynx)
Regurgitation - Failure to pass the oesophagus

Question 4

What are causes of dysphagia?

Answer 4

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

Question 5

What are causes of regurgitation?

Answer 5

• Dilatation (megaoesophagus) – may be congenital or occurring via either being active stretch (e.g. a 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)
• Neuro-muscular disorder – Myasthenia gravis, botulism, tetanus, distemper, dysautonomia, peripheral neuropathy (e.g. autoimmune), Addisons, Hypothyroidism

Question 6

How can you use history and clinical exam to diagnose vomiting/regurgitation?

Answer 6

• 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 the possible causes and therefore questions/findings that might be useful e.g.
• Recent medical history – aspiration risk in surgery for oesophagitis, or medications e.g. doxycycline and risk of oesophagitis.
• GI disease –dietary changes/scavenging/foreign body risk/access to toxins/worming regime/diarrhoea/constipation
• Neurological abnormalities – behavioural changes, ataxia, cranial nerve deficits, exhaustible blink etc.
• Pain!
• Body condition score to assess for true acute vs chronic but missed by the owners.
• Muscle quality e.g. masticatory muscles.
• Signs of systemic disease e.g. PUPD, Jaundice

Question 7

What diagnostic testing can you use to find the cause of vomiting/regurgitation?

Answer 7

• Imaging – primarily looking for obstructive/anatomical disease
• Radiography - (L5/SI ratio > 1.7 -> Use of the SI/L5 ratio was not associated with increased accuracy of diagnosis for any observer, regardless of experience, hence this test may have no diagnostic impact – Ciasca et al., 2013)
• Ultrasound – operator dependant, don’t forget POCUS for free fluid!
• (CT/fluoroscopy)
• Direct Visualisation – Examination under GA, Endoscopy – Upper GI foreign bodies, inflammatory disease – biopsy opportunity.
• Look for systemic/metabolic diseases – Haematology/Biochemistry
• Specific blood tests – e.g. cPLI (Pancreatitis), AChR (M. Gravis), basal cortisol (Addisons), T4/TSH (HypoT4)

Question 8

What initial management can you undertake when treating vomiting?

Answer 8

Consider the cause and treat the underlying.
Be aware – reaching for drugs may just mask the problem e.g. FB.

• Maropitant – NK1 antagonist -> helps with centrally mediated vomiting e.g. metabolic, CRTZ, Vestibular
• Metoclop – D2 receptor antagonist and 5-HT3 receptor antagonist -> Dual effect, CRTZ and lower oesophageal sphincter, BUT prokinetic so if FB present could rupture the GI Tract
• Ondansetron – 5HT3 – centrally acting (CRTZ) – very effective at reducing nausea
• Nutrition:
  ◦ Especially in chronic cases where BCS is reducing.
  ◦ Consider feeding tubes – bypass the problem if you can; NO/NG tube, O tube, PEG tube.
  ◦ TPN/PPN – parenteral nutrition; ideally a central line is required so not often a routine first opinion approach but it is feasible with good nursing.

Question 9

What initial management can you undertake when treating regurgitation?

Answer 9

• Abnormal swallowing:
  ◦ Trial and error to find the food type tolerated – may require a feeding tube in the short term to stabilise.
• Regurgitation - depends on the cause:
  ◦ Megaoesophagus - Difficult to manage!
  ◦ Omeprazole (PPI) – risk of worsened aspiration.
  ◦ Feed from a height – 5-10 minutes! Small balls rather than big amounts. Could consider a feeding tube. Prognosis is often poor for chronic regurgitation.
  ◦ Treat any concurrent/underlying disease e.g. hypothyroidism, PRAA, etc.
  ◦ Oesophagitis – Pain relief!! Feeding Tube (bypass the oesophagus)
  ◦ Oesophageal Foreign body – remove it, endoscopy, consider referral – rupture -> thoracotomy

Question 10

What are the 4 types of gastroprotectants?

Answer 10

◦ Omeprazole – Proton Pump Inhibitor, reduced H+ secretion -> useful for gastric ulceration (and reducing CSF production e.g. Syringomyelia). Long term use -> Dysbiosis. <3-4 weeks.
◦ Misoprostol – Prostaglandin analogue – Increases mucosal blood flow and therefore healing e.g. ulcers – DON’T USE IN PREGNANCY – primarily used for NSAID tox
◦ H2 Receptor antagonists e.g. cimetidine – reduce acid secretion, effectiveness is questionable, minimal research in small animal and not supportive.
◦ Sucralfate – polyionic surfactant (anion) binds to damaged mucosa (positively charged proteins exposed) – weak evidence for use in oesophagitis, probably not helpful in gastric ulceration – use liquid not tablets.