Regurgitation and vomiting Flashcards
What clinical features in the dog or cat make you think it has oropharyngeal dysphagia?
Hunger with multiple messy attempts to eat
Pharyngeal retching
Food and saliva brought back immediately.
Difficulty +/- pain and distress on attempted swallowing.
Repeated unsuccessful attempts at swallowing. Liquids may come back down nose if severe (nasal discharge)
May be anorexic and cachexic.
Aspiration (with resultant pneumonia and cough) common.
Regurgitation
More passive than vomiting - lowers head with no abdominal effort.
Tube of undigested food + white saliva (usually not bile-stained) falls out.
Can be soon after feeding or delayed several hours - ingesta sits in dilated oesophagus and regurgitation triggered by increased intrathoracic pressure
Often bright and try to eat it again.
Aspiration pneumonia and cachexia common.
Uncommon in cats
True vomiting
Active process involving reflex and muscular contractions.
Usually preceded by nausea (prodromal signs e.g. agitation, salivation, swallowing, lip smacking).
Forceful ejection of vomit.
Less likely to eat vomitus afterwards (but may do).
Vomit may be partially digested food, fluid (often bile stained) and/or haematemesis.
Aspiration pneumonia unusual
pH is a poor indicator but would expect stomach contents to have low pH
Congenital abnormalities that could cause vomtining/regurgitation
Vascular ring anomaly
Oesophageal diverticulum
Broncho-oesophageal fistula
Hiatal hernia
Most common dog breed to get foreign body in the oesophagus
West highland white terrier
Which breeds are overrepresented for regurgitation and hiatal hernia?
Brachycephalic dogs
What disorder could be worse when ingesting liquid?
pharyngeal dysphagia
Which disorders could be worse when ingesting food (rather than liquid)?
crichophalangeal achalasia
oesophagitis
What could cause gas in the oesophagus on radiograph?
Megaoesophagus
Vascular ring anomaly
Stricture
Severe oesophagitis
Aerophagia
What can cause aerophagia?
Excitement
Nausea
Anaesthesia/GA
Dyspnoea
Innervation of the pharynx
IX and X sensory and motor
Anatomy of oesophagus (layers)
mucosa, submucosa with mucous glands, muscularis + loose connective tissue (no serosa)
Canine muscularis muscle of the oesophagus
Two intertwining layers of striated muscle
Feline muscularis muscle of the oesophagus
Cranial and middle sections mixed smooth and striated
terminal 35% entirely smooth muscle
Upper oesophageal sphincter
cricopharyngeal sphincter (cricopharyngeal and thyropharyngeal muscles).
Relaxation co-ordinated with swallowing.
Prevents aerophagia and reflux of food from oesophagus into pharynx
Lower oesophageal sphincter
gastro-oesphageal sphincter = not a true sphincter but “distal high pressure zone” (inner layer of gastric smooth muscle with outer oesophageal striated muscle in dog + contributions from diaphragm and intra-abdominal pressure).
Swallowing
Ingesta pushed to caudal part of mouth by movement of base of tongue against hard palate
Hyoid apparatus moves larynx cranially, base of tongue moves caudally, epiglottis flips up over larynx and bolus forced through relaxed UOS to proximal oesophagus
Larynx then moves caudally again and epiglottis returns to original position under soft palate
Oesophagus stimulated by stretch -> primary peristaltic wave which propels food to stomach
Differential diagnoses of pharyngeal retching/dysphagia
Oropharyngeal trauma
Oropharyngeal foreign body
Oropharyngeal inflammation
Oropharyngeal mass
Salivary mucocoele, polyp, abscess
Neurological and muscular problems
Oropharyngeal trauma
Mandible
Maxilla
TMJ
Hyoid bones
Soft tissue
Oropharyngeal inflammation
Gingivitis
Stomatitis
Pharyngitis
Tonsillitis
Oropharyngeal masses
Tonsillar squamous cell carcinoma
Peripharyngeal lymphoma
Neurological and muscular problems leading to pharyngeal retching or dysphagia
Masticatory myositis
Cranial nerve deficits e.g. V (trigeminal neuritis - often just motor), VII, IX, X.
Pharyngeal dysphagia
Dysautonomia
Botulism
Rabies
Myasthenia gravis (focal form: extraocular muscles, V, VII, IX ± oesophagus)
Cricopharyngeal achalasia or stenosis
Idiopathic hypersialosis
Cricopharyngeal achalasia
Upper oesophageal sphincter = cricopharyngeal sphincter (cricopharyngeal and thyropharyngeal muscles)
Rare congenital (v. rarely acquired). Cocker spaniels
Disrupted co-ordination between cricopharyngeal relaxation and swallowing
Cricopharyngeus remains contracted during swallowing.