ch 30 Esophagus Flashcards
How might scintigraphy be used in esophageal diagnostics?
can be used to quantify motility and transit time, and to diagnose gastroesophageal reflux
Which muscle determines the start of the esophagus, i.e. is the cranial esophageal sphincter?
cricopharyngeal sphincter muscle = cricopharyngeus + thyropharyngeus
Which muscles are closely associated with the dorsal esophagus in the cranial thorax?
longus colli
longus capitis
The esophagus is to the left/right of the trachea at the thoracic inlet.
left
what are the layers of the esophagus?
fibrous, muscular, submucosa, mucosa
what kind of muscle is the feline esophagus?
cranial 2/3: striated
caudal 1/3: smooth - oblique arrangement /herringbone pattern
what does the canine esophageal mucosa look like?
longitudinal folds
what kind of muscle is the canine esophagus?
striated
what makes up the caudal esophageal sphincter?
what artery supplies the cranial 2/3 thoracic esophagus?
bronchoesophageal
blood supply of the esophagus?
cervical: thyroid arteries
cranial 2/3 thoracic: bronchoesophageal
caudal 1/3 thoracic: intercostal and/or esophageal branches of aorta
terminal portion: left gastric
what artery supplies the cervical esophagus?
thyroid
what artery supplies the caudal 1/3 thoracic esophagus?
intercostal and/or esophageal branches of aorta
what artery supplies the terminal esophagus?
left gastric
Which veins drain the thoracic part of the esophagus?
azygous & left gastric
lymphatics of the esophagus
med retropharyngeal
deep cervical
cran mediastinal
bronchial
portal, splenic, gastric
esophageal innervation
CN 5, 7, 9, 10, 12
in which projection can the normal caudal thoracic esophagus be visualised?
left lateral
rare in RL
When and where can gas accumulate focally in the esophagus (under normal circumstances)?
Gas can accumulate focally in the esophagus in animals that are excited, sedated, and dyspneic or under general anesthesia; this gas accumulation is usually minimal, and the most common location for this to occur is just cranial to the tracheal bifurcation
What is the tracheal stripe sign?
Summation of ventral esophageal wall with dorsal tracheal wall, visible due to gas in the esophagus
Typical signalment for redundant esophagus?
Young or short-necked brachycephalic dogs
Which type of contrast medium is contraindicated for patients with increased risk of aspiration?
Barium paste; may cause airway obstruction
What is a potential complication of contrast esophagrams?
Barium aspiration; small amount usually asymptomatic, but pneumonia and lung granulomas can occur.
How long does it take for barium to be cleared if it reaches the alveoli?
It may remain there forever/permanently.
It may also be found in the tracheobronchial and mediastinal lymph nodes permanently.
Are esophograms performed conscious, sedate, or under GA?
conscious
During an esophogram, how much contrast should be left in the oral cavity and pharynx after swallowing?
None
Which contrast is the best for suspected esophageal perforation?
Non-ionic (low osmolar)/ iohexol or iopamidol
What is the disadvantage of ionic (hyperosmolar) contrast medium?
can induce pulmonary edema if aspirated. do not use!
What are 2 ionic (hyperosmolar) contrast mediums?
diatrizoate sodium, meglumine
What is the advantage of barium sulfate paste?
Adheres to the esophageal mucosa and is best for diagnosing esophagitis, mucosal irregularities, or infiltration
What is the disadvantage of barium sulfate liquid?
It does not adhere well to mucosa (to show mucosal disease), and is contraindicated if perforation is suspected
What is the advantage of barium sulfate?
Relatively safe if aspirated, may pass through incomplete obstructions or strictures
How many mLs of barium (60%) should you administer to a small dog / large dog / cat, for a static barium esophagram?
small dog (15ml), large dog (20-30ml), cat (5-7 ml)
What percentage barium sulfate is used?
60%
What happens during the cricopharyngeal phase of swallowing?
Which CN?
- relaxation of cricopharyngeal sphincter during pharyngeal contraction, which propels the bolus aborally (CN IX, X)
What are the control mechanisms for the oral phase of swallowing?
Hyoid apparatus
Tongue
Nerves: Facial, Vagus, Hypoglossal
How much dry kibble with how much barium suspension, for a barium meal esophagram?
1 cup dry kibble + 20 mL barium
1/2 for cats
Which phases of swallowing does the facial nerve control?
Oral and Pharyngeal
What are the 5 phases of swallowing?
OPCEG
Oral
Pharyngeal
Cricopharyngeal
Esophageal
Gastric
When should secondary peristalsis occur?
2 to 4 seconds; in the esophageal phase
What happens during the oral phase of swallowing?
The liquid or food bolus is formed, and reflex pharyngeal peristalsis starts.
what happens during the pharyngeal phase of swallowing?
- craniodorsal movement of the hyoid (caused by pharyngeal contraction)
- the bolus enters the laryngopharynx
- the glottis closes the entrance to the trachea
Which frame rate is recommended for fluoroscopic examination of dysphagia?
30 - 60 fps
Which 4 assessments during fluoroscopy will help assess and categorise dysphagia as oral / pharyngeal / cricopharyngeal in origin?
1) bolus formation
2) pharyngeal and tongue movement
3) pharyngeal clearing of barium
4) cricopharyngeal sphincter function
Which phase of swallowing is voluntary?
The oral phase
Normal cricopharyngeal phase of swallowing. The bolus passes through the cricopharyngeal sphincter into the cranial aspect of the esophagus (large white arrow), and the cricopharyngeal sphincter (small white arrows) is open momentarily.
What characterises oral dysphagia?
Dropping food
salivating / drooling
failure to form a bolus (thus no swallowing reflex is induced)
Which phase?
Pharyngeal
Normal esophageal phase of swallowing. A tight bolus with a convex cranial border that tapers caudally is present in the cranial aspect of the esophagus.
Is the pharyngeal constriction ratio higher or lower in cricopharyngeal dysphagia?
higher
Which pharyngeal disorder could be misinterpreted as a cricopharyngeal disorder?
small sphincter opening
what is the discerning factor between pharyngeal and cricopharyngeal dysphagia?
time to opening of the cricopharyngeal sphincter - this is significantly shorter in pharyngeal dysphagia
What is the pharyngeal constriction ratio?
pharyngeal area at max contraction / pharyngeal area at rest
In which phase dysphagia (pharyngeal or cricopharyngeal) is the time to opening of the cricopharyngeal sphincter, shorter?
pharyngeal
Toy breeds are associated with which type of dysphagia?
Cricopharyngeal achalasia
Which type/breed of dog is associated with cricopharyngeal achalasia?
Toy breeds
What are the 2 types of cricopharyngeal dysphagia?
achalasia or dyssynchrony
what is cricopharyngeal achalasia?
failure of the CP sphincter to open fully
what is cricopharyngeal dyssynchrony?
failure of the CP sphincter to open at the appropriate time
In which dysphagia(s) can aspiration pneumonia be found?
pharyngeal (can), cricopharyngeal (common)