Chapter 27 - Esophagus Flashcards
What structures make up the upper esophageal sphincter?
Cricopharyngeus
Thyropharyngeus
What is the path of the esophagus - where does it lie in regards to the trachea?
Proximal - ventral and to the right of the trachea
Cervical - slightly to left of trachea
Thoracic inlet - to the left of trachea and courses dorsally
What are hte layers of the esophagus?
fibrous, muscular, submucosa, mucosa
What is the difference between a dog and cat esophagus histologically?
Dog - striated the entire length
Cat - caudal third is smooth muscle - striated/herringbone appearance
What is the blood supply to the esophagus?
Thyroid arteries - supply cervical portion
Bronchoesophageal artery - cranial 2/3 of thoracic portion
Esophageal branches of aorta/intercostal arteries - supply remaining intra-thoracic structures
Left gastric - terminal most portion fo esophagus/sphincter
What are radiographic signs of esophageal disease? (very general)
Increased opacity of mediastinum - foreign body, retention of ingesta, esophageal mass
Increased radiolucency of mediastinum: esophageal dilation, pneumomediastinum, pneumothorax
Ventral displacement of trachea Tracheal stripe Visaulization of longus colli Pleural effusion Aspiration pneumonia
What are broad categories of causes for dysphagia?
morphologic
functional
What are the phases of swallowing?
Oropharyngeal, esophageal and gastroesophageal
Oropharyngeal phase contains 3 portions: oral, pharyngeal, pharyngoesophageal phase.
The first stage of swallowing has 3 stages. What are they?
Oropharyngeal phase
1) oral
2) pharyngeal
3) pharyngoesophageal
Describe the three oropharyngeal stages in the oropharyngeal phase of swallowing.
Normal swallowing in the dog: a cineradiographic study VRU 1979
Oral: voluntary stage. Stripping action of tongue to organize a bolus in the oropharynx. Bolus formation at the oropharynx elicits the next 2 stages
Pharyngeal: Peristaltic cranial contraction of pharynx and propulsion of bolus from the tongue into the laryngopharynx. Blockage of egresses (tongue - plunger like action to roof of mouth to block oropharynx, pharyngeal arch - nasopharynx, and epiglottis - larynx). At time of pharynx contraction - cricopharyngeal sphincter opened and allowed passage of bolus into the esophagus.
Pharyngoesophageal stage - closure of cricopharyngeal sphincter and relaxation of pharynx, epiglottis, tongue and pharyngeal arch.
Morphologic vs functional causes of dysphagia?
Quantitative evaluation of pharyngeal function in the dog. VRU 41.5
Morphologic: foreign body, neoplasia, trauma
Functional: inability of muscles to relax, incoordination of ontraction, flaccidity of muscles
What will dogs with oral dysphagia do clinically?
What will radiographic signs appear?
Clinically: animal will not be able to prehend, form a bolus, or transport the bolus tot he pharynx
Signs: dropping food, drooling, lots oflicking
Fluoro: retention of contrast in oropharynx, lack of contrast in pharynx, pooling in vestibule
What will a pharyngeal dysphagia appear as?
On fluoroscopic exam, how will this appear?
Multiple swallowing attempts before moving a bolus into the proximal esphagus
Having this abnormality on its own is rare (usually in conjunction with cricopharyngeal phase)
Abnormality in pharyngeal contraction (incomplete enclosure of the bolus, incomplete rostral and dorsal movement of bolus into the larynx, absent contraction forcing bolus through the UES)
What will a dog with a cricopharyngeal dysphagia appear as clinically? on fluoroscopic examination?
Clinically - failure of the cricopharyngeal sphincter to open fully (achalasia) or at the appropriate time with contraction of pharynx (dyssynchrony)
Time from onset of swallowing (closure of epiglottis) to opening of sphincter is dealyed
What is normal opening times for the cricopharyngeal sphincter after closure of the epiglottis for liquids? kibble?
- 09s for liquids
0. 1s for solids
What is abnormal opening times for the cricopharyngeal sphincter after closure of the epiglottis for liquids in dogs with dysphagia? kibble?
- 31s for liquids
0. 37s for solids
What is achalasia vs chalasia?
Achalasia - not fully relaxing
Chalasia - not maintaining positive pressure between swallows
What mechanisms are important in the oral phase of swallowing?
hyoid apparatus tongue facial nerve vagus nerve hypoglossal nerve
What structures are important in the pharyngeal phase?
pharyngeal musculature
facial nerve
vagus nerve
glossopharyngeal nerve
What are fluoroscopic features are seen in the oral phase of dysphagia?
Bolus not formed or delaye dformation Bolus not propelled to pharynx weak plungerlike movement of tongue weak pharyngeal contractions subsequent phases are normal
What are fluoroscopic features are seen in the pharyngeal phase of dysphagia?
normal oral stage
remains synchronous with cricopharyngeal phase
retention of contrast medium int eh pharynx
no change im time to cricopharyngeal sphicnter opening
inadequate pharyngeal contraction
mis-direction of bolus into larynx or nasopharynx
What are fluoroscopic features are seen in the cricopharyngeal chalasia?
Relaxation of incompetence of cricopharyngeal sphincter
Prolonged opening time of scphincter
Weak pharyngeal contractions may be present
aspiration of contrast into lraynx or trachea
What are fluoroscopic features are seen in the cricopharyngeal achalasia?
incomplete or lack of opening of the cricopharyngeal sphincter
vigorous attempts to pass bolus to cricopharyngeal sphincter
synchrony/timing with pharyngeal contraction is off
delayed opening time of sphincter
barium tention
aspiration of contrast
What are causes of cricopharyngeal achalasia?
idiopathic
Causes for cricopharyngeal chaslaia
cricopharyngeus myotomy
radiation therapy
myasthenia gravis
Causes for pharyngeal dysphagia?
myositis/myopathy cricopharyngeus myectomy NM disease inflammation trauma idiopathic
Causes for oral dysphagia
NM disease
inflammation
oral foreign body
tongue abscess
Disease of what structures may lead to generalized esophageal dilation?
disease of neuromuscular junction (myasthenia), striated muscle (myositis), peripheral nerves (polyneuropathy), CNS disease (toxin, neoplasia)
DDx for dilated esophagus?
hypothyroidism hypoadrenocorticism myasthenia thymoma idiopathic VRA lead/organophosphates other toxins esophagitis
What are the two types of hernias associated with the esophageal hiatus?
sliding hiatal hernia
paresophageal hernias
Which breed is pre-disposed to sliding hiatal hernias?
shar-peis
What is a sliding hiatal hernia
caudal esophageal sphincter and part of the gastric fundus move in and out of the caudal mediastinum through a weakened esophageal hiatus at the diaphragm.
What does a sliding hiatal hernia appear like on radiographs?
soft tissue/gas between aorta and CVC on lateral radiographs that silhouettes with the cranial diaphragmatic contour
What is a paresophageal hernia?
fundus herniated within the mediastinum alongside of the esophagus with the caudal esophageal sphincter remaining in the abdomen
What is gastroesophageal intussusception, how does this differ radiographically from other hernias?
Stomach/spleen evert into the esophageal lumen
(a) Feature that distinguishes gastroesophageal intussusception from sliding/paraesophageal hernia is sharply marginated cranial edge of intussusceptum contrast against gas-filled esophageal lumen
What are most common locations for an esophageal foreign body?
thoracic inlet
base of heart
cranial to diaphragm
What are contraindications for performing a positive contrast esophageal/swallow study?
Concern for perforation, evidence of pneumomediastinum, pleural fluid
Use a non-ionic compound instead
What are the types of vascular ring anomalies? (VRA)
Types 1-7
1-3 - persistent right aortic arch
IV - double aortic arch
V-VII - left aortic arch with persistent right ligamentum arteriosum and subclavian arteries
What is the most common type of VRA?
Why do these occur embryologically/anatomically
persistent right aortic arch
Normally - aortic arch, MPA, interconnecting ligamentum arteriosum are all on the left side of the trachea and esophagus
If aortic arch persists on the right side - leads to entrapment by lgiament arteriosum between the right sided aorta and the left pulmonary artery
What is difference between a right fourth aortic arch VRA and a subclavian artery?
Subclavian is more cranially located (not over heart base)
What structure will be displaced by a VRA, and which direction?
Trachea
ventrally and towards the left side
DDx for esophagitis?
infection, corrosive substances, vomiting, GE reflux, obstruction with FB, megaesophagus
What does esophagitis appear like on contrast study?
segmental narrowing, irregular contour, indistinct folds, thickened esophageal wall
What are common causes of esophageal strictures?
Secondary to FB or reflux
What can cause an extramural narrowing of the esophagus?
lymphadenopathy
abscess
neoplasia
Most common esophageal tumor?
neoplastic transformation of spirocerca lupi granulomas –> osteosarcoma
What are differentials for esophageal diverticula?
Acquired: esophagitis, strictures, ucleration from FB, VRA, periesophageal inflammation, hiatal hernia, parasites
What are two forms of esophageal diverticula?
Pulsion or traction
What is a pulsion diverticula?
Increased intraluminal pressure from FB or chronic functional obstruction
What is a traction diverticula?
adhesions on esophageal wall
What do diverticular appear like radiographically?
Circumscribed soft tissue mass or outpouching of esophagus which may be filled with impacted ingesta/contrast, or air/soft tissue
What are esophageal fistulas?
abnormal communication between esophagus and other structures.
What is most common congenital esophageal fistula?
Bronchoesophageal is the most common congenital
What is most common acquired esophageal fistulas?
communication with the lung or trachea
