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Flashcards in Esophagus Deck (17):
1

Anatomy

  • Muscular tube with luminal mucosa
  • It extends from the craniodorsal aspect of the larynx and travels caudally in the neck, through the left aspect of the mediastinum and enters the diaphragm obliquely
  • There is an upper and lower esophageal spincter
  • Upper: helps prevent aerophagia and reflux of esophageal contents back into the pharynx
  • Lower: prevents reflux of gastric contents (acid) into caudal esophagus
  • 4 layers:
    • Submucosa
    • Smooth muscle and mucous glands
    • Muscularis (striated or caudal 1/3 smooth)
    • Mucosa

2

Normal appearance on radiographs?

  • Normally not visible
  • Occasionally small amount of gas or fluid, esp. in left lateral view
    • Fluid often accumulates in esophagus on L lateral view
  • Tracheoesophageal stripe sign

3

Radiographic anatomy

  • General anesthesia may result in signs that mimic megaesophagus and aspiration pneumonia
  • Absence of abnormal radiographic findings does not rule out esophageal disease

4

Clinical significance

  • Esophageal disease may result in regurg, dysphagia, cough, nasal discharge, abnormal swallowing, gagging, and retching
  • Chronic clinical signs include weight loss, abnormal growth and recurrent resp. problems
  • Aspiration pneumonia is a common secondary complication
  • Indications for examination of the upper alimentary tract are related to dysphagia, recurrent or unexplained resp. disease, and regurg 

5

Methods of evaluating esophagus

  • Survey radiography
  • Contrast radiography
  • Contrast fluoroscopy (dynamic)

6

Esophagram: value? Indications/

  • Valuable for assessing esophageal structure and fx
    • Assessing fx req. dynamic evaluation
    • Easy and safe to access structure
  • Indications
    • Regurg (vs. vomiting)
    • Dysphagia
    • Survey rad findings

7

Esophagram: contrast? Views?

  • Contrast used to see:
    • Mucosa
    • Intraluminal lesions
    • Dynamic nature of bolus formation
    • Dynamic nature of swallowing
  • Must select an agent that will adhere to mucosa and be safe for the patient
  • Always obtain 2 orthogonal views (surveys) of the thorax and neck before contrast
  • Since DV and VD views result in a superimposed esophagus, slight rotation or obliquity to this view is often helpful
  • Avoid drugs that effect CNS

8

Radiographic exam

  • After survey films and administration of contrast
    • Quickly obtain films during swallowing phase
    • Then obtain a subsequent set after swallowing

9

Normal radiographic contrast findings

  • Normal esophagus will appear as thin longitudinal lines--contrast attached to and in between mucosa folds
  • Lines slightly diverge at thoracic inlet
  • Cat has oblique lines in the caudal third of the esophagus due to a change to smooth muscle fibers--"herring bone pattern"

10

Esophageal lesions

  • Obstructive vs. non-obstructive
  • Focal vs. generalized
  • Congenital vs. acquired
  • Location (cervical, cranial thoracic, caudal thoracic)
  • Dysphagia
  • Megaesophagus
  • Foreign body
  • Strictures
  • Vascular ring anomaly
  • Neoplasia 
  • Granulomas
  • Hernias

11

Radiographic signs: generalized megaesophagus

  • Esophagus is dilated along its entire length but prominent in mediastinum
  • May be filled with gas, fluid, ingesta,...
  • Horizontal beam radiography may demonstrate fluid line
  • May result in ventral depression of trachea
  • Watch for soft tissue margins along paired longus colli muscles from thoracic inlet to T5-6
  • Tracheoesophageal stripe sign present if esophagus is gas-filled
  • Wide mediastinum

12

Radiographic signs: diffuse megaesophagus

  • "V" sign on the VD view, when the enlarged esophagus is gas-filled, the L and R walls of the esophagus are sometimes visible as 2 soft tissue stripes that converge at the esophageal hiatus of the diaphragm
  • 2, converging, soft tissue lines form a V at the diaphragm

13

Radiographic signs: focal megaesophagus

  • Focal and persistent air accumulation or fluid-mixed opacity
  • Mixed opacity may appear like a mediastinal mass
  • Material is usually trapped cranial to the lesion
  • Maybe the result of a chronic foreign body, hypomotility, vascular ring anomaly, esophagitis

14

Radiographic signs: vascular ring anomaly

  • Persistant right fourth aortic arch is most common malformation
  • Constricts esophagus at heart-base
  • May result in sacculations or diverticula of the oral part of the esophagus
  • Displacement of the trachea
  • May be assoc. w/ generalized megaesophagus

15

Radiographic signs: foreign bodies

  • Usual sites for entrapment include cranial cervical, thoracic inlet, heart base, caudally at esophageal hiatus
  • Variable opacities
  • Common items are bones, fish hooks, rawhides, chew toys, needles (attached to thread)
  • If not radiopaque, consider scoping or CM
  • Contrast will outline and fill foreign body
  • Appearance of the 'filling defect' will depend on foreign body characteristics
  • If the foreign body is detected, evaluation with contrast studies are of little value
  • Esophageal obstruction may be complete or partial
  • Be sure to evaluate for aspiration pneumonia, tracheal necrosis, or perforation (peri-tracheal gas, pneumomediastinum and/or mdiastinitis)

16

Radiographic signs: esophageal granuloma

  • Spirocerca lupi common here
  • Granulomas variable in size and are typically caudal to the heart
  • Ventral margin of the aorta is usually obscured
  • Contrast studies reveal displacement of the esophagus and mucosal irregularities 

17

Radiographic signs: esophageal strictures

  • Persistent focal narrowing with dilation of the oral portion of the esophagus
  • Easily demonstrated with contrast radiography or contrast fluoroscopy
  • History of this lesion often involves surgery, subsequent reflux, esophagitis, inflammation, scarring and luminal narrowing