Esophagus Flashcards
1
Q
Anatomy
A
- 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
Q
Normal appearance on radiographs?
A
- 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
Q
Radiographic anatomy
A
- General anesthesia may result in signs that mimic megaesophagus and aspiration pneumonia
- Absence of abnormal radiographic findings does not rule out esophageal disease
4
Q
Clinical significance
A
- 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
Q
Methods of evaluating esophagus
A
- Survey radiography
- Contrast radiography
- Contrast fluoroscopy (dynamic)
6
Q
Esophagram: value? Indications/
A
- 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
Q
Esophagram: contrast? Views?
A
- 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
Q
Radiographic exam
A
- After survey films and administration of contrast
- Quickly obtain films during swallowing phase
- Then obtain a subsequent set after swallowing
9
Q
Normal radiographic contrast findings
A
- 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
Q
Esophageal lesions
A
- 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
Q
Radiographic signs: generalized megaesophagus
A
- 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
Q
Radiographic signs: diffuse megaesophagus
A
- “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
Q
Radiographic signs: focal megaesophagus
A
- 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
Q
Radiographic signs: vascular ring anomaly
A
- 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
Q
Radiographic signs: foreign bodies
A
- 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)
