Esophageal obstruction and rectal tears

Question 1

What is choke?

Answer 1

the obstruction of the esophagus, not the trachea/airway

Question 2

Esophagus anatomy

Answer 2

cranial 1/3 of the neck is dorsal to the trachea
mid 1/3 of the neck- the esophagus is on the L side of neck (rarely on the right)
thoracic inlet is ventral to trachea

Question 3

Causes of esophageal obstruction:

Answer 3

Intra-luminal is MOST COMMON can be from FB or feed

Question 4

extramural–>

Answer 4

neoplasia, vascular ring anomaly, granuloma**

Question 5

Intramural=

Answer 5

Esophageal abscess, granuloma, neoplasia, cyst, diverticulum, stenosis*

Question 6

Functional disorders=

Answer 6

Dehydration, exhaustion, pharmacologic, primary megaesophagus, esophagitis, dysautonomia, vagal neuropathy*

Question 7

What are the rx needed for a choking horse?

Answer 7

Sedation to lower head and prevent further aspiration, oxytocin (smooth muscle relaxer where smooth muscle is in proximal 2/3 of the esophagus), NG tube with water +/- Lidocaine

Question 8

What are the four surgery options for horses who chronically choke?

Answer 8

Esophagotomy, esophagomyotomy, partial R and A, esophagostomy

Question 9

what is the primary choice for avoidance of surgery and to tx chronic choke horses

Answer 9

endoscopic balloon dilation to dilate the stricture

Question 10

Rectal tears occur from ____ ___ to anus

Answer 10

pelvic inlet to anus

Question 11

What are high risk horses for rectal tears?

Answer 11

o Arabian horses, ponies, small breeds
o Previous rectal tears
o Unaccustomed to palpation
o Fractious or colicky horses

Question 12

Prevention of rectal tears-

Answer 12

Reduce GI motility with Buscopan before rectal exam, use LOTS of lube, proper restraint as indicated, do not fight peristalsis

Question 13

Where do rectal tears most commonly occur?

Answer 13

In the dorsal aspect

Question 14

Grade 1 rectal tear

Answer 14

Mucosa + submucosa

Question 15

Grade 2 rectal tear

Answer 15

Muscular layer disrupted, with mucosa and submucosa prolapsed through defect

Question 16

Grade 3 rectal tear (split into A and B)

Answer 16

A – all layers except serosa

B – all layers except mesorectum and peritoneum (dorsal tear)

Question 17

Grade 4 rectal tear

Answer 17

All layers –>peritonitis within two hours

Question 18

May feel flap of mucosa with grade ___ tears

Answer 18

Grade 1

Question 19

Tx for grade 1 or 2 tears:

Answer 19

NSAIDs, stool softeners, diet change, monitor

Question 20

Tx for grade 3 tears:

Answer 20

NSAIDs, stool softeners, diet change, manual removal of feces, monitor for cellulitis, abscess, severe toxemia, sepsis, laminitis, recurrent obstructions due to adhesions

Question 21

what part of the esophagus (layer aka tunic) has the most tensile strength for incision closure?

Answer 21

Mucosa

Question 22

what part of the esophagus is freely movable/elastic?

Answer 22

submucosa

Question 23

___ tunic is striated from pharynx to the base of the heart and to the stomach

Answer 23

Muscularis

Question 24

What are the four most common locations for obstruction?

Answer 24

Thoracic inlet, cervical esophagus, heart base, terminal esophagus

Question 25

Why is there transient metabolic acidosis that turns to metabolic alkalosis with time in choking horse?

Answer 25

renal compensation

Question 26

_____ is full thickness incision into lumen of esophagus but ____ is partial thickness, NOT into mucosa (to tx mural strictures only)

Answer 26

Esophagotomy; esophagomyotomy

Question 27

_____ is a type of sx to place a feeding tube into the esophagus (like Dr. Masters does with cats), to avoid further injury to nasal passages and pharynx

Answer 27

Esophagostomy