-
what is first structure visualized w/ventral midline incision?
cecum
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what is the cecocolic fold?
lateral band of the cecum (continuous with lateral free band of right ventral colon)
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Of the 4 bands on the cecum, which are vascularized?
- which bands extend to apex of cecum?
- medial and lateral = vascularized
- dorsal and medial = apex
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which cecal band is continuous with ileocecal fold?
- which is continuous with the cecocolic fold?
- dorsal band continuous with ileocecal fold
- lateral band continuous with cecocolic fold
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how many bands are on the ventral large colons? on pelvic flexure?
- how many bands are on the dorsal large colons? small colon?
- 4 on ventral (4 on the floor) - 1 on pelvic flexure
- 3 on dorsal - 2 on small colon
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where are pacemaker cells for the colon motility located?
in the pelvic flexure
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is transverse colon accessible in surgery? by rectal palpation?
- difficult to visualize in sx (attached to dorsal body wall)
- NOT palpable per rectum
-
how is descending/small colon distinguished from small intestine on rectal palpation?
colon has wide antimesenteric band and "road apples"
-
why is it important to get vital parameters before giving an alpha 2 agonist as sedation for rectal palpation? what about Buscopan to relax GI tone (not a sedative)?
- alpha agonists cause bradycardia
- buscopan = parasympatholytic - tachycardia
-
how much of the abdomen is palpable per rectum?
caudal 1/3
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what is one of the first things that needs to be done if rectal tear occurs?
- epidural w/xylazine and lidocaine to reduce straining
- (takes 30 min. to effect - lose rectal/tail tone)
-
which vertebral spaces are used for caudal epidural administration? what is then desensitized?
- cranial space of S6-Co1 or Co1-2
- large portion of small colon and rectum
-
what are signs of severe, acute colic? 4
- down and rolling (evidence = bedding between ears)
- breathing hard
- sweating
- abdominal distention (bloat)
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what other medication should be administered if there is a rectal tear? 4
- sedation (xylazine, detomedine)
- broad spectrum Abs (penicillin, metro, gentocin)
- Tetanis prophylaxis
- flunixin meglumine
-
why is acepromazine a poor choice for sedation of a horse with rectal tear?
- causes hypotension
- (avoid since concerned about sepsis which will also lower BP)
-
what is the difference between Grade 1 and 2 rectal tear?
- 1: mucosa + submucosa
- 2: muscularis ONLY (other layers remain intact)
-
what is recommended tx for grade 1 rectal tear? medical or surgical? 6
- good success w/medical mgmt
- Abs (TMS)
- NSAIDs (Banamine)
- laxatives (mineral oil for movement)
- pelleted diet/softened
- monitor for dyschezia, fever, LPS
-
what is recommended tx for grade 2 rectal tear?
- can be incidental and require NO treatment
- can predispose to rectal impactions or progress to Gr4
-
what is the difference between grade 3a, 3b and 4 tear? 4
- 3: all layers except serosa (abdominal fluid can accumulate in abd)
- -3a: serosal diverticulum forms
- -3b: tear enters mesentery
- 4: full thickness/all layer tear; extends into peritoneal cavity (usu. fatal)
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Grade 3 is life threatening and requires what treatment? 5
- same as Gr1 (Abs, NSAIDs, laxatives, soft diet)
- + IV antibiotics (penicillin, gentocin, metro)
- + anti-endotoxemia tx (polymycin B)
- + tetanis prophylaxis
- + rectal packing
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with Grade 3 what diagnostic helps determine if surgery is required?
peritoneal paracentesis
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Grade 4 is life threatening and usually requires what treatment?
often fatal due to contamination of abdomen - Euthanasia
-
what is a salvage surgical option for repairing grade 3/4 rectal tear?
loop colostomy (poop comes out of the side/flank)
-
what is normal peritoneal fluid's total protein and WBC count?
- clear transudate, straw to yellow
- TP <2.0 g/dl
- WBC < 5000
-
what are some causes of serosanguinous fluid?
- bowel devitalization (as w/volvulus and strangulating lesions)
- splenic puncture
- SQ blood vessel
-
what are some causes of green fluid?
- enterocentesis (no WBCs)
- bowel rupture (+WBCs)
-
what is cause of thick orange fluid?
peritonitis
-
what is expected glucose with septic peritoneal fluid? lactate? pH?
- glucose < 50 pt lower than serumBG (bacteria use glucose)
- elevated lactate (bacteria prod. lactate)
- very low pH (lactic acid)
-
should adults be fasted prior to endoscopy? what about nursing foals? is sedation recommended?
- yes for 12-18 hours so food bolus not in the way
- no need to fast nursing foals
- sedate adults and older foals
-
is laparoscopy better for acute or chronic diseases? is fasting necessary?
- chronic
- yes, fasting is ideal (18-24 hours)
-
why is it important that horse has balanced acid/base status prior to laparoscopy?
pumping CO2 into abdomen for visualization - would worsen metabolic acidosis
-
what can not be visualized when ultrasounding abdomen?
small colon (behind large colon)
-
where is US probe placed to visualize the stomach?
left ICS 9-13
-
Anatomically where can the duodenum be seen in the abdomen with US?
right side ventral to caudal pole of kidney and caudal to liver
-
what are some findings on US that suggest enteritis? 4
- thickened walls
- distended SI
- sediment
- lack of motility
-
what is role of scintigraphy in diagnosing GI disease? what are limitations?
- uses technitium 99 to diagnose/document delayed gastric emptying
- lacks anatomical specificity
- (better tool for evaluating bone than GI)
-
on fecal evaluation, what are some of the more common eggs seen?
- large and small strongyles
- tapeworms, round worms
- Strongyloides westerii
-
In case of chronic weight loss, patient can be fasted for 18-24hours so an absorption test can evaluation what? what are normal v. abnormal findings?
- glucose response in relation to D-xylose or D-glucose administration
- normal = inverted "V"; glucose peak of 80-120mg/dL w/in 60-100min
- abnormal= low baseline and no spike
-
how much gastric reflux is considered abnormal? what should be done if there is positive reflux?
>2L strongly suggests need for referral (may transport with tube in place)
-
what is the most common clinical signs for esophageal disease?
ptyalism
-
what muscle is responsible for the upper esophageal sphincter? what about caudal esophageal sphincter?
- cricopharyngeal muscle
- caudal sphincter is indistinct
-
what cranial nerves are required for proper mastication?
- 5 (trigeminal)
- 7 (facial)
- 12 (hypoglossal)
-
what cranial nerves are required for swallowing?
- 5 (trigeminal)
- 9 (glossopharyngeal)
- 10 (vagus)
-
what cranial nerves run through the guttural pouch?
-
what type of muscle is the esophagus?
- cranial 2/3 = skeletal
- caudal 1/3 = smooth
-
where is the only place the esophagus is covered in serosa?
short distance btwn diaphragm and stomach w/in abdominal cavity
-
what is the most common esophageal disease? what are the most common sites for this disease?
- choke = esophageal obstruction
- cervical esophagus, thoaracic inlet/cranial to heart, terminal esophagus
-
what are CS of choke? 7
- ACUTE
- frothy nasal discharge
- feed in nostrils
- ptyalism
- gagging/retching
- coughing
- colic, signs of discomfort, neck extended
-
what is treatment for choke?
- sedation so head lower than shoulders/relax esoph. (xylazine)
- endoscope so visualize mucosa
- nasogastric tube to point of resistence - pump water
-
If tube + water is unsuccesful at relieving choke, what should you do?
place in stall + NPO + IV fluids to hydrate + meds to relax esophagus and sedate
-
what are some drug options for relaxing the esophagus?
- buscopan (N-butylscopolammonium bromide)
- oxytocin
-
what treatments need to be added if choke is prolonged?
- broad spectrum Abs
- NSAIDs
- sucralfate
-
what are considerations for returning horse to feed after relieving obstruction? 4
- could reobstruct or have motility issues
- slowly return to feed after confirm mucosa is healed via endoscope
- feed fresh grass and pelleted/soft feed (no long stem fibers)
- +/-esophagotomy
-
once the choke is resolved, what are some complications to be aware of? 5
- dilation cranial to the obstruction; reobstruction
- traumatic mucosal injury; stricture
- esophagitis; ulceration
- rupture
- aspiration pneumonia w/prolonged cases
-
will choke cause metabolic acidosis or alkalosis?
alkalosis from loss of saliva (NaCl)
-
what type of fluids would you use for horse with choke?
- isotonic crystalloids + K and Ca
- (dehydration, not getting K/Ca since off feed)
-
what are clinical signs of esophageal rupture? what is common sequella of ruptured esophagus?
- palpate crepitus if ruptures in neck
- pleura fluid accumulation if intrathoracic
- -leads to cellulitis and endotoxemia
-
what is a functional obstruction? how do these clinical signs compare to mechanical obstruction?
- motility dysfunction of esphagus - megaesophagus
- same clinical signs
-
is megaesophagus usually acquired or conenital?
- acquired - after prolonged episode of choke (may only be transient)
- congenital from myopathy is rare
-
how do you treat esophageal stricture?
- allow up to 60 days for esophagus to heal on its own (maximum stricture will occur around 30 days then hopefully improve)
- -sx/bouginage not successful in the horse
-
how do you treat ruptured esophagus? 4
- debride/lavage tissues
- esophageal rest - esophagotomy tube -
- broad Abs + tetanus prophy
- hopefully heals by 2nd intention
-
what additional complications are associated with ruptured esophagus?
- Horner's syndrome
- left laryngeal hemiplasia
-
how do you definitively diagnose esophageal motility problem?
barium and fluoroscopy
-
If megaesophagus is secondary to esophageal reflux, it may respond well to what treatment?
metaclopramide or bethanecol (prokinetic agents) to tighten lower esophageal sphincter
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