Equine Acute Abdomen, Pt. 3 Flashcards

1
Q

What 2 attachments does the small colon have? Where are the taeniae located?

A
  1. duodenocolic
  2. mesocolon
    (suspension to the dorsal body wall)

mesenteric and anti-mesenteric

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2
Q

What is responsible for the blood supply to the small colon?

A

caudal mesenteric artery - left colic, cranial rectal

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3
Q

What is thought to be the cause of atresia coli/ani? What are the 3 kinds?

A

vascular injury

  1. membrane
  2. cord
  3. blind-ended
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4
Q

What is the most common clinical sign associated with atresia coli/ani?

A

36-48 hour old foal with abdominal tympany and no meconium passed

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5
Q

What treatment is recommended for atresia coli/ani?

A

rectal pull-through - often too mismatched and dysfunctional to anastomose

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6
Q

What breeds are commonly associated with aganglionosis?

A

American Mini Horse, American Paint Horse, or American Quarterhorse with overo pattern

  • Lethal White Syndrome
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7
Q

What causes agangliosis?

A

genetic disorder causes ileocolic aganlgiosis —> dysfunctional GIT due to lack of submucosal and myenteric plexi without melanocytes or ganglia

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8
Q

How do horses with simple colonic obstructions present?

A

initial presentation with mild colic signs that can progress to gas distention, tachycardia, and moderate to severe pain

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9
Q

What is meconium impaction?

A

inability of a foal to pass the mucilaginous material made up of amniotic fluid, bile, epithelial cells, and secretions

  • usually passed by 12-24 hours
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10
Q

How do patients with meconium impaction present?

A

foals 1-2 days unable to defecate, straining, tai lflagging, and tympany

  • gas buildup!
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11
Q

What are the 2 major ways to diagnose meconium impaction?

A
  1. digital rectal exam - may feel tip of meconium in the proximal or transverse colon
  2. radiography - barium contrast moves orally until obstruction
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12
Q

What medical treatment is recommended for meconium impaction?

A
  • IV support
  • analgesia - low dose Flunixin
  • enema - soapy water + acetylcysteine to break down mucous
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13
Q

What surgery is recommended for meconium impaction?

A

massage and pass meconium through rectum

  • not commonly recommended, adhesions are common in foals
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14
Q

What are the 2 most common etiologies of small colon impaction? How is it diagnosed?

A
  1. poor quality feed/dentition
  2. altered motility (Salmonella)

rectal palpation - largely distended with doughy tecture

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15
Q

What medical treatment is recommended for large colon impaction?

A
  • IV and enteral fluid therapy
  • laxative and cathartic
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16
Q

What are 2 options for surgery to treat small colon impaction?

A
  1. enema, massage, and rectal evacuation
  2. small colon enterotomy if above fails
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17
Q

What are 4 risk factors that predispose to fecaliths?

A
  1. older foals/weanlings - self-weaning, eating hay without properly chewing
  2. American miniature horses
  3. poor quality hay
  4. poor dentition (older horses!)
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18
Q

What are the 2 major types of fecaliths? How are they treated?

A
  1. phytobezoar
  2. trichophytobezoar

surgical enterotomy of small colon and pelvic flexure - dried plant material and hair make it difficult to break them down by medical therapy

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19
Q

What is the most common way of diagnosing small colon enteroliths? What sequelae is associated with chronicity?

A

radiographs

rupture due to transmural necrosis —> requires surgical treatment

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20
Q

What kind of growth is associated with strangulations of the small colon? How do patients present?

A

lipomas

small colon obstruction

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21
Q

How are strangulating lipomas diagnosed? How are they treated?

A
  • peritoneal fluid
  • construction of small colon on rectal exam

R&A

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22
Q

Where is the rectum located? What attachment does it have?

A

pelvic inlet to anus

retroperitoneal portion is attached by the mesocolon, hanging by the dorsal body wall

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23
Q

What is the most common cause of rectal tears? Where is the most commonly located?

A

force applied by hand or forearm against straining or peristaltic waves on examination

15-55 cm from anus at 10 and 2 o’clock where the mesocolon attaches to serosa (parallel to long axis)

  • (transverse for idiopathic)
24
Q

What are the most common clinical signs associated with rectal tears?

A
  • release of pressure and blood on rectal sleeve upon palpation
  • colic signs progress to depression
25
Q

What is the first step in evaluating rectal tears?

A

eliminate straining, which typically makes the tear worse

  • caudal epidural with lidocaine or xylazine (C1-C2, L7-C1)
  • sedation with xylazine or butorphanol
26
Q

In what 3 ways are rectal tears evaluated?

A
  1. careful rectal palpation with Buscopan (smooth muscle relaxer) and lidocaine enema or jelly - bare hand preferred (sleeve can make it worse)
  2. visualization with speculum or proctoscopy
  3. abdominocentesis
27
Q

What is a Grade I rectal tear? How is it diagnosed? What is prognosis like?

A

tear only through mucosa

palpation or proctoscopy shows a mucosal defect = focal bleeding with slight indent

good to excellent - 93-100%

28
Q

How are Grade I and Grade II rectal tears treated?

A

MEDICAL - heal by second intention

  • antibiotics
  • NSAIDs
  • laxative diet - pelleted feed mash, mineral oil, MgSO4
29
Q

What are Grade II rectal tears? How are they diagnosed? What is prognosis like?

A

tear only through muscularis

palpation and scope - can be difficult to feel (no blood on sleeve)

good to excellent - possible diverticulum formation

30
Q

What is a Grade III rectal tear? What are the 2 subtypes?

A

tear through mucosa, submucosa, and muscularis

  1. 3a = only serosa remains
  2. 3b = only mesocolon remains, allowing it ot defect cranially and dorsally
31
Q

How are Grade III rectal tears diagnosed? What is prognosis like?

A

palpation or scope shows a large cavity with thin membranes

guarded - 38-70% (referral center recommended)

32
Q

What is a Grade IV rectal tear? How are they diagnosed? What is prognosis like?

A

tear through all layers

palpation or scope shows a palpable intestine

poor to grave

33
Q

What initial treatment is recommended for rectal tears? What is done prior to making it to the surgical suite/referral?

A
  • gently remove feces
  • broad-spectrum antibiotics
  • NSAIDs

pack rectum with rolled cotton stocked into a stockinette (+ lubed!) to prevent feces from packing into defect (keeps Grade III from developing into a Grade IV)

34
Q

How is the rectum packed prior to surgical resolution of rectal tears?

A
  • place tied end of stockinette 10 cm proximal to the tear
  • fill with cotton
  • close anus with a purse string and place a clamp on the external stockinette
35
Q

How can Grade III rectal tears be medically managed? How long does it typically take for resolution?

A
  • pack rectal defect with antiseptic-soaked gauze
  • manual evacuation of feces q 2-3 hours
  • minimize straining with epidural (Lidocaine, alpha-2 agonist, Morphine)
  • broad spectrum. antibiotics
  • NSAIDs
  • laxative diet - pelleted feed mash, mineral oil, MgSO4

2+ weeks

36
Q

When is surgical management recommended for rectal tears? What 3 procedures can be done?

A

Grade III - Grade IV (w/o peritoneal contamination)

  1. temporary rectal liner
  2. primary closure - midline celiotomy, suture or staple
  3. colostomy - loop (stoma between colon and body wall) vs. complete
37
Q

Colostomy:

A
  • TOP = loop between colon and body wall that can be reversed
  • BOTTOM = complete
38
Q

What is the most common cause of rectal prolapses?

A

straining

  • diarrhea
  • perirectal abscess
  • dystocia
39
Q

What are the 4 grades of rectal prolapses?

A
  1. mucosal membrane protrudes, resembling the protrusion of loose lining of a sleeve beyon the cuff
  2. complete prolapse of the nonperitoneal rectal mucosa and muscularis layers
  3. complete prolapse with invagination of the small colon
  4. intussuscepted peritoneal rectum or colon
40
Q

Type I rectal prolapse:

A
41
Q

Type II rectal prolapse:

A
42
Q

Type III rectal prolapse:

A
43
Q

Type IV rectal prolapse:

A
44
Q

How can rectal prolapses be medically managed?

A
  • reduce straining with epidurals and sedation
  • reduce inflammation by compression and anti-inflammatories
  • reduce prolapse + purse-string suture
  • treat primary cause
45
Q

When is surgery indicated for rectal prolapses?

A

resection of necrotic tissue

46
Q

What is intestinal rupture? What are some clinical signs?

A

compromised intestinal wall causes ingesta to leak into peritoneal cavity

  • septic shock
  • tachycardic (>80 bpm)
  • dark MM
  • depressed with minimal pain
  • fasciculations
47
Q

How are intestinal ruptures diagnosed? What treatment is recommended?

A
  • rectal - seems empty
  • ultrasonography
  • anbominocentesis - intracellular bacteria

none —> euthanasia

48
Q

What are the 4 most common causes of post-op ileus?

A
  1. small intestinal lesions
  2. endotoxemia
  3. stricture
  4. adhesions

(18-50% of cases)

49
Q

How is post-op ileus diagnosed? What are 4 treatments?

A

persistent reflux + abdominal ultrasonography

  1. lidocaine CRI
  2. Yohimbine
  3. erythromycin
  4. metoclopramide
50
Q

What 4 complications are associated with the incision post-op?

A
  1. acute dehiscence
  2. edema
  3. drainage (infection!)
  4. hernia
51
Q

What are 4 risk factors associated with post-op incision complications?

A
  1. enterotomy, resection
  2. endotoxemia
  3. obesity
  4. post-operative pain
52
Q

How common are post-op adhesions? How are they diagnosed?

A

reported 8-26%, but there is considered an unknown number that are silent

  • relaparotomy
  • necropsy
53
Q

What are 2 risk factors for developing diarrhea post-op?

A
  1. colon surgery - pelvic flexure enterotomy, bowel inflammation/edema
  2. if patient is NPO
54
Q

What is the major indication to perform a repeat celiotomy? What are some causes?

A

pain following surgery

  • persistent ileus
  • ischemia
  • impaction
  • anatomical malposition
  • anastomotic stricture
  • adhesion
55
Q

How can laminitis post-op be prevented?

A
  • MEDICAL - treat endotoxemia, encourage blood flow perform cryosurgery
  • foot support
56
Q

What are 3 risk factors for developing post-op peritonitis?

A
  • enterotomy
  • R&A
  • ischemia

(relatively rare)