Lecture 8: Abnormal Conditions of Equine Large Intestine Flashcards
What is included in large intestine
Cecum, large colon, small colon, rectum
Where is the cecum located
Between small intestine and large colon on right side
What are the three parts of the cecum
- Base- most dorsal
- Body- 4 longitudinal bands
- Apex- narrow blinded end directed cranially
What are the two primary functions of the cecum
Water absorption, microbial digestion
What is the most common pathological condition of the cecum
Cecal impaction
What is the fatality rate in cecal impactions and why
43%, due to rupture
What are some causes of cecal impactions
Poor dentition, feeding poor quality roughage, decreased water intake, patrurition, parasite induced thromboembolism, hospitalization with GA within 5 days, use of NSAIDS and lack of exercise
How do you diagnose cecal impactions
1.Mild signs of pain
2. lying down, looking at flank, decreased appetite, depression
3. HR normal to slightly elevated
4. Borborygmi decreased with decreased fecal production
5. Rectal palpation- tension in ventral cecal band, lack of sacculations, can’t pass hand dorsal over impaction
What does the rectal exam reveal for cecal impaction
- Tension in ventral cecal band
- Lack of sacculations due to increased filling
- Can’t pass hand dorsally
Is BW normal or abnormal in cecal impactions
Normal
What are some characteristics of type 1-mechanical cecal impactions
Causes: Firm, dry or doughy ingesta
Location: base or body
Impaction indented with fingers
Cecal wall does not feel thickened
Normal peritoneal fluid
What are some characteristics of type 2 cecal dysfunction
- Cecum is tightly distended with gas and ingesta
- More painful
- Higher heart rate
- May be endotoxin
How do you tx type 1 mechanical cecal impactions
Soften ingesta to allow cecal contractions to empty cecal contents into right ventral colon
How do you tx type 2 cecal dysfunction
Surgical- decompression, typhlotomy and evacuation, cecal bypass- cecocolic anastomosis
What are the medical treatments in cecal impactions
- Withhold feed
- IV fluids
- Oral laxatives via NG tube
- Psyllium
- Walking and limited controlled grazing to stimulate motility
- Analagesics
What analgesics do you need to have caution with in cecal impactions
Xylazine, detomidine, butorphanol
When should surgery be considered for cecal impactions
- No improvement on rectal palpation for 24-36hrs
- Systemic deterioration (increase HR)
- Increase pain
- Cecum feels tight enough to rupture
What is the large colon composed of
Dorsal and ventral colons connected by short mesentery
Describe the order through the large colon
- Right ventral colon
- Sternal flexure
- Left ventral colon
- Pelvic flexure
- Left dorsal colon
- Diaphragmatic flexure
- Right dorsal colon
What are some abnormal conditions of large colon
Tympany, impaction, sand, enteroliths, nephrosplenic displacement, right dorsal displacement, volvulus
What is the most commonly reported colic in horses
Large colon tympany
What is large colon tympany
Gas colic, spasmodic colic
What causes large colon tympany
Excessive gas fermentation, resulting in distention and pain
What are some risk factors for large colon tympany
Cribbing, increased time in stall, recent change to exercise, lack of deworming, hx of travel within 24hrs, recent lameness, infrequent dentals, tapeworms, diet with lots of carbs and less fiber
How do you diagnose large colon tympany
- Acute pain +/- visible abdominal distention
- Rectal palpation- moderate to severe gas distention of large colon
What are some differentials for large colon tympany
Large colon displacement, large colon torsion, ileus, impending colitis, small colon obstruction
What is treatment for large colon tympany
Withhold food, analgesics
If you suspect large colon tympany but horse does not respond to analgesics what is a more concerning differential
Large colon volvulus
What is the most frequent type of simple obstruction
Large colon impaction
What are some risk factors for large colon impaction
Cribbing, increase time in stall, lack of deworming, hx travel within 24hrs, recent changes to exercise, hx of colic, recent lameness, infrequent dentals, high grain diet, hospitalization, general anesthesia, medications (atropine and morphine)