Large Intestine, Rectum, and Anus

Question 1

How is the large intestine different from the small intestine in regards to healing?

Answer 1

• higher bacterial count
• increased collagenase after surgery
• different blood supply

Question 2

What is cecal inversion?

Answer 2

• cecal intussuseption

- causes obstruction of the ileocolic junction

Question 3

What are the clinical signs associated with cecal inversion?

Answer 3

diarrhea
hematochezia
tenesmus
weight loss

Question 4

How is cecal inversion diagnosed?

Answer 4

• radiographs
• contrast radiographs
• endoscopy

Question 5

How is cecal inversion treated?

Answer 5

• manual reduction
• colotomy
• typhylectomy

Question 6

What are the indications for typhylectomy?

Answer 6

• cecal impaction
• cecal inversion
• perforation
• neoplasia

Question 7

What are the most common cecal neoplasms?

Answer 7

leiomyoma/sarcoma

Question 8

What are the causes of megacolon?

Answer 8

• mostly idiopathic
• pelvic obstruction
• neurologic
• endocrine

Question 9

Describe the pathophysiology of idiopathic megacolon

Answer 9

• feces retained in colon becomes dehydrated and solidifies
• leads to chronic colonic distension
• smooth muscle and nerve damage
• increased absorption of bacterial toxins

Question 10

What are the clinical signs associated with megacolon?

Answer 10

• straining to defecate
• hard mass on abdominal palpation
• depression
• anorexia
• vomiting
• dehydration

Question 11

What is the medical treatment for megacolon?

Answer 11

• correct dehydration
• deopstipate
• increased fiber diet
• stool softeners
• osmotic laxatives
• prokinetics (Cisapride)

Question 12

What is the surgical treatment for megacolon?

Answer 12

subtotal colectomy

• remove as much colon as possible
• colocolostomy helps retain ileo-colic valve
• ileocolostomy may result in severe diarrhea

Question 13

What is atresia ani?

How is it treated?

Answer 13

• congenital abnormality
• stenosis or membrane over the anal tissue
• unable to defecate
• transect/resect the membrane

Question 14

What is rectovaginal fistula?

Answer 14

• congenital abnormality
• connection between the vaginal vault and rectum
• associated with UTIs

Question 15

What is anogenital cleft?

Answer 15

• congenital abnormality
• common opening for anus and genital tract
• leads to UTI

Question 16

What is anal prolapse?

How is it treated?

Answer 16

• incomplete prolapse
• anal mucosa protrudes from orifice
• manually reduce and place purse string

Question 17

What is rectal prolapse?

Answer 17

• complete prolapse: all layers of rectum protrude through anal orifice

Question 18

What are the predisposing factors for rectal prolapse?

Answer 18

• parasites
• colitis
• urogenital disease
• tumors
• younger animals

Question 19

What are the treatments for rectal prolapse?

Answer 19

if viable

• manually reduce
• saline, lubricant, mannitol
• purse string

if non-viable

• resect 1-2 cm from anus
• reduce prolapse

Question 20

What are the complications associated with surgical treatment of rectal prolapse?

Answer 20

• infection
• dehiscence
• stricture
• recurrence

Question 21

What are the most common tumors of the rectum?

Answer 21

adenomatous polyps

adenocarcinoma

Question 22

How are rectal tumors diagnosed?

Answer 22

• direct observation
• digital rectal palpation
• colonoscopy
• biopsy

Question 23

When is the trans-anal approach used?

Answer 23

• excision of small, non-invasive, pedunculated polyps

- lesions in the caudal 4-6 cm of rectum

Question 24

When is the dorsal approach used?

Answer 24

tumors of mid-rectum

Question 25

When is the rectal pull through approach used?

Answer 25

lesions in mid/caudal rectum

Question 26

When is the ventral approach used?

Answer 26

lesions at colorectal junction or more extensive lesions

Question 27

What are the common causes of anal sac disease?

Answer 27

infection of duct obstruction

Question 28

What is the medical management of anal sac disease?

Answer 28

• express gland
• cannulate and irrigate
• infuse antibiotics and steroids
• drain/flush abcesses

Question 29

What is the surgical management for anal sac disease?

Answer 29

anal sacculectomy

Question 30

What are the complications associated with anal sacculectomy?

Answer 30

• infection
• draining tracts
• fecal incontinence

Question 31

What is the most common anal sac tumor?

Answer 31

• apocrine gland adenocarcinoma

- highly malignant

Question 32

What is the treatment for anal sac adenocarcinoma?

Answer 32

surgical excision and chemotherapy

Question 33

What is perianal fistula?

Answer 33

chronic suppurative ulcerative tracts

Question 34

What is the possible etiology of perianal fistulas?

Answer 34

• broad base low carriage tail
• abscessed anal glands
• hair follicle infection
• immune-mediated

Question 35

Who is predisposed to perianal fistulas?

Answer 35

middle-aged GSDs

Question 36

What is the medical management for perianal fistulas?

Answer 36

• perianal cleansing
• antibiotics
• immunosuppressive therapy

Question 37

What is the surgical management for perianal fistulas?

Answer 37

• surgical excision
• anal sacculectomy
• cryosurgery
• fulguration
• tail amputation
• laser excision
• anoplasty