Large Intestine, Rectum, and Anus Flashcards
(37 cards)
How is the large intestine different from the small intestine in regards to healing?
- higher bacterial count
- increased collagenase after surgery
- different blood supply
What is cecal inversion?
- cecal intussuseption
- causes obstruction of the ileocolic junction
What are the clinical signs associated with cecal inversion?
diarrhea
hematochezia
tenesmus
weight loss
How is cecal inversion diagnosed?
- radiographs
- contrast radiographs
- endoscopy
How is cecal inversion treated?
- manual reduction
- colotomy
- typhylectomy
What are the indications for typhylectomy?
- cecal impaction
- cecal inversion
- perforation
- neoplasia
What are the most common cecal neoplasms?
leiomyoma/sarcoma
What are the causes of megacolon?
- mostly idiopathic
- pelvic obstruction
- neurologic
- endocrine
Describe the pathophysiology of idiopathic megacolon
- feces retained in colon becomes dehydrated and solidifies
- leads to chronic colonic distension
- smooth muscle and nerve damage
- increased absorption of bacterial toxins
What are the clinical signs associated with megacolon?
- straining to defecate
- hard mass on abdominal palpation
- depression
- anorexia
- vomiting
- dehydration
What is the medical treatment for megacolon?
- correct dehydration
- deopstipate
- increased fiber diet
- stool softeners
- osmotic laxatives
- prokinetics (Cisapride)
What is the surgical treatment for megacolon?
subtotal colectomy
- remove as much colon as possible
- colocolostomy helps retain ileo-colic valve
- ileocolostomy may result in severe diarrhea
What is atresia ani?
How is it treated?
- congenital abnormality
- stenosis or membrane over the anal tissue
- unable to defecate
- transect/resect the membrane
What is rectovaginal fistula?
- congenital abnormality
- connection between the vaginal vault and rectum
- associated with UTIs
What is anogenital cleft?
- congenital abnormality
- common opening for anus and genital tract
- leads to UTI
What is anal prolapse?
How is it treated?
- incomplete prolapse
- anal mucosa protrudes from orifice
- manually reduce and place purse string
What is rectal prolapse?
- complete prolapse: all layers of rectum protrude through anal orifice
What are the predisposing factors for rectal prolapse?
- parasites
- colitis
- urogenital disease
- tumors
- younger animals
What are the treatments for rectal prolapse?
if viable
- manually reduce
- saline, lubricant, mannitol
- purse string
if non-viable
- resect 1-2 cm from anus
- reduce prolapse
What are the complications associated with surgical treatment of rectal prolapse?
- infection
- dehiscence
- stricture
- recurrence
What are the most common tumors of the rectum?
adenomatous polyps
adenocarcinoma
How are rectal tumors diagnosed?
- direct observation
- digital rectal palpation
- colonoscopy
- biopsy
When is the trans-anal approach used?
- excision of small, non-invasive, pedunculated polyps
- lesions in the caudal 4-6 cm of rectum
When is the dorsal approach used?
tumors of mid-rectum
