Anal and rectal conditions

• Common diseases of the rectum and anus

  Anal sac disease

  Anal furunculosis

  Anal adenomas

  Other peri-anal neoplasia.

  rectal prolapse

  Rectal stricture

  Rectal neoplasia.
• Infection risk of anal and rectal conditions

  Bacteria and faeces.

  Large clip

  Evacuate rectum and place.

  Purse string or pack with swabs.

  Don’t use enemas.
• Heamorrhage risk of anal and rectal conditions

  Very vascular.

  Lots of perineal branches of major vessels.

  Electrocautery/ vessel sealing/ harmonic scalpel useful.
• Faecal incontinence risk of anal and rectal conditions

  External anal sphincter is important in faecal continence.

  Disruption by sections/ damage to nerve supply.

  50% of sphincter can be safely resected.
• Anal sac disease - scent glands

  Located at 4 and 8 o’clock in between external and internal anal sphincters.

  Discharge through ducts at defecation.
• Anal sac disease - impaction or abscessation 


  Due to a change in consistency of secretion or interference with normal duct emptying e.g. diarrhoea, diet, tapeworm, seborrhoea, oestrus, scar tissue.

  Remember neoplasia and bites in cats.
• Anal sac disease - perineal irritation

  Clinically, perineal irritation ‘scooting’.

  Impaction/ infection very readily diagnosed on palpation.

  Manual expression of the gland.

  Address underlying cause - diarrhoea/ skin allergy.

  Inspissated content may need irrigation.

  Blood tinged material/ pus requires lavage and packing with local antibiotic - cow mastitis tubes/ ear drops normally under GA.
• Anal sacculectomy - indications

  Recurrent imaction

  Neoplasia

  On occasion, an additional component of the treatment for perianal fistula (anal furunculosis).
• Anal sac disease - complications

  Bilateral surgery is a perfectly acceptable as one procedure.

  Complications

  • Draining sinus (some gland left).
  • Infection
  • Dehiscence
  • Tenesmus
  • Faecal incontinence.
• Anal furunculosis (perineal fistulae) - general

  Supportive, progressive, deep ulcerating tracts in the perineal tissues. Can be very difficult to manage. GSD but any breeds including cross breeds.

  Low tail carriage. Increased density of apocrine glands in perineum. Immunological theory.
• Anal furunculosis (perineal fistulae)
 - treatment


  Cyclosporin for 12 weeks will resolve 60% but 70% of these will recur in 4 to 17 months.

  Very expensive, may £100’s.

  Can have multiple adverse effects; e.g. vomiting and diarrhoea, nephrotoxic it’s or hepatotoxicity to, gingival hyperplasia.
• Anal furunculosis (perineal fistulae) - management


  Hypoallergenic diet and immunosuppressive doses of prednisolone.

  Only helped in 1/3 of very mild cases.

  Based on theory that there is an association between IBD and fistulae
• Perineal adenomas - overview

  Perianal sebaceous gland adenoma.

  Third most common tumour in male dog. Hairless area of anal ring most common locations, can see at tail base, prepuce and ventrum. Must differentiate from malignant adenocarcinomas. Biopsy, testosterone dependant benign masses. Normally seen in older patients. Cats have no perianal glands.
• Anal adenocarcinoma - overview

  malignant lesion of the perianal sebaceous glands. Occurs in the same areas as adenomas. Can diffusely infiltrate anal areas. Often adherent to deeper tissues. Rapidly grwoing. Clinical signs of dyschezia and pain. Rare to metastasise to other organs
• Anal adenocarcinoma - treatment/ management

  Do not respond to castration. Aggressive surgical removal with adequate margins is indicated. Adjunctive radiotherapy but rarely curative. Regional lymph node excision. Poor prognosis due to local recurrence and metastasis. Distant metastasis can take many years to develop, repeat palliative local surgeries justified.
• Anal sac adenocarcinoma

  Generally older female dogs (over 10 years).

  Small discrete nodules in the wall of either sac. Paraneoplastic syndrome often accompanies.

  Tumour secretes PTH-like substance. Hypercalcaemia causes PU/PD, depression, weight loss and weakness. This is an aggressive tumour, 50% metastasised at presentation.
• Anal sac adenocarcinoma - diagnosis and treatment.

  Prolonged Hypercalcaemia can produce irreversible renal damage. Diagnosis based:

  • Palpation
  • Biochemical findings
  • Abdominal/ thoracic radiographs
  • Abdominal/ thoracic CT.
  • Ultrasound of sub lumbar lymph nodes.

  Treat Hypercalcaemia prior to surgery.

  Treatment - excision of primary mass, metastectomy, adjunctive.
• Perineal rupture - overview

  Not uncommon

  Can be spectacular

  Bulging perineal area.

  Faecal tenesmus/dysuria

  Normally entire older male, occasionally in bitch/cat.
• Perineal rupture - cause


  Progressive weakening of pelvic diaphragm

  Hormonal influence

  Tenesmus

  Congenital/acquired weakness

  Colitis/prostatomegaly.
• Perineal rupture - diagnosis

  Reducible perineal swelling.

  On rectal, absence of pelvic diaphragm. Always check for bilateral disease.

  Asses sphincter tone - chronic case can remain incontinent. Ultrasound hernia/ contrast urethrography will highlight bladder. Bladder retroflexion - emergency, stranguria, hyperkalaemia, azotaemia, a vascular necrosis.
• Problems with the pelvic diaphragm

  Lavator ani, coccygeus and external anal sphincter muscles provide lateral support to the anus. Disruption to this causes rectal enlargement, faecal impaction and tenesmus. Can be bilateral. Pelvic fat, peritoneal fat, prostate and bladder hernia.
• Perineal rupture - treatment

  Cystocentesis through perineum if bladder retroflexed and can not pass urethral catheter. IVFT (check K+ levels if urinary obstruction).

  Herniorrhaphy.
• Rectal prolapse - overview

  Associated with endoparasites/enteritis in young animals and tumours or perineal hernias in middle aged/older animals. Incomplete prolapse - mucosa only.

  Complete prolapse - mucosa only. Complete prolapse - all layers of rectal wall in entire circumference. Few mm to many cm. Everted tissue is oedematous, excoriated and can be bleeding.
• Rectal prolapse - treatment

  Ensure not intussusception.

  Acute presentation:

  • Lavage
  • Lubricate
  • Reduce and place purse suture.

  Non-reducible or severely traumatised - amputation

  Recurrent - colopexy.
• Rectal stricture - overview

  Normally occur secondary to proctatitis chronic anal sacculatis, penetrating foreign bodies or as complication of anorectal.

  Clinically cause dyschezia, constipation and tenesmus. Diagnosed by digital rectal exam. Contrast radiography/ colonoscopy are difficult as superficially located. Deep biopsy differentiates from neoplasia.
• Renal stricture - treatment


  Superficial strictures treated by bougienage (well lubricated finger/blunt instrument).

  This may need to be repeated at regular intervals for many days. Corticosteroids then 2-3 weeks. Extensive strictures requires resection by, for example, rectal pull-through.
• Rectal polyps - overview

  Benign, adenomatous polyps, male and female equally affected. Mean age 7 years. Sessile, raised pr pedunculated. Single or multiple. Cause unknown.
• Rectal polyps - clinically and treatment

  Clinically:

  • Blood/mucus in faeces.
  • Tenesmus can occur
  • Polyp can occasionally prolapse from anus.
  • Secondary rectal prolapse can occur.

  Treatment:

  • Small pedunculated masses can be removed from distal rectum masses with elextrocautery, or excision and suture placement.
  • Larger polyps may need intestinal resection.
• Rectal adenocarcinoma - overview.

  Infiltration, ulcerative or Proliferative. Invades rectal wall causing fibrosis and stricture. Clinically cause tenesmus, dyschezia, weight loss and lethargy with advanced malignancy. Diagnose on palpation, radiography, ultrasound, endoscopy/proctoscopy.
• Rectal adenocarcinoma - sites and surgery


  Three sites:

  • Colorectal junction and cranial 1/3 rectum.
  • Middle 1/3 rectum
  • Caudal 1/3 rectum and anal canal.

  Surgery:

  • Colorectal resection and anastomosis +/- ischial pubic flap Osteotomy
  • Doral perineal approach.
  • Rectal pull-through
• Rectal surgery - preoperative considerations

  Same as for anal surgery, care with enemas, evacuate distil rectum, large clip, Antibiotics effective against gram negative aerobes and anaerobes.
• Atresia ani


  Uncommon, can be associated with recto-vaginal or recto-urethral fistulae. Secondary Megacolon. Neonate with absent anus. Tenesmus and bulging of perineum. Diagnosis confirmed by radiography. Treatment involves creation of an anus by excision of skin and terminal rectal mucosa and careful suturing. Subtotal colectomy.