Perianal Flashcards
How long is the rectum and anal canal?
Rectum = 12cm, anal canal = 4cm
Where does the rectum begin and end?
Sacral promontory to levator ani muscle
What forms the rectum’s continuous muscle layer?
The 3 tenia coli fusing around the rectum
Where does the anal canal begin and end?
Levator ani muscle to anal verge
What kind of epithelium is in the anal canal?
Upper 2/3 - columnar
Lower 1/3 - squamous
Is the anal canal sensate or insensate?
Upper 2/3 is insensate, lower 1/3 is sensate
What is the blood supply to the anal canal?
Upper 2/3: superior rectal artery and vein
Lower 1/3: middle and inferior rectal arteries and veins
Which lymph nodes does the anal canal drain to?
Upper 2/3 - internal iliac nodes
Lower 1/3 - superficial inguinal nodes
What are the dentate and white lines of the anal canal?
Dentate - squamomucosal junction
white - where anal canal becomes true skin
What’s the difference between the internal and external anal sphincters?
- Internal
- Thickening of rectal smooth muscle
- Involuntary
- External
- Three rings of skeletal muscle (deep, superficial, subcutaneous)
- Voluntary
Where is the anorectal ring located and what is it composed of?
Deep segment of the external sphincter which is continuous with the puborectalis muscle (part of levator ani). Palpable on PR about 5cm from the anus.
Demarcates teh junction between teh anal canal and the rectum and must be preserved to maintain continence
Define perianal haematoma
How does a perianal haematoma present?
- Tender blue lump at the anal margin
- Pain worsened by defecation or movement
How is a perianal haematoma treated?
Analgesia and wait for spontaneous resolution, or can be evacuated under local
How does proctalgia fugax present?
- Young, anxious men
- Crampy anorectal pain which is worse at night
- Unrelated to defecation
- Associated with trigeminal neuralgia
How is proctalgia fugax treated?
Reassurance
GTN cream
What are the 2 most common kinds of perineal warts and who are they common in? How are they treated?
MSM:
- Condylomata accuminata:
- HPV
- Podophyllin paint, cryo, surgical excision
- Condylomata lata
- Syphilis
- Penicillin
What are the causes of pruritus ani?
- 50% idiopathic
- Poor hygiene
- Haemorrhoids
- Anal fissure
- Anal fistula
- Fungi
- Worms
- Crohn’s
- Neoplasia
What are haemorrhoids?
Disrupted and dilated anal cushions
What is the pathophysiology of haemorrhoids?
- Anal cushion = mass of spongy vascular tissue.
- Gravity and straining cause engorgement and enlargement of the anal cushions
- Hard stool disrupts connective tissue around cushions
- Cushions protrude and can be damaged by hard stool causing bright red bleeding (capillary)
Where do haemorrhoids tend to be positioned and why?
At 3, 7 and 11 o’clock because this is where the three major arteries that feed the vascular plexused enter the anal canal
What are the causes of haemorrhoids?
- Constipation with prolonged straining
- Venous congestion can contribute:
- Pregnancy
- Abdominal tumour
- Portal hypertension
How do you classify haemorrhoids?
- 1st degree: never prolapse
- 2nd: prolapse on defecation but spontaneously reduce
- 3rd: prolapse on defecation but require digital reduction
- 4th: remain permanently prolapsed
How do haemorrhoids present?
- Fresh painless PR bleeding
- Bright red
- On paper, on stool, may drip into pan
- Pruritus ani
- Lump in perianal area
- Severe pain = thrombosis
- Discharge - faecal soiling or mucus - because they prevent complete anal closure
What causes thrombosis of haemorrhoids?
Gripping by the anal sphincter (can ulcerate or infarct)
What investigations should be done for suspected haemorrhoids?
- Full abdo exam and palpate for masses
- Inspect perianal area: masses, recent bleeding
- DRE: can’t palpate them unless they’re thrombosed
- Rigid sig to identify higher rectal pathology
- Proctoscopy (also allows treatment)
What are the differentials for haemorrhoids?
- Perianal haematoma
- Fissure
- Abscess
- Tumour (must exclude in all cases)
What are the conservative management options for haemorrhoids?
- Increase fibre and fluid intake
- Stop straining at stool
- May resolve on its own
What are the medical management options for haemorrhoids?
- Topicals
- Anusol: hydrocortisone
- Topical analgesics
- Laxatives: lactulose, fybogel
What are the interventional management options for haemorrhoids?
- Injection with sclerosant (5% phenol in almond oil)
- Injection above dentate line
- SE: impotence, prostatitis
- Barron’s banding -> thrombosis and separation
- SE: bleeding, infection
- Cryotherapy
- SE: watery discharge post procedure
- Infra red coagulation
Describe the surgical management options for haemorrhoids
Haemorrhoidectomy
- Excision of piles and ligation of vascular pedicles
- Lactulose + metronidazole 1 week post op
- Discharge with laxatives post op
- SE: bleeding, stenosis