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Haemorrhoids and Anal fissures

1. HAEMORRHOIDS

  • Disrupted and dilated anal vascular cushions

Epidemiology

  • Prevalence in US – 4%
  • Most common in Caucasians

Etiology

  • Excessive straining – chronic constipation, diarrhoea
  • Increased intra-abdominal pressure – pregnancy, ascites
  • Lack of exercise, diet lacking in fibre, obesity
  • Congestion from pelvic tumour

Pathophysiology

  • Haemorrhoids are cushions of submucosal tissue containing venules, arterioles and smooth muscle fibres
    • Located in the anal canal – part of normal anorectal anatomy
  • They function as part of the continence mechanism and aid in complete closure of the anal canal at rest
  • Haemorrhoids are attached by smooth muscle and elastic tissue – makes them prone to displacement and disruption
  • Effects of gravity, anal tone and straining – makes them bulky and loose
    • Protrude and form piles
    • Vulnerable to trauma and bleed readily from capillaries
  • Positions of haemorrhoidal cushions – see pic
    • 11, 3 and 7 o’clock

Types

External

  • Located distal to dentate/pectinate line, covered with anoderm
  • Anoderm is richly innervated therefore thrombosis of external piles causes pain

Internal

  • Proximal to dentate line, covered by insensate anorectal mucosa
  • May prolapse/bleed
  • Rarely become painful – only when they develop thrombosis/necrosis (strangulation or severe prolapsed)
  • Classification
    • First degree – don’t prolapse through the anus
    • Second degree – prolapse through the anus but reduce spontaneously
    • Third degree – prolapse through the anus and require manual reduction
    • Fourth degree – prolapse through the anus but cannot be reduced; they are at risk for strangulation

Combined

  • Straddle the dentate line
  • Characteristics of both

Clinical features

  • Features of irritation – pruritis, mucus discharge, discomfort
  • Features of damage to mucosal lining – recurrent post-defecatory bleeding (bright red blood)
  • Features of prolapse – intermittent lump appearing at anal margin, usually after defecation

Investigations

  • Physical exam – usually diagnostic
  • Colonoscopy, flexible sigmoidoscopy
  • FBC – may indicate anaemia

Complications – Thrombosis, gangrene, fibrosis, strangulation

Treatment

1st and 2nd degree

  • Improves with increased fibre and fluid in diet

2nd and 3rd degree

  • Non-operative
    • Ligation – band strangulates underlying tissue
    • Sclerosants – 2ml of 5% phenol injected into piles above dentate line
    • Infrared coagulation – coagulates vessels
    • Cryotherapy – has high complication rates
  • Surgery
    • Excisional haemorrhoidoplexy – excision of piles and ligation
    • Stapled haemorrhoidoplexy – for prolapsing piles
    • Complications – constipation, infection, stricture, bleeding

2. ANAL FISSURES

  • Tear in the anoderm distal to the dentate line

Epidemiology

  • Males and females are equally affected
  • Peak incidence 15-40 yrs
  • Can occur in kids due to poor toileting

Etiology

  • Initiating factor thought to be from trauma from the passage of hard stools, low fibre diets or previous anal surgery

Pathophysiology

  • Tear in anoderm leads to spasm of internal anal sphincter – causes pain, tearing and decreased blood supply to anoderm
  • This cycle of pain, spasm and ischemia contributes to the development of a poorly healing wound that becomes a chronic fissure
  • Most anal fissures occur in the posterior midline

Clinical features

  • Tearing pain with defecation
  • Hematochezia – passage of fresh blood in stool
  • Intense and painful spasm – lasts for several hrs post defecation
  • Lateral location of fissure may indicate underlying disease – Crohn’s disease, HIV, syphilis, TB

Investigations

  • Digital and anoscopic exam can result in severe pain – not needed if fissure can be visualised
  • If necessary then exam should be done under anaesthesia

Treatment

  • Focuses on breaking cycle of pain, spasm, ischemia

Medical

  • Stool softeners, warm sitz bath
  • 2% lidocane jelly – symptomatic relief
  • Nitroglycerine ointment – improve local blood flow
  • Calcium channel blocker – diltiazem, nifedipine
    • Decreases spasm

Surgical

  • For chronic fissures that have failed medical therapy
  • Lateral internal sphincterotomy – to decrease spasm of sphincter by dividing a portion of the muscle
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