Haemorrhoids

Abnormally swollen vascular mucosal cushions that are present in the anal canal.

Anatomy

  • NB Haemorrhoids are NOT varicose veins, but rather they are clusters (cushions) of vascular tissue (i.e. containing arterioles, cappillaries and venules), smooth muscle and connective tissue lined by the normal epithelium of the anal canal.  Bleeding coming from haemorrhoids actually comes from the perisinusoidal arteries (haemorrhoid=sinusoid).
  • They lie along the anal canal in 3 columns
    • left lateral (3 o’clock)
    • right posterior (7 o’clock)
    • right anterior (11 o’clock)
  • Haemorrhoids play an important role in adjusting anal tone during increased abdominal pressure (e.g. coughing) and may be important in distinguishing between faeces and flatus.
  • Haemorrhoids can be classified as either
    • External
      • located below the dentate line
      • drain via inferior rectal veins to pudendal vessels to internal iliac
      • covered by squamous cell epithelium
      • has somatic sensory innervation (pudendal nerve)
    • Internal
      • lie above the dentate line
      • drain via middle rectal veins to internal iliac
      • covered by columnar epithelium
      • has visceral sensory innervation (not usually felt)
      • Can further be classified based on location
        1. 1st degree protrude into the anal canal
        2. 2nd degree prolapse outside of the canal but reduce spontaneously
        3. 3rd degree prolapse outside of the canal but require manual reduction
        4. 4th degree prolapse outside of the canal and are irreducible.

Pathophysiology

  • There are two main theories as to how haemorrhoids develop (the first is a pressure problem, the second more likely explains the increased incidence with age).
    1. Long-standing straining/constipation causes increased pressure within the anal canal and increased engorgement of the anal cushions.  If this eventually becomes great enough to interfere with venous return, engorgement may not resolve.  Repetition of this cycle leads to enlarged haemorrhoids.  It is known that a low-fibre diet and constipation are risk factors.
    2. Sliding anal canal lining suggests that haemorrhoids develop when the supporting tissues of the anal cushions deteriorate.  Here, venous dilatation is a consequence of a downward ‘sliding’ of anal cushions (rather than the cause).  It is thought that inflammatory processes may be involved in this.

Presentation

  • History
    • PR bleeding
      • Usually painless (see below)
      • Bright red (fresh arterial)
      • Associated with defecation
      • Amount can vary- from streaks on toilet paper to in the bowl, never mixed with stool (consider another cause if this is the case)
    • Anal itch
    • Prolapse
      • usually with bowel movement; often described like fullness, incomplete evacuation or a lump at the end of going to the toilet.
    • Pain
      • Pain is not normally relevant but may be present in 3rd/4th degree haemorrhoids if the haemorrhoid becomes strangulated
      • In external haemorrhoids, the haemorrhoid can thrombose and cause severe pain/discomfort then
      • Discomfort is more common (rather than acute pain)
    • Mucus/faeculant discharge
  • Examination
    • May be normal (if grade I)
    • The perineum may appear irritated from chronic discharge
    • If visible, the haemorrhoids usually appear at the anal verge (on coughing) as bluish, soft bulging vessels covered by mucosa (or if external they may be covered by skin)
    • Digital rectal examination should be performed to rule out any other causes of rectal bleeding and to check for any other haemorrhoids and for their reducibility

Investigations

  • Protoscopy may be useful if initial examination was difficult/inconclusive
  • FBC (anaemia/infection)

Management

trsgsrrs

  • *  Advise about a high fibre diet; fluid intake; weight loss and perianal hygiene.  Discourage straining and ‘holding in’ (i.e. advise to go to the toilet as soon as the urge comes).
  • **   Prescribe a laxative if the patient is constipated (bulk-forming is the preferred choice; stimulant laxatives are not recommended as they may worsen the haemorrhoids).  Prescribe pain relief where appropriate.  Topical creams (e.g. steroid/local anaesthetic creams) may be used in the short term ONLY.  Long-term use is not advised.
  • Rubber band ligation
    • A band is applied to the base of the haemorrhoid. The strangulated haemorrhoid becomes necrotic and sloughs off.  Up to 3 can be treated at once.  Minor complications include thrombosis, bleeding and ulceration.
  • Sclerotherapy
    • Phenol in oil is injected at the base of the haemorrhoids to induce a fibrotic reactions and cutting off the blood supply.  The haemorrhoids with atrophy, but can recur.
  • Haemorrhoidectomy
    • Only recommended for grade III/IV symptomatic haemorrhoids as there is a risk of incontinence
    • Other complications include post-operative urinary retention, bleeding, anal stricture, abscess, fistula, infection
  • Stapled haemorrhoidopexy
    • Staples are used to lift the haemorrhoids up back into the canal.
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