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haemorrhoids

haemorrhoids

Introduction

  • haemorrhoidal issues affect up to a third of adults and is most prevalent in 45-65 yr olds while being uncommon under 20 yrs old
  • internal haemorrhoids
    • arise internal to the dentate line, are covered by columnar epithelium, which lacks pain receptors, and are not usually palpable, and thus rarely cause pain
    • are the usual cause of “haemorrhoidal bleeding”
    • may prolapse and if they do, they may become strangulated or incarcerated which is painful
      • 2nd degree prolapse on defaecation but spontaneously reduce
      • 3rd degree external haemorrhoids require digital reduction
      • 4th degree do not reduce
  • external haemorrhoids
    • are located at 11 o'clock (R anterior), 7 o'clock (R posterior) and 3 o'clock (L anterior) when viewed in lithotomy position (patient lying on their back and legs up)
    • arise external to the dentate line are covered proximally by anoderm and distally by skin, both of which are sensitive to pain and temperature
    • commonly present as a painful external lump when they become thrombosed
      • resolution of which takes 1-2 weeks and results in a residual annoying skin tag which makes hygiene more difficult and can result in pruritus ani
      • incision and evacuation can be performed but may increase recurrence rate, while being painful and causing bleeding, most would prefer to allow it to resolve spontaneously

Aetiology

  • it seems constipation may not be the cause of haemorrhoids as was once thought, although an episode of diarrhoea does appear to be a precipitant, as is prolonged sitting on the toilet and straining at stool which is a particular risk for haemorrhoidal bleeding rather than thrombosed haemorrhoids or prolapsed internal haemorrhoids
  • pregnancy is a common cause
  • it seems it is more likely to be a vasomotor issue related to:
    • the terminal branches of the superior rectal artery supplying the anal cushion in patients with hemorrhoids had a significantly larger diameter, greater blood flow, higher peak velocity and acceleration velocity, compared to those of healthy volunteers while an increase in arterial caliber and flow was well correlated with the grades of hemorrhoids
    • the a-v plexus theory:
      • a smooth muscle sphincter in the arteriovenous plexus helps in reducing the arterial inflow, thus facilitating an effective venous drainage
      • vascular smooth muscle is regulated by the autonomic nervous system, hormones, cytokines and overlying endothelium.
      • if this mechanism is impaired, hyperperfusion of the arteriovenous plexus will lead to the formation of hemorrhoids 1)
  • the other theory is based on prolapsed anal cushions causing sliding of the anal lining
  • it also seems that the noted increased resting anal sphincter pressure seen in these patients is an effect of the haemorrhoids, not the cause as haemorrhoidectomy restores this to normal

Mx of "haemorrhoidal bleeding"

  • exclude a more sinister cause such as rectal cancer, colitis, diverticulitis, etc
    • this is largely based upon the history of the bleeding being bright red blood on the toilet bowel separate to stool
    • consider PR exam to exclude local pathology
  • reassurance
  • advice to avoid straining at stool
  • minimise time sitting on toilet (NO reading while on toilet!)
  • consider elevating feet while on toilet to improve pelvic floor control
  • minimise sitting as this increases venous pressures
  • encourage exercise and adequate fluid and dietary fibre intake as this improves constipation
  • use of stool softeners and laxatives as indicated
  • consider venotonics:
    • oral flavonoids such as micronized purified flavonoid fraction (MPFF), consisting of 90% diosmin and 10% hesperidin
      • decrease risk of bleeding and pain by 2/3rds, and decreases recurrence by 50%
    • oral calcium dobesilate
      • provides effective symptomatic relief from acute bleeding, and reduces inflammation
  • consider topical vasoconstrictors such as Preparation H may be useful for reducing bleeding and pain on defecation
  • problematic bleeding may require local procedures such as:
    • sclerotherapy
      • an option for first- and second-degree hemorrhoids
      • important that the injection be made into submucosa at the base of the hemorrhoidal tissue and not into the hemorrhoids themselves; otherwise, it can cause immediate transient precordial and upper abdominal pain
      • misplacement of the injection may also result in mucosal ulceration or necrosis
      • risk of bacteraemia thus susceptible patients may require antibiotic coverage (eg. heart valve patients)
    • rubber band ligation
      • may be considered for first- and second-degree hemorrhoids and selected patients with third-degree hemorrhoids
      • NB. placement of rubber band too close to the dentate line may cause severe pain due to the presence of somatic nerve afferents and requires immediate removal
      • often requires two operators and rectoscope and does result in some pain/discomfort
      • patients should stop taking anticoagulants for one week before and two weeks after RBL
      • may cause mucosal ulceration, acute urinary retention and thrombosed external haemorrhoids, and rarely, pelvic sepsis
    • other newer local therapies
    • haemorrhoidectomy if large prolapsed haemorrhoids are problematic, but there will be post-op pain, and potential for complications

Mx of thrombosed external haemorrhoid

  • examine to exclude perianal abscess or anal fissure as the differentials of ano-rectal pain
  • advise of the usual pattern of self-resolution but some will “burst” spontaneously and bleed but this will usually settle within a few days
    • consider using feminine hygiene pads on underwear to absorb any bloody discharge
  • topical anesthetics prn such as Rectinol
  • reassurance
  • advice to avoid straining at stool
  • use of stool softeners and laxatives as indicated
  • topical nitrates (glyceryl trinitrate 0.2% ointment) or calcium channel blockers (nifedipine ointment) reduce anal tone and pain but nitrates are likely to cause troublesome headache
  • topical vasoconstrictors such as Preparation H may be useful for pain on defecation
  • if very large and painful, refer to surgical team for possible clot evacuation
haemorrhoids.txt · Last modified: 2018/08/18 12:54 (external edit)