Anal Fistulas Flashcards

1
Q

Definition

A

Anal fistulae are abnormal communications, hollow tracts lined with granulation tissue connecting the primary opening inside the anal canal to a secondary opening in the perineal skin. They are usually associated with anorectal abscesses (obstruction of ducts leading to infection).

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2
Q

Clinical Presentation

A
  • Intermittent purulent discharge ± bleeding
  • Pain – which increases till temporary relief occurs with pus discharge
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3
Q

Associated conditions

A
  • Crohn’s disease
  • Unusual Infection (i.e. TB, Actinomycosis, Chlamydia, HIV)
  • Systemic disease (i.e DM)
  • Hidradenitis suppurativa
  • Malignancy
  • Radiation
  • History of trauma to anal region
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4
Q

PE

A
  • Assess for external opening on perineum seen: may be open, covered in granulation tissue
  • Assess for fibrous tract that can be felt underneath skin on DRE
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5
Q

What is Goddsall’s Rule

A

Goddsall’s Rule
- For fistula within 3cm of the anal verge and posterior to line drawn through ischial spines if
▪ Anterior to transverse anal line: straight radially directed tract into anal canal
▪ Posterior to transverse anal line: curve tract open into anal canal midline posteriorly (at level of dentate line)
- Exception: anterior external opening is >3cm from the anal margin – such fistula usually tack to the posterior midline

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6
Q

What is the classification

A
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7
Q

What investigations?

A
  • Endoanal U/S (H2O2 aided for hyperechoic effect) – to view course of fistula tract – more accurate than Goodsall’s Rule
  • MRI – able to visualise entire pelvis, beyond the sphincter complex (gold standard)
  • CT/fistulography (in emergency situation) – for complex fistulas / unusual anatomy
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8
Q

What is the management?

A
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