Perineal Abscess + Fistula Flashcards
What is a Perineal Abscess?
A pus collection in the perineal region (surface region between pubic symphysis + coccyx)
What is a Perineal Fistula?
an abnormal chronically infected tract communicating between the perineal skin + either the anal canal or rectum
What causes a perineal abscess?
Bacterial infection
What causes a perineal fistula?
Fistulae develop as a complication of an abscess
List 4 risk factors for development of perineal abscesses and fistulas
IBD
Diabetes mellitus
Malignancy
Diverticulitis
Multiple Perineal fistulae can develop as a complication of which disease? What is this called?
Crohn’s disease
Pepper pot perineum
Describe the epidemiology of perineal abscesses and fistulae
COMMON
Give 2 symptoms of perineal abscesses and fistulae
Constant throbbing pain in the perineum Intermittent discharge (mucus or faecal staining) near the anal region
What may be present in the history of a patient presenting with perineal abscesses and fistulae?
Personal hx / FH of IBD
List 3 signs of perineal abscesses and fistulae on examination
Localised tender perineal mass (may be fluctuant)
Small skin lesion near the anus (opening of the fistula)
Painful hardened tissue felt
Describe DRE findings in perineal abscesses and fistulae
A thickened area over the abscess/fistula may be felt
DREs not always possible due to pain + anal sphincter spasm
What is Goodsall’s Law?
Rule to correlate location of internal fistula opening based on location of external fistula opening
External opening ANTERIOR to anal canal (i.e. anterior to transverse anal line); fistula runs radially + directly into anal canal
External opening POSTERIOR to anal canal or 3 cm away follows a curved path + open internally in the posterior midline
What bloods should be taken for perineal abscesses and fistulae?
FBC
CRP
ESR
Blood culture
What may be assessed on MRI in perineal abscesses and fistulae?
Fstular tracts
Opening + closing of any fistulas
Location of deep abscesses
Damage to the anal sphincter
What treatment is required for perineal abscesses and fistulae?
SURGICAL tx
Open Drainage of Abscess
How are low fistulae managed?
Fistulotomy
Care must be taken to prevent damage to the anal sphincter
How are high fistulae managed?
Seton: a non-absorbable suture that is threaded through the fistula to allow it to stay open + therefore drain
OR
Advanced flap procedure: cutting or scraping out the fistula + covering the hole where it entered the bowel with a flap of tissue taken from inside the rectum
OR
LIFT procedure: fistula sealed at both ends
OR
Endoscopic ablation to seal the fistula
Abx
What is the prognosis for patients with perineal abscesses and fistulae?
High recurrence rate without complete excision
What investigation may be performed to exclude differentials of suspected anal abscesses and fistulae?
Proctosigmoidoscopy
