Anorectal disease Flashcards
Anal fissue : Definition
An anal fissure is a tear in the mucosal lining of the anal canal, most commonly due to trauma from defecation of hard stool. It can be classified according to its duration:
- Acute – present for <6 weeks
- Chronic – present for >6 weeks
Anal fissure : Risk factors
Anal fissures are usually caused by inflammation or trauma to the anal canal. The major risk factors include:
- Constipation
- Dehydration
- Inflammatory bowel disease
- Chronic diarrhoea
Anal fissure : Clinical presentation
intense pain post-defecation
Bleeding (bright, red) and itching post-defecation
Examination : visible or present during palpation in DRE
Anal fissure : Medical management
- Lifestyle : increase fluid, fibre, softening laxative (movicol/lactulose)
* Short term : topical lidocaine - Second line - if still stymptomatic
* GTN / Diltiazem cream - increases blood supply to the region and relaxes anal sphincter - reduce pressure and pain
Anal fissure : Surgical management
Third line : when medical management has failed to resolve the symptoms after at least 8 weeks.
- Botox injections
the internal anal sphincter, to relax the sphincter and promote healing of the fissure. - Lateral sphincterotomy
can be performed, involving division of the internal anal sphincter muscle.
Perinanal fistula : Definition
A perianal fistula (fistula-in-ano) refers to an abnormal connection between the anal canal and the perianal skin.
* majority are associated with anorectal abscess formation
Perinanal fistula : Pathophysiology
Perianal fistulas arise from infections in the anal glands
1 . Abscess in anal gland -
* Inflammation of surrounding tissue - damage tissue integrity
* increases pressure within surrounding tissues
2 . Rupture of abscess
* Released pus follow path of least resistance
* Creates tunnel/fistula that connects the anal gland to skin around the anus or other structures
Perinanal fistula : Risk factors
- Inflammatory bowel disease, mainly perianal Crohn’s Disease
-Persistent inflammation weakens tissue integrity, increasing risk of fistulas forming - Systemic diseases, typically Diabetes Mellitus : increases risk of abscess formation
- History of trauma to the anal region
- Previous radiation therapy to the anal region
Perinanal fistula : Investigations
- MRI imaging
* used to visualise the anatomy of the tract
Perinanal fistula : Management
Surgical intervention
* Superficial disease : Fistulotomy
Laying the tract open by cutting through skin and subcutaneous tissue
* High tract disease : Placement of seton through fistula
Anorectal abscess : Definititon
An anorectal abscess refers to a collection of pus in the anal or rectal region.
* One third of patients with an anorectal abscess have an associated perianal fistula at the time of presentation.
* They are more common in men than in women and have high rates of recurrence.
Anorectal abscess : Pathophysiology
- Anal glands : secrete mucous fluid into the anal canal via the anal canal
to facilitate the passage of stool - Blockage of anal duct
Fluid which will lead to infection of the anal glands
Anal abscess : location
Anal glands are located in the intersphincteric space (between the internal and external anal sphincters)
Infection can spread to;
(1) Perianal
(2) Ischiorectal
(3) Intersphincteric
(4) Supralevator
Anal abscess : Clinical presentation
- Severe pain in the perianal region, worse with direct pressure (i.e. when sat down)
- Discharge or bleeding from perianal space
- Eythematous, fluctuant, tender perianal mass
Severe abscesses may present with systemic features *such as fever or rigors, general malaise, or clinical features of sepsis
Anal abscess : Investigations
- Clinical diagnosis
* Anal abscess without fistula/rectal pathology : Ix for underlying diabetes mellitus - MRI pelvis : if complex perinal fistula or Perianal Crohns disease
Anal abscess : Management
- Examine under anaesthesia
- Incision and drainage of abscess
- Intraoperative proctoscopy : check of presence of fistula
Anal canal : Physiology
Internal mucous membrane of the anus
* Divided by Pectinate line into two portions
- Above Pectinate line : columnar epithelium, lacks pain receptors
- Below Pectinate line : non keratinised squamous epithelium has no ducts
* Sensitive to pain
Haemorrhoids : Pathophysiology
Anal valvular cushions : collection of venous/arterial plexus, highly vascular
Haemorrhoids are defined as an abnormal swelling or enlargement of the anal vascular cushions.
Haemorrhoid may occur due to ;
1. Chronic increased intra abdominal pressure - causes swelling of vasculture
2. Increase in venous pressure - 2nd to portal hypertension
Hemorrhoids can be either;
inside your anus (internal)
or
under the skin around your anus (external).
Haemorrhoids : Risk factors
excessive straining (from chronic constipation), increasing age, and raised intra-abdominal pressure (such as pregnancy, chronic cough, or ascites).
Other less common risk factors include pelvic or abdominal masses, family history, cardiac failure, or portal hypertension.
Internal haemorrhoids : Physiology
- Upper anal canal : Internal haemorrhoid site
- Above dentate line : no sensation
3x vascular anal cushions
Supply : contain venous plexus from the retinal artery and vein - superior haemorroidal plexus
Location : right anterior at 11 o’clock, right posterior at 7 o’clock and left lateral aspect at 3 o’clock
Continence : contribute to closure pressure at rest or when there is increase in abdominal pressure
-Blood drains away during defectation, allowing anal pressure to relax
Internal haemorrhoids : Classification
When these cushions become abnormally enlarged, they can cause symptoms and become pathological, termed haemorrhoids.
1st Degree Remain in the rectum
2nd Degree Prolapse through the anus on defecation but spontaneously reduce
3rd Degree Prolapse through the anus on defecation but require digital reduction
4th Degree Remain persistently prolapsed
External haemorrhoids
- Below the dentate (or pectinate) line.
- covered proximally by anoderm and distally by skin, both of which are sensitive to pain and temperature } sensoru supply by pudendal nerve
Supply : Inferior haemorrhoidal plexus
, external hemorrhoids are drained via the inferior rectal vein into the inferior vena cava.
Location;
occur circumferentially under the anoderm and can occur in any location.
Finally, external hemorrhoids are drained via the inferior rectal vein into the inferior vena cava.
Haemorrhoids : Clinical presentation
Internal haemorrhoids
1. Painless bright red rectal bleeding
* Commonly after defecation
2. Itching, pruritus - due to chronic mucus discharge
3. Assoc changes in bowel movements
External haemorrhoids
1. Pain
2. Rectal lump, fullness
3. A thrombosed prolapsed haemorrhoid will present as a purple/blue, oedematous, tense, and tender perianal mas
Haemorrhoids : Investigation
- Prostoscopy : confirm diagnosis
- Colonoscopy : exclude any concurrent anorectal pathology
