diseases of rectum and anal canal

Diseases of Rectum and Anal Canal

Prof. G. BandyopadhyayProfessor

Deptt. of SurgeryMedical College, Kolkata

Anatomy Rectum – distal part of gastrointestinal tractIt´s about 12 – 18 cm long and it´s divided into

three parts: 1. proximal part 2. middle part 3. distal part ( anal canal )

Anatomy contd. Blood supply : 1. superior rectal artery ( inferior mesenteric artery ) 2. two middle rectal arteries ( internal iliac artery ) 3. two inferior rectal arteries ( internal pudendal artery )

Internal rectal venous plexus - lies in the submucosa of the anal canal above the level of the dentate line ( internal haemorrhoids)

External rectal venous plexus - lies under the skin of the anal canal below the dentate line ( external haemorrhoids )

Congenital abnormalities

Imperforate anus – one infant in 4500-5000

A. Low abnormalities : anal stenosis ( treatment-dilatation ) anal membrane - anus is covered with a thin membrane (treatment-incision ) B. High abnormalities : ano – rectal agenesis ( 80-85 % ), often with recto-urethral or recto - vaginal fistula rectal atresia – anal canal is normal but ends blindly above the pelvic floor

Congenital abnormalities contd.

Examination : inspection, X-ray picture ( infant is held upside down with the coin or metal button in the site of the anus and the gas in the rectum will rise to the top and indicate the distance )

Treatment : operation incision, dilatation, colostomy, reconstruction of the anorectum

Fissure-in-ano - longitudinal ulcer in the distal part of anal canal

The site of location: - mid-line posteriorly - 80% - mid-line anteriorly - 10% - lateral – 10 % ( Crohn´s disease )

Ethiology – unknown ( passage of a hard stool ) - resting anal pressure is raised, but this may be due to secondary sphincter spasm induced by pain

Two types: 1. acute 2. chronic ( hypertrophic anal papila and sentinel tag )

Fissure-in-ano contd.Symptoms : pain, bleeding, pruritus,constipation,discharge

Management : 1. conservative ( acute) - sitz baths, laxatives, anal dilatation, local creams 2. operation ( chronic) - excision of fissure, posterior or lateral sphincterotomy to reduce the high resting anal pressure

Haemorrhoids ( Piles )Haemorhoids ( the dilatated rectal venous plexus ) consists of an internal and external component ( haemorhoidal disease ).

- very frequent disease Etiology - hereditary ( weakness of the vein walls ) - higher pelvic pressure ( pregnancy ), - constipation, straining at stool

Haemorrhoids contd.

Symptoms : bleeding, prolapse, pruritus, pain, discharge

Diagnosis: inspection - at 3,7 and 11 o´clock in litothomy position rectoscopy, anoscopy

Complications : bleeding, thrombosis, inflammation

Haemorrhoids cond.

Classification: 4 degrees

I. degree : occasional bleeding only II. degree : prolapse after defecation with spontaneous repositionIII. degree : prolapse needs to be replaced manuallyIV. degree : permanent prolapse with inflammation, thrombosis etc.

Haemorrhoids contd.Management :

A. conservative : sitz baths, local creams and suppositories

B. semiconservative : injection sclerotherapy, infrared coagulation, rubber band ligation

Haemorrhoids cotd..

C. Operative treatment :• - Haemorhoidectomy• -open/closed Stapled hemorrhoidectomy/haemorrhoidopexy

-PPH (procedure for prolapsed haemorrhoids) Adv- no external skin wound, recovery

is rapid and relatively pain free Disadv.-recurrence rate higher,costly

Haemorrhoids cotd..

• Complications of PPH• Rectal perforation• • Recto-vaginal fistula• • Severe pelvic sepsis• • Anastomotic dehiscence

Internal haemorrhoids

external haemorrhoids

PPH device

PPH procedure

Peri-anal Abscess and Fistula

Peri-anal abscess and fistula are two phases of the same disease.Abscess - acute phaseFistula – chronic phase

Etiology : - majority of abscesses originate in the intersphincteric space from infection of anal gland.

Inter-sphincteric abscess &Routes of spread

Rectal lumen

Abscess

Internal sphincter

External sphincter

Peri-anal Abscess and Fistula contd.

Fistula-in-ano ( anal fistula ) usually consists of : - internal opening - primary tract - external opening

Primary tract connects the internal and external openings.

Intersphincteric fistula Transsphincteric fistula

External sphincter

Internal sphincter Fistula tract Fistula tract

puborectalis

Suprasphincteric fistula Extrasphincteric fistula

Fistula tract

Levator ani

Peri-anal Abscess and Fistula contd.Symptoms : acute abscess – pain, fever fistula- in- ano – chronic purulent discharge

Management :

Acute abscess– surgical inicision and drainage (Hilton’s method) cavity is dressed with gauze ( changing every 24 hours ) wound is left open for secondary healing

Peri-anal Abscess and Fistula contd.

• Anal fistula – treatment according to the type of fistula

• 1. Incision( lay open the primary track )-

fistulotomy• 2. Excision-fistulectomy• 3. Seton• 4. Anal Plug• 5. Advancement flap• 6. Kharsutra

Fistula tract

Fistulectomy: step-I

Fistulectomy: step-II

Fistulectomy: step-III

Multiple Fistulae

Benign rectal tumorsThe most frequent are polyps.

Polyp is a localised elevated lesion arising from an epithelial surface.Polyp - adenoma : 90% - other ( inflammatory, hyperplastic etc. ) : 10%

2 types of adenoma : tubular ( pedunculated ) 20% villous ( sessile ) 80%

Symptoms : bleeding, mucoid discharge ( villous )

Treatment : polypectomy by colonoscopy surgical excision – large sessile polyp

Colonoscopic polypectomy

Colorectal Cancer

Epidemiology– Most common internal cancer in Western Societies

– Second most common cancer death after lung cancer

– Generally affect patients > 50 years (>90% of cases)

Colorectal Cancer• Forms– Hereditary• Family history, younger age of onset, specific gene defects• E.g. Familial adenomatous polyposis (FAP), hereditary

nonpolyposis colorectal cancer (HNPCC or Lynch syndrome)

– Sporadic• Absence of family history, older population, isolated

lesion

– Familial

Pathology

• Spreads circumferentially • 6 months required to involve a quarter and 18 months to

2 years for complete encirclement.

• Histopathology– Generally adenocarcinoma– Squamous cell carcinoma in some cases of anal CA

Colorectal CA

Duke’s classification of rectal CA

• A- limited to rectal wall- excellent prognosis

• B- extended to the extrarectal tissues but no mets to lymph nodes- reasonable prognosis

• C- secondary deposites in the regional lymph nodes

C1- local pararectal lymph nodes only C2- nodes along blood vessels also

Histological Grading

Low grade- well differentiated- 11% -good prognosis

Average grade- 64%- fair prognosis

High grade- 25%- poor prognosis

Clinical Presentation

• Depends on location of cancer• Locations– ⅔ in descending colon and rectum– ½ in sigmoid colon and rectum (i.e. within reach of

flexible sigmoidoscope)• Caecal and right sided cancer – Iron deficiency anaemia (most common)– Distal ileum obstruction (late)– Palpable mass (late)

Clinical Presentation

• Left sided colon and sigmoid carcinoma

– Change of bowel habit

• Alternating constipation + diarrhoea• Tenesmus• Thin stool

– PR bleeding, mucus

Clinical Presentation

• Rectal carcinoma

– PR bleeding, mucus– Change of bowel habits– Anal, perineal, sacral pain

• Constitutional symptoms– Loss of appetite, loss of wt., malaise

• Bowel obstruction

Clinical Presentation

• Local invasion• Anterior- prostate(male),vagina, uterus(female) bladder,

posterior- sacrum, sacral plexus, laterally- pararectal tissue, ureter

• Metastasis– Liver (hepatic pain, jaundice)– Lung (cough)– Bone (pain,leucoerythroblastic anaemia)– Regional lymph nodes– Peritoneum (Sister Marie Joseph nodule)– Others

Examination• Signs of primary cancer– Abdominal tenderness and distension – large bowel

obstruction– Intra-abdominal mass– Digital rectal examination – most are in the lower

part of rectum and can be reached by examining finger

– Sigmoidoscopy & biopsy• Signs of metastasis and complications– Signs of anaemia– Hepatomegaly (mets)– Bone pain

Investigations

• Faecal occult blood– Guaiac test (Hemoccult) – based on pseudoperoxidase

activity of haematin

– Immunochemical test (HemeSelect, Hemolex) – based on antibodies to human haemoglobins

– Used for screening and NOT for diagnosis

Investigations• Colonoscopy & biopsy– Can visualize lesions < 5mm

– Small polyps can be removed or at a later stage by endoscopic mucosal resection

– Performed under sedation

lesioncolonoscope

Investigations• Double contrast barium enema– Cannot detect very small lesions– All lesions need to be confirmed by colonoscopy

and biopsy– Performed with sigmoidoscopy– Second line in patients who failed / cannot

undergo colonoscopy

Other Investigations• CT colonoscopy

• Endorectal ultrasound

• CT and MRI – staging prior to treatment

• Blood tests- Complete blood count, Ur/Cr, LFT, coagulation profile– Tumour marker CEA• Useful for monitoring progress but not specific for

diagnosis

MANAGEMENT

principles

• Surgery is the treatment of choice whenever possible

• In cases of locally advanced tumors pre-op chemoradiotherapy may downstage the tumor

• Palliative treatment in inoperable cases

Management

• Caecum or ascending colon– Right hemicolectomy– Vessels divided – ileocaecal and right colic– Anastamosis between terminal ileum and transverse colon

• Transverse colon– Close to hepatic flexure right hemicolectomy– Mid-transverse extended right hemicolectomy (up to

descending) + omentum removed en-bloc with tumour– Splenic flexure subtotal colectomy (up to sigmoid)

Management

• Descending colon– Left hemicolectomy– Vessels divided – inferior mesenteric, left colic, sigmoid

• Sigmoid colon– High anterior resection– Vessels ligated – inferior mesenteric, left colic and sigmoid– Anastomoses of mid-descending colon to upper rectum

Management

• Obstructing colon carcinoma– Right and transverse colon – resection and primary anastomosis– Left sided obstruction• Hartmann’s procedure – proximal end colostomy (LIF) +

oversewing distal bowel + reversal in 4-6 months• Primary anastamosis – subtotal colectomy (ileosigmoid or

ileorectal anastomosis)• Intraoperative bowel prep with primary anastomosis (5%

bowel leak)• Proximal diverting stoma then resection 2 weeks later• Palliative stent

Resection

Rectal Cancer

• Options– Low anterior resection

– Transanal local excision

– Abdomino-perineal resection

– Palliative procedure

Rectal Cancer• Anterior resection

– Upper and mid rectum cacinoma– Sigmoid and rectum resected– Vessels divided – inferior mesenteric

and left colic– Mesorectum resected– Coloanal anastomosis– High – intraperitoneal anastamosis

(upper 1/3 of rectum)– Low – extra-peritoneal anastomosis– Post-op recovery

• Increased stool frequency• 12-18 month to acquire normal

bowel function• 1~4% anastamotic leak

Rectal Cancer• Abdominoperineal resection– Larger T2 and T3 or poorly

differentiated tumour– Rectum mobilised to pelvic floor

through abdominal incision– Sigmoid end colostomy– Separate perianal elliptical

incision to mobilise and deliver anus and distal rectum

– Vessels ligated – inferior mesenteric

Rectal Cancer• Hartmann’s procedure– Acute obstruction– Palliative

• Transanal local exision– Early stage– Too low to allow restorative surgery

• En block resection – for locally advanced colorectal carcinoma (remove adherent viscera and abdominal wall)

Palliative procedures

– Diverting stoma

– Radiotherapy

– Chemotherapy

– Local therapy – laser, electrocoagulation, cryosurgery

– Nerve block

Complications

• Liver metastasis

• Local invasion → perineal and pelvic pain

• Bowel obstruction

• Fistula to skin or bladder

• Rectal discharge and bleeding

• Hypoproteinaemia

• Poor appetite

Prognosis

• 5 yr survivals– T1 = >90%, T2 = >80%. T3 = >50%– LN involvement = 30~40%– Distant mets = <5%

Hereditary Colorectal Cancer

• Familial adenomatous polyposis– FAP account for <1% of all colorectal cancers– Due to mutation of the adenomatous polyposis coli

(APC) gene– Numerous adenomas appear as early as childhood

and virtually 100% have colorectal cancer by age 50 if untreated

Hereditary Colorectal Cancer

• Hereditary non-polyposis colorectal cancer / Lynch syndrome– More common than FAP and account for ~1-5% of all

colonic adenocarcinomas– Due to a mutation in one of the mismatch repair genes– Earlier age onset of colorectal cancer and predominantly

involve the right colon– HNPCC also increases the risk of• Endometrial, ovarian, breast ca• Stomach, small bowel, hepatobiliary ca

– Renal pelvis or ureter ca

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