General - anorectal Flashcards
Anal cancer
Relatively rare cancer
Majority of anal cancers are SCCs arising from below the dentate line
Remainder are adenocarcinomas
Pre-cancerous condition, anal intraepithelial neoplasia (AIN), may precede the development of invasive squamous anal carcinoma
Anal cancer risk factors
HPV infection (HPV-16 and HPV-18)
HIV infection
Increasing age
Smoking
Immunosuppression
Crohn’s disease
Anal cancer clinical features
Rectal pain/rectal bleeding
Anal discharge
Pruritis
Presence of palpable mass
Perianal infection and fistula-in-ano can be seen in locally invasive disease
Examination – perineal and perianal regions should be screened for any ulceration/presence of wart-like lesions, inguinal lymph nodes should be examined for any lymphadenopathy
Anal cancer initial investigations
Proctoscopy
Undergo examination under anaesthetics (EUA), allows for much better assessment for tumour size and invasion of local structures, as well as a biopsy to be taken
Women – cervical smear
HIV test
Anal cancer imaging
USS-guided fine needle aspiration
CT thorax-abdomen-pelvis
MRI pelvis
Anal cancer management
MDT approach
Chemo-radiotherapy is often the first choice treatment for anal tumours (external beam radiotherapy to the anal canal and inguinal lymph nodes, combined with dual-chemotherapy agents)
Surgical excision usually reserved for management of advanced disease/in early T1N0 carcinomas (abdominoperineal resection)
Patients should be reviewed every 3-6 months for a period of 2 years
Anal cancer management complications
Chemoradiation-related pelvic toxicity is the most common short term complication, which can present with dermatitis, diarrhoea, proctitis and/or cystitis
Fertility issues, faecal incontinence, vaginal dryness, ED and rectovaginal fistula
Anal fissure
Tear in the mucosal lining of the anal canal, most commonly due to trauma from defecation of hard stool
Acute – present for <6 weeks
Chronic – present for >6 weeks
Anal fissure risk factors
Constipation
Dehydration
IBD
Chronic diarrhoea
Anal fissure clinical features
Intense pain post-defecation which can last several hours
Bleeding or itching, typically post-defecation
Examination – fissures can be visible and/or palpable on DRE & most present in the posterior midline
Often patients will refuse a DRE due to intense pain & EUA may be necessary for diagnosis
Anal fissure medical management
Reducing risk factors and providing adequate analgesia
Increasing fibre and fluid will help, stool softening laxatives can be trialled if no change following conservative management
Topical anaesthetics can provide short term symptomatic relief
Next line – GTN cream/diltiazem cream -> increased blood supply to the region and relaxes the internal anal sphincter, putting less pressure on the fissure
Anal fissure surgical management
Reserved for chronic fissures, where medical management has failed to resolve the symptoms after at least 8 weeks
Botox injections – given into the internal anal sphincter, to relax sphincter and promote healing of the fissure
Lateral sphincterotomy – division of the internal anal sphincter muscle
Anorectal abscess
Collection of pus in the anal/rectal region
More common in men than in women and have high rates of recurrence
1/3 patients with an anorectal abscess have an associated perianal fistula at the time of presentation
Anorectal abscess pathophysiology
Caused by plugging of the anal ducts, which drain the anal glands in the anal wall
Blockage of an anal duct results in fluid stasis -> lead to infection, common causative organisms include E. coli, bacteriodes spp. and Enterococcus spp.
Anal glands are located in the intersphincteric space, therefore infection from the glands here spreads to adjacent areas (perianal is most common)
Anorectal abscess clinical features
Severe pain in the perianal region, worse with direct pressure, alongside potential perianal discharge/bleeding
Severe – may present with systemic features
Examination – erythematous, fluctuant, tender perianal mass which may be discharging pus/have surrounding erythema and induration
Deeper abscesses – severe tenderness in PR examination
Anorectal abscess investigations
Typically a clinical diagnosis
Routine bloods, HbA1c
MRI pelvis scan for patients with atypical presentation
Anorectal abscess management
Should be started on abx therapy and provided with sufficient analgesia
Main management – EUA rectum and incision and drainage of the abscess, which should always be performed under general anaesthetic wherever possible
Intra-operative proctoscopy should be performed to check for the presence of any identifiable fistula-in-ano
Haemorrhoids
Defined as an abnormal swelling or enlargement of anal vascular cushions (act to assist the anal sphincter in maintaining continence)
Haemorrhoids classification
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
Haemorrhoids risk factors
Excessive straining
Increasing age
Raised intra-abdominal pressure
Less common risk factors – pelvic/abdominal masses, family history, cardiac failure or portal hypertension
Haemorrhoids clinical features
Painless bright red rectal bleeding, commonly after defecation, blood is seen on the surface of the stool not mixed in
Pruritus, rectal fullness/anal lump, soiling
Large prolapse haemorrhoids can thrombose
Examination usually normal unless haemorrhoids have prolapsed -> present as a purple/blue, oedematous, tense & tender perianal mass
Haemorrhoids investigations
Proctoscopy
FBC, clotting screen – any significant/prolonged bleeding
Colonoscopy is often advised to exclude any concurrent anorectal pathology
Haemorrhoids conservative management
Nearly all managed conservatively – increasing daily fibre, fluid intake, laxatives, topical analgesia
Symptomatic 1st and 2nd degree – rubber band ligation
Haemorrhoids surgical management
Haemorrhoidal artery ligation (2nd/3rd degree) – main vessel supplying the haemorrhoid is identified through Doppler and then tied off, such that the haemorrhoids infarcts and falls off
3rd and 4th degree – haemorrhoidectomy: haemorrhoidal tissue is excised, ensuring the internal sphincter muscle remains
Main complications – recurrence, anal structuring or faecal incontinence
Perianal fistula
Abnormal connection between the anal canal and the perianal skin
Majority are associated with anorectal abscess
4 distinct types:
1) Inter-sphincteric
2) Trans-sphincteric
3) Supra-sphincteric
4) Extra-sphincteric
Perianal fistula aetiology
Anorectal abscess
Inflammatory bowel disease
Diabetic mellitus
History of trauma
Previous radiation therapy to the anal region
Perianal fistula clinical features
Recurrent perianal abscesses
Intermittent/continuous discharge onto the perineum (mucus, blood, pus or faeces)
Examination – external opening on the perineum may be seen, fibrous tract may be felt underneath the skin on DRE
Goodsall rule
Used clinically to predict the trajectory of a fistula tract:
External opening posterior to the transverse anal line – fistula tract will follow a curved course to the posterior midline
External opening anterior to the transverse anal line – fistula tract will follow a straight radial course to the dentate line
Perianal fistula investigations
MRI imaging
Perianal fistula management
Fistulotomy – laying the tract open by cutting through skin and subcutaneous tissue, allowing it to heal by secondary intention
Placement of a seton through the fistula to bring together and close the tract, passing out at opening of the perianal skin adjacent to the external opening
Rectal prolapse
Protrusion of mucosal or full-thickness of rectal tissue out of the anus
Relatively uncommon, mainly affecting older females
Rectal prolapse pathophysiology
Full prolapse – form of sliding hernia, through a defect of the fascia of the pelvic region, may be caused by chronic straining secondary to constipation/chronic cough/from multiple vaginal deliveries
Partial thickness – associated with loosening and stretching of the connective tissue that attaches the rectal mucosa to the remainder of the rectal wall
Rectal prolapse risk factors
Increasing age
Female gender
Multiple deliveries
Straining
Anorexia
Previous traumatic vaginal delivery
Rectal prolapse clinical features
Rectal mucus discharge, faecal incontinence, PR bleeding or visible ulceration
Rectal fullness, tenesmus, repeated defecation = full thickness prolapses
Examination – prolapse can be identified by asking the patient to strain, DRE shows a weakened anal sphincter is identified
Rectal prolapse conservative management
More common in those unfit for surgery/minimal symptoms/children
Increasing dietary fibre and fluid intake
Minor mucosal prolapses may be banded in clinic
Rectal prolapse surgical management
Surgical repair is the only definitive management
1) Perineal approach – Delormes operation and Altemeier’s operation
2) Abdominal approach – rectopexy, whereby the rectum is mobilised and fixed onto the sacral prominence via sutures or mesh
