7 - Anorectal Flashcards
What are haemorrhoids and how are they classified?
Abnormal swelling or enlargement of the anal vascular cushions at 3, 7, 11 o clock in lithotomy position
1-4th degree based on size
What are some risk factors for haemorrhoids?
- Excessive straining from constipation
- Increasing age
- Raised intrabdominal pressure (pregnancy, chronic cough, ascites)
- Pelvic or abdominal masses
- Family history
- Cardiac failure
- Portal hypertension
What are the clinical features of haemorrhoids?
- Painless bright red rectal bleeding after defecation on paper or on surface of stool (NOT mixed in)
- Pruitis
- Rectal fullness or anal lump
- Soiling
- If thrombosed can be painful, blue, oedamtous and tender
What are some differentials for haemorrhoids??
Need to exclude other causes of rectal bleeding
- Malignancy
- IBD
- Diverticular disease
- Sentinel piles from fissure-in ano
How are haemorrhoids investigated?
- Do a PR exam if possible and look at perianal skin
- Proctoscopy to confirm
- FBC to checl for anaemia
May need to do flexi sig or colonoscopy to rule out malignancies
How are haemorrhoids managed?
Conservatively (more common)
- Lifestyle advice (increase fibre and fluid intake)
- Laxatives
- Topical lignocaine
- Avoid opioids
- Reassurance bleeding not sinister
Non Surgical (symptomatic 1st and 2nd degree)
- Rubber band ligation
Surgical (2nd-4th degree)
- Haemorrhoidal artery ligation for 2nd+3rd degree
- Haemorrhoidetomy for 3rd or 4th not suitable for banding (Milligan Morgan or Stapled)
What are the complications of RBL and haemorrhoidectomy used in the treatment of haemorrhoids?
RBL: recurrence, pain, bleeding
Haemorrhoidectomy: bleeding, infection, constipation, stricture, anal fissure, fecal incontinence
What are the complications of haemorrhoids themselves?
- Thrombosis
- Ulceration
- Gangrene (secondary to thrombosis)
- Skin tags
- Perianal sepsis
What is the pathophysiology of a pilonidal sinus?
Formation of a sinus in the cleft of the buttocks, usually affect males 16-30 years
Hair follicle in the intergluteal cleft becomes infected or inflammed. The inflammation obstructs the opening of the follicle which extends inwards forming a pit
Foreign body type reaction then leads to formation of a cavity connected to the surface of the skin via sinus tract
What are some risk factors for developing a pilonidal sinus?
- Caucasian with coarse dark body hair
- Those who sit for prolonged periods of time
- Increased sweating
- Obesity
- Poor hygeine
- Local trauma
What are the clinical features of a pilonidal sinus?
- Discharging and intermittently painful sinus in sacrococcygeal region
- Abscess can arise when sinus infected and this is swollen, erythematous region with fluctuant tender mass
Distinguish from perianal fistula as does not communicate with anal canal. If not sure do rigid sigmoidoscopy or MRI to see internal opening of tract
How are pilonidal sinuses managed?
Conservative
- Shave affected region and pluck sinus free of any hair
- Wash sinus out with water to prevent infection
- Give antibiotics and surgical drainage if abscess
Surgical
- For abscess I+D with wash out and further later surgery to remove sinus tract
- For chronic disease two methods of removing tract (see image)
What is the aetiology of a fistula-in-ano?
Abnormal connection between anal canal and perianal skin, often as a consequence of an anorectal abscess
Other risk factors: (see image)
What are the clinical features of a fistula?
Present with either recurrent perianal abscesses OR intermittent/continuous discharge onto the perineum (faeces, blood, pus, mucus)
External opening on the perinueum may be seen or covered in granulation tissue
May feel fibrous tract under skin on DRE
What is the Goodsall rule?
Predicts trajectory of fistula tract based on external opening
How do you investigate an anal fistula and how are they classified on diagnosis?
Proctoscopy to visualise the opening of the tract or MRI imaging if complex
Intersphincteric are most common, suprasphinteric least common
Patients are treated conservatily for fistulas if they are asymptomatic. If patients are symptomatic, what is the course of treatment?
No difference in recurrence rates between different methods. High tract course fistula has a higher change of incontinence impairment from treatment
- Fistulotomy: lay tract open by cutting through skin and subcut tissue and leave to heal by secondary intention
- Placement of Seton: more for high tract disease, placed through the fistula to try and bring it together and close the skin
If a patient has an anal fistula or recurrent peri-anal abscesses, what should you investigate the patient for?
Crohn’s
What is the pathophysiology of an anorectal abscess and how are they categorised?
Collection of pus in anal or rectal region, more common in men
Caused by plugging of the anal ducts that drain the anal glands that normally produce mucus to help the passage of faecal matter
Blockage of duct leads to fluid stasis and infection due to flora overgrowth by E Coli, Bacteriodes spp or Enterococcus spp
Anal glands in intersphincteric space so infection can spread to other areas and form abscesses in different areas
What is the most common location of an anorectal abscess?
Perianal
What are the clinical features of an anorectal abscess?
- Pain in the perianal region exacerbated when sat down
- Localised swelling, itching or discharge
- Will be erythematous, fluctuant, tender perianal mass that could be discharging puss or have cellulitis
(if deeper abscess may not see anything perianally but may have severe tenderness on DRE so need anesthesia for full assessment or CT/MRI)
How are anorectal abscesses managed?
- Abx (ciprofloxacin/metronidazole for 7/7)
- Analgesia
- I+D under GA left to heal by secondary intention
- Once drained do proctoscopy to check for any fistula-in-ano and if so use seton
- Post ob abx to lower risk of fistula formation
What is an anal fissure and how are they classified?
Tear in the mucosal lining of the canal often due to trauma from defecation of hard stool
- Acute <6 weeks
- Chronic >6 weeks
Can also be primary or secondary (IBD)
What are the risk factors for developing an anal fissure?
- Constipation
- Dehydration
- IBD
- Chronic diarrhoea
What are the clinical features of an anal fissure?
- Intense sharp pain post defecation lasting several hours
- Bleeding and itchy
- On exam often visible or palpable painfully on DRE
- Most fissures in posterior midline (anterior in female after child birth or due to underlying cause)
How are anal fissures diagnosed if patients cannot tolerate a DRE due to the pain?
Examination under anaesthesia with proctoscopy
How are anal fissures managed?
Medical
- Reduce risk factors
- Adequate analgesia (e.g topical lidocaine and hot baths)
- Increase fibre and fluid intake and consider stool softening laxatives (movicol and lactulose)
- GTN or Diltiazem cream to increase blood supply to region and relax internal anal sphincter so less pressure on sphincter so can heal
Surgical (for chronic fissures)
- Botox injections into internal anal sphincter to relax
- Lateral sphincterotomy
What are the complications of anal fissure surgery?
- Recurrence in 1-5% of patients
- Faecal incontinence
What is a rectal prolapse and what are the different types?
Protrusion of mucosal or full thickness layer of rectal tissue out of the anus, more affecting women
Partial thickness: rectal mucosa protrudes out of anus
Full thickness: rectal wall protrudes out of anus
Internal intussusception: prolapse of rectum into distal rectum or anal canal without protrusion out
What is the pathophysiology of a rectal prolapse and what are some risk factors?
Full prolapse: Form of sliding hernia due to defect of fasica in pelvic region. May be caused by chronic straining, chronic cough or multiple vaginal deliveries
Partial prolapse: Loosening and stretching of connective tissue that attaches mucosa to rest of the rectal wall. Usually from long standing haemorrhoids
Risk factors: increasing age, female gener, multiple deliveries, straining, anorexia, previous traumatic vaginal delivery
What are the clinical features of a rectal prolapse?
- Rectal mucus discharge, faecal incontinence, PR bleeding, visible ulceration
- Full thickness starts internally so rectal fullness, tenesmus, repeated defecation
How do you examine and investigate a suspected anal prolapse?
- If not evident ask patient to strain to see if comes out
- DRE will have weakened anal sphincter
- Do defecating proctography and examination under anaesthesia if still cannot see
How is a rectal prolapse managed?
Conservative (children, unfit for surgery, minimal symptoms)
- Increase dietary fibre and fluid intake
- If mucosal prolapse can band but high recurrence
Surgical (definitive)
- Perineal or Abdominal approach
- No difference in post operative outcomes but perineal preferred for the elderly as safer
What is the histology of anal cancers?
Rare cancer that is usually SCC below dentate line
If above dentate line it is adenocarcinoma but only 10% of anal cancers
What are the risk factors for developing anal cancer?
- HPV 16 and 18
- HIV infection
- Increasing age
- Smoking
- Immunosuppression
- Crohn’s
What are the clinical features of anal cancer?
- Rectal pain or PR bleeding
- Anal discharge
- Pruritus
- Palpable mass
- Can have faecal incontinence and tenesmus if internal sphincter involved
What should you do on examination if you suspect anal cancer?
- Look for ulceration or wart like-lesions in perineal areas
- Check for mass on PRI and note distance from anal verge and proportion of circumference involved
- Check inguinal lymph nodes for lymphadenopathy (drains anal canal below dentate line but paraaortic drains above line)
What investigation should you do after examination raises suspicion for anal cancer?
Diagnosis
- Proctoscopy
- Examination under anaesthesia with biopsy
- Can do smear and vulvar biopsies to check for CIN, VIN and can consider HIV test
Staging
- USS guided fine needle aspiration of inguinal lymph nodes
- CT thorax/abdo/pelvis for metastases
- MRI pelvis to look for local invasion (T stage)
How is anal cancer managed?
- Wide local excision if T1N0
- Chemoradiotherapy (1st line): external beam radiotherapy to anal canal and inguinal lymph nodes then dual chemotherapy (5FU and mitomycin C)
- Abdominoperineal resection with colostomy if advanced and failed chemo then review every 3-6 months for perioid of 2 years. Most relapses in first 3 years
What are some complications of the treatment for anal cancer?
- Chemoradiation-related pelvic toxicity: dermatitis, diarrhoea, proctitis and or cystitis
- Fertility issues
- Faecal incontinence
- Vaginal dryness
- ED
- Rectovaginal fistula
