DEFINITION
Anal vascular cushions (that
contribute to anal closure) become enlarged and engorged with a tendency
to protrude, bleed or prolapse into the anal canal.
- Internal (arising from superior haemorrhoidal plexus and lie above the dentate line)
- External (from inferior haemorrhoidal plexus, below dentate line) Classified by degree of prolapse:
- First degree: Haemorrhoids that do not prolapse.
- Second degree: Prolapse with defaecation, but reduce spontaneously.
- Third degree: Prolapse and require manual reduction.
- Fourth degree: Prolapsed and not reducible.
ASSOCIATIONS/RISK FACTORS
Constipation, prolonged straining, pregnancy, portal hypertension.
EPIDEMIOLOGY
Common (prevalence 4–5%). Peak age is 45–65 years. Predominantly a disease of the Westernised world.
HISTORY
Commonly asymptomatic
Bleeding, usually bright red blood, on toilet paper or dripping into pan after passage of stool, can be on surface of stool but never mixed within. Alarm symptoms should be absent (weight loss, anaemia, change in bowel habit, passage of clotted, dark blood or mucus mixed with stool). Other symptoms are itching, anal lumps or prolapsing tissue. External haemorrhoids that have become thrombosed can cause severe pain.
EXAMINATION
First- or second-degree haemorrhoids are not usually apparent on external inspection, and uncomplicated haemorrhoids are impalpable and only seen on proctoscopy, where they are evident as red granular mucosal swellings bulging into view on straining and withdrawal of the proctoscope at 3, 7 and 11 o' Differential diagnoses include anal tags, anal fissure, rectal prolapse, polyps or tumour
PATHOLOGY/PATHOGENESIS
Excessive straining causes engorgement of anal cushions, together with shearing by hard stools resulting in disruption of tissue organisation, hypertrophy and fragmentation of muscle and elastin fibres and downward displacement, raised resting anal pressures and bleeding from pre-sinusoidal arterioles.
INVESTIGATIONS
Rigid or flexible sigmoidoscopy is usually important to exclude a rectal source of bleeding as haemorrhoids are common and may coexist with colorectal tumours.
MANAGEMENT
Conservative: Advice on a high-fibre diet, " fluid intake, bulk laxatives. Topical creams are available that contain mild astringents combined with local anaesthetic; those with corticosteroids should only be used on a short-term basis.
Local therapy (for first or second degree): Injection sclerotherapy: 5% phenol in almond oil is injected above the dentate line (no sensory fibres) into the submucosa above a haemorrhoid, inducing inflammation and subsequent fibrosis resulting in mucosal fixation. Banding: Barron’s bands are applied just proximal to the haemorrhoid- incorporating tissue that falls away after 2–3 days, leaving a small ulcer to heal by secondary intention. Higher cure rates but can be more painful. Other techniques include infrared coagulation, radio frequency ablation and heamorrhoidal artery ligation.
Surgical: Reserved for symptomatic third- or fourth-degree haemorrhoids. Milligan–Morgan open haemorrhoidectomy involves excision of haemorrhoidal cushions with preservation of skin/mucosal bridges between haemorrhoids to avoid stricturing. Stapled haemorrhoidectomy involves mucosectomy 2 cm proximal to the dentate line to ‘hitch up’ the prolapsing anal lining and disrupting the proximal blood flow (# pain and shorter convalescence in randomised control trials). Post-op, laxatives to avoid constipation, metronidazole.
COMPLICATIONS
Bleeding, prolapse, and thrombosis. From injection sclerotherapy: prostatitis, perineal sepsis, rarely impotence, retroperitoneal sepsis or hepatic abscesses. From haemorrhoidectomy: pain, bleeding, recurrence, more rarely incontinence due to sphincteric injury, anal stricture.
PROGNOSIS
Often a chronic problem, with recurrence of symptoms necessitating repeat local treatments. Surgery can provide long-term relief for severe symptoms.