General Surgery
Final Professional MBBS — General Surgery. Explanation-first answers that teach the reasoning behind every fact, with classifications, comparison tables, drug doses, clinical pearls and key-point recaps from Bailey & Love and SRB's Manual.
THE CONCEPT
Haemorrhoids ('piles') are the symptomatic enlargement and downward displacement of the anal cushions — normal masses of vascular submucosal tissue in the anal canal. Everyone has anal cushions (they help seal the anus and maintain continence); they become 'haemorrhoids' only when they enlarge, engorge and prolapse and cause symptoms. Understanding them as displaced normal cushions rather than varicose veins makes the classification and treatment logical.
ANATOMY & TYPES
The anal cushions lie in three constant positions — 3, 7 and 11 o'clock (left lateral, right anterior and right posterior with the patient in the lithotomy position). Haemorrhoids are classified by their relation to the dentate line:
- Internal haemorrhoids — above the dentate line, covered by insensate columnar mucosa, so they are typically painless.
- External haemorrhoids — below the dentate line, covered by sensate squamous epithelium, so they are painful when thrombosed.
GRADING OF INTERNAL HAEMORRHOIDS
Grade Features I Bleed, but do not prolapse II Prolapse on straining, reduce spontaneously III Prolapse, need manual reduction IV Permanently prolapsed, irreducible AETIOLOGY & CLINICAL FEATURES
Contributing factors are constipation and straining, a low-fibre diet, pregnancy, and any cause of raised intra-abdominal pressure. The typical symptom is bright red, painless bleeding (coating the stool or dripping after defecation), with prolapse, mucus discharge, pruritus and discomfort; pain occurs only with thrombosis or strangulation.
EXAMINATION & MANAGEMENT
Examination involves inspection, digital rectal examination (internal piles are usually not palpable), and proctoscopy to visualise them. Crucially, in any patient with rectal bleeding one must exclude colorectal cancer with sigmoidoscopy/colonoscopy rather than assume the bleeding is from piles. Management is graded:
- Conservative (grades I–II) — high-fibre diet, fluids, avoiding straining, and stool softeners.
- Non-surgical (II–III) — rubber-band ligation, sclerotherapy, or infrared coagulation.
- Surgical (III–IV or failed treatment) — haemorrhoidectomy (open Milligan–Morgan or closed Ferguson), or stapled haemorrhoidopexy.
💡CLINICAL PEARL: Anchor the topic: haemorrhoids are enlarged anal cushions at 3, 7 and 11 o'clock; internal piles cause painless bright-red bleeding and are graded I–IV. The safety rule is to always exclude colorectal cancer in a patient with rectal bleeding (do not attribute it to piles without investigation). Band ligation suits grades II–III, haemorrhoidectomy grades III–IV.WHY THEY ARE NOT VARICOSE VEINS
A common misconception is that haemorrhoids are 'varicose veins of the anus'. In fact the modern understanding is that they are displaced anal cushions — the normal vascular submucosal tissue that helps seal the anal canal. With chronic straining, the supporting connective tissue that anchors these cushions fragments and stretches, allowing them to slide downward and engorge. This is why treatment aims to fix the cushions back in place or reduce their bulk (band ligation, haemorrhoidopexy) rather than simply 'removing a vein', and why straining prevention is central.
THROMBOSED & STRANGULATED HAEMORRHOIDS
The painful complications deserve attention. A thrombosed haemorrhoid occurs when a clot forms in a prolapsed pile, causing sudden severe pain and a tense, tender swelling. A strangulated haemorrhoid arises when prolapsed piles are gripped by the sphincter, cutting off their venous return and causing intense pain, oedema and possible gangrene. These acute presentations are managed initially with analgesia, ice, stool softeners and rest (most settle), with surgery reserved for severe or gangrenous cases — a contrast to the painless bleeding of uncomplicated internal piles.
A NOTE ON EXCLUDING SINISTER CAUSES OF BLEEDING
The most important safety principle in managing 'piles' bears repeating: rectal bleeding must never be assumed to be haemorrhoidal without excluding colorectal cancer, particularly in patients over 40, those with a change in bowel habit, weight loss, anaemia, or a family history. Haemorrhoids are extremely common and may coexist with a cancer, so attributing bleeding to visible piles can dangerously delay a cancer diagnosis. A full lower-GI evaluation (colonoscopy) is therefore the rule for significant or atypical bleeding, whatever the anal findings.
A NOTE ON HAEMORRHOIDS IN PREGNANCY & PORTAL HYPERTENSION
Two special contexts are worth noting. In pregnancy, haemorrhoids are common because of the combination of raised intra-abdominal pressure, constipation and the vascular effects of progesterone; they usually improve after delivery, so treatment is conservative (fibre, fluids, topical measures) during pregnancy. Separately, it is a classic teaching point that although engorged, haemorrhoids are not simply a manifestation of portal hypertension — the true portosystemic connection in that condition is anorectal varices, a distinct entity, and it is important not to confuse the two.
💊KEY POINTS / NUMBERS (viva)- Anal cushions at 3, 7, 11 o'clock; internal (above dentate line, painless) vs external (below, painful if thrombosed).
- Grading: I bleed only, II prolapse + spontaneous reduction, III need manual reduction, IV irreducible.
- Always exclude colorectal cancer (colonoscopy) in rectal bleeding; band ligation (II–III), haemorrhoidectomy (III–IV).
🔑KEY POINTS TO REMEMBER- Haemorrhoids = symptomatic enlargement/prolapse of the normal anal cushions (3, 7, 11 o'clock).
- Internal (above dentate line, painless bleeding) vs external (below, painful if thrombosed); internal graded I–IV.
- Bright red painless bleeding, prolapse, mucus, pruritus; pain only with thrombosis/strangulation.
- ALWAYS exclude colorectal cancer with colonoscopy in a patient with rectal bleeding.
- Conservative (fibre/fluids, I–II), band ligation/sclerotherapy (II–III), haemorrhoidectomy (III–IV).
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
An anal fissure is a longitudinal tear (split) in the anoderm — the sensitive lining of the lower anal canal below the dentate line. It is one of the commonest causes of severe anal pain, and its whole behaviour is explained by a self-perpetuating cycle of pain, sphincter spasm and poor blood supply that prevents healing.
PATHOPHYSIOLOGY — THE VICIOUS CYCLE
The usual trigger is the passage of a hard stool that tears the anoderm. The tear causes pain, which provokes reflex spasm of the internal anal sphincter; the raised sphincter pressure in turn reduces blood flow to the anoderm — and because the posterior midline is a relative 'watershed' with a poor blood supply, the fissure there fails to heal. This spasm → ischaemia → poor healing cycle converts an acute tear into a chronic fissure.
SITE & THE IMPORTANT EXCEPTION
About 90% of fissures are in the posterior midline (the poorly-perfused watershed); anterior fissures occur, especially in women after childbirth. A crucial exam and clinical point: fissures that are lateral, multiple, or otherwise atypical should raise suspicion of an underlying disease — Crohn's disease, tuberculosis, malignancy or HIV.
CLINICAL FEATURES
The hallmark is severe, sharp, tearing pain during and (for hours) after defecation, often with a small amount of bright red bleeding (streaking the stool or paper). Fear of pain leads to constipation, worsening the cycle. A chronic fissure shows a characteristic triad: the fissure itself, a sentinel skin tag at its lower end, and a hypertrophied anal papilla at its upper end, often with exposed internal sphincter fibres in the base.
MANAGEMENT
- Medical (first-line) — high-fibre diet, fluids, stool softeners and warm sitz baths, plus topical agents that relax the sphincter and improve blood flow — GTN (glyceryl trinitrate) or diltiazem ointment — to break the spasm–ischaemia cycle; botulinum toxin injection is an option.
- Surgical (chronic/refractory) — lateral internal sphincterotomy (LIS) is the gold standard, dividing part of the internal sphincter to relieve spasm and allow healing (with a small risk of incontinence).
💡CLINICAL PEARL: The essence: an anal fissure is a painful posterior-midline tear maintained by a sphincter-spasm/ischaemia cycle. Treat first with fibre, sitz baths and sphincter-relaxing ointment (GTN/diltiazem), reserving lateral internal sphincterotomy for chronic cases. Remember that a lateral or atypical fissure suggests Crohn's, TB or malignancy.A NOTE ON THE INTERNAL SPHINCTER'S ROLE
The internal anal sphincter is central to both the disease and its cure. Its resting tone is normally high, and in a fissure this tone becomes abnormally raised (hypertonic), which is what perpetuates the spasm–ischaemia cycle. Every effective treatment works by lowering internal sphincter pressure — GTN and diltiazem relax it pharmacologically ('chemical sphincterotomy'), botulinum toxin paralyses it temporarily, and lateral internal sphincterotomy divides part of it surgically. Understanding this shared mechanism explains why all these treatments help.
THE RISK OF SPHINCTEROTOMY
The main drawback of lateral internal sphincterotomy must be understood: dividing part of the internal sphincter carries a small but real risk of impaired continence (especially to flatus or, rarely, faeces), which is more likely in patients with an already weak sphincter — such as older patients and women who have had obstetric injury. This is why medical (sphincter-relaxing) therapy is tried first, and why sphincterotomy is used cautiously and selectively, particularly in those at higher risk of incontinence.
A NOTE ON THE ACUTE VS CHRONIC FISSURE
Distinguishing the acute from the chronic fissure guides treatment. An acute fissure is a simple superficial tear, usually of recent onset, that often heals with conservative measures alone (fibre, fluids, sitz baths, stool softeners). A chronic fissure (present beyond about 6 weeks) shows the characteristic triad — sentinel tag, hypertrophied papilla and visible internal sphincter fibres in the base — and reflects the established spasm–ischaemia cycle, so it usually needs sphincter-relaxing therapy or surgery. This distinction determines how aggressively the fissure is treated.
💊KEY POINTS / NUMBERS (viva)- ~90% posterior midline (watershed); anterior in postpartum women; lateral/atypical → suspect Crohn's/TB/malignancy.
- Vicious cycle: tear → pain → internal sphincter spasm → ischaemia → poor healing.
- Medical first: fibre, sitz baths, topical GTN/diltiazem (± botulinum toxin); chronic → lateral internal sphincterotomy (gold standard).
🔑KEY POINTS TO REMEMBER- Anal fissure = longitudinal tear in the anoderm (lower anal canal); severe pain, usually posterior midline.
- Vicious cycle: hard stool tears anoderm → pain → internal sphincter spasm → ischaemia (posterior watershed) → poor healing.
- Severe tearing pain during/after defecation + bright red bleeding; chronic fissure triad = fissure + sentinel tag + hypertrophied papilla.
- Lateral/multiple/atypical fissure → suspect Crohn's, TB, malignancy, HIV.
- Medical first (fibre, sitz baths, topical GTN/diltiazem, botulinum toxin); lateral internal sphincterotomy for chronic/refractory.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
An anorectal abscess is a collection of pus in one of the potential spaces around the anus and rectum. Its importance lies in understanding its origin (which explains why it recurs and why it leaves fistulas) and in recognising that it is a condition requiring prompt surgical drainage rather than antibiotics alone.
ORIGIN — THE CRYPTOGLANDULAR THEORY
Most anorectal abscesses arise by the cryptoglandular mechanism: the anal glands, which open into the anal crypts at the dentate line, become infected and obstructed, and the infection then spreads into the adjacent spaces to form an abscess. This same origin explains why an abscess so often leaves a fistula-in-ano once it has drained — the track back to the infected gland persists.
TYPES (BY SPACE)
Abscesses are named by the space they occupy: perianal (the commonest, superficial, near the anal verge), ischiorectal (ischioanal — larger, lateral), intersphincteric, and supralevator (pelvirectal — deep). The deeper the abscess, the fewer the external signs and the more prominent the systemic upset.
CLINICAL FEATURES
A superficial (perianal) abscess causes severe, throbbing, constant perianal pain (worse on sitting and defecation), with a tender, red, hot, fluctuant swelling at the anal margin, often with fever. A deep (ischiorectal or supralevator) abscess may have few external signs but marked systemic features — fever, malaise and deep-seated pain — so a high index of suspicion is needed. Risk is increased by diabetes, immunosuppression and Crohn's disease.
MANAGEMENT
The treatment is urgent surgical incision and drainage — pus must be let out, and antibiotics alone are inadequate (they are an adjunct for diabetics, the immunosuppressed, or associated cellulitis). At drainage the cavity is examined for an underlying fistula, and pus is sent for culture. The important complications are fistula-in-ano (a common sequel), recurrence, and — dangerously in diabetics — Fournier's gangrene (necrotising infection) and generalised sepsis.
💡CLINICAL PEARL: Two teaching points: an anorectal abscess arises from an infected anal gland (cryptoglandular) and is treated by prompt incision and drainage — never antibiotics alone. Remember it commonly leaves a fistula-in-ano, and always beware Fournier's gangrene in a diabetic with perianal sepsis and pain out of proportion to the signs.A NOTE ON THE HORSESHOE ABSCESS
A dangerous pattern worth knowing is the horseshoe abscess, in which infection in the deep post-anal space spreads laterally on both sides to form a horseshoe-shaped collection encircling the anus through both ischiorectal fossae. It can be extensive with relatively few external signs, and requires thorough drainage of all its extensions. Recognising that a deep post-anal infection can track widely explains why deep abscesses need careful assessment (and often imaging) rather than a single small incision.
A NOTE ON DRAINAGE TECHNIQUE
The technique of drainage reflects the underlying principle. The abscess is deroofed with an adequate incision placed as close to the anal verge as possible (to shorten any resulting fistula track), loculations are broken down, and the cavity is left open to heal by secondary intention (packing or a drain) rather than closed. A cautious search for an internal opening is made, but aggressive probing is avoided in the acute phase as it can create false tracks; a fistula, if present, is dealt with later.
A NOTE ON DIABETES & IMMUNOSUPPRESSION
Special caution applies to the diabetic and immunosuppressed patient with anorectal sepsis. In these patients infection can be more extensive, more deep-seated, and progress more rapidly — with a real risk of necrotising infection (Fournier's gangrene) — while the external signs may be deceptively modest. Such patients warrant early, thorough surgical assessment (often under anaesthesia), a lower threshold for imaging and antibiotics, and close monitoring, because a delayed or inadequate drainage can be rapidly life-threatening in this group.
A NOTE ON RECURRENCE & THE UNDERLYING FISTULA
A frequently-examined point is why anorectal abscesses recur. Because the abscess originates from an infected anal gland, simple drainage of the pus may leave the underlying source (the gland) and its track intact, so infection re-accumulates — and roughly a third of abscesses are followed by a persistent fistula-in-ano. This is why patients are counselled that a further procedure may be needed, and why the abscess and its potential fistula are conceptually two phases of the same cryptoglandular disease process rather than separate problems.
💊KEY POINTS / NUMBERS (viva)- Cryptoglandular origin: infected anal glands at the dentate line → spread to spaces; perianal type commonest.
- Treat by URGENT incision and drainage (antibiotics alone inadequate; adjunct in diabetes/immunosuppression/cellulitis).
- Common sequel = fistula-in-ano; beware Fournier's gangrene (necrotising) in diabetics.
🔑KEY POINTS TO REMEMBER- Anorectal abscess = pus in a perianal/pararectal space, usually from infected anal glands (cryptoglandular).
- Types by space: perianal (commonest, superficial), ischiorectal, intersphincteric, supralevator (deep → fewer external signs, more systemic).
- Severe throbbing perianal pain, tender red fluctuant swelling, fever; risk with diabetes, immunosuppression, Crohn's.
- Treat by URGENT incision and drainage (not antibiotics alone); antibiotics adjunctive in diabetes/immunosuppression/cellulitis.
- Complications: fistula-in-ano (common), recurrence, Fournier's gangrene (diabetics), sepsis.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
A fistula is an abnormal, epithelialised track connecting two epithelial surfaces. A fistula-in-ano connects the anal canal (an internal opening, usually at the dentate line) to the perianal skin (an external opening). It usually represents the chronic phase of an anorectal abscess — after the abscess drains, a persistent track remains, keeping the cycle of infection going. The central challenge in treatment is to cure the fistula while preserving the anal sphincter and continence.
AETIOLOGY
The great majority are cryptoglandular (following an abscess); other causes are Crohn's disease, tuberculosis, malignancy and previous radiation, which should be suspected in atypical, multiple or recurrent fistulas.
CLASSIFICATION (PARKS)
The Parks classification describes the track's relation to the sphincters: intersphincteric (commonest), transsphincteric, suprasphincteric, and extrasphincteric. Practically, fistulas are also grouped as 'low/simple' (crossing little sphincter — safe to lay open) or 'high/complex' (crossing much sphincter — where laying open would threaten continence).
GOODSALL'S RULE
Goodsall's rule helps predict the internal opening from the external one. If the external opening lies anterior to an imaginary transverse line across the anus, the track usually runs in a straight, radial line to the nearest point in the anal canal; if it lies posterior, the track usually curves to open in the posterior midline.
CLINICAL FEATURES, INVESTIGATION & MANAGEMENT
Patients have persistent or recurrent perianal discharge (pus or blood), recurrent abscesses and discomfort, often with a palpable track or a visible external opening. Assessment uses examination, gentle probing and proctoscopy, with MRI or endoanal ultrasound for complex or recurrent fistulas. Treatment depends on the anatomy:
- Fistulotomy (laying the track open) — for low/simple fistulas; the laid-open track heals by secondary intention.
- Seton (a thread through the track) — for high/complex fistulas, to drain and gradually manage the track while protecting the sphincter (cutting, loose or draining setons).
- Sphincter-preserving techniques — advancement flap, the LIFT procedure, and fibrin glue/plug — for complex fistulas.
The guiding principle throughout is to eradicate the fistula while preserving continence.
💡CLINICAL PEARL: Key facts: a fistula-in-ano usually follows an anorectal abscess (cryptoglandular); Goodsall's rule predicts the internal opening, and the Parks classification relates the track to the sphincters. Treat low fistulas by fistulotomy and high fistulas with a seton (to preserve continence); suspect Crohn's or TB in atypical cases.WHY CONTINENCE IS THE KEY CONCERN
The reason fistula surgery is more nuanced than simply cutting the track open is the anal sphincter mechanism. A track that crosses a large proportion of the sphincter (a 'high' fistula) cannot be laid open without dividing enough muscle to cause incontinence. This is the whole rationale for the seton and the sphincter-preserving procedures: they allow the fistula to be treated while keeping the sphincter intact. Judging how much sphincter a track crosses — clinically and on MRI — is therefore the crucial decision in planning surgery.
HOW A SETON WORKS
The seton deserves explanation as it is frequently asked about. A thread is passed along the fistula track and tied. A loose (draining) seton keeps the track open so it drains and settles, preventing recurrent abscesses while preserving the sphincter. A cutting seton is gradually tightened so that it slowly divides the sphincter muscle while fibrosis forms behind it, so the muscle ends do not spring apart — allowing the track to be cut through over time with less risk of incontinence than a single division. This staged approach is the classic solution to the high fistula.
A NOTE ON CROHN'S FISTULAS
Crohn's disease is an important cause of complex, recurrent and multiple perianal fistulas, and it changes management. Crohn's fistulas are often high, branching and associated with proctitis, and aggressive fistulotomy risks both poor healing and incontinence. Management therefore combines medical therapy (including anti-TNF agents such as infliximab) with conservative surgery (long-term draining setons) rather than attempts at cure by laying open. Suspecting Crohn's in any patient with atypical or recurrent perianal fistulas is a key clinical point.
💊KEY POINTS / NUMBERS (viva)- Usually follows an anorectal abscess (cryptoglandular); atypical/recurrent → Crohn's, TB, malignancy.
- Goodsall's rule: anterior external opening → straight radial track; posterior → curved track to posterior midline.
- Low/simple → fistulotomy (lay open); high/complex → seton or sphincter-preserving techniques (preserve continence).
🔑KEY POINTS TO REMEMBER- Fistula-in-ano = epithelialised track from the anal canal (internal opening at dentate line) to perianal skin; usually post-abscess (cryptoglandular).
- Parks classification: intersphincteric (commonest), transsphincteric, suprasphincteric, extrasphincteric; low/simple vs high/complex.
- Goodsall's rule predicts the internal opening (anterior = straight/radial; posterior = curved to posterior midline).
- Persistent/recurrent perianal discharge and abscesses; MRI/endoanal ultrasound for complex/recurrent.
- Fistulotomy for low fistulas; seton or sphincter-preserving techniques for high fistulas (preserve continence); suspect Crohn's/TB if atypical.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
Rectal prolapse is the protrusion of the rectum through the anus. The essential distinction — which determines both the causes and the treatment — is between a partial (mucosal) prolapse, in which only the rectal mucosa protrudes, and a complete (full-thickness) prolapse (procidentia), in which the entire thickness of the rectal wall comes down through the anus.
TYPES
- Partial (mucosal) prolapse — only the mucosa protrudes, showing radial folds; common in children and the elderly.
- Complete (full-thickness) prolapse — procidentia — all layers of the rectal wall protrude, showing concentric (circular) rings of mucosa; typically in elderly women.
- Internal intussusception — an 'occult' prolapse that does not appear externally.
AETIOLOGY
In children, prolapse is associated with straining, diarrhoea, malnutrition and cystic fibrosis, and is usually self-limiting. In adults, it results from a weak pelvic floor and anal sphincter, chronic straining, multiparity, and increasing age (hence its predominance in elderly women), sometimes with neurological disease.
CLINICAL FEATURES
Patients describe a mass protruding on defecation or straining (which reduces spontaneously or must be pushed back), with mucus discharge, bleeding, faecal incontinence (from a stretched sphincter), constipation, and ulceration of the exposed mucosa. On examination the patient is asked to strain to demonstrate the prolapse, and concentric rings (complete) are distinguished from radial folds (partial); digital examination assesses sphincter tone.
MANAGEMENT
- Children — usually conservative: treat the underlying cause (constipation, nutrition, cystic fibrosis), with digital reduction; it typically resolves.
- Adults — surgical repair, by an abdominal approach (rectopexy — fixing the rectum to the sacrum, ± resection, often laparoscopic) for fitter patients, or a perineal approach (Delorme's or Altemeier's procedure) for the frail elderly; constipation is also treated.
💡CLINICAL PEARL: The core distinction: partial (mucosal) prolapse shows radial folds and occurs in children and the elderly, while complete (full-thickness) procidentia shows concentric rings and occurs in elderly women. Children are managed conservatively (treat the cause), whereas adults usually need surgery — rectopexy (abdominal) or a perineal procedure (Delorme's/Altemeier's) for the frail.A NOTE ON ASSOCIATED PELVIC-FLOOR PROBLEMS
Full-thickness rectal prolapse in adults is often the visible tip of a wider pelvic-floor weakness, and may coexist with other prolapses (such as a cystocele or uterine/vaginal prolapse) and with faecal incontinence or obstructed defecation. This is why assessment may include examination of the whole pelvic floor and investigations such as defecating proctography or anorectal physiology, and why management sometimes involves a coordinated approach to several pelvic-floor problems rather than the rectum alone.
ABDOMINAL VS PERINEAL REPAIR
The choice between abdominal and perineal repair is a practical, examinable decision. Abdominal rectopexy (increasingly laparoscopic) fixes the rectum to the sacrum and has the lowest recurrence rate, making it preferred in fitter patients. Perineal procedures (Delorme's, Altemeier's) avoid an abdominal operation and general anaesthetic stress, so they suit the frail, elderly or high-risk patient, but have a somewhat higher recurrence rate. The decision balances durability against operative fitness.
A NOTE ON THE SOLITARY RECTAL ULCER SYNDROME
Related to the straining and internal intussusception that underlie prolapse is the solitary rectal ulcer syndrome — a condition in which chronic straining and internal prolapse cause an ulcer (or ulcers) on the anterior rectal wall, presenting with bleeding, mucus, straining and a sense of incomplete evacuation. It is important because it can be mistaken for malignancy or inflammatory bowel disease and needs biopsy to confirm; treatment addresses the underlying disordered defecation (biofeedback, bulking agents) rather than the ulcer itself.
A NOTE ON REDUCING AN IRREDUCIBLE PROLAPSE
An acute clinical scenario is the irreducible (incarcerated) full-thickness prolapse, in which the protruded rectum becomes oedematous and cannot be reduced, risking ulceration and, rarely, strangulation. Initial management is gentle manual reduction aided by measures that reduce the oedema (such as applying granulated sugar, which draws out fluid osmotically, then steady pressure). If reduction fails or the bowel is compromised, emergency surgery is required. Recognising and promptly reducing an incarcerated prolapse prevents progression to strangulation.
💊KEY POINTS / NUMBERS (viva)- Partial (mucosal, radial folds — children/elderly) vs complete (full-thickness procidentia, concentric rings — elderly women).
- Children: conservative (treat constipation, nutrition, cystic fibrosis); usually resolves.
- Adults: surgery — abdominal rectopexy (± resection) or perineal Delorme's/Altemeier's for the frail.
🔑KEY POINTS TO REMEMBER- Rectal prolapse = protrusion of the rectum through the anus; partial (mucosal only) vs complete (full-thickness, procidentia).
- Partial: radial folds, children/elderly; complete: concentric rings, elderly women; also occult internal intussusception.
- Children: straining, diarrhoea, malnutrition, cystic fibrosis; adults: weak pelvic floor/sphincter, chronic straining, multiparity, age.
- Protruding mass on straining, mucus, bleeding, incontinence, constipation, ulceration; ask patient to strain to demonstrate.
- Children conservative (treat cause); adults surgery — abdominal rectopexy or perineal Delorme's/Altemeier's for the frail.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
A pilonidal sinus is a sinus (a blind-ending track) in the natal cleft over the sacrococcygeal region, containing hair and debris — the name means 'nest of hair'. It develops when loose hairs are driven into the skin of the cleft, provoking a foreign-body reaction and recurrent infection. It classically affects young, hirsute men who sit for long periods (historically called 'jeep disease' in wartime drivers).
CLINICAL FEATURES
It presents with one or more midline pits in the natal cleft (often with a tuft of hair), a discharge, discomfort, and recurrent painful abscesses when the sinus becomes infected. An acutely infected pilonidal sinus forms a tender, red, fluctuant swelling just off the midline.
MANAGEMENT
General measures are meticulous hygiene and hair removal from the cleft. An acute abscess is treated by incision and drainage. Definitive treatment of the chronic sinus is excision of the sinus tracks, using various techniques — excision with primary or secondary (open) healing, or a flattening flap procedure (Karydakis or Limberg flap) that moves the scar off the midline and reduces recurrence. Recurrence is common, which is why cleft-flattening techniques and hair control are emphasised.
A NOTE ON PREVENTING RECURRENCE
Because pilonidal disease is notorious for recurrence, prevention is emphasised alongside surgery. Measures include keeping the natal cleft clean and dry, regular hair removal (shaving or depilation) from the area, and weight management. The modern surgical preference for off-midline and cleft-flattening techniques (such as the Karydakis or Limberg flap) reflects the understanding that midline wounds in the depth of the cleft heal poorly and recur — flattening the cleft and moving the scar laterally addresses the underlying mechanism.
THE BOTTOM LINE
A pilonidal sinus is a hair-containing sinus of the natal cleft in young hirsute men, treated by hygiene and hair control, incision and drainage of any abscess, and excision or a flattening flap for the chronic sinus, with recurrence common.
A NOTE ON THE MANAGEMENT OF THE ACUTE ABSCESS
When a pilonidal sinus presents as an acute abscess, the priority is simple incision and drainage under local (or general) anaesthetic to relieve pain and control infection — definitive excision of the sinus tracks is deferred to a later, quiescent stage. This two-stage approach mirrors the general surgical rule of not performing definitive reconstructive surgery in acutely infected tissue, and it gives the best chance of a durable result once the inflammation has fully settled and the anatomy of the tracks can be assessed.
🔑KEY POINTS TO REMEMBER- Pilonidal sinus = hair-containing sinus in the natal cleft (sacrococcygeal); from ingrowing hair → foreign-body reaction/infection.
- Young hirsute men who sit a lot ('jeep disease'); midline pits with hair, discharge, recurrent abscess.
- Hygiene + hair removal; acute abscess → incision and drainage.
- Definitive: excision of tracks (primary/secondary closure) or flattening flap (Karydakis/Limberg) to reduce recurrence; recurrence common.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
Carcinoma of the anal canal is important partly because it differs from the cancers just above it: whereas rectal and colonic cancers are adenocarcinomas, anal canal cancer is usually a squamous cell carcinoma (reflecting the squamous lining of the lower canal). It is strongly associated with human papillomavirus (HPV, types 16/18), anoreceptive intercourse, HIV and immunosuppression, and chronic irritation.
CLINICAL FEATURES & SPREAD
It presents with anal bleeding, pain, a mass or ulcer, pruritus, tenesmus, a change in bowel habit, and eventually incontinence. Its lymphatic spread depends on the level: lesions below the dentate line drain to the inguinal lymph nodes, while those above drain to the pelvic/mesorectal nodes — so the groins must be examined.
INVESTIGATION & MANAGEMENT
Diagnosis is by examination and biopsy, with MRI and assessment of the lymph nodes for staging. The key management point is that, unlike rectal cancer, the first-line treatment is chemoradiotherapy (the Nigro regimen — 5-fluorouracil and mitomycin with radiotherapy), which is sphincter-preserving and often curative. Radical surgery (abdominoperineal resection) is reserved for residual or recurrent disease.
A NOTE ON THE CONTRAST WITH RECTAL CANCER
The contrast with rectal cancer is instructive and examinable. Rectal adenocarcinoma is treated primarily by surgery (with neoadjuvant chemoradiotherapy for advanced disease), whereas anal squamous cell carcinoma is treated primarily by chemoradiotherapy (Nigro regimen), with surgery held in reserve. This difference — driven by the different histology (adenocarcinoma vs squamous) and the desire to preserve the sphincter — is a key point, as is the different lymphatic drainage (inguinal nodes for lower anal lesions).
THE BOTTOM LINE
Anal canal carcinoma is usually an HPV-related squamous cell carcinoma treated first-line by sphincter-preserving chemoradiotherapy (Nigro regimen), with surgery reserved for residual or recurrent disease — contrasting with the surgical treatment of rectal adenocarcinoma.
A NOTE ON SCREENING & PREVENTION
Because anal cancer is strongly linked to HPV, there is an important preventive dimension: HPV vaccination reduces the risk of the disease, and surveillance (anal cytology/examination) of high-risk groups — particularly HIV-positive individuals and other immunosuppressed patients — allows detection of premalignant anal intraepithelial neoplasia (AIN) before invasive cancer develops. This parallels cervical screening and reflects the shared HPV aetiology, making prevention and early detection a genuine part of managing anal cancer risk.
A NOTE ON THE INGUINAL NODES
A practical examination point is the importance of the inguinal lymph nodes in anal cancer. Because lesions below the dentate line drain to the groin, palpable inguinal lymphadenopathy may represent nodal metastasis and must be assessed (by examination, imaging and, if needed, biopsy) as it affects staging and the radiotherapy field. This differs from rectal cancer, which spreads to mesorectal and pelvic nodes, and it is why the groins are always examined in a patient with a suspected anal canal tumour.
🔑KEY POINTS TO REMEMBER- Anal canal carcinoma = usually squamous cell carcinoma (vs adenocarcinoma of rectum/colon); linked to HPV (16/18), anoreceptive intercourse, HIV/immunosuppression.
- Bleeding, pain, mass/ulcer, pruritus, tenesmus, incontinence; below dentate line → inguinal nodes, above → pelvic nodes.
- Diagnose by biopsy + MRI/node assessment.
- First-line = chemoradiotherapy (Nigro regimen: 5-FU + mitomycin + radiotherapy), sphincter-preserving; surgery (APR) for residual/recurrent disease.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
A perianal haematoma — also called a thrombosed external pile or 'acute painful pile' — is a small subcutaneous haematoma at the anal margin, caused by the rupture (and thrombosis) of a small vein in the external haemorrhoidal plexus, typically after an episode of straining. Despite its alarming pain, it is a benign, self-limiting condition.
CLINICAL FEATURES
It presents as a sudden, painful, tense, tender, bluish-purple lump at the anal verge — the pain is caused by the tension of the clot within the sensitive perianal skin. It is easily recognised on inspection as a smooth, dark, 'dome-shaped' swelling at the anal margin.
MANAGEMENT
The natural history is spontaneous resolution over a few days to weeks as the clot is absorbed. Management depends on timing: if the patient presents late or the pain is already easing, conservative treatment (analgesia, warm sitz baths, stool softeners) is sufficient; if the patient presents early (within about 48–72 hours) with severe pain, evacuation of the clot under local anaesthesia gives rapid relief.
A NOTE ON DISTINGUISHING IT FROM A PROLAPSED PILE
It is useful to distinguish a perianal haematoma from a prolapsed, thrombosed internal haemorrhoid. The perianal haematoma is a discrete, dark, smooth lump at the anal verge arising from the external plexus, whereas a prolapsed thrombosed internal pile is a larger, more circumferential, oedematous mass originating above the dentate line. The distinction matters because the small perianal haematoma is easily and safely evacuated under local anaesthetic when acute, whereas extensive thrombosed prolapsing piles are usually managed conservatively first.
THE BOTTOM LINE
A perianal haematoma is a benign, self-limiting thrombosed external vein at the anal verge, managed conservatively when settling or by clot evacuation under local anaesthetic when acutely painful.
A NOTE ON THE NATURAL HISTORY
Understanding the natural history reassures both clinician and patient: left alone, the clot in a perianal haematoma gradually organises and is reabsorbed over one to two weeks, occasionally leaving a small residual skin tag. Because the condition is self-limiting, the decision to intervene rests entirely on the severity and timing of the pain — early evacuation for severe acute pain, conservative management otherwise. Explaining this benign course is itself a valuable part of treatment, preventing unnecessary anxiety about the alarming-looking lump.
🔑KEY POINTS TO REMEMBER- Perianal haematoma ('thrombosed external pile', 'acute painful pile') = subcutaneous haematoma at the anal margin from a ruptured/thrombosed perianal vein, usually after straining.
- Sudden, painful, tense, tender, bluish-purple lump at the anal verge.
- Self-limiting (resolves over days to weeks).
- Conservative (analgesia, sitz baths) if presenting late; evacuation of clot under local anaesthesia if early (<48–72 h) with severe pain.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
Pruritus ani is itching around the anus, a common and often distressing complaint. It is best approached by remembering that it is usually a symptom of an underlying cause rather than a disease in itself, and that a self-perpetuating itch–scratch cycle (scratching damages the skin, which itches more) keeps it going once established.
CAUSES
The causes are grouped as: idiopathic (the commonest); local anorectal conditions (haemorrhoids, fissure, fistula, skin tags, and discharge or leakage causing moisture, plus poor or over-zealous hygiene); infective/dermatological (threadworms — especially in children, fungal/candidal infection, and eczema, psoriasis or contact dermatitis); and systemic disease (diabetes, obstructive jaundice, and occasionally lymphoma).
MANAGEMENT
Management is to identify and treat any underlying cause and to break the itch–scratch cycle with good hygiene advice — keep the area clean and dry, avoid soap, scratching and irritants, and avoid excess moisture — together with appropriate topical treatment. It is important to exclude threadworm (in children), diabetes, and any anorectal malignancy before labelling it idiopathic.
A NOTE ON THREADWORM IN CHILDREN
A specific and common cause worth highlighting is threadworm (Enterobius vermicularis) infestation, especially in children, which classically causes nocturnal perianal itching (the female worm emerges at night to lay eggs). It is diagnosed by the 'sticky-tape' test (applying tape to the perianal skin in the morning to collect eggs) and treated with an anthelmintic (mebendazole/albendazole), treating the whole household and reinforcing hygiene. Considering threadworm is essential in any child with pruritus ani.
THE BOTTOM LINE
Pruritus ani is perianal itching that is usually secondary to a local, dermatological or systemic cause and maintained by an itch–scratch cycle, managed by treating the cause and strict hygiene, having excluded threadworm, diabetes and malignancy.
A NOTE ON THE ROLE OF HYGIENE PRACTICES
A subtle but important point is that both too little and too much hygiene can perpetuate pruritus ani. Inadequate cleaning leaves irritant faecal residue, while over-washing with soap, vigorous wiping, or the use of scented products and moist wipes strips and irritates the delicate perianal skin. The advice is therefore for gentle cleaning, thorough drying, avoidance of soaps and irritants, and breaking the habit of scratching — a measured middle path that, together with treating any underlying cause, resolves most cases.
A NOTE ON WHEN TO INVESTIGATE FURTHER
While most pruritus ani is benign and idiopathic, certain features should prompt further investigation rather than symptomatic treatment: persistent symptoms despite good hygiene, associated bleeding or a palpable lesion, or systemic features (such as weight loss or the pruritus of jaundice or diabetes). In these situations a careful anorectal examination, proctoscopy and relevant blood tests are warranted to exclude an underlying anorectal or systemic disease, ensuring a treatable or serious cause is not overlooked behind a 'simple itch'.
🔑KEY POINTS TO REMEMBER- Pruritus ani = perianal itching; usually a symptom of an underlying cause, maintained by an itch–scratch cycle.
- Causes: idiopathic (commonest); local (haemorrhoids, fissure, fistula, tags, moisture, hygiene); infective/skin (threadworm, candida, eczema, psoriasis); systemic (diabetes, jaundice, lymphoma).
- Treat the underlying cause; hygiene advice (keep clean and dry, avoid soap/scratching/irritants/moisture) + topical treatment.
- Exclude threadworm (children), diabetes and malignancy before labelling idiopathic.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
Rectal (and colonic) polyps are protruding growths arising from the mucosa. Their great importance is that some are premalignant, so identifying and removing them can prevent colorectal cancer. The key is to distinguish neoplastic (adenomatous) polyps from non-neoplastic ones.
TYPES
- Neoplastic (adenomatous) polyps — tubular, tubulovillous or villous — are premalignant and give rise to cancer through the adenoma–carcinoma sequence; the villous adenoma carries the highest malignant risk and may secrete mucus, causing mucoid diarrhoea and hypokalaemia.
- Non-neoplastic polyps — hyperplastic, inflammatory, and hamartomatous (juvenile polyps, Peutz–Jeghers) — have low or no malignant potential.
CLINICAL FEATURES & MANAGEMENT
Polyps may be asymptomatic or cause rectal bleeding, mucus discharge, or prolapse of the polyp. They are diagnosed and treated at colonoscopy, which allows both biopsy and polypectomy. Because adenomas are premalignant, all such polyps are removed and sent for histology, and patients are entered into a surveillance programme — the basis of colorectal cancer prevention.
A NOTE ON POLYPOSIS SYNDROMES
Beyond isolated polyps, certain inherited polyposis syndromes are high-yield. Familial adenomatous polyposis (FAP) — hundreds to thousands of adenomatous polyps carpeting the colon — carries a near-100% risk of colorectal cancer if untreated, requiring prophylactic colectomy. Peutz–Jeghers syndrome features hamartomatous polyps with mucocutaneous pigmentation. Recognising that multiple polyps or a strong family history may indicate such a syndrome (needing genetic counselling and surveillance) is an important extension of the polyp topic.
THE BOTTOM LINE
Rectal polyps matter because adenomatous (neoplastic) polyps are premalignant via the adenoma–carcinoma sequence, so all are removed at colonoscopy with histology and surveillance, and multiple polyps may indicate a polyposis syndrome.
A NOTE ON THE ADENOMA–CARCINOMA SEQUENCE
The concept underpinning polyp management is the adenoma–carcinoma sequence — the stepwise accumulation of genetic mutations by which a normal mucosa progresses through adenoma → dysplasia → invasive carcinoma over years. This slow progression is precisely what makes colonoscopic detection and removal of adenomas so effective at preventing colorectal cancer, and it is the rationale for both screening programmes and post-polypectomy surveillance. Larger, villous and more dysplastic adenomas carry the greatest risk and warrant the closest follow-up.
A NOTE ON THE MALIGNANT POTENTIAL BY TYPE
It is worth being precise about which polyps carry risk. Villous adenomas have the highest malignant potential (greater than tubular adenomas), and risk also rises with increasing size (especially >1 cm), the degree of dysplasia, and the number of polyps. Hyperplastic polyps, by contrast, are generally benign. This gradation is why the histology of every removed polyp matters, and why patients with larger, villous or numerous adenomas are placed on shorter-interval surveillance than those with small, single tubular adenomas.
🔑KEY POINTS TO REMEMBER- Rectal/colonic polyps = mucosal protrusions; some are premalignant, so removal prevents colorectal cancer.
- Neoplastic (adenomatous — tubular/villous): premalignant (adenoma–carcinoma sequence); villous adenoma = highest risk, may cause mucoid diarrhoea + hypokalaemia.
- Non-neoplastic: hyperplastic, inflammatory, hamartomatous (juvenile, Peutz–Jeghers).
- Present with bleeding, mucus, prolapse; colonoscopy for diagnosis + polypectomy + histology; remove all adenomas and enter surveillance.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
Fournier's gangrene is a necrotising fasciitis of the perineum, scrotum and genitalia — a life-threatening surgical emergency. It is a polymicrobial (synergistic aerobic and anaerobic) infection that spreads with alarming speed along the fascial planes, causing progressive gangrene of the overlying skin and soft tissue.
RISK FACTORS & CLINICAL FEATURES
The overwhelming risk factor is diabetes mellitus; others include immunosuppression, alcoholism, and local perianal or urological infection. It presents with severe pain (characteristically out of proportion to the visible signs), swelling and redness, rapidly progressing to skin necrosis, crepitus (gas in the tissues), a foul smell, and marked systemic toxicity (fever, tachycardia, septic shock).
MANAGEMENT — AN EMERGENCY
Survival depends on speed. Management combines aggressive resuscitation, broad-spectrum intravenous antibiotics, and — the mainstay — urgent, radical surgical debridement of all necrotic tissue, which frequently must be repeated as the infection is controlled. Despite treatment, mortality remains high, underscoring the need for early recognition — particularly of 'pain out of proportion' in a diabetic patient — and immediate surgery.
💡CLINICAL PEARL: Recognise it early: severe perianal/genital pain out of proportion to the signs, with skin necrosis, crepitus and systemic toxicity, especially in a diabetic, is Fournier's gangrene until proven otherwise. It is treated with resuscitation, antibiotics and immediate radical surgical debridement — delay costs lives.A NOTE ON EARLY RECOGNITION
The feature that most often allows a life-saving early diagnosis is pain out of proportion to the visible signs: a patient (typically diabetic) who is systemically unwell with severe perineal/scrotal pain but only modest early skin changes should raise immediate suspicion of a necrotising infection. Later signs — skin discolouration, blistering, crepitus and a foul odour — indicate advanced disease. Because delay dramatically worsens outcome, a low threshold for urgent surgical exploration is the single most important principle.
THE BOTTOM LINE
Fournier's gangrene is a rapidly spreading necrotising fasciitis of the perineum, usually in diabetics, recognised by pain out of proportion and systemic toxicity, and treated as an emergency with resuscitation, antibiotics and urgent radical debridement.
A NOTE ON RECONSTRUCTION AFTER DEBRIDEMENT
An often-forgotten aspect is what follows the life-saving debridement: patients who survive Fournier's gangrene are frequently left with large soft-tissue defects of the perineum, scrotum and genitalia that require reconstructive surgery (skin grafts, flaps, and sometimes staged repair) once the infection is controlled and the wounds are clean. Some also need diversion (a colostomy or suprapubic catheter) to protect the healing area. This reconstructive burden underscores that Fournier's gangrene is a major, life-changing illness even in survivors.
🔑KEY POINTS TO REMEMBER- Fournier's gangrene = necrotising fasciitis of the perineum/scrotum/genitalia; polymicrobial synergistic infection; surgical emergency.
- Major risk factor = diabetes (also immunosuppression, alcohol, perianal/urological infection).
- Severe pain out of proportion, swelling, redness → necrosis, crepitus, foul smell, systemic toxicity/septic shock.
- Treat with aggressive resuscitation + broad-spectrum antibiotics + urgent radical (repeated) surgical debridement; high mortality.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
Imperforate anus (anorectal malformation) is a congenital abnormality in which the normal anal opening is absent or abnormally formed, resulting from failure of normal development of the anorectum. It is an important neonatal surgical condition, recognised at the first newborn examination, and it exists as a spectrum of severity.
CLASSIFICATION — LOW VS HIGH
The malformations are broadly divided by the level at which the rectum ends relative to the levator ani (puborectalis):
- Low anomalies — the rectum has descended through the levator (e.g. an anal membrane, anal stenosis, or an ectopic/covered anus); generally simpler to correct.
- High anomalies — the rectum ends above the levator, often with a fistula to the urethra or bladder (in boys) or the vagina (in girls); more complex.
It is often part of the VACTERL association of anomalies, so a search for other defects is needed.
CLINICAL FEATURES & MANAGEMENT
At birth there is no anal opening, failure to pass meconium, and progressive abdominal distension; passage of meconium in the urine indicates a fistula. Assessment uses examination, an invertogram/X-ray (to judge the level) and ultrasound (for associated anomalies). Management depends on the level: a low lesion is treated by anoplasty, while a high lesion is managed by an initial defunctioning colostomy, followed by a definitive pull-through (posterior sagittal anorectoplasty, PSARP), and later closure of the colostomy.
A NOTE ON THE IMPORTANCE OF ASSOCIATED ANOMALIES
A key management point is the frequent association with other congenital anomalies, captured in the VACTERL acronym — Vertebral, Anorectal, Cardiac, Tracheo-Esophageal, Renal and Limb defects. Because these often occur together, a neonate with an anorectal malformation should be screened for the other components (with echocardiography, renal ultrasound and spinal imaging). Overlooking a serious associated cardiac or renal anomaly can be more dangerous than the anorectal lesion itself, which is why systematic screening is emphasised.
THE BOTTOM LINE
Imperforate anus is a congenital anorectal malformation (low or high, often with a fistula) presenting in the newborn, assessed for its level and for VACTERL anomalies, and treated by anoplasty (low) or colostomy and later pull-through/PSARP (high).
A NOTE ON EARLY RECOGNITION AT BIRTH
The importance of the routine newborn examination cannot be overstated: imperforate anus should be detected at the first inspection of the perineum after birth, before feeding is established and distension develops. Early recognition allows timely referral, prevents the complications of a missed obstruction (distension, vomiting, aspiration, perforation), and gives time to screen for associated anomalies. A simple, careful look at the anus in every newborn is therefore the key to a good outcome in this condition.
🔑KEY POINTS TO REMEMBER- Imperforate anus (anorectal malformation) = congenital absence/abnormality of the anal opening; neonatal surgical condition.
- Low (rectum through levator — anal membrane/stenosis/ectopic anus) vs high (rectum above levator, often with fistula to urethra/bladder/vagina); part of VACTERL association.
- Presents at birth: no anal opening, no meconium passed, abdominal distension; meconium in urine = fistula.
- Assess with invertogram/X-ray + ultrasound; low → anoplasty; high → colostomy → definitive pull-through (PSARP) → colostomy closure.
📚SOURCES: Bailey & Love's Short Practice of Surgery.