Hemoroid

01Pathophysiology

The anal canal contains three submucosal vascular cushions located at the left lateral, right anterior, and right posterior positions (classically described at the 3, 7, and 11 o'clock positions in the lithotomy view). These cushions are composed of arteriovenous communications fed by terminal branches of the superior rectal artery (internal haemorrhoidal plexus) and the inferior rectal artery (external haemorrhoidal plexus), supported by smooth muscle fibres known as Treitz's muscle and connective tissue of the Park ligament.
Haemorrhoids develop when repeated straining, increased intra-abdominal pressure, or chronic constipation leads to engorgement of the vascular plexus and progressive stretching and fragmentation of the supporting connective tissue. This allows the cushions to slide downward (the "sliding anal lining" theory). The key anatomical landmark is the dentate (pectinate) line, which divides the anal canal into two zones with different embryological origins, nerve supplies, and venous drainage.
Internal haemorrhoids arise from the superior haemorrhoidal plexus above the dentate line. Because this area is lined by columnar epithelium innervated by visceral autonomic nerves, internal haemorrhoids are typically painless. They bleed because the thin mucosa overlying engorged arterioles is easily traumatized by passing stool.
External haemorrhoids arise from the inferior haemorrhoidal plexus below the dentate line. This region is covered by anoderm (modified squamous epithelium) innervated by somatic sensory nerves (inferior rectal nerve, branch of the pudendal nerve). This is why external haemorrhoids, and especially thrombosed ones, are intensely painful.
The classic exam connection: painless bleeding points to internal haemorrhoids (visceral innervation above the dentate line); painful perianal mass points to external or thrombosed haemorrhoids (somatic innervation below the dentate line). Portal hypertension does not directly cause haemorrhoids but can contribute to engorgement of anorectal varices, which is a distinct entity that should not be confused with haemorrhoids on exam vignettes.

02Classification and Clinical Manifestation

Internal Haemorrhoid Grading (Goligher Classification)

External Haemorrhoid Presentations

03Diagnostic Workup

The diagnosis of haemorrhoids is fundamentally clinical. The best initial test for a patient presenting with painless rectal bleeding and suspected internal haemorrhoids is anoscopy, which allows direct visualization of the anal canal and the vascular cushions. A DRE should be performed first but internal haemorrhoids are soft and typically not palpable, so a normal DRE does not exclude the diagnosis.
There is no confirmatory "gold standard" laboratory test for haemorrhoids. The gold standard is direct visualization via anoscopy (for haemorrhoids themselves) or colonoscopy (to rule out other causes of rectal bleeding). In any patient with alarm features (age over 45 with new-onset bleeding, unexplained iron-deficiency anaemia, weight loss, change in stool calibre, or family history of colorectal malignancy), a colonoscopy is mandatory before attributing symptoms to haemorrhoids alone. This is a heavily tested concept: do not diagnose haemorrhoids and stop the workup in a patient who has red-flag symptoms for colorectal cancer.
A CBC is useful when the history suggests chronic or recurrent bleeding to evaluate for iron-deficiency anaemia ($\downarrow \backslash downarrow$ haemoglobin, $\downarrow \backslash downarrow$ MCV, $\downarrow \backslash downarrow$ ferritin, $\uparrow \backslash uparrow$ TIBC).

04Management and Treatment

Conservative management is the foundation for Grade I and early Grade II disease. The single most important intervention is increasing dietary fibre to 25 to 30 grams per day (or supplementation with psyllium husk 1 tablespoon in 240 mL water, one to three times daily). This softens stool, reduces straining, and decreases recurrence. Sitz baths (warm water immersion of the perineum for 10 to 15 minutes, two to three times daily) provide symptomatic relief. Topical agents containing hydrocortisone (1% to 2.5%) can reduce inflammation but should be limited to short courses (no more than 7 to 10 days) to avoid perianal skin atrophy.
Rubber band ligation is the most commonly tested office-based procedure. The band is placed at the base of the internal haemorrhoid above the dentate line (critical point: banding below the dentate line on somatic-innervated tissue causes severe pain and is a contraindication). It works by strangulating the tissue, which sloughs off in 5 to 7 days. Patients should be warned about mild discomfort, the sensation of rectal fullness, and a small risk of delayed bleeding at 7 to 10 days. Rubber band ligation is contraindicated in patients on anticoagulants and in those with active anorectal infection or inflammatory bowel disease due to bleeding risk and impaired healing.
Excisional haemorrhoidectomy is reserved for Grade III haemorrhoids that fail banding, all Grade IV haemorrhoids, and mixed internal-external haemorrhoids. The two main approaches are the Milligan-Morgan (open) technique (wound left open to heal by secondary intention) and the Ferguson (closed) technique (wound closed with sutures). This is the most effective treatment with the lowest recurrence rate but carries the highest postoperative pain.
Thrombosed external haemorrhoid management is time-dependent. If the patient presents within 72 hours of symptom onset and pain is still worsening, the correct answer is bedside excisional thrombectomy (not just incision and drainage of the clot, but complete excision of the haemorrhoid and its clot to prevent recurrence). After 72 hours, pain is typically improving and conservative management is preferred because the natural history is spontaneous resolution over 1 to 2 weeks.
Contraindications to note: avoid topical nitroglycerin or calcium channel blocker ointments intended for anal fissures, as they are not indicated for haemorrhoids. In patients with portal hypertension and rectal varices, conventional banding or surgical approaches are dangerous due to the risk of catastrophic bleeding; manage the underlying portal hypertension instead.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The single most common way students lose points on haemorrhoid questions is failing to pursue further workup when alarm features are present. A vignette describing a 55-year-old with rectal bleeding, recent weight loss, and iron-deficiency anaemia is not asking you to choose "reassurance and fibre supplementation." Even if haemorrhoids are present on exam, the correct next step is colonoscopy to exclude colorectal malignancy. Test-writers exploit the instinct to anchor on the most obvious diagnosis.
The second classic trap involves thrombosed external haemorrhoids and the 72-hour rule. If the vignette says the patient developed a painful perianal lump "this morning" or "yesterday," the answer is excisional thrombectomy. If it says the lump appeared "5 days ago and the pain is getting better," the answer is conservative management. Read the timeline carefully.
Another commonly tested distinction is internal versus external haemorrhoids and the dentate line. If the question describes painless bleeding, think internal (above the dentate line, visceral innervation). If the question describes a painful perianal mass, think external or thrombosed (below the dentate line, somatic innervation). A question that asks about rubber band ligation will often test whether you know it must be applied above the dentate line only.
Finally, do not confuse haemorrhoids with rectal prolapse. The discriminator is the mucosal fold pattern: concentric rings mean rectal prolapse; radial folds mean haemorrhoidal prolapse. This visual or descriptive clue is a favourite among exam writers. Keep the anatomy, the timeline, and the red flags straight, and haemorrhoid questions become reliable points.