Internal Medicine



Symptomatic enlargement and distal displacement of the normal anal cushions.

Rectal anatomy: The anus is approximately 4 cm long in adults, with the dentate line located roughly at the midpoint. Haemorrhoids developing above the dentate line are internal. They are painless because they are viscerally innervated. External haemorrhoids develop below the dentate line and can become painful when swollen. | Illustration by Myriam Kirkman-Oh: Pfenninger JL, Zainea GG. Common anorectal conditions: part I. Symptoms and complaints. Am Fam Physician. 2001;63(12):2392.


Hemorrhoids are highly vascular submucosal cushions that generally lie along the anal canal in three columns—the left lateral, right anterior, and right posterior positions.

These vascular cushions are made up of elastic connective tissue and smooth muscle, but because some do not contain muscular walls, these cushions may be considered sinusoids instead of arteries or veins.

  • Physiologic role:
    • Protecting the anal sphincter muscles
    • Augment closure of the anal canal during moments of increased abdominal pressure (e.g., coughing, sneezing) to prevent incontinence (contribute 15-20% of the resting anal canal pressure). Increases in abdominal pressure increase the pressure in the inferior vena cava that cause these vascular cushions to engorge and prevent leakage.
    • Help differentiate stool, liquid, and gas in the anal canal.
Diagram of common sites of major anal and internal hemorrhoids. A: Diagram of common sites of major anal cushions; B: Common sites of internal hemorrhoids. | Lohsiriwat, V. (2012). Hemorrhoids: from basic pathophysiology to clinical management. World Journal of Gastroenterology, 18(17), 2009–2017.

Alteration of venous drainage of the anus
Destructive changes in supporting connective tissue within the anal cushion

Dilation of venous plexus and connecting tissue

Outgrowth of anal mucosa from the rectal wall


  1. Internal haemorrhoids
  2. External haemorrhoids

Internal haemorrhoids:

  • Above the dentate line
  • Drain via the middle rectal veins into the internal iliac vessels
  • Covered by mucosa comprised of columnar epithelium
  • Visceral innervation (painless)

External haemorrhoids:

  • Below the dentate line
  • Drain via the inferior rectal veins into the pudendal vessels and then into the internal iliac vein
  • Covered by anoderm comprised of modified squamous epithelium.
  • Somatic innervation (inferior rectal branch of pudendal nerve) (painful if thrombosed)

Goligher classification:

  • Grade I: Bleed but do not prolapse
  • Grade II: Prolapse but spontaneously reduce
  • Grade III: Prolapse but have to be manually reduced
  • Grade IV: Prolapse but cannot be reduced
    • Also includes:
      • Acutely thrombosed
      • Incarcerated internal haemorrhoids
      • Incarcerated, thrombosed haemorrhoids involving circumferential rectal mucosal prolapse
Grading of internal hemorrhoids. (Patients may experience painless bleeding with any grade.): Grade I = asymptomatic outgrowth of anal mucosa caused by engorgement of underlying venous plexus and connective tissue; grade II = hemorrhoid prolapses but spontaneously reduces; grade III = hemorrhoid prolapses and must be manually reduced; often accompanied by pruritus and soilage; grade IV = hemorrhoid prolapse that cannot be reduced; often accompanied by chronic local inflammatory changes. | Illustration by Dave Klemm: Mott, T., Latimer, K., & Edwards, C. (2018). Hemorrhoids: Diagnosis and Treatment Options. American Family Physician, 97(3), 172–179.
Complicated hemorrhoids. A: Strangulated internal hemorrhoid; B: Acutely thrombosed external hemorrhoid. | Lohsiriwat, V. (2015). Treatment of hemorrhoids: A coloproctologist’s view. World Journal of Gastroenterology, 21(31), 9245–9252.

Clinical features

  • Painless rectal bleeding associated with bowel movement. (M/C symptom)
  • Prolapsing haemorrhoids: Perineal irritation or anal itching (due to mucous secretion or faecal soiling)
  • Large haemorrhoids: Feeling of incomplete evacuation or rectal fullness
  • Pain: Anal fissure and perianal abscess (common causes of anal pain in hemorrhoidal patients)
    • Pain is not usually caused by the hemorrhoids themselves unless:
      • Thrombosed external hemorrhoid “Meleney’s 5-day lesion”
      • Strangulated fourth-degree internal haemorrhoid



  • Perianal area for:
    • Anal skin tags
    • External haemorrhoid
      Perianal dermatitis (from anal discharge or fecal soiling)
    • Fistula-in-ano and anal fissure
  • Observing patients sitting and straining in squatting position: To watch for the prolapse.

Digital examination (left lateral position):

Hemorrhoid cannot be felt on DRE except when thrombosed.
  • Abnormal anorectal mass
  • Anal stenosis and scar
  • Evaluate anal sphincter tone
  • Determine the status of prostatic hypertrophy (which may be the reason for straining as this aggravates descent of the anal cushions during micturition)

Anoscopy (left lateral position):

Intrarectal retroflexion of the colonoscope or transparent anoscope with flexible endoscope also allow excellent visualization of the anal canal and haemorrhoid and permit recording pictures.
  • Hemorrhoidal size, location, severity of inflammation
  • Bleeding

Differential diagnosis:

Other causes of severe anal pain
  • Thrombosed external haemorrhoids
  • Anal fissure
  • Acute herpetic ulceration or other STD
  • Crohn’s ulceration & inflammation
  • Anal, rectal or pelvic cancer
  • Lymphoma/leukaemia


Current treatment of internal hemorrhoids based on their severity and degree of prolapse. DG-HAL: Doppler-guided hemorrhoidal artery ligation; SH: Stapled hemorrhoidopexy; PPH: Procedure for prolapse and hemorrhoids. | Lohsiriwat, V. (2015). Treatment of hemorrhoids: A coloproctologist’s view. World Journal of Gastroenterology, 21(31), 9245–9252.

Conservative management:

  • High-fiber diet (25-35 g/day)
  • Fiber supplementation (decreases bleeding of haemorrhoids by 50% and improves overall symptoms)
  • Increased water intake
  • Warm water (sitz) baths (decrease pain temporarily)
  • Stool softeners

OPD procedures:

To treat grade I to III internal haemorrhoids. Have more recurrence than surgical methods but better pain management.
  • Banding (better long-term success)
  • Infrared photocoagulation (better pain management)

Rubber band ligation (RBL):

More effective than sclerothearpy
Rubber band ligation. When an internal hemorrhoid is present in the anorectal canal, an anoscope may be used as a guide to identify the hemorrhoidal complex. With a speculum in place, a ligating device (ligator) is positioned over the base of the hemorrhoid, isolating it (A). Some ligators use forceps, whereas others use suction (as in this figure) to draw the hemorrhoid taut. Once the ligator is positioned at its base, bands are released (B). After the procedure is completed, the constricting bands remain in place (C) until they eventually fall off (typically because the tissue distal to the constricting bands sloughs) (D). | Illustration by Dave Klemm: Mott, T., Latimer, K., & Edwards, C. (2018). Hemorrhoids: Diagnosis and Treatment Options. American Family Physician, 97(3), 172–179.

Surgical management:

Most effective for recurrent, highly symptomatic grade III or IV haemorrhoids. Conventional haemorrhoidectomy is more painful and associated with more blood loss and longer recovery time, but it has significantly lower rates of recurrence
  • Closed hemorrhoidectomy (mucosal defect typically closed)
  • Open hemorrhoidectomy (removal of hemorrhoidal tissue with mucosal defect left open)

Minimally invasive perineal hemorrhoidopexy (MIPH):

Also known as stapler hemorrhoidopexy. Purse string suture applied 2cm over dentate line.

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