Hemorrhoids

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Physiological hemorrhoids are arteriovenous cushions within the rectal corpus cavernosum, which may become pathological hemorrhoids following abnormal enlargement and possible protrusion. Hemorrhoids are divided into three categories: internal (above the dentate line), external (below the dentate line), or mixed (above and below the dentate line). Individuals at higher risk of contracting hemorrhoids are typically above the age of 45, have constipation or connective tissue disorders, or engage in activities that require prolonged sitting. The patient may present with rectal bleeding, pain, prolapse, and pruritus. The diagnosis of hemorrhoids involves careful inspection of the anal area during clinical examination, especially when the patient increases intra‑abdominal pressure by straining. Anoscopy and proctoscopy may be necessary to confirm the diagnosis. Internal hemorrhoids are classified into four grades, depending upon the extent of prolapse: Conservative management is recommended in grades I or II (anal hygiene, anti‑inflammatory ointments), while surgical intervention is indicated in grades III or IV (e.g., Milligan‑Morgan hemorrhoidectomy).

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Internal hemorrhoids

Grade	Palpation Findings
I	Hemorrhoids are not prolapsed (only projected into the anal canal); above the dentate line; reversible; often bleed
II	Prolapse when straining, but hemorrhoids spontaneously reduce at rest
III	Prolapse when straining; hemorrhoids only reducible manually
IV	Irreducible prolapse; hemorrhoids may be strangulated and thrombosed with possible ulceration

References:^[2][1]

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Anatomy of the anal canal

Structure	Characteristics
Anal cushions	Thickenings of the anal mucosa Specialized structures comprised of blood vessels, (e.g., arteriovenous), smooth muscle (e.g., Treitz's muscle), and fibroelastic (e.g., collagen, elastic fibers) tissue. Located on the right anterior, right posterior, and left lateral position (3, 7 and 11 o'clock in the lithotomy position) Play an important role in maintaining tight closure of the rectum and continence Defecation causes contraction of supportive structures (e.g., Treitz's muscle) → compression of anal cushions → increased diameter of the anal canal for adequate passage of stool.
Anal columns	Folds of mucous membrane formed by anal cushions (arterial cavernous bodies) in the submucosa
Anal valves	Transverse folds that connect the distal end of the anal columns
Crypts of Morgagni	Area within the anal valves where excretory ducts of the anal glands drain
Pectinate line	Formed be the fusion of anal valves

Regional differences of the anal canal

	Above the pectinate line	Below the pectinate line
Embryological origin	Endoderm (from the hindgut)	Ectoderm (from the cloaca)
Epithelium	Simple columnar epithelium	Stratified nonkeratinized squamous epithelium
Arterial supply	Superior rectal artery (branch of the inferior mesenteric artery)	Inferior rectal artery (branch of the internal pudendal artery)
Venous drainage	Venous drainage: internal hemorrhoidal plexus → superior rectal vein (drains into the inferior mesenteric vein → splenic vein → portal vein → hepatic veins → inferior vena cava)	Venous drainage: external hemorrhoidal plexus → inferior rectal vein (drains into the internal pudendal vein → internal iliac vein → common iliac vein → inferior vena cava)
Lymphatic drainage	Paraaortic (lumbar) lymph nodes	Inguinal lymph nodes
Innervation	Visceral Sympathetic: inferior mesenteric plexus Parasympathetic: inferior hypogastric plexus and pelvic splanchnic nerves	Somatic Inferior rectal nerve (branch of the pudendal nerve)

Hemorrhoids

Hemorrhoids are engorgements of the corpus cavernosum recti, which are arteriovenous structures above the pectinate line. The corpus cavernosum recti function to help maintain continence. They drain into the superior or inferior hemorrhoidal veins.

The pathophysiology of hemorrhoids is not very clear, and multiple theories exist regarding their origin.

• "Sliding anal canal" theory
  • Widely accepted theory
  • Degeneration of supportive fibroelastic tissue → abnormal downward displacement of anal cushions (prolapse) → venous engorgement and enlargement of the cushions
• Other theories
  • Inadequate compression of anal cushions during defecation → venous engorgement
  • Anorectal bowel obstruction (e.g., caused by stool masses, inflammation) → increased pressure on the rectal corpus cavernosum (arteriovenous obstruction) → hyperplasia → increased tone in the anal sphincter complex→ further obstruction → repetitive cycle of worsening obstruction and arteriovenous cushion hyperplasia

Internal vs. external hemorrhoids

Hemorrhoids are classified as internal , external or mixed .

• Internal hemorrhoids
  • Prolapse of internal hemorrhoids, with possible incarceration and strangulation, may cause pain by triggering an anal sphincter complex spasm. → possible ischemia and necrosis of internal hemorrhoids → worsening anal sphincter complex spasm → may result in an external hemorrhoid thrombosis → triggers cutaneous pain → combination of both results in an acute hemorrhoidal crisis
  • Do not cause cutaneous pain!
  • Bleeding and/or prolapsed internal hemorrhoids irritate sensitive perianal skin → perianal itching
• External hemorrhoids
  • Acute thrombosis triggers cutaneous pain → pain lasts for 7–14 days → thrombosis resolves → residual skin or skin tags of distended anal skin

Hemorrhoids are not varicose veins (= widening of the veins)! However, anorectal varices do exist, e.g., following portal hypertension! The terms anorectal varices and hemorrhoids are often used interchangeably, but this is incorrect!

References:^[2][3][4]

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• Internal hemorrhoids
  • Often painless, bright red bleeding at the end of defecation (possible dull, aching pain with severe sphincter spasm)
  • Possible perianal mass if prolapsed
  • Pruritus
  • Discharge (containing excessive mucus or fecal debris)
  • Ulceration (in grade IV)
  • Difficulty maintaining perineal hygiene
• External hemorrhoids
  • Painful perianal mass
  • Pruritus
  • Difficulty maintaining perineal hygiene
• Clinical examination
  • Inspect perianal area for external hemorrhoids and prolapsed internal hemorrhoids; exclude other conditions (e.g., anal skin tags, polyps).
  • Digital rectal examination may show abnormal masses or tenderness or blood on gloved finger

References:^[1][2]

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Hemorrhoids are a clinical diagnosis!

Anoscopy

• For assessing the anus and distal rectum
• Useful when hemorrhoids are suspected, but rectal examination is inconclusive
  • Purplish blue veins (internal hemorrhoids)
  • Dark pink structures at the anal margin (prolapsed internal hemorrhoids)
  • Tender, purplish masses (thrombosed external hemorrhoids)
• In addition, proctoscopy may be used to support anoscopy findings.

Other procedures

• Flexible sigmoidoscopy, colonoscopy, or barium enema: to exclude suspected malignancy (especially in patients over the age of 40)

References:^[1][2][5]

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• Anal skin tags = harmless, skin‑colored folds at the anal verge, often at 12 o'clock in the lithotomy position
• Hypertrophied anal papillae
• Polyps
• Anal and colorectal carcinoma
• Anal fissures
• Anorectal varices
• Proctitis
• Condyloma acuminata
• Inflammatory bowel disease (often associated with anal fistulas and abscesses)

Always consider the possibility of a concurrent colorectal carcinoma!

References:^[2][1]

The differential diagnoses listed here are not exhaustive.

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Hemorrhoids should only be treated in a symptomatic patient!

Conservative treatment

• Indications: grade I–II internal hemorrhoids and external hemorrhoids
• Interventions
  • Lifestyle modifications: weight loss, exercise, high fiber diet, avoid fatty and spicy foods, increase water intake
  • Alter stool habits (e.g., avoid excessive straining or > 5 min periods on the toilet)
  • Sitz baths
  • Stool softeners (e.g., docusate)
  • Topical or suppository analgesia (e.g., lidocaine)
  • Topical anti‑inflammatory (e.g., hydrocortisone, especially with pruritus, but no longer than 1 week), but NSAIDS should be avoided
  • Topical antispasmodic agents (e.g., nitroglycerin)

Outpatient treatment

• Indications: all internal hemorrhoids with persistent symptoms despite conservative treatment or grade III internal hemorrhoids
• Interventions
  • Rubber band ligation (RBL)
  • Sclerotherapy
  • Infrared coagulation

Surgical treatment (stages III–IV)

• Indications: grade IV internal hemorrhoids or no improvement of condition after clinical interventions
• Interventions
  • Arterial ligation of hemorrhoids (HAL)
  • Submucosal hemorrhoidectomy
    • Ferguson approach (closed approach )
    • Milligan‑Morgan approach (open approach )
  • Stapled hemorrhoidopexy (e.g., using the Longo procedure), which is only effective for internal hemorrhoids

References:^[6][2][7]