Hemorrhoids

Hemorrhoids, also called piles, arise from a cushion of dilated arteriovenous blood vessels and connective tissue in the anal canal that may abnormally enlarge or protrude. Hemorrhoids are divided into three categories: internal (above the dentate line), external (below the dentate line), or mixed (above and below the dentate line). Hemorrhoids are caused by increased straining or intra-abdominal pressure (e.g., due to constipation, pregnancy, or extended periods of sitting). Patients may present with prolapse, rectal bleeding, pain, and pruritus. The diagnosis of hemorrhoids involves careful inspection of the anal area during clinical examination, especially as 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 and II (anal hygiene, anti‑inflammatory ointments), while surgical intervention is indicated in grades III and IV (e.g., Milligan‑Morgan hemorrhoidectomy).

Internal hemorrhoid stages
Grade	Palpation findings
I	Hemorrhoids do not prolapse (only project into the anal canal); above the dentate (pectinate) line; reversible; often bleed
II	Prolapse when straining, but spontaneously reduce at rest
III	Prolapse when straining; only reducible manually
IV	Irreducible prolapse; may be strangulated and thrombosed with possible ulceration

There is no widely used classification system for external hemorrhoids.

References:^[2][1]

Anatomy of the anal canal

• Anal cushions
  • Areas of thickened anal mucosa that consist of arteriovenous blood vessels (corpus cavernosum recti), smooth muscle (e.g., Treitz muscle), and fibroelastic tissue (e.g., collagen, elastic fibers)
  • Located at 11, 7 and 3 o'clock in the lithotomy position (right anterior, right posterior, and left lateral position)
  • Play an important role in maintaining continence by enabling tight closure of the rectum
  • Defecation causes contraction of supportive structures (e.g., Treitz muscle) → compression of anal cushions → increased diameter of the anal canal for adequate passage of stool
• Anal columns: longitudinal folds of mucous membrane that are fused at their inferior ends by transverse folds (anal valves)
• Anal sinuses: small, mucus-secreting pouches between the anal columns above the anal valves
• Dentate line
  • Circular separation line formed by the fusion of anal valves (hindgut-proctodeum junction)
  • Divides anal canal into an upper and lower part (also see characteristics of the anal canal above and below the dentate line below)
• External anal sphincter
  • Surrounds lower third of anal canal
  • Consists of skeletal muscle and functions to open and close the anal canal and opening
  • Innervated by the pudendal nerve and under voluntary control
• Internal anal sphincter
  • Surrounds upper two-thirds of anal canal
  • Consists of involuntary circular smooth muscle and is responsible for ∼ 85% of the resting pressure of the anal canal
  • Innervated by the enteric nervous system

Characteristics of the anal canal above and below the dentate line
	Above the dentate line	Below the dentate line
Embryological origin	Endoderm (from the hindgut)	Ectoderm (from the cloaca)
Epithelium	Simple columnar epithelium	Stratified nonkeratinized squamous epithelium (known as anal pecten)
Arterial supply	Superior rectal artery (branch of the inferior mesenteric artery)	Inferior rectal artery (branch of the internal pudendal artery)
Venous drainage	Internal hemorrhoidal plexus → superior rectal vein (drains into the inferior mesenteric vein → splenic vein → portal vein → hepatic veins → inferior vena cava)	External hemorrhoidal plexus → inferior rectal vein (drains into the internal pudendal vein → internal iliac vein → common iliac vein → inferior vena cava)
Lymphatic drainage	Internal iliac lymph nodes	Superficial 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

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 → potential external hemorrhoid thrombosis → cutaneous pain
  • 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 and may occur, e.g., as a result of portal hypertension. The terms anorectal varices and hemorrhoids are often used interchangeably, but this is incorrect.

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

• Internal hemorrhoids
  • Often painless, bright red bleeding at the end of defecation (potentially dull, aching pain with severe sphincter spasm)
  • Perianal mass in the event of prolapse
  • Pruritus
  • Discharge (containing mucus or fecal debris)
  • Ulceration (in grade IV)
• External hemorrhoids
  • Painful perianal mass
  • Pruritus
• 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 bleeding.

References:^[1][2]

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]

• Anal skin tags: folds of skin at the anal verge, often at 12 o'clock in the lithotomy position (benign, but may become inflamed or itch)
• 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 concurrent colorectal carcinoma!

References:^[2][1]

The differential diagnoses listed here are not exhaustive.

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)
  • Topical antispasmodic agents (e.g., nitroglycerin)

Outpatient treatment

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

Surgical treatment (stages III–IV)

• Indications: grade IV internal hemorrhoids and 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): only effective for internal hemorrhoids

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