- Clinical science
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).
- Excessive straining; (e.g., from chronic constipation, frequent bowel movements, chronic cough, heavy lifting, benign prostatic hyperplasia)
- Extended periods of sitting (e.g., due to occupation or sedentary lifestyle)
- Connective tissue disorder (e.g., Ehlers‑Danlos syndrome, scleroderma)
|Internal hemorrhoid stages|
|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.
Anatomy of the anal canal
- 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
- External anal sphincter
- Internal anal sphincter
|Characteristics of the anal canal above and below the dentate line|
|Above the dentate line||Below the dentate line|
|Embryological origin|| |
|Epithelium|| || |
|Venous drainage|| |
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 .
- 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
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.
- Internal hemorrhoids
- Painful perianal mass
- Clinical examination
Hemorrhoids are a clinical diagnosis!
- For assessing the anus and distal rectum
- Useful when hemorrhoids are suspected but rectal examination is inconclusive
- In addition, proctoscopy may be used to support anoscopy findings.
- Flexible sigmoidoscopy, colonoscopy, or barium enema: to exclude suspected malignancy (especially in patients over the age of 40)
- 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
- Anal and colorectal carcinoma
- Anal fissures
- Anorectal varices
- Condyloma acuminata
- Inflammatory bowel disease (often associated with anal fistulas and abscesses)
Always consider the possibility of concurrent colorectal carcinoma!
The differential diagnoses listed here are not exhaustive.
Hemorrhoids should only be treated in a symptomatic patient!
- Indications: grade I–II internal hemorrhoids and external hemorrhoids
- 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)
- Indications: all internal hemorrhoids with symptoms persisting despite conservative treatment and grade III internal hemorrhoids
- Rubber band ligation (RBL)
- Infrared coagulation
Surgical treatment (stages III–IV)
- Indications: grade IV internal hemorrhoids and no improvement of condition after clinical interventions
- Internal: prolapse of internal hemorrhoid → accumulation of mucus and fecal debris in external anal tissue → local irritation and inflammation
- External: may become acutely thrombosed (e.g., with excessive straining) → necrosis of overlying skin and bleeding
We list the most important complications. The selection is not exhaustive.