- Clinical science
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).
- Chronic straining; (e.g., associated with chronic constipation, frequent bowel movements, chronic cough, heavy lifting, benign prostatic hyperplasia)
- Extended periods of sitting (e.g., occupation‑related)
- Connective tissue disorder (e.g., Ehlers‑Danlos syndrome, scleroderma)
|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|
Anatomy of the anal canal
|Anal cushions|| |
|Anal columns|| |
|Anal valves|| |
|Pectinate line|| |
Regional differences of the anal canal
|Above the pectinate line||Below the pectinate line|
|Embryological origin|| |
|Epithelium|| || |
|Venous drainage|| |
|Lymphatic drainage|| |
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 .
- 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
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!
- Internal hemorrhoids
- Painful perianal mass
- Difficulty maintaining perineal hygiene
- 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 = harmless, skin‑colored folds at the anal verge, often at 12 o'clock in the lithotomy position
- 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 a 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), but NSAIDS should be avoided
- Topical antispasmodic agents (e.g., nitroglycerin)
- Indications: all internal hemorrhoids with persistent symptoms despite conservative treatment or grade III internal hemorrhoids
- Rubber band ligation (RBL)
- Infrared coagulation
Surgical treatment (stages III–IV)
- Indications: grade IV internal hemorrhoids or no improvement of condition after clinical interventions
- Internal: Mucous and fecal debris deposited by prolapsed internal hemorrhoids onto external anal tissue causes local irritation and inflammation.
- External: may become acutely thrombosed (e.g., with excessive straining) → necrosis of overlying skin → bleeding
We list the most important complications. The selection is not exhaustive.