Description

• Varicosities of the hemorrhoidal venous plexus
• External hemorrhoids
  • Located below (distal to) the dentate line; somatic innervation (painful)
  • Covered by squamous epithelium
• Internal hemorrhoids
  • Located above (proximal to) the dentate line; visceral innervation (painless)
  • Covered by columnar epithelium
  • Classification of internal hemorrhoids (1):
    • Grade I: Hemorrhoid vessel bulges without prolapse.
    • Grade II: Hemorrhoid prolapses with straining but reduces spontaneously.
    • Grade III: Hemorrhoid prolapses with straining and requires manual reduction.
    • Grade IV: chronically prolapsed—cannot be reduced
• Internal and external hemorrhoids often coexist.
• Although often asymptomatic, hemorrhoids can present with itching, bleeding, soilage, prolapse, or pain.
• Pain and thrombosis more common with external than internal hemorrhoids

Geriatric Considerations
Hemorrhoids and rectal prolapse are more common in elderly.

Pediatric Considerations

• Uncommon in infants and children; most common cause is chronic liver failure; other findings (rectal polyps, skin tags, condyloma) often misdiagnosed as hemorrhoids.
• In adolescents, chronic constipation and prolonged toilet time can result in hemorrhoids.

Pregnancy Considerations

• Common in pregnancy
• Usually resolves after delivery
• No treatment required, unless extremely painful

Epidemiology

• Predominant age: adults; peak from 45 to 65 years (2)
• Predominant sex: male = female

Incidence
Common; over 3.5 million office visits in United States per year are related to hemorrhoidal disease (1).

Prevalence

• ~4–5% in general population in the United States
• 39% prevalence on routine screening colonoscopy (2)

Etiology and Pathophysiology

• Exact pathophysiology is unknown.
• There are three primary hemorrhoidal cushions—typically located in left lateral, right anterior, and right posterior positions. Hemorrhoidal cushions augment anal closing pressure and protect the anal sphincter during stool passage. During Valsalva, increased intra-abdominal pressure raises pressure within the hemorrhoidal cushions. Mechanisms implicated in symptomatic hemorrhoidal disease include the following:
  • Dilated veins of hemorrhoidal plexus
  • Tight internal anal sphincter
  • Abnormal distention of the arteriovenous anastomosis
  • Prolapse of the cushions and the surrounding connective tissues

Genetics
No known genetic pattern

Risk Factors

• Pregnancy
• Pelvic space-occupying lesions
• Liver disease; portal HTN
• Constipation (prolonged straining)
• Occupations that require prolonged sitting
• Loss of perianal muscle tone due to old age, rectal surgery, birth trauma/episiotomy, anal intercourse
• Obesity
• Chronic diarrhea

General Prevention

• Avoid constipation by consuming high-fiber diet (>30 g/day) and ensuring proper hydration.
• Avoid prolonged sitting or straining on the toilet.

Commonly Associated Conditions

• Liver disease; cirrhosis, ascites
• Pregnancy
• Constipation