A 42-year-old woman presents to the office with rectal pressure and occasional bright red blood on the toilet paper when wiping after bowel movements (Figure 66-1). She has had difficulty with constipation off and on for many years and had large hemorrhoids during her last pregnancy. Physical examination confirms the diagnosis of external hemorrhoids.
External hemorrhoid that is symptomatic. The patient had some bleeding with bowel movements. (Courtesy of Richard P. Usatine, MD.)
Hemorrhoids are cushions of highly vascular structures found within the submucosa of the anal canal. They become pathologic when swollen or inflamed.
- More than 1 million people in Western civilization suffer from hemorrhoids each year.1
- Estimated at 5% prevalence in the general population.2
- Approximately half of those older than age 50 years have experienced hemorrhoidal symptoms at some time.2
- More frequent in whites and in those of higher socioeconomic status.2
- Three hemorrhoidal cushions (comprised of subepithelial connective tissue, elastic tissue, blood vessels, and smooth muscle) surround and support distal anastomoses between the terminal branches of the superior and middle rectal arteries and the superior, middle, and inferior rectal veins.2 The hemorrhoidal cushions have several functions, including maintaining fecal continence by engorging with blood and closing the anal canal and by protecting the anal sphincter during defecation.
- Hemorrhoidal tissue provides important sensory information, enabling the differentiation between solid, liquid, and gas and subsequent decision to evacuate.2
- Abnormal swelling of the anal cushions can occur from a number of causes (see “Risk Factors” below) resulting in increased pressure, with dilation and engorgement of the arteriovenous plexuses. Increased pressure can lead to stretching of the suspensory muscles, laxity of connective tissue, and eventual prolapse of rectal tissue through the anal canal.2 The engorged anal mucosa is easily traumatized, leading to rectal bleeding. Prolapse predisposes to incarceration and strangulation.
- Hemorrhoids are classified with respect to their position relative to the dentate line.
- Internal hemorrhoids (Figure 66-2) develop above the dentate line and are covered by columnar epithelium of anal mucosa. Internal hemorrhoids lack somatic sensory innervation.
- External hemorrhoids (Figure 66-1) arise distal to the dentate line. They are covered by stratified squamous epithelium and receive somatic sensory innervation from the inferior rectal nerve.
- Hemorrhoids are further classified into four stages of disease severity:1,2
- Stage I—Enlargement and bleeding.
- Stage II—Protrusion of hemorrhoids with spontaneous reduction.
- Stage III—Protrusion of hemorrhoids with manual reduction possible.
- Stage IV—Irreducible protrusion of hemorrhoids usually containing both internal and external components with or without acute thrombosis or strangulation.
A large prolapsed internal hemorrhoid. (Courtesy of Charlie Goldberg, MD, and the Regents of the University of California.)