The primary disease process affecting external hemorrhoids is thrombosis. The mainstay of treatment is excision. It is important to remember that the excision is to alleviate or palliate the pain. The natural history of an untreated thrombosed external hemorrhoid is to rupture and spontaneously evacuate the clot or to resorb the clot over time. Therefore, treatment should give the maximum amount of pain relief with the least chance of complications. To make this decision it will be important to obtain a good history of the length of the pain, how severe it is, and whether there has been improvement. It is important to perform a physical examination to rule out prolapsed grade IV internal hemorrhoids, perianal abscesses, and other perianal masses.
External hemorrhoids fall into three main groups: left lateral, right anterior, and right posterior (Figure 68-1). They are covered with anoderm and visible on the outside of the anal canal. They are composed of a venous plexus mixed with connective tissue. They drain into the middle and inferior rectal veins that terminate into the internal iliac and femoral veins, respectively. External hemorrhoids do not prolapse like internal hemorrhoids. They engorge and thrombose. It will not benefit the patient to try to reduce an external hemorrhoid since their normal location is mostly outside the anal canal and reduction will not remove the clot. External hemorrhoids are never covered with mucosa. The overlying skin may appear to look shiny, swollen, gangrenous, or like an orange peel mimicking the look of mucosa.
The position of the three main groups of external hemorrhoids.
It is important to differentiate internal versus external hemorrhoids. Internal hemorrhoids originate above the dentate line, lack sensation, and are covered with mucosa. Prolapsed internal hemorrhoids are painless unless they become gangrenous, infected, strangulated, or thrombosed. External hemorrhoids originate below the dentate line, have sensory innervation, and are covered with squamous epithelium that matches the surrounding skin.
The patient usually complains of a history of the sudden onset of pain and swelling. The exact cause of thrombosed external hemorrhoids is unknown. It is probably related more to straining with lifting, jogging, or bicycling than chronic constipation. This explains why this problem occurs more often than internal hemorrhoidal disease in a younger age group.
External hemorrhoids can be diagnosed when a patient complains of a sudden onset of pain and swelling, usually with no bleeding. The physical examination will reveal a tensely swollen area covered with anoderm. The swelling will be visible by gently spreading the buttocks and inspecting the area near the anal canal. They have a bluish coloration, especially in patients with little skin pigmentation, and almost no redness. The swelling is abrupt, like placing a marble under a sheet and tucking in the edges. This differentiates the appearance of a thrombosed external hemorrhoid from ...