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INTRODUCTION

Thrombosed external hemorrhoids consistently cause patient pain and embarrassment. The etiology is still unclear. The mainstay of treatment is excision. It is important to remember that excision is performed to alleviate or palliate pain and shorten the course of the disease. 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 is important to take a thorough history from the patient and include questions about the time course, severity, improvement or deterioration, and what has worked or failed in the past. It is also important to perform a physical examination to rule out prolapsed grade IV internal hemorrhoids, perianal abscesses, and other perianal masses.

ANATOMY AND PATHOPHYSIOLOGY

External hemorrhoids fall into three main groups: left lateral, right anterior, and right posterior (Figure 86-1).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. External hemorrhoids 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 to cause significant pain and discomfort. 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.

FIGURE 86-1.

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 rectal 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 sudden onset of pain and swelling. The exact cause of thrombosed external hemorrhoids is unknown.2 Some studies have shown correlations between thrombosed external hemorrhoids and constipation, excess straining during defecation, and strenuous exercise (e.g., bicycling, jogging, or weight lifting). Since this disease process affects younger individuals more frequently, it seems that intense physical activity plays a more prominent role than does constipation or straining to defecate.

External hemorrhoids can be diagnosed when a patient complains of sudden onset of pain, swelling, and usually no bleeding. The physical examination will reveal a tensely swollen area covered with anoderm. The swelling ...

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