Anoscopy

Anoscopy is usually an office examination and is performed in patients with a variety of anorectal symptoms. The examination can be performed with the patient in left lateral or knee chest position and uses one of a variety of rigid anoscopes. These usually come with a bevel.

Anoscopy starts with an anal examination. If this shows a classical anal fissure the examination stops there and anoscopy is aborted. Acute anal sepsis is also a contraindication, as is external hemorrhoidal thrombosis. The most common indications for anoscopy are anal or rectal bleeding, constipation, a wet, irritated, or itchy anus, and incontinence.

Choice of the instrument depends on the indication and the results of the initial digital exam. In patients with a high basal resting tone (such as young men), use the pediatric anoscope. In patients with likely hemorrhoidal symptoms use a short anoscope. In patients with possible low rectal disease use the longer anoscopes

A gentle digital anal examination with plenty of lubricant will encourage the anus to relax and make insertion of the anoscope easier. (see “Open Sesame” , Farmer KC, Church JM. Open sesame: tips for traversing the anal canal. Dis Colon Rectum. 1992 Nov;35(11):1092-3.)

The anoscope is inserted gently, on its side so that the bevel is facing laterally, and with two or three gradual insertions before the full diameter is inserted. The buttocks often must be distracted to allow the anoscope to be maximally inserted, at which time the obturator is removed and the scope slowly with drawn, looking at the rectal mucosa, the hemorrhoidal tissues and the anoderm. Before the scope comes out, reintroduce the obturator, reinsert the scope to its hilt, turn it through 90 degrees and gradually withdraw again. This is repeated 2 more times so that the entire circumference of the anus is seen.

Internal hemorrhoids are seen as three distinct vascular cushions that descend through the lower rectum to the dentate line. They are usually anterior, and right and left lateral (4 o’clock, 7 o’clock and 11 o’clock). Asking the patient to bear down with the scope inserted and the hemorrhoids in view will reveal their tendency to prolapse. A whitish plaque (pseudoepitheliomatous hyperplasia) on the mucosa is an indication of significant recurrent prolapse.

Redundant low rectal mucosa is more likely anterior and may exist in association with internal hemorrhoid prolapse. Rectal intussusception can be seen if the patient is asked to strain down while the anoscope is being removed. The mucosa descends to impact into the anus, potentially blocking it.

The anoderm is examined for tags, hypertrophied anal papillae, and possible condylomas.