An anoscopy is a medical procedure that uses a specialized instrument called an anoscope to visually examine the lining of the anal canal and the lower portion of the rectum. This rapid procedure is typically performed by a gastroenterologist or a colorectal surgeon. It allows for the direct inspection of the anal area for signs of injury or disease. Anoscopy is frequently utilized when a patient experiences symptoms related to the lower gastrointestinal tract, providing immediate diagnostic information without the need for sedation or extensive preparation.
Anatomy and Function of the Anoscope
The anoscope is a rigid, tube-like instrument, also known as an anal speculum, designed to be shorter than scopes used for the upper colon. Its length typically ranges from three to five inches, with a diameter slightly wider than a finger, often between 16 and 24 millimeters. The instrument is constructed from either plastic or metal and is hollow to allow the physician a clear view of the tissues.
To facilitate smooth insertion, the anoscope uses a component called an obturator, which is a rounded tip that fits snugly inside the hollow tube. This obturator creates a blunt, tapered end for gentle placement past the anal sphincter. Once the anoscope is positioned inside the anal canal, the obturator is removed, leaving the hollow cylinder in place. The anoscope provides an open channel for the physician to visualize the internal tissues and often includes a light source to illuminate the area.
Medical Indications for Anoscopy
A doctor recommends anoscopy to investigate various anorectal symptoms. The most common reason is the evaluation of rectal bleeding, allowing the physician to identify the source. Anoscopy is effective for diagnosing internal hemorrhoids and for assessing anal fissures, which are small tears that cause pain.
The procedure is also performed to investigate chronic symptoms such as anal pain, itching, discharge, or the sensation of a mass or protrusion. It helps in the diagnosis of conditions including:
- Anal abscesses
- Fistulas
- Anal yeast infections
- Anal dysplasia, which involves abnormal cell growth
The anoscope is also used for treatment, such as guiding rubber band ligation to treat hemorrhoids. If the physician observes suspicious tissue, the anoscope provides access to obtain a biopsy for laboratory analysis.
The Patient Experience: What Happens During the Procedure
Patients are asked to remove their undergarments and change into a gown before the anoscopy begins. Preparation usually consists of emptying the bladder and attempting a bowel movement before the appointment. The patient is then positioned on the examination table, most commonly lying on their left side with knees bent toward the chest (the fetal position).
The clinician usually begins with a digital rectal examination (DRE), gently inserting a lubricated, gloved finger into the anus to feel for any immediate abnormalities or masses. This initial step also helps to relax the anal muscles and ensure the passage is clear for the anoscope. If the patient is experiencing significant pain, the physician may apply a topical numbing medication, such as lidocaine jelly, before proceeding.
The anoscope, with the obturator in place and coated with lubricant, is gently inserted a few inches into the anal canal. Patients may be asked to bear down, which can help ease the placement of the instrument. Once inserted, the obturator is immediately removed, allowing the physician to look through the hollow tube at the lining of the anal canal and lower rectum.
The physician slowly withdraws the anoscope while examining the tissue for lesions, inflammation, or hemorrhoids. The entire examination is brief, often lasting only a few minutes. Following the procedure, no recovery time is needed, and the patient can immediately return to their normal daily activities.