An anoscopy is a common, non-surgical medical procedure used to examine the lining of the anal canal and the lowest part of the rectum. This examination is performed with a device called an anoscope, a short, specialized viewing instrument. Its purpose is to allow a healthcare provider to directly visualize internal structures to identify and assess the cause of symptoms like pain, bleeding, or itching in the anorectal region. The procedure is typically brief, often completed within minutes, and is performed in a doctor’s office or outpatient setting. It offers a quick, focused way to investigate conditions.
The Device
The anoscope is a hollow, rigid or semi-rigid tube, often referred to as an anal speculum, typically measuring between three and five inches in length and one to two inches in diameter. It is commonly made from either disposable translucent plastic or sterilizable metal. To ensure clear visualization of the tissue lining, the anoscope is equipped with a light source, such as a fiber optic system, that illuminates the internal passage.
For smooth insertion, the anoscope utilizes a rounded, blunt-tipped insert called an obturator, which fits snugly inside the hollow tube. This obturator helps guide the anoscope gently past the anal sphincter muscles, minimizing discomfort during entry. Once the anoscope is correctly positioned within the anal canal, the obturator is carefully removed, leaving the hollow speculum in place to provide the clear channel necessary for the physician’s examination.
Diagnostic Applications
The primary reason for performing an anoscopy is to obtain a direct, detailed view of the anal canal and distal rectum that cannot be achieved by a simple external examination. This visualization is effective for identifying specific medical conditions, often in response to symptoms such as rectal bleeding or pain. The procedure allows for the accurate assessment of internal hemorrhoids, which are swollen, inflamed veins that can be a frequent source of discomfort and blood loss.
Anoscopy is also instrumental in diagnosing anal fissures, which are small tears or cuts in the lining of the anus that cause sharp pain, particularly during bowel movements. Additionally, the procedure helps detect and evaluate other abnormalities, including anal polyps, abnormal growths on the lining, and signs of inflammation or infection. For patients at higher risk, a high-resolution anoscopy (HRA) uses magnification and a special solution to highlight abnormal cell changes, screening for anal dysplasia or early-stage cancerous growths.
Preparing and Performing the Examination
Unlike procedures such as a colonoscopy, an anoscopy requires minimal patient preparation, making it a convenient in-office diagnostic tool. Healthcare providers usually advise patients to empty their bladder and bowels shortly before the procedure for comfort, though extensive bowel preparation is not necessary. The physician may also request that the patient avoid using enemas, douches, or inserting any medications into the anal area leading up to the appointment.
The examination begins with the patient being positioned on the exam table, most commonly lying on their left side with their knees drawn toward the chest. Before the anoscope is introduced, the clinician performs a digital rectal exam (DRE) by inserting a lubricated, gloved finger to check for any obvious masses or tender areas. This step helps ensure the anal canal is relaxed and aids in guiding the subsequent insertion of the anoscope.
After the DRE, the anoscope, heavily coated with a lubricating gel, is gently inserted into the anal canal. Patients may be asked to bear down or relax their muscles, which facilitates the smooth entry of the instrument. Once the anoscope is advanced, the inner obturator is withdrawn, leaving the hollow tube in place for the physician to inspect the tissue lining using the internal light source.
The clinician slowly rotates and withdraws the anoscope, carefully examining the walls of the anal canal and distal rectum for any signs of disease, such as swollen veins, tears, or suspicious lesions. The procedure is quick, often lasting only a few minutes from insertion to removal. Following the exam, most patients can immediately resume their normal daily activities, as the procedure does not require sedation. While mild discomfort or minor spotting may occur, especially if a biopsy was taken, this typically resolves quickly without complication.