Anorectal Evaluations: Diagnosing & Treating Benign Conditions

Anorectal pain and discomfort can stem from several possible etiologies, most of which are benign. As such, many patients with anorectal complaints who present in the primary care setting can be adequately evaluated, diagnosed, and treated without referral to a colorectal specialist. However, the clinician must be able to differentiate between common benign anorectal symptoms and red flags that should prompt referral.

Anorectal disorders are common in the United States and result in numerous primary care visits each year. Presentations range from pain and itching to bleeding and lesions. Common anorectal conditions include hemorrhoids, perianal skin tags, fissures, pruritus ani, perianal abscess, and condyloma. Most are benign and can be managed in the primary care setting.

Before a provider can competently diagnose and treat anorectal conditions, however, a comprehensive history and physical examination must be conducted. Grucela and colleagues documented that physicians’ diagnostic accuracy with anorectal conditions is about 50%—highlighting the need for providers to become more familiar with the history and clinical elements associated with anorectal complaints.¹

This article reviews the assessment of the anorectum, diagnosis of common disorders and their recommended treatments, and red flags for referral to a colorectal specialist.

ANORECTAL ANATOMY

The beginning of the anal canal is demarcated by its moist, hairless appearance. Just inside the anal opening are two palpable circular muscles, the internal and external anal sphincters, separated by an intersphincteric groove. The sphincters are firmly closed in the resting state, which helps maintain continence.

The anal canal is generally 3 to 4 cm long and ends at the dentate line, a series of crypts in the anal mucosa.² The crypts are openings into the anal glands, which are mucus-secreting structures in the anus. The dentate line is easily identified on anoscopy as a discrete change in the appearance of the mucosa. The dentate line is an important landmark because it delineates the boundary between somatic and visceral nerve supplies.³ Tissue proximal to the dentate line is innervated by visceral nerves and is insensate, and thus usually not a cause of pain; tissue distal to the dentate line, however, is highly innervated by somatic nerves and can be intensely painful.²

The anorectal canal is lined by three fibrovascular cushions, located in the left lateral, right posterior, and right anterior positions.⁴ Inside each cushion is a venous structure, called a hemorrhoid, which allows the cushion to enlarge and help maintain continence.⁵

Proximal to the anus is the rectum, the 12- to 15-cm long terminus of the colon. Anorectal examination in the primary care setting will typically not progress beyond the last 2 to 3 cm of the rectum.

TAKING THE HISTORY

A thorough history will provide clues about potential underlying anorectal pathology. Patients may not be forthcoming about symptoms due to embarrassment, fear of a cancer diagnosis, or cultural customs or habits. A thorough history should elicit information about all of the patient’s symptoms (see Table 1), including bleeding, change in bowel habits, and unintended weight loss.

PHYSICAL EXAM

Positioning the patient

Undergoing an anorectal examination can be embarrassing, whether it be from exposure of sensitive body parts or the less-than-desirable prone jackknife positioning. Patients often have preconceived notions that the exam will be humiliating and/or painful. Care should be taken to minimize any embarrassment and discomfort.

Positioning of the patient is a matter of provider preference. Options include the left lateral decubitus, prone jackknife, or lithotomy positions.

Positioning should always be done with draping. Regardless of position, ensure the draping exposes only the perineum. This can be achieved by encircling the patient’s bare bottom with a plain white sheet that exposes only the anus and surrounding skin, keeping the lower back, lateral buttocks, and thighs covered.

Interestingly, data on patient preference for positioning during anorectal exams are limited. In a 2009 study of 178 patients undergoing anorectal exam, more than half of patients (up to 71.4%) expecting to or having already had a proctologic exam reported that no specific type of positioning (eg, Sims, lithotomy with lifted legs, knee-chest, knee-chest with patient’s body bent forward) was most embarrassing to them.⁶ The report revealed that while most patients would favor the Sims position if they had a choice, they deferred to their examiner to choose the position that seemed most suitable to get a reliable diagnosis.⁶