Introduction
The rectum is a large intestine structure where feces (stool) are stored for excretion from the anus. Anorectal disorders occur frequently in about 25 percent of the population. Various structural or functional abnormalities of the anus, rectum, or pelvic floor occur in the respective patients. These disorders include benign (non-cancerous) conditions, such as hemorrhoids (piles), and more significant conditions, such as malignancy (cancer). Hence, the clinician must be familiar with these disorders and arrive at a proper diagnosis for better treatment outcomes.
What Is the Normal Physiology of the Anus and Rectum and Its Significance?
Sound knowledge is crucial regarding normal defecation and bowel continence (ability to control bowel movements). These processes depend on the anatomy and interaction between the pelvic floor (comprises bladder and bowel) muscles and the nervous system. During normal defecation, conscious pushing increases the intra-abdominal pressure (within the abdomen) along with the contraction of the rectal muscles. Simultaneously, the anal sphincters relax, leading to the widening of the anorectal angle (ARA, an angle between the rectum and anus that facilitates continence). These movements facilitate stool excretion from the rectum and anus. However, pelvic floor muscle incoordination can lead to defecation disorders. Furthermore, muscle and nerve weakness leads to fecal incontinence. Similarly, pelvic floor nerve dysfunction can cause abnormal muscle control leading to constipation or rectal pain.
What Are the Common Disorders of the Anus and Rectum?
Anorectal disorders can occur due to improper diet, lifestyle, and fecal bacteria. Common anorectal disorders include:
1. Hemorrhoids: Hemorrhoids affect more than 50 percent of the population above 50. These represent swollen veins in the lower rectum and anus that may be internal or external. The disease mechanism of hemorrhoids is unclear but may involve the weakening of connective tissue. The venous swelling and engorgement occur due to increased intra-abdominal pressure, such as excessive pushing, constipation, pregnancy, and extended sitting. Symptoms include painless rectal bleeding, itching, involuntary passage of feces, irritation around the anus, and mucus discharge.
Hemorrhoid treatment is divided into nonsurgical and surgical. Further, the foundation of treatment is pain control. The conservative measures are Sitz baths (a soothing combination of warm water and sodium bicarbonate) and taking painkillers. Surgical removal is most effective during the first three days after symptom appearance. However, surgical removal is reserved for advanced diseases.
2. Anal Fissures: An anal fissure is an anal skin tear that can be acute (short-term) or chronic (long-term). The disease mechanism includes injury, reduced blood flow, and raised anal pressure. Acute fissures are present for less than two months and heal with local management. Chronic anal fissures require surgical treatment due to failed conservative management, scarring, and poor blood supply. Patients with an anal fissure complain of sharp and tearing pain during and after the passage of feces.
Treatment of an anal fissure is medical or surgical (in case of refractory cases). Medical treatment aims to relax the anal sphincter (a ring of muscles in the anus) and stop spasms and tearing. Local application of Nitroglycerin, Nifedipine, and Diltiazem ointments increases the blood flow to the area. The gold standard for chronic and refractory cases is to cut the anal sphincter (sphincterotomy). The procedure is effective and has a low recurrence rate.
3. Anorectal Abscesses and Fistulae: Anorectal abscesses (pus collection) and fistulae (an abnormal connection) are considered a spectrum of the same disease. Perianal (around the anus) abscess is the initial feature of the infection that may lead to a perianal fistula. One must note that the conversion of an abscess to a fistula occurs in about 40 to 50 percent of cases. Perianal abscess patients have persistent pain and swelling. On the other hand, perianal fistulas comprise blood, pus, or stool drainage. Treatment of the abscess requires incision and drainage to prevent spread and recurrence, whereas a perianal fistula treatment is surgical and depends on its anatomy.
4. Fecal Incontinence: Fecal Incontinence (FI) is an embarrassing and devastating disorder. It affects approximately 24 percent of the general population. Moreover, the percentage of affected individuals is higher in hospitalized and nursing home patients. Complaints range from minor incontinence to frank and involuntary passage of feces. The mainstay of treatment is lifestyle changes. Avoiding diarrhea-inducing medications can significantly improve FI. Furthermore, patients should restrict diets high in artificial sugars and caffeine. Biofeedback therapy (a technique employed to gain muscle control) and Hyaluronic acid injection to the anal area can also improve continence in such patients.
5. Pruritus Ani: Pruritus ani leads to itching or burning in the perianal area. The causes include irritants (soaps or laundry solutions), foods (coffee, chocolate, and citrus), infections, skin disorders, and malignancy. The clinicians must direct the treatment to the underlying cause after diagnosis.
How Are the Disorders of the Anus and Rectum Diagnosed?
Clinicians diagnose an anorectal disorder with the following tools after a meticulous history and examination.
1. Digital Rectal Examination: It is an overlooked part of the physical examination. The clinician inserts a gloved and lubricated finger through the anus into the rectum. It is a beneficial diagnostic process in rectal bleeding, hemorrhoids, constipation, and trauma. An absolute contraindication is an immunocompromised patient (a patient with impaired immunity) because of the risk of introducing infection in such patients.
2. Anoscopy: It is a diagnostic procedure in which a small tube (anoscope) is used to view the rectum and anus. It is an inexpensive procedure that can be performed without bowel cleansing or sedation. An anoscopy can diagnose hemorrhoids, anal growths, anal fissures, anal inflammation, and malignancy.
3. Colonoscopy: A colonoscopy is a vital tool in modern medicine. It is a versatile life-saving procedure used for diagnosis and treatment. Diagnostic colonoscopy can detect acute and chronic anorectal conditions and treat early colorectal cancers. It also can direct steps in cancer treatment for surgery. The disadvantage is that it requires a thorough bowel cleansing and sedation.
4. Flexible Sigmoidoscopy: It is a diagnostic procedure used to view the end portion of the large intestine. It can explore the causes of abdominal pain, rectal bleeding, bowel habit changes, diarrhea, and other intestinal issues. Sigmoidoscopy is also used for colon cancer screening above the age of 50.
5. Imaging Studies: Noninvasive imaging tests such as ultrasound or magnetic resonance imaging (MRI) show the structure of the rectum, anus, and sphincter function.
6. Rectal Biopsy: A rectal biopsy removes a sample from the rectum during anoscopy or sigmoidoscopy for laboratory analysis.
Conclusion
To conclude, anorectal disorders can impair the quality of life of a patient. Diagnosis is made by a symptom history, inspection, digital rectal examination, and selective tests. One must note that clinical correlation is essential before labeling an abnormal finding. With these methods, a clinician can diagnose an anorectal disorder and provide the appropriate treatment.
