Anal fissure: An anal fissure is a tear in the anal mucosa. Causes include passing hard stools, tuberculosis, syphilis, carcinoma, herpes, IBD, and AIDS. It presents with acute, severe rectal pain that worsens with defecation. On per-rectal examination, there is increased tone of the anal sphincter and rectal bleeding. A chronic fissure may show a sentinel tag, which is a protruding perianal tag of anal mucosa. Acute fissures are treated with stool softeners and rectal suppositories or creams containing a steroid and local anesthetic. Nitroglycerine ointment with misoprostol and botulinum toxin can also be used. Chronic fissures are treated with sphincterotomy.
Anal abscess: An anal abscess is a collection of pus in the anorectal area that usually begins as an infection of the anal glands in the crypts. Abscesses may be superficial or deep. Superficial abscesses present with pain, perianal swelling, redness, tenderness, and less commonly fever. Deeper abscesses are typically less painful, but they cause fever, chills, and malaise, and they may be palpated as a fluctuant bump on per-rectal examination. It is a mixed infection with E.coli, Proteus vulgaris, Bacteroides, Streptococci and Staphylococci. Treatment is incision and drainage plus antibiotics. Some abscesses may form fistulas after rupture.
| Type | Features |
| Perianal | Most common, superficial |
| Ischiorectal | Deeper, extends across the anal sphincter into the ischiorectal space, bilateral involvement may cause a “horseshoe-shaped” abscess |
| Intersphincteric | Pus collects between the external and internal anal sphincters |
| Supralevator | Deep, above the levator ani, may extend to peritoneum and abdominal organs, associated with IBD, diverticulitis, PID |
Anal fistula: A fistula is a tract that is open at both ends. An anal fistula may be caused by rupture of an anal abscess, IBD, diverticulitis, Chlamaydiasis, syphilis, tuberculosis, cances, HIV, etc. Infection typically begins in a clogged anal gland. The outer opening appears as a red, inflamed area that oozes pus and blood. The internal opening can be visualized by MRI, endoscopic ultrasound, or fistulography with contrast. Treatment includes fistulotomy, cutting or draining setons (non-absorbable nylon or silk suture), fibrin glue, or fistulectomy.
Hemorrhoids: Hemorrhoids are dilated and tortuous veins in the anorectal mucosa. They can be external or internal. External hemorrhoids begin below the dentate line, while internal hemorrhoids begin above the dentate line. They present with a bulge during defecation, itching or irritation, hematochezia with small amounts of fresh blood that coats the stool or stains the toilet tissue, and pain (typically with external hemorrhoids or thrombosed hemorrhoids). Internal hemorrhoids are painless. Pregnancy, obesity, chronic diarrhea or constipation, a low-fibre diet, and weight lifting are associated with increased risk. Band ligation and infrared coagulation are preferred treatments for grades I to III internal hemorrhoids. Radiofrequency treatments can be used for all grades. Supportive treatment for all hemorrhoids includes sitz baths, stool softeners, and analgesics. Thrombosed hemorrhoids are acutely painful and are treated by incision and removal of thrombus or excision of clot. Sclerotherapy is not preferred nowadays. Surgical excision can be done for unresponsive cases and for complications such as strangulated, gangrenous, or thrombosed hemorrhoids.
Proctitis: Proctitis is inflammation of the rectal mucosa. It can result from IBD, radiation, infections with N.gonorrhoeae, Chlamydia, Campylobacter, Shigella, Salmonella, Cl.difficile, HSV, and CMV, and anal intercourse. It presents with tenesmus, bleeding, mucousy stools, and pain. Diagnosis is by proctoscopy or sigmoidoscopy, along with testing for infections. Treatment depends on the cause.
Rectal prolapse: In rectal prolapse, the mucosa of the rectum and anal canal or the entire thickness of the rectal wall prolapses (procidentia) through the anal opening. You can differentiate these by looking for a sulcus between the anus and the prolapsed rectum: this sulcus is present in a full-thickness prolapse and absent in a mucosal prolapse. Causes include long-term constipation, childbirth, cystic fibrosis, COPD, whooping cough, surgery, etc. Surgical resection (full-thickness prolapse) or excision (mucosal prolapse) is needed.
Anorectal cancer: Anorectal cancer is common. Most tumors are adenocarcinomas above the denate line, while squamous cell carcinomas are more common in the anal area. Risk factors include age >50 years, obesity, smoking, polyposis syndromes, Lynch syndrome, immunosuppression, anal intercourse, and HPV 16 and 18. It can present as a mass, ulcer, polyp, or verrucous growth. Biopsy shows neoplastic columnar epithelium, glands (in adenocarcinoma), and mucin. Tumors are cytokeratin positive. Depth of invasion is an important prognostic factor in rectal cancer, while size of the lesion is important in anal cancer. Rectal cancers are treated with surgery, chemotherapy, and/or radiation (for higher stages). Anal cancer is treated with combination chemotherapy with mitomycin C and fluorouracil plus radiation. Resistant cases are treated with abdomino-perineal resection.
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