Chapter 29: Rectal Pain, Itching & Bleeding Evaluation

Rectal Pain, Itching & Bleeding Evaluation begins by establishing the essential anatomy of the anorectal region, particularly the dentate line which separates somatic from visceral nerve supply, a critical factor in distinguishing painful external hemorrhoids from typically painless internal hemorrhoids. The text details the diagnostic reasoning process for rectal bleeding, helping clinicians differentiate between upper gastrointestinal sources manifesting as melena and lower gastrointestinal causes presenting as hematochezia, such as diverticulosis, anal fissures, or colorectal cancer. Significant attention is given to pediatric-specific conditions, including life-threatening necrotizing enterocolitis in premature infants, intussusception characterized by currant jelly stools, Meckel diverticulum, and allergic colitis, alongside the use of the APT test to identify swallowed maternal blood. The summary covers the differential diagnosis of rectal pain, contrasting the sharp, tearing sensation of anal fissures—often associated with sentinel tags and constipation—with the continuous, throbbing pain of perirectal abscesses and fistulas originating in the anal glands. It also examines infectious etiologies like proctitis and proctocolitis, frequently caused by sexually transmitted infections such as gonorrhea, chlamydia, syphilis, and herpes simplex virus, emphasizing the importance of sexual history and risk assessment. Pilonidal disease is described as a structural cyst or sinus in the sacrococcygeal area, often affecting young men. Furthermore, the chapter outlines the evaluation of pruritus ani, exploring causes ranging from hygiene practices and pinworm infestation to fungal infections. The text reviews essential physical examination techniques, including inspection, digital rectal examinations (DRE), and anoscopy, as well as laboratory and diagnostic studies like fecal occult blood testing (FOBT/FIT), stool DNA markers, and colonoscopy screening guidelines for patients with risk factors like familial adenomatous polyposis (FAP) or hereditary nonpolyposis colon cancer (HNPCC).