Lower gastrointestinal bleeding is defined as hemorrhage originating distal to the ligament of Treitz (Davila et al. 2005). Rectal bleeding seems to be the sixth most common cause of presentation to emergency department, yet rarely requires blood transfusion or radiological/surgical intervention. In 80 % of patients it is self-limiting and resolves spontaneously (Lee et al. 2009). In case of acute bleeding the vital part is identifying risk in patients, to allow care to be appropriately directed. Naturally, hemodynamically unstable patients or in presence of fragile, medical comorbidities, or concurrent sepsis, the hospital admission is required. Three criteria are been identified to stratify the risk: (1) hemoglobin level, (2) systolic blood pressure, and (3) antiplatelet/anticoagulant therapy, to be significant factors in predicting the need for a blood transfusion (Patel et al. 2014). For the identification of the “high risk” patient Kollef et al. added elevated prothrombin time, erratic mental status, and unstable comorbid disease (1997). The patients identified as “low risk” could be booked for outpatient flexible endoscopy within 6 weeks, unless they have had a recent colonic investigation (Vanhegan et al. 2011; Patel et al. 2014).

Although rare, massive bleeding typically is thought to require more than 3–5 unit of blood transfused in 24 h. Mortality, ranging about 0.6 %, is lower than that from upper gastrointestinal bleeding, which is about 2 % (Kollef et al. 1997).

Massive lower gastrointestinal bleeding can occur at any age, even though there are specific diseases afflicting different age group, showing a familiarity which can help in planning diagnostic workup (Raphaeli and Menon 2012).

Meckel’s diverticulum, inflammatory bowel disease (IBD), and juvenile polyps are the most common causes of lower gastrointestinal hemorrhage in young people.

IBD can afflict adult people too, according to its bimodal distribution, with a second peak about age of 60. Bleeding is a typical initial symptom, while massive hemorrhage is present in about 1 % of cases (Robert et al. 1991).

Common cause of intestinal bleeding in adults is the diverticular disease, more frequently (about 50 %) arising from right colon. Colorectal cancer (CRC), the most frequent intestinal cancer and the second cause of mortality for cancer, can arise with bleeding, typically slow and insidious, till chronic anemia. Advanced age, personal or familiar history of polyps, personal history of IBD, or gynecological cancer increase the risk of presenting CRC (Table 21.1).

Less frequent causes of lower gastrointestinal hemorrhage, but more frequent causes of bleeding are the hemorrhoids, colitis (with ischemic, diversion, radiation, infectious nature), solitary rectal ulcer, stercoral ulcer, post-polypectomy bleeding, and small bowel tumors.

In presence of massive bleeding, after resuscitation maneuvers (i.e., crystalloid and blood product) and obtaining stabilization of the patient and information about his history, the goal is the identification of the source of bleeding. The literature reports that the first steps consist of sampling the gastro-duodenal contents, through carefully position of nasogastric tube and performing an esophago-gastro-duodenoscopy to investigate and exclude a proximal source (Jensen and Machicado 1988; Laine and Shan 2010). The second step consists of investigating the “distal potential source” of bleeding: anus, rectum, and till the entire colon. The digital rectal examination, followed by anoscopy, is a fast tool to check for palpable causes of bleeding. The digital rectal examination alone can reveal common cause of bleeding but rare cause of massive bleeding, such as hemorrhoids, fissure, external fistulous opening, perianal dermatitis, traumatic lesions, rectal prolapsed, condyloma, and mass. Anoscopy allows a direct vision of entire anal canal and the most distal part of rectum also, in order to obtain rapid and direct information about anorectal mucosa and its characteristic and rectal contents. The presence of blood and stools could obstruct and limit the inspection of the lumen, so the evaluation can be performed after an enema or a rectal washing. At this point the patient can be submitted to urgent rectosigmoidoscopy, or, if the bleeding has stopped and the patient can sustain a mechanical bowel preparation, a pancolonoscopy. If bleeding is not massive, endoscopy can be booked outpatient in patients who belong to risk group (i.e., older than 50 years, older than 40 years with familiar history of CRC or polyps, personal history of IBD), unless they have had a recent colonic investigation.

Colonoscopy is one of the mainstays of both diagnostic and therapeutic management in case of gastrointestinal bleeding, since the 1970s, though actuating this examination in presence of unprepared bowel or massive bleeding is difficult. Colonoscopy can survey a large spectrum of colorectal abnormalities which could be responsible of rectal bleeding, including benign or malignant diseases (Image 21.2).

If colonoscopy is not useful (e.g., unprepped bowel, negative examine, massive hemorrhage) other diagnostic tools to localize lower GI hemorrhage are:

In several diseases colonoscopy can represent the last diagnostic tool (e.g., direct disease visualization, indirect disease stigmata, obtaining a biopsy), and it can become an useful therapeutic tool, not only in case of polyps which can be removed by polypectomy. Endoscopic treatment options include thermal coagulation with argon plasma coagulation (APC), bipolar or heater probes, cryotherapy, or neodymium-doped yttrium aluminum garnet laser therapy, and endoscopic topical application of formalin (e.g., in case of chronic radiation proctopathy). Another important role played by colonoscopy is in the follow up period, to verify the pertinence of a therapy, due to the possibility of serial endoscopic monitoring (Image 21.3).

Either benign or malign proctologic disease can present a nontypical endoscopic scene as in case of a rectal ulcer.

A rectal ulcer , as reveled at colonoscopy, needs a biopsy to clarify its nature, and obtain a definitive diagnosis, because it presents a frequent misdiagnosis due to its nonpathognomic symptoms (including bleeding, mucus discharge, and anorectal pain) and varied endoscopic appearance. Solitary rectal ulcer syndrome is a common end-pathophysiologic process of focal rectal mucosa ischemia and ulcer formation. Many factors may play a role in its etiology: rectal intussusception, pelvic floor dyssynergia, and local rectal trauma. Contrary to the name, less than one third of the patients (more frequently women in the third-fourth decade) present a single lesion; many ulcers are observed in about 40 % of patients, hyperemic mucosa and polypoid mucosal change in less than one fourth of patients. The anterior rectal wall is the most frequent part involved. The absence of malignancy or suspect of IBD at biopsy, in young adults with no history of radiotherapy for pelvic tumor or suspect of ischemic colitis, is suggestive of solitary rectal ulcer. Either defecography or dynamic magnetic resonance is useful in finding suggestive anatomo-functional alteration frequently associated to this syndrome as the presence of rectal intussusceptions or pelvic dyssynergia (Sharara et al. 2005). Moreover pelvic dyssynergia may be investigated with anorectal manometry (ARM) and balloon expulsion test (BET) (Image 21.4).

In case an ischemic proctitis is the responsible of rectal ulcers (e.g., when the patient is submitted to radiation therapy, aortic aneurysm repair, or aorto-iliac intervention with theoretical insult to blood supply to the rectum), the endoscopic findings are represented by mucosal ischemia with associated ulceration, and, sometimes, when the ischemia is severe, confluent ulcers, pseudomembranes, and poor bleeding when submitted to biopsies. Histopathologic confirmation is mandatory. The evidence of pneumatosis and extraluminal air-findings at CT scan suggest transmural necrosis and represents an indication to surgical treatment (Image 21.5).

The presence of a rectal mass, polyp, or ulcer with malignancy at biopsy starts the diagnostic falls for rectal cancer staging, according to NCCN guidelines (Version 2.2015). In case of noncomplete colonoscopy, it is important to “extend” the endoscopic examination to the whole colon. Blood tumor marker test should be performed to report the level of CEA (carcinoembryonic antigen) and Ca 19.9, to help monitoring the response to treatment or providing an early warning of recurrence.

Additional information regarding the extent of disease and distant metastases can be determined through: endorectal ultrasound and pelvic MRI to assess the depth of tumor penetration through the rectal wall and spread to local lymph nodes (N+); contrast CT scan of chest, abdomen, and pelvis for the preoperative staging of rectal cancer; PET/CT to evaluate an equivocal finding on a contrast CT scan.

Evidence supports an integrated therapeutic approach to rectal cancer. Local excision is appropriated for early stage without N+. Neoadjuvant chemoradiotherapy is indicated for patients with stage II-III rectal cancer and surgical strategy depending on the extent of disease. However, total mesorectal excision (TME) is recommended. Adjuvant chemotherapy is only suggest following neoadjuvant chemoradiotherapy and surgery in case of suboptimal treatment (e.g., positive circumferential resection margins, perineural invasion, and /or lymphovascular invasion) (Images 21.6, 21.7, and 21.8).