Introduction

Gastrointestinal symptoms are very common within the general population (Thompson et al., 2003). There is a high prevalence of rectal bleeding (Crossland and Jones, 1995; Thompson et al., 2000), change in bowel habit (Everhart et al., 1989) and abdominal pain (Sandler, 1990). Since any one of these symptoms alone can be due to benign, transient disease, symptom complexes are more useful for predicting serious pathology (Thompson et al., 2007). In the UK, this has led to the ‘two week wait guidelines’ for suspected cancer (Department of Health, 2000). This means that patients with symptoms most predictive of colorectal cancer (Table 10.1) must be seen within 2 weeks from the date of referral.

Table 10.1 Criteria for urgent referral for suspected colorectal cancer under the two-week rule

This chapter will explore symptoms and symptom complexes of lower gastrointestinal disease, the possible diagnosis and the investigation performed for each symptom group.

Rectal bleeding

Bleeding from the gastrointestinal tract can be overt or occult. With overt rectal bleeding, the blood is recognized and is usually noticed on defecation. If this is the case, the origin of the bleeding is usually in the left colon or distal transverse colon. If the bleeding is occult, the blood loss is not recognized in the stool and the patient presents with anemia.

When a patient presents with rectal bleeding, there are features that can help locate the source of the bleeding, such as the color of the blood. Bright red rectal bleeding tends to originate from a distal source such as the rectum, whereas dark red blood tends to originate from a more proximal source but within the left colon or distal transverse colon. Another feature is whether the blood is separate to the stool or mixed in when it is passed. If the blood is separate to the stool, the patient notices it on the toilet paper or in the water in the toilet bowl, this usually suggests a very distal source such as hemorrhoids. If blood has had time to mix in with the stool, it suggests a more proximal source of bleeding.

Coexisting symptoms are also very important. A change in bowel habit to looser stools coupled with rectal bleeding is a symptom complex with a high predictive value for cancer (see above) or colitis. Anal pain may suggest a fissure. Change in bowel habit to constipation may merely mean that constipation has exacerbated hemorrhoids. Common combinations of symptoms associated with rectal bleeding, the possible causes and appropriate investigations are detailed below.

Bright red rectal bleeding with anal symptoms

Rectal bleeding with anal symptoms without a change in bowel habit is the lowest predictor of colorectal cancer (Thompson et al., 2007). It usually suggests hemorrhoids (associated with mucus, skin tags or prolapsing lumps) or an anal fissure (associated with anal pain on defecation). Distal proctitis (inflammation of the very distal rectum) may also be a cause. The exception to this is anal cancer that may present with these symptoms but is often associated with a lump or ulcer in the anal canal

Investigation: no radiological investigation may be necessary. This diagnosis can usually be made in the outpatient clinic on rigid sigmoidoscopy and/or proctoscopy. In the case of a fissure, examination may not be possible and a painful per rectum (PR) examination may be diagnostic.

Bright red rectal bleeding without anal symptoms

This may suggest a distal rectal cancer, although this is often associated with change in bowel habit to looser stools, fecal leakage or a feeling of incomplete evacuation (tenesmus).

Investigation: radiological investigation may not be necessary for this symptom complex. It should be diagnosed on PR examination ± rigid sigmoidoscopy or proctoscopy. Flexible sigmoidoscopy would be appropriate in the over 40s to exclude malignancy. Should a stricture prevent the passage of the endoscope, a barium enema (Figure 10.1) or computed tomography (CT) should be considered.

Figure 10.1 Rectal synchronous tumors.