Digital Rectal Examination
Digital rectal examination is a very important part of physical examination. It should be performed when the patient complains about gastrointestinal problems, especially diarrhea, constipation, abdominal pain or information about stool color change. The examination should be also performed in patients with sudden collapse or short-term unconsciousness as these conditions may be related to acute gastrointestinal bleeding.
The examination in not pleasant for both the patient and the doctor, but it is important and it allows a skilled doctor to gain a lot of valuable information.
The patient must be correctly positioned. There are more positions possible, but the most ideal is on all four extremities with bent elbows and knees. Other frequently used position is on the side with bent legs (the knees should point towards the chin). The doctor takes a glove, applies a numbing gel on a finger and inserts it cautiously into the rectum.
When performed cautiously, the examination should be painless. Pain may be present in diffuse inflammation in the abdominal cavity (peritonitis) or in wounds or other diseases of the anus (local fistulas, anal fissure).
The finger reaches up to about 4 inches (10 centimeters) of the rectum. In this area, we are able to find any obstacle such as solid stool in constipation, larger rectal polyp or even rectal form of colorectal cancer.
Anatomically, the prostate is located in front of the anterior wall of the rectum and can be indirectly palpated during the digital rectal exam. Healthy prostate should be soft, supple and of a size of a small chestnut. The palpation may help a skilled physician (especially urologist) to suspect a benign enlargement of the prostate (enlarged soft tissue) or prostate cancer (hard as stone). When there is prostatitis, the examination is very painful.
Stool remnants on the glove
After pulling the finger out of the rectum, it is necessary to evaluate the stool on the glove. Its color should be brown, but we may find green stool (typically in infectious diseases), red blood in stool, or black stool (usually melena). More about the importance of these findings can be found in the related texts.
Results of the examination
The digital rectal examination may give us a guide for further investigation, which may lead to proper diagnosis. Probably the most valuable is the confirmation of melena, which is mostly followed by upper GI endoscopy. The examination is quick, usually painless and the result is available immediately.