Digital rectal exam: side view of the male reproductive and urinary anatomy, including the prostate, rectum, and bladder.
The digital rectal examination (DRE, Latin palpatio per anum or PPA) is a relatively simple procedure. The patient undresses, then is placed in a position where the anus is accessible (lying on the side, squatting on the examination table, bent over the examination table, or lying down with feet in stirrups).
If the patient is lying on their side, the physician will usually have them bring one or both legs up to their chest. If the patient bends over the examination table, the physician will have them place their elbows on the table and squat down slightly. If the patient uses the supine position, the physician will ask the patient to slide down to the end of the examination table until their buttocks are positioned just beyond the end. The patient then places their feet in the stirrups.
The physician spreads the buttocks apart and will usually examine the external area (anus and perinium) for any abnormalities such as hemorrhoids, lumps, or rashes. Then, as the patient relaxes, the physician slips a gloved and lubricated finger into the rectum through the anus and palpates the insides for approximately sixty seconds.
This examination may be used:
- for the diagnosis of rectal tumors and other forms of cancer;
- for the diagnosis of prostatic disorders, notably tumors and benign prostatic hyperplasia;
- for the diagnosis of appendicitis or other examples of an acute abdomen (i.e. acute abdominal symptoms indicating a serious underlying disease);
- for the estimation of the tonicity of the anal sphincter, which may be useful in case of fecal incontinence or neurologic diseases, including traumatic spinal cord injuries;
- in females, for gynecological palpations of internal organs;
- for examination of the hardness and color of the feces (i.e. in cases of constipation, and fecal impaction);
- prior to a colonoscopy or proctoscopy;
- to evaluate hemorrhoids;
- In newborns to exclude imperforate anus.
The DRE is inadequate as a screening tool for colorectal cancer because it examines less than 10% of the colorectal mucosa; sigmoidoscopy is preferred. However, it is an important part of a general examination, as many tumors or other diseases are made manifest in the distal part of the rectum.
Sometimes proctoscopy may also be part of a rectal examination.
In veterinary medicine rectal examination is useful in dogs for analysis of the prostate (as in men), pelvic urethra, sublumbar lymph nodes, and anal glands. In horses it is a vital component of the clinical examination for colic, to determine the presence or absence of bowel torsion, impaction, or displacement. When horses undergo a rectal examination there is a small risk of a rectal tear occurring, which can be a life-threatening event, rapidly leading to peritonitis and septic shock. It is also a common procedure in cattle, and is one method of diagnosing pregnancy in both the horse and the cow.
The procedure in dogs and cats is similar to humans. For the horse, the patient stands in a stock and may be sedated. The examiner puts on a long glove that extends to the shoulder. The examiner inserts the hand and arm into the rectum as far as necessary.
Due to the taboos surrounding the anus, and the potential for discomfort and embarrassment, the rectal exam is a common comedic device. Generally, it is not shown directly, but implied as the examiner dons and lubricates a glove while behind the patient. The Family Guy episode Stewie Loves Lois even uses the rectal exam as the main plot, when Peter Griffin, not realizing it is a routine medical procedure for checking for prostate cancer, thinks he is being "raped". The body cavity search is frequently used the same way.
- Chodak, GW.; Keller, P.; Schoenberg, HW. (May 1989). "Assessment of screening for prostate cancer using the digital rectal examination.". J Urol 141 (5): 1136–8. PMID 2709500.
- Schroder, F. H.; Kruger, A. B.; Rietbergen, J.; Kranse, R.; Maas, P. v. d.; Beemsterboer, P.; Hoedemaeker, R. (1998). "Evaluation of the Digital Rectal Examination as a Screening Test for Prostate Cancer". JNCI Journal of the National Cancer Institute 90 (23): 1817–1823. doi:10.1093/jnci/90.23.1817. ISSN 0027-8874.