From the Guidelines
A digital rectal examination (DRE) should be performed in patients with back pain when there is suspicion of cauda equina syndrome or other serious underlying conditions, such as spinal stenosis or radiculopathy, as indicated by "red flag" symptoms or severe neurological deficits 1.
Indications for DRE
The examination is specifically indicated when patients present with back pain accompanied by:
- Saddle anesthesia (numbness in the perineal region)
- Recent onset of bladder dysfunction (urinary retention or incontinence)
- Bowel incontinence
- Severe or progressive neurological deficits in the lower extremities
- Bilateral leg weakness or numbness During the DRE, the clinician should assess for decreased anal sphincter tone, reduced perineal sensation, and absent anal wink reflex, all of which suggest possible compression of the cauda equina nerve roots.
Importance of DRE in Back Pain Evaluation
This examination is crucial because cauda equina syndrome requires immediate surgical decompression to prevent permanent neurological damage 1. The pathophysiology involves compression of the nerve roots at the end of the spinal cord, typically from a large central disc herniation, tumor, infection, or hematoma, which disrupts innervation to the bladder, bowel, and perineal region. While most back pain does not require a DRE, missing this diagnosis can lead to permanent disability, making the examination essential in these specific clinical scenarios.
Additional Considerations
In patients with low back pain, clinicians should consider the use of medications with proven benefits in conjunction with back care information and self-care, and assess severity of baseline pain and functional deficits, potential benefits, risks, and relative lack of long-term efficacy and safety data before initiating therapy 1. However, the primary focus should be on identifying and addressing any underlying serious conditions that may require urgent intervention, such as cauda equina syndrome. In the context of evaluating patients with back pain, a DRE is also relevant when assessing for other conditions, such as benign prostatic hyperplasia (BPH), where a DRE can help exclude locally advanced prostate cancer as a cause of voiding dysfunction 1. Nevertheless, the immediate concern in patients with back pain is to identify any signs of serious neurological compromise that necessitate prompt medical attention.
From the Research
Digital Rectal Examination (DRE) in Patients with Back Pain
- The decision to perform a DRE in a patient with back pain should be based on specific clinical indications, such as suspected prostate cancer or spinal metastasis 2.
- A DRE may be useful in patients with back pain who are at high risk for prostate cancer, particularly those with urinary frequency, nocturia, or other symptoms suggestive of prostate disease 2.
- The presence of a suspicious nodule on DRE can predict the presence of clinically significant prostate cancer, even in patients with low prostate-specific antigen (PSA) values 3.
Clinical Indications for DRE
- Penetrating injuries in proximity to the lower gastrointestinal tract 4
- Questionable spinal cord damage 4
- Severe pelvic fractures with potential urethral disruption or open fractures in continuity with the rectal vault 4
- Suspected prostate cancer, particularly in patients with elevated PSA or abnormal DRE findings 2, 5, 3
Limitations and Considerations
- DRE is an invasive diagnostic test that can cause patient anxiety and discomfort 6
- The utility of DRE in patients with normal PSA values is still uncertain and requires further study 5
- A better understanding of the limitations and constraints involved from both the patient and physician perspective can help improve patient experience and overall clinical outcomes 6