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“You need to have a rectal exam” you explain to one of your patients. He’s a 47-year-old with chronic back pain who is in the ED for an exacerbation of his pain accompanied by many of the associated accoutrements, such as sciatica, numbness and trouble urinating. You wonder if some time later during his ED course he will also inform you that he is out of his pain medication. “I’m not a fan of doing rectal exams,” you explain, “but sometimes it’s very important. If you are having trouble urinating, it might mean that you have a herniated disc pressing on nerves at the tail of your spinal cord and that could cause permanent neurological damage. I need to check your muscle strength down there and also see if you have something else that could be causing the trouble urinating such as an enlarged prostate gland.”
“No way, Doc! No way anyone’s going to stick their finger in my bum, not even you! There’s gotta be some other test you can do. How about an MRI?” You try a half dozen ways to convince him that the rectal exam is the best way to figure things out rapidly, and that the radiologist won’t approve an MRI unless the physical exam, including the rectal exam, has been completed. You’ve already done a chart biopsy, so you know that this particular patient is in the ED frequently for back pain and opiate refills and has had prior negative MRIs for the same exact presentation, including urinary retention. You also know that BPH and opiate-induced urinary retention are both far more common than cauda equina syndrome. You don’t want to give this guy more narcotics and you definitely don’t want him lingering in your ED for the 4+ hours it will likely take to get an MRI done and read by the radiologist. However, what you don’t want even more is to miss cauda equina syndrome just because your patient is a frequent flier. A rectal exam for tone, sensation and volition, plus a check of the bulbocavernosus reflex for completeness sake is the best and quickest way to confirm your suspicions and send him packing. Unfortunately, you can’t do the rectal without his consent.
Your next proposed solution, a Foley catheter to check for a post-void residual, is also met with the same excited refusal. So far, all of your objective examination and reflex testing has been normal, but you really need the rectal exam to make a bullet-proof chart. What other options do you have? You decide that the best plan B is to carefully document in the chart your attempts to convince the patient, along with his reasons for refusal, and then use your ED’s bedside ultrasound machine to do a post-void residual estimate of his bladder volume. While you are there you can try to take a look at his prostate size as well. Fortunately he agrees to let you scan him. With the machine plugged in and powered up, you take the following images.
How big is his prostate gland? How large is his bladder volume? Are these values normal or pathologic?
Conclusion on next page