Why Focusing On Tidbits Of Information Can Lead You Down The Wrong Diagnostic Path

Stephen Barrett DPM FACFAS

I had a very interesting patient come in last month. Sadly, she was in an automobile accident about four years ago, which resulted in an intracranial bleed. She ended up with severe vertigo and loss of strength on her left side. The car hit her from the left side, causing trauma to the entire aspect of her left side, including an ulna fracture as well as a tibial plateau fracture of the left knee.

Sometimes, there is a dilemma in figuring out the true etiology of symptoms in any semi-complex case. Many times, once we label a patient with a diagnosis, as with this brain injury, we attribute everything to that diagnosis.

One rule I learned is that humans can be affected by more than one thing at the same time. This is often more the rule than the exception. However, when a patient comes in with “I have RA,” she receives a diagnosis of arthritis and then all of her foot conditions henceforth are “arthritic.” I have noticed too that “arthritis” is a great way to ameliorate the pain that patients still have postoperatively, even when everything looks perfect on X-ray and they still have some less than ultimate outcome. “Oh! Mrs. Jones, you just have some arthritis, which is why your bunion still hurts.”

Patients know that as they get older, they become arthritic. Perhaps this is too simplistic though. Unfortunately, “arthritis” may be perceived as a term like “that’s not my department or my area of expertise.” The term allows a very quick escape route during today’s extremely busy postoperative clinic when everything is going crazy and things that shouldn’t be a problem are and things that are a problem are bigger than they should be. You know the feeling of that clinic today exploding into the next supernova.

A Closer Look At The Patient’s Presentation And History

In this particular example, this middle-aged lady had been falling frequently and has had a very less than desirable quality of life because her left foot did not work. She accepted and believed this was her lot in life because all of her doctors told her she would have to live with this the rest of her life because of the brain injury. However, she was lucky enough to have a big, painful bone spur on the top of her foot. Her podiatrist referred her to me because of my interest in nerves. When he touched the bony area, she got a “zinger” and I was fortunate enough to examine her.

Interestingly, she did have a large exostosis on the dorsal aspect of the first metatarsocuneiform articulation, which demonstrated a very significant Tinel's sign with distal radiation into her big toe. On further examination, however, I noticed that she had virtually no motor strength for the extensor hallucis longus and tibialis anterior on her left side. Her peroneals were also extremely weak.

Her brain injury, interestingly enough, was on her left side. We do know that cortical things make a little crisscross somewhere up there in the noggin, right? Yet for four years, she had heard that it was her brain injury that caused all her left lower extremity problems. I will bet that not one of her doctors will tell her that the bone spur on the top of her left foot was caused by the brain bleed though. I guess the intracranial hematoma could have calcified and then migrated south down to the first metatarsocuneiform articulation like the “magic bullet.”

Continued examination revealed a very significant provocation sign of her common peroneal nerve on the left side. She received appropriate testing and underwent a workup for surgery. Interestingly enough, after a 20-minute neurolysis of the common peroneal nerve, she was able to move her big toe — after waking up in the post-anesthesia care unit — in dorsiflexion with about 80 percent strength. Obviously, this was not due to the brain bleed but rather due to the blunt force of the car that “T-boned” her tibial plateau into a rippled mesa. This was certainly enough of a tectonic shift to cause some soft tissue like the common peroneal nerve to get dinged a little.

In Conclusion

So what is the point of this story? I guess we tend to go through our clinical days in a routine in which patients tell us the problem, which gives us a segment of their history. (Keep in mind that what they remember is not always what someone told them.) We hang on to one or two of the tidbits the patient gave us, however poorly the patient remembered them. This can lead us down the wrong diagnostic path very rapidly.

Remember that patients tell you what they remember and human memory is pathetic (mine is worse than that). They will also tell you what they wanted to hear their other doctors say, not necessarily what they said.

Look at more than just the bone spur for a second and see what else could be occurring. A great example of this is that patient who complains with nebulous lateral ankle pain, and all the magnetic resonance imaging and computed tomography scans show nothing abnormal. The patient gets a few steroid injections that do not help with some patients even lucky enough to have had a lateral ankle stabilization of some type. Then by happenstance, someone presses on the patient’s lower leg about 16 cm proximal to the lateral malleolus between the tibial crest and fibula, and he or she jumps out of the chair. That’s right. It is superficial peroneal nerve entrapment.

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