If you are a busy primary care physician, wouldn’t you like to get some quick confirmation that your patient with a fever and runny nose has a viral upper respiratory infection? If there were a test or a simple physical finding that could give you the answer while the patient was still in the office, you could dispense a quick dose of reassurance and send him or her on their way. It would probably help you inch a bit closer to relieving the congestion in your waiting room.
I am sure most of you realize that relying on the patient’s temperature or the color of his or her nasal mucus is not going to give you that reliable and swift answer you would like. There have been rapid diagnostic tests for influenza on the market for several years, but I have not been aware of a similar test for rhinovirus. But I recently came across a study that offers some hope that such a test might become a reality in the future (EBioMedicine. 2017 Mar;17:172-81). In the study, researchers at Duke University and elsewhere identified a group of proteins in mucus that can confirm – with 86% accuracy – that the patient is infected with a cold or flu virus. They anticipate that this discovery could be adapted into a rapid test that could be performed in the doctor’s office.
Dr. William G. Wilkoff
However, I am sure that most of you would do a careful exam and spend a few minutes on a slightly more detailed discussion of what worrisome symptoms the parents should be watching for. But let’s be honest. Isn’t it likely that knowing that the patient has a rhinovirus infection might derail your diagnostic process short of a full consideration? Isn’t it tempting to say to yourself, “He only has a viral URI, and I even know the name of the virus. My job is done.”
Although the odds are that the virus is causing all your patient’s symptoms, there is always the chance that he or she is harboring a bacterial coinfection. Or, that what appears to be “only” a virus is actually an early step in the deadly spiral of the first episode of diabetic ketoacidosis.
This quandary is another example of the paradox in which more information can make your job as a diagnostician more difficult. Does your patient’s positive rapid strep test mean that strep is the primary cause of your patient’s fever and sore throat? Couldn’t he or she just be a carrier? Should a positive test that confirms your clinical impression put an end to your evaluation of the patient?
You could answer that you don’t have the time to go looking for zebra stripes hidden on the underbelly of every equine that gallops into your exam room. Of course you don’t. But, you are obligated to keep your mind open to the possibility that a lab test promising to make your job easy may not be telling you the whole story.
Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics, including “How to Say No to Your Toddler.” Email him at pdnews@frontlinemedcom.com.