It took me 18 months of residency to learn that decision making in medicine is generally not based on pure science. Many people choose medicine as a career because they enjoy the scientific physiology of problems and making decisions on which tests to order and treatments to choose based purely on a history, physical exam, and what is best for the patient.
The truth is that as a neurology resident, the right decision is not always what makes the most sense. You can make a diagnosis based on a history and physical exam, but the plan that gets set in place is affected by uncontrollable variables including expectations of the physicians requesting the consult, expectations of the patient, and opinions of other residents and attending physicians on your team.
For example, consider a 48 year old woman with hypertension who comes into the ER with a chief complaint of left arm, face, and leg tingling and intermittent headaches all of which resolved in 45 minutes. She has a normal physical exam. This history isn't entirely consistent with migraine; it could possibly be a transient ischemic attack, or even a thalamic stroke. But if the problem is gone, why should any further diagnostic measures or treatment be pursued?
Maybe because her primary care physician told her to come to the ER because he is concerned his patient is having a stroke. And who can say with 100% certainty that her brain MRI will be normal? Afterall she has a stroke risk factor of hypertension. So because of the expectations of the referring physician, the patient receives an MRI of her brain and an MRA head/neck. The MRI reveals no evidence of stroke, but an abnormally high amount of cortical (brain) atrophy which doesn't explain her symptoms of headache and left sided tingling/numbness. Her MRA head and neck are normal (the work normal must always be used with caution) with no evidence of carotid arterial stenosis.
The patient is told that her brain MRI showed no evidence of stroke and she is diagnosed with a diagnosis of a transient ischemic attack. She is started on aspirin 81mg once daily to help prevent future stroke.
Realistically it seems unlikely that for a 45 minute period in time the right side of her brain was receiving insufficient blood flow giving her transient numbness. However it is easier to disagree with a 27 year old neurology resident than it is with an MRI. And it is easier to order a test than it is to get a history and physical exam. What would be accomplished from bypassing the MRI? Saving thousands of dollars on a test, sparing the patient from receiving radioactive/nephrotoxic gadolinium? None of this would be worth a 30 minute discussion/arguement with an ER attending who will likely order the test anyway.
The patient is discharged from the ER relieved that she doesn't have a stroke and now has piece of mind. She is not informed of her cortical atrophy. Perhaps she will be at an increased risk to develop cognitive symptoms/memory loss in the future, and there is very little that can be done to prevent this. The medical community is open to reason and evidence based medicine, but ultimately uninformed physicians will often succumb to unfounded gut instinct. And perhaps the boldest question of all for patients, medical students, interns, and junior residents to ask of senior members on the team, is why. But I try not to think too hard about this, or anything else for that matter!
