getting the call wrong

Tuesday, September 27, 2016

One wonders why anybody would aspire to be a referee. It is a thankless job that somebody has to do, especially in the amateur ranks. There is some glamour in being on the field, ice or court as the best players in the world perform, and in that regard professional referees and umpires are also the best at what they do. Less glamourous are the little league umpires or soccer referees who suffer just as much scorn ads the pros. But it’s the beginning of the week and fans, especially those of the losing team, are vocal in blaming officiating as the cause of their favorite team’s demise.

There are very few sports that have black and white results. Racing against the clock provides an arbitrary score but most team sports are at the mercy of the officials. The same is true in medicine. One would think that doctors could agree on the results of an X-ray, blood test or EKG, but one might be wrong. Black and white don’t often exist in medicine and even grey is often in dispute. Not that one shouldn’t trust test results, but they are just one part of a patient’s evaluation and need to be taken into context.

Radiology

cxr

Let’s consider the basic X-ray. The radiologist can take as long as needed to interpret the images, but the in box is always being filled with new cases to read and there is a time crunch. It’s no different than instant replay; the referees could take forever to review play to the detriment of the game and the enjoyment of the fan. Many studies have looked at the radiology miss rate and it tends to be about 3-5%. Interestingly, that percent stays about the same whether the radiologist quickly looks at the film or whether inordinate amount of time is spent reviewing the images. One study reviewed chest X-rays and defined visual dwell as spending too much time on one specific part of the film. Those who spent too much time had the same error rate as the radiologist who spent less than 4 seconds reading an X-ray. The researchers’ conclusion: “Common experience in radiology suggests that many errors are of little or no significance to the patient, and some significant errors remain undiscovered.”

 

Cardiology

echo

Like radiologists, cardiologists (heart specialists) often interpret tests without physically seeing and touching the patient. Presumably, a test result is a test result, but just like fans from opposing teams who can’t agree on what constitutes a catch in the NFL, cardiologists reading the same test may come to different conclusions. Echocardiograms are ultrasounds of the heart that help diagnose structural abnormalities. Add exercise (or inject a chemical to get the heart to do more work and the echo can help diagnose narrowing of the coronary arteries. Researchers had two or more cardiologists review echocardiograms and compared their interpretations. In patients with normal hearts and those with bad heart disease, the docs agreed. But is patients with intermediate disease, cardiologists could only agree 75% of the time.

For most patients, diagnosis and treatment involves being touched by a health care provider and test results are put in perspective. Clinical situation and tests have to make sense together and the art of medicine involves interpreting the situation. There may not be a wrong, just a gray shade of not right. This perhaps does not satisfy the Monday morning quarterback since everybody, including medical people strive for perfect. But in the imprecise world that is medicine, black and white don’t routinely exist.

Radiology Quality Institute. White Paper: Diagnostic Accuracy in Radiology 2012

Brady A, etal. Discrepancy and Error in Radiology. Ulster Med J. 2012 81(1).

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normal exam..abnormal head ct

Tuesday, September 6, 2016

Concussion is supposed to be a football and hockey issue, but this weekend it was baseball that reminded us that head injury isn’t limited to “contact” sports. Angels pitcher Matt Shoemaker was hit in the heads with a line drive and though he was not knocked out and had a normal neurological examination, he was not immune from injury. In the real world that mechanism of injury is one of the indications to perform a CT and image the brain.

Mr. Shoemaker cut his forehead but otherwise walked off the field under his own power as he was attended to by the medical staff. Based on being hit by a ball hit at an estimated 105 mph, a CT was done, finding a skull fracture (usually not a big deal) and bleeding inside his head. Press releases weren’t specific about what type of bleeding, but blood in or near the brain is never good.

The skull is a solid box and is mostly filled with brain tissue. If there is swelling or bleeding, there is no place for it to go and the brain may get squashed, which it does not really like. Bleeding in the skull is categorized based on its location.

  • Epidural hematoma or blood clot is located between the brain lining and the skull. This is caused by torn arteries that line the skull
  • Subdural hematoma is located between the lining and the brain tissue and is due to tearing of the bridging veins that travel from the skull to the brain
  • Subarachnoid hemorrhage is located in the space where fluid bathes the brain
  • Intracerebral hemorrhage or hematoma is located within the brain tissue.

ic hematoma

Not all bleeding in the brain needs an operation. Regardless of whether Mr. Shoemaker had an epidural or subdural hematoma, he was watched closely in ICU and had repeated CT scans to monitor the amount of bleeding, whether the clots were enlarging and whether there was pressure being exerted on the brain. Within a few hours, bleeding had progressed and an operation was needed to fix the bleeding issue and prevent brain damage.

There are a variety of guidelines that help decide who might need a CT scan in the first place and who can just be watched. There are all sorts of caveats for each guideline and the purpose is to prevent too many CT scans and the potential radiation risk while not missing significant brain injury. It’s easy to decide to do a CT scan when a head injury victim is not acting normally or has an abnormal physical exam. But Mr. Shoemaker reminds us that one can act normally and still have brain issues. For that reason, “significant mechanism of injury” is an indication to get a CT scan. What is significant? The Ottawa CT head guidelines suggest a couple, including a pedestrian being struck by a motor vehicle, a passenger ejected from a car or falling more than 5 stairs. A 105 mph baseball probably qualifies.

While violent head injuries are self evident, too often injuries can’t easily be appreciated from the sideline and initial symptoms may be shortlived. This week, the NFL Players Association sent out information packets to all its players to teach them about concussion symptoms so that they can help check on their teammates. It’s about time; we called for this to happen in 2011.

And some final food for thought. Mr. Shoemaker has a significant head injury/concussion. Is one big blow enough to cause CTE in the future? Do you need to endure multiple “small” head injuries to cause future chronic brain disease? The joy of not being able to predict the future.

 

 

 

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