Monday, June 17, 2013
The art of medicine and philosophy are intimately related when it comes to the question of life. Doctors are able to answer the what, where and how of diagnosis and treatment, but have to take the back seat to PhDs as to the why. Why does the same injury cause devastation to one victim but not another? Why does one patient sail through treatment, yet another suffers complication after complication. Baseball is often a teacher of philosophy and there is a minor epidemic of pitchers being hit in the head by line drives.
This week, Tampa bay pitcher Alex Cobb was felled by a ball that hit him in the head above the right ear. There was no loss of consciousness, he did suffer a concussion and spent the night in hospital for observation. Ct scan of the brain did not show any injury but that does not mean that the brain did not sustain microscopic damage and Mr. Cobb is not allowed to play for now. Less than a year ago, Brandon McCarthy, a pitcher for the Oakland A’s was hit in the head by a liner, above the right ear. He had no loss of consciousness but CT scan showed a skull fracture plus an epidural hematoma, a blood clot located in the space between the skull and brain, which required surgery to drain.
There are a few parts of the body that have design flaws and the parietal bone is one place that could have used additional oversight. The bone, located along the side of the skull, has areas that are very thin and surprisingly, the middle meningeal artery is located in an area where the bone is thinnest, just above the ear. While the occipital bone in the back of the skull is about 9mm (a little more than 1/3 of an inch) thick and the frontal bone is more than 8mm thick, the parietal bone is less than 6 mm or about a 1/5 of an inch. To make matters worse, the artery runs in a groove carved out of the bone, making the bone that much thinner.
Should the parietal bone fracture through the middle meningeal groove, the artery can be damaged and bleed. Blood accumulates in the space between the bone and the brain in the epidural space (epi= outside + dura=lining of the brain). As the artery pumps blood into that space, the clot can put pressure on the brain causing potential damage. The diagnosis is made by CT scan but the question for doctors is who to scan. McCarthy and Cobb had the exact same injury pattern, both hit in the head, both alert, neither with loss of consciousness and yet only one sustained a life threatening injury. There are guidelines as to when a CT scan is indicated but they only work if the patient shows up to be seen.
How many people get hit in the head, shake it off and never seek medical care? There is a presumption that being knocked unconscious is a requirement for a major head injury. But head injury CT guidelines don’t consider being knocked out. Instead, it is the mechanism of injury and brain function that gets the CT scanner warmed up. And for brain function, in addition to a normal neurologic exam, there needs to good memory. The patient needs to know what happened and they need to be able to lay down new memory.
Baseball fans know that it is a game of inches. Medicine is no different. Both pitchers sustained concussions but only one needed an operation. Doctors can explain how each player was injured, what the damage was and how it can be fixed. It takes a philosopher to know why a fraction of an inch spared the middle meningeal artery for one player and not for another.This entry was tagged alex cobb, brandon mccarthy, concussion, CT scan, epidural hematoma