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While doing some catch-up reading, I recently came across an article about the Ottawa screening tool for subarachnoid hemorrhage. It noted clinical factors that best predicted a bleed were as follows:
• Age 40 years or older.
• Neck pain or stiffness.
• Witnessed loss of consciousness.
• Onset during exertion.
• Thunderclap onset of headache.
• Limited neck flexion. (I’m not sure why this was separated from the second factor.)
In the validation cohort that the investigators used to devise the rule, these factors resulted in 100% sensitivity and 15% specificity for subarachnoid bleed, which increased to an overall sensitivity of 99.2% and a specificity of 99.6% when the derivation cohort and the validation cohort were combined
This is, admittedly, interesting, and certainly of value in a situation where imaging isn’t immediately available. But, realistically, how often does that happen in a modern ER?
Not to put down the research, but in everyday practice no one is going to rely on a basic guideline of this sort. Will it change the number of CT scans or lumbar punctures done? Probably not. The risk of missing a bleed is so potentially serious that CT scans are routinely done for most headache symptoms. "Well, the Ottawa SAH rule said ..." is unlikely to protect you in court.
So why do people keep coming up with scales of this sort? Part of it, I suspect is the disconnect between academic centers (where most of these are created) and front-line medicine. There’s also likely an element of "publish or perish," in which fellows have to come up with things like this.
But, realistically, do they change the way nonacademic medicine (which is most of it) is practiced? Probably not.
Dr. Block has a solo neurology practice in Scottsdale, Ariz.
While doing some catch-up reading, I recently came across an article about the Ottawa screening tool for subarachnoid hemorrhage. It noted clinical factors that best predicted a bleed were as follows:
• Age 40 years or older.
• Neck pain or stiffness.
• Witnessed loss of consciousness.
• Onset during exertion.
• Thunderclap onset of headache.
• Limited neck flexion. (I’m not sure why this was separated from the second factor.)
In the validation cohort that the investigators used to devise the rule, these factors resulted in 100% sensitivity and 15% specificity for subarachnoid bleed, which increased to an overall sensitivity of 99.2% and a specificity of 99.6% when the derivation cohort and the validation cohort were combined
This is, admittedly, interesting, and certainly of value in a situation where imaging isn’t immediately available. But, realistically, how often does that happen in a modern ER?
Not to put down the research, but in everyday practice no one is going to rely on a basic guideline of this sort. Will it change the number of CT scans or lumbar punctures done? Probably not. The risk of missing a bleed is so potentially serious that CT scans are routinely done for most headache symptoms. "Well, the Ottawa SAH rule said ..." is unlikely to protect you in court.
So why do people keep coming up with scales of this sort? Part of it, I suspect is the disconnect between academic centers (where most of these are created) and front-line medicine. There’s also likely an element of "publish or perish," in which fellows have to come up with things like this.
But, realistically, do they change the way nonacademic medicine (which is most of it) is practiced? Probably not.
Dr. Block has a solo neurology practice in Scottsdale, Ariz.
While doing some catch-up reading, I recently came across an article about the Ottawa screening tool for subarachnoid hemorrhage. It noted clinical factors that best predicted a bleed were as follows:
• Age 40 years or older.
• Neck pain or stiffness.
• Witnessed loss of consciousness.
• Onset during exertion.
• Thunderclap onset of headache.
• Limited neck flexion. (I’m not sure why this was separated from the second factor.)
In the validation cohort that the investigators used to devise the rule, these factors resulted in 100% sensitivity and 15% specificity for subarachnoid bleed, which increased to an overall sensitivity of 99.2% and a specificity of 99.6% when the derivation cohort and the validation cohort were combined
This is, admittedly, interesting, and certainly of value in a situation where imaging isn’t immediately available. But, realistically, how often does that happen in a modern ER?
Not to put down the research, but in everyday practice no one is going to rely on a basic guideline of this sort. Will it change the number of CT scans or lumbar punctures done? Probably not. The risk of missing a bleed is so potentially serious that CT scans are routinely done for most headache symptoms. "Well, the Ottawa SAH rule said ..." is unlikely to protect you in court.
So why do people keep coming up with scales of this sort? Part of it, I suspect is the disconnect between academic centers (where most of these are created) and front-line medicine. There’s also likely an element of "publish or perish," in which fellows have to come up with things like this.
But, realistically, do they change the way nonacademic medicine (which is most of it) is practiced? Probably not.
Dr. Block has a solo neurology practice in Scottsdale, Ariz.
