Saturday, January 21, 2012

Observation For Anticoagulated Head Trauma

Coming in a future issue of Annals, the Editor's capsule summary: "Delayed intracranial hemorrhage is common after minor head injury when patients are receiving warfarin. A minimum protocol of 24-hour observation followed by repeated scanning is necessary to detect most such occurrences."

Now, this isn't a terribly management agnostic statement.  It does not specifically state this is something we need to start doing - but it rather implies that, if you don't, you'll be missing this "common" phenomenon.  It isn't an alien concept - since 2002, the European Federation of Neurological Societies has recommended admission for observation after minor head trauma - but it's certainly not the standard of care here.  So, for the Annals editors to state that observation and repeat scanning is "necessary", they must obviously have excellent evidence.

Or they have an observational case series consisting of 87 patients from Italy.

These authors present a prospective case series of all patients at their institution who were admitted for observation specifically for minor head trauma while on oral anticoagulation.  At the time of repeat CT scanning 24 hours later, the authors report five of them had new bleeding detected.  In addition, two patients who were discharged after two negative CT scans returned with symptomatic bleeding, one at two days, and one at eight days.

So, should we be observing and rescanning every anticoagulated minor head trauma patient as these authors suggest (and as they do in Europe)?  If you practice in a zero-miss litigation environment, this article and ACEP's apparent embrace of the results will hamstring your decision-making.  This data is completely inadequate to change clinical practice, and inconsistent with prior literature documenting delayed hemorrhage in only 2 of 137 patients.

Clearly, some patients will have delayed bleeding - a subset of which will be clinically significant.  However, we simply cannot expose all anticoagulated patients with minor head trauma to the harms and costs of hospitalization.  Better studies are required to prospectively determine the risk profile of patients who require further observation in a hospital setting, rather than a watchful discharge home.

"Management of Minor Head Injury in Patients Receiving Oral Anticoagulant Therapy: A Prospective Study of a 24-Hour Observation Protocol"

Friday, January 20, 2012

Correspondence in Nature Reviews Neurology

After publishing an article that alluded to the "antipathy" of emergency physicians towards TPA in acute ischemic stroke, the editors were nice enough to publish my correspondence defending the reasonableness of a cautious attitude.

"Skepticism about thrombolytics in stroke is not unreasonable."

Thursday, January 19, 2012

EMLit on ERCast

It's like podcasting with Jack Buck - always a pleasure.  Rob Orman does great work, and he's got a huge archive of invaluable wisdom accumulated through his podcasts.  I hope you enjoy our most recent episode together.

"Decision Tools: PERC, NEXUS and CURB-65"

Lies, Damned Lies, and Tamiflu (oseltamivir)

Receiving quite a bit of press yesterday, and rightfully so, the Cochrane Collaboration published their analysis of oseltamivir - the miracle influenza antiviral that (at great cost) is part of our nation's strategic stockpile for an influenza pandemic.  The story is interesting both regarding what they found, and what they didn't find.

As for the data from the review, the numbers are similar to what we've been basing our practice upon - oseltamivir significantly shortens the length of time until symptom improvement from 160 hours to 139 hours.  However, it did not demonstrate any difference in hospitalization rates.  Additionally - whether through study bias or by direct medication effects - the oseltamivir groups were significantly less likely to have a confirmed diagnosis of influenza.

So, this suggests that it's a little troubling that we've gone to all the expense to stockpile this expensive medication that does not appear to reduce hospitalizations from influenza - and it remains an individual decision whether that extra day of symptom improvement is worth exposure to the side effects of the medication.  But the reason this is national news is that Roche pharmaceuticals refused to supply the promised clinical data requested by the Cochrane Collaboration; the published analysis is based on 15 oseltamivir studies with complete information, and excludes 42 other studies with discrepancies in the data.  This sort of behavior is just another representative sample of the unethical, but completely understandable, profit-motivation of pharmaceutical corporations protecting their financial interests.

I would be greatly surprised if the clinical data Roche is holding onto supports oseltamivir efficacy.

"Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children - a review of clinical study reports"

"Flu Drugs: Search for evidence goes on"

Tuesday, January 17, 2012

100,000 Incorrect TIA Diagnoses Every Year

...if we extrapolate the results from this single-center study to the entire United States.

In Annals this month, a chart review of the "discordance" between the final neurologist "gold standard" diagnosis and the provisional Emergency Department diagnosis.  Apparently, in Cleveland, 36% of the patients receiving an initial diagnosis of transient ischemic attack in the Emergency Department are subsequently evaluated by a neurologist and given an alternative diagnosis.  As the authors note in their introduction, the diagnosis of TIA is made 300,000 yearly - and if 36% of those cases are made incorrectly, then we're theoretically admitting 100,000 patients for extensive and expensive evaluation.

So, are they right?  Well, if the three neurologists responsible for 93% of their 427 evaluations are representative of the entire country, perhaps.  Or, if their chart review methods are adequate - as the authors note, one of their chart audits changed an abstracted diagnosis of TIA to "right hip pain" - then, perhaps.  If you ignore that ED physicians have a few minutes of history, examination, and limited imaging available at their disposal - compared with the neurologists that can subsequently perform any manner of inpatient studies that might uncover an alternative diagnosis mimicking a TIA - then, perhaps.

If neurologists are walking into the ED and evaluating patients under the same constraints as we are and producing this level of discordance, then we have a problem.  But, I don't think this study tells us anything we can use to evaluate ED physicians' ability to appropriately include or exclude TIA in the differential for neurologic complaints of a transient nature.

Somewhat disappointing that a small, retrospective chart review with results that might not be internally or externally valid are in the premier, #1 Impact Factor journal of our profession.

"Variables Associated With Discordance Between Emergency Physician and Neurologist Diagnoses of Transient Ischemic Attacks in the Emergency Department"

Sunday, January 15, 2012

PERC - Still (Mostly) Useless

...except, perhaps, in a risk-management sense - but, only if we keep beating it down into its narrowest application due to its terrible specificity.

This most recent Annals publishes a systematic review of the Pulmonary Embolism Rule-Out Criteria, a decision instrument recommended in ACEP's pulmonary embolism clinical guidelines as a reasonable tool to risk-stratify a patient into a so-called "zero-risk" population that does not require any testing - not even a D-dimer.  And, I think they do a reasonable job including studies and summarizing the data, especially considering the width of the error bars on a lot of these studies.

The key points - pooled sensitivity is 97% when applied to a low-risk (Wells, Geneva, gestalt, whichever) population with a negative LR of 0.18.  This means, if you had someone who you already didn't think had a PE and they meet PERC criteria, it helps you with your medicolegal documentation, since it's in ACEP's guidelines.  The negative LR is strong enough to be helpful - but when you're already looking at single-digit percentage risk for PE, the absolute reduction in risk is quite small.

The important point to hammer home is the positive LR is only 1.23, which makes it the D-dimer of decision instruments.  Please don't justify further work-up just because they fail PERC - it barely moves the needle with its terrible specificity.  You need to have another clinical justification for further work-up in pulmonary embolism.

As an aside, in this era of over-testing and over-diagnosis of PE, the diagnosis of PE isn't necessarily the ideal endpoint - what we should be following are patient-oriented outcomes such as death/heart failure in untreated PE in PERC-negative patients to truly make it a valid tool.

"Diagnostic Accuracy of Pulmonary Embolism Rule-Out Criteria: A Systematic Review and Meta-analysis"