The Gabapentinoid Cure-All

Gabapentinoids – gabapentin and pregabalin – were traditionally prescribed for their approved indications: the treatment of seizures and various manifestations of neuropathic pain. Of course, there are many newer agents for epilepsy, and the the market for neuropathic pain ought to remain fairly stable. Therefore, why has gabapentinoid use effectively tripled over the past decade, as generally described by this research letter?

Most notably, in this letter, gapapentin use increased most in those with multiple comorbidities, as well as those with concurrent opioid and benzodiazepine prescriptions. Considering the lack of proven efficacy and the potential for misuse or adverse effects, there’s frankly no excuse for such rampant overuse. Nearly all this expansion represents waste and harm in our health system, with mixed and scattershot evaluation of its various applications almost certain to mislead rather than inform true treatment effects.

It seems it really ought to be time to reduce prescribing of gabapentinoids – particularly off-label – but the reverse seems true!

“Gabapentinoid Use in the United States 2002 Through 2015”

Would You Use A Syncope SDM Instrument?

Much has been made, off and on, about the chest pain shared decision-making tool rolled out over the past couple years. It turns out, when properly informed of their low risk for subsequent cardiac events, most patients look at you sideways and wonder why anyone was offering them admission in the first place.  Whether that was its intended purpose, or a happy little accident, is a subject of controversy.

Their next target: syncope.

The content of this article is not very profound, other than to show the first step in the process of developing such an SDM instrument. These authors detail their involvement of emergency physicians, cardiologists, and patient stakeholders to inform their iterative design process. In the end, their tool looks a lot like the their chest pain instrument:

Generally speaking, because the approach to low-risk syncope has some of the same issues as low-risk chest pain, I have essentially the same fundamental problems. Much like for chest pain, inpatient evaluations for syncope are generally unrevealing. We probably ought not be admitting most of these patients. Therefore, this SDM instrument is again addressing the problem of low-value resource utilization by shifting the burden of the decision onto the patient, and trying to convince them to make what we already know to be the correct one (go home). That’s not how the Force works.

Then, just like the chest pain tool, this fails to convey the benefit of hospitalization for comparison. In their pictogram, two out of 100 patients suffer an adverse event after fainting. Is admission to the hospital protective against those adverse events – even if a diagnosis is made? The patient needs to receive some simplified visualization of their expected benefit from staying in the hospital, not just simply the base rate for deterioration.

I love shared decision-making. I use it constantly in my practice in situations where the next step in evaluation or treatment has no clearly superior path. Again, I don’t think this reflects the same uncertainty.

“Development of a Patient Decision Aid for Syncope in the Emergency Department: the SynDA tool”

The HSV Meningitis Question

This is one of those questions that always crops up when evaluating an infant for sepsis and meningitis – should we test and/or empirically cover for herpes simplex virus infection? Just how frequently is this diagnosis made?

The answers, as described in this retrospective, multi-center study, are complex. First, the basics: 26,533 total encounters analyzed, with 112 children ultimately diagnosed with HSV meningitis. Then, it’s basically chaos. The percent of patients whose CSF was tested for HSV ranged from 12.5% to 70.9% across hospitals included, along with empiric coverage with acyclovir ranging from 4.2% to 53.0%. Rates of positive HSV results were unrelated to overall institutional testing or empiric acyclovir coverage rates, excepting in the sense that HSV infection was more frequent in younger infants – and younger infants were more likely to be tested and empirically treated, in general.  A handful of patients with ultimate diagnoses of HSV meningitis were not treated or tested initially, and were found on a subsequent visit.

The authors go into some detail regarding the questionable value of empiric treatment, citing a number needed to treat of 152 for infants 0-28 days and an NNT of 583 for infants from 29-60 days. Generally speaking, these authors agree with a prior cost-effectiveness analysis recommending waiting for the initial CSF cell count, and empirically treating those with a CSF pleocytosis. Consequently, these authors would therefore recommend testing only those ultimately treated empirically – but this is naturally a pragmatic consideration, rather than a statistically modeled balance between sensitivity and specificity.

There are a few more nuances within the paper with regard to their gold standard for diagnosis of HSV meningitis, limitations with regard to selection of patients undergoing testing, and generalizability from these tertiary referral settings, but it is still generally an interesting snapshot of data. Unfortunately, their ultimate conclusion is still back at square one – reiterating a call for specific clinical and laboratory data to help guide clinicians in selecting patients for HSV testing and empiric treatment. In the meantime, we’ll just keep doing our best to differentiate the ill child at the bedside based on gestalt and the culture of our practice setting.

“Herpes Simplex Virus Infection in Infants Undergoing Meningitis Evaluation”

Influenza, Sideways

Hello, everyone! Influenza, influenza, influenza. Influenza? Influenza. Influenza influenza, influenza – influenza – influenza, influenza!

It’s that time of year in the Northern Hemisphere, following up last year’s busy season, and a terrible one in the Southern Hemisphere in the interim. At this point, for your general ambulatory patient, I hope you’ve stopped sending swabs. If you think they have it, they probably do – although, there is some respiratory syncytial virus out there, too.

But, I’ve also been surprised by a couple of people who didn’t look like typical influenza, and this little expert commentary is a nice reminder of the less-common manifestations of influenza infection. The respiratory compromise is well-documented, but patients can not uncommonly become seriously ill with myocarditis, myositis, and viral encephalitis, as well as causing less serious serious hepatic injury and acute tubular necrosis. There have also been case reports implicating influenza less frequently in a scattershot of clinically interesting entities.

Just in case you weren’t getting enough influenza in your life.

“The hidden burden of influenza: A review of the extra- pulmonary complications of influenza infection” [open access]