Friday, August 10, 2012

Here Comes Gonorrhea (Again)

Good news for the monogamous – bad news for the rest – Neiserria gonorrhoeae is rapidly becoming resistant to cefixime, an oral third-generation cephalosporin.  The resistance rates are low – a maximum of 17% in Honolulu – but the fear is that continued cefixime use will carry-over into an increased resistance for ceftriaxone.

This follows the 2007 declaration that fluoroquinolone resistance had obviated their use.

For now, the CDC recommendations have narrowed to 250mg IM/IV ceftriaxone plus 1g oral azithromycin once or 100mg oral doxycycline BID for seven days.

"Update to CDC's Sexually Transmitted Diseases Treatment Guidelines, 2010: Oral Cephalosporins No Longer a Recommended Treatment for Gonococcal Infections"

Thursday, August 9, 2012

Cited in Journal Watch

My dabigatran article from Annals of Internal Medicine has been cited in Journal Watch.  Huzzah!

"Within 12 weeks of marketing approval, dabigatran was found to be 
responsible for more adverse events than nearly all other medications.
   By David Green, MD, PhD"

Dabigatran:  How Safe?

Wednesday, August 8, 2012

Ketamine - Cure For Everything

There aren't many medications I love using more than ketamine.  I use it for adjunctive pain control, to control agitation, and for induction prior to intubation.  Now, chances are, it's probably useful in seizures.

This is a case report and review of the literature for the use of ketamine in the control of refractory status epilepticus.  The literature is profoundly weak – the "review" is essentially a review of case reports.  And, the patient outcomes describe in the case reports are replete with "All died" or "Survived but severely disabled."  However, this is primarily due to the serious cause of the underlying disorders – encephalitis, neurosyphilis, meningitis, anoxic brain injury – and less likely the ketamine, although this does not provide the evidence to that effect.  The proposed mechanism is via NMDA receptor antagonism, which the author proposes works better by synergy with GABA antagonism, rather than either as monotherapy.

Seems like a fair physiologic mechanism, and it's nice to have something additional to consider in refractory disease.  Ketamine also was noted in this case report to counteract the hypotensive effects of midazolam and propofol, consistent with prior literature describing its beneficial effect on cerebral perfusion pressure.  It's pretty much a "I tried this and I like it" article, but I think it's probably likable and not the last we've heard about ketamine for status.

"Early Ketamine to Treat Refractory Status Epilepticus"

Monday, August 6, 2012

When Do Patients Need Blood Cultures?

Another lovely JAMA Rational Clinical Examination article relevant to the Emergency Department – this time regarding the utility of blood cultures.  Blood cultures are frequently requested for febrile inpatients, however, the incidence of false positive ranges between 2.5% and 8%.  This leads, unfortunately, to additional patient harms from additional treatment or observation.

This article is a systematic review of several studies gathering clinical features of patients for whom blood cultures were requested, as well as the clinical outcomes of the cultures, in an attempt to identify features predictive of positive or negative cultures.  They also examine a couple validated clinical decision instruments to determine their potential utility in stratifying the appropriateness of cultures.

Essentially, based on a few pieces of decent evidence and a few pieces of poor evidence, the authors determine a few general categories of infectious etiology with varying pretest probability for bacteremia.  These are:
 • Cellulitis, community-acquired pneumonia, community-acquired fever: low (<14%) probability
 • Pyelonephritis: mid (19-25%)
 • Severe sepsis, septic shock, bacterial meningitis: high (38-69%)

In general, however, no individual clinical feature had a positive or negative likelihood ratio of sufficient magnitude to guide testing.  Combinations of clinical features – such as patients with SIRS – were capable of excellent sensitivity & negative likelihood ratios, but only had specificities of 0.27 to 0.47.

However, the more important clinical aspect of blood cultures and bacteremia is not addressed in this article, which is how frequently the true positives even change clinical management.

"Does This Adult Patient With Suspected Bacteremia Require Blood Cultures?"