An ongoing dialogue on HIV/AIDS, infectious diseases,
January 22nd, 2019
Unanswerable Questions in Infectious Diseases — Treatment Duration in Endocarditis: 4 Weeks, 6 Weeks, Other?
Time to get back to some tough clinical decisions. It’s been a while.
However, that series of posts appeared here in early 2014, which means it’s been 5 years with no “Unanswerable Questions.”
Lest you think that all Unanswerable Questions have been answered — ha — here’s another one, inspired by a flurry of papers recently on a favorite topic, duration of antimicrobial therapy.
To summarize virtually all of them — shorter is usually as good, if not better, than longer. Nice editorial here.
Before we get to the case, an up-front apology that the question might seem simple. But I assure you, the answer is anything but straightforward. Bold prediction: there will be a substantial divergence in responses.
Additionally, while the question may not seem like such a big deal, there are many interested parties eagerly awaiting our answer — including our hospitalist, cardiology, and primary care colleagues, diverse insurance plans, homecare companies, outpatient pharmacies, and skilled nursing facilities. Most importantly, our patients and their families care a lot, too.
And even though the correct answer to “How long should I treat?” is “Long enough” (thank you, Bob Rubin!), this doesn’t change the fact that consulting services really want to know a precise answer. Ironic, huh?
Here’s the case, an amalgam of many seen over the years:
A 52 year old man is admitted with fever. On exam, he has a temperature of 101.5F and a loud systolic murmur. Two sets of admission blood cultures grow methicillin-sensitive Staph aureus. A cardiac ECHO shows a bicuspid aortic valve with a 0.5-cm vegetation.
He is treated with oxacillin; follow-up blood cultures are negative by hospital day 3, and fevers slowly resolve. A peripherally inserted central catheter (PICC) is placed on hospital day 5, and cefazolin replaces oxacillin in anticipation of discharge home on IV antibiotics.
The patient, the medical team, the homecare company, and your OPAT colleagues all await a specific “stop date” for the IV cefazolin.
If he has a clinically stable course (no further positive cultures, no recurrent fevers, and no metastatic sites of infection), how long would you treat him with intravenous antibiotics?
Before you answer, you’re welcome to look at the guidelines — this is an open-book blog, after all:
- American Heart Association
- European Society of Cardiology
- British Society for Antimicrobial Chemotherapy
Or, you could just wing it based on your clinical experience and judgment, or cite the POET study if you’re feeling cutting edge. Clock starts the day of the first negative blood culture.
And please defend your choice in the comments section, especially if you choose option 4!
(Apologies to Drs. Wald-Dicker and Spellberg for the Days-of-the-Week Units.)