HIV and ID Observations

You youngsters out there might not believe this, but there was a time when passing out copies of published papers — actual hard-copies — was a major part of the teaching hospital experience.

Now that this tree-destroying practice is over, many still regularly cite published studies on rounds. The goal is to provide some guidance and reason to clinical practice — that has to be better than the less rigorous approach of applying anecdote to an amorphous blob of clinical data.

In other words, taking care of patients is hard, and never more so than when seeing ID consults. After all, no one ever consults ID when the diagnosis is clear, the treatment straightforward, and the patient improving.

Remember that at your next salary negotiation!

Here, then, are a bunch of studies that came up in the past few weeks while seeing consults with an outstanding first-year ID fellow — who is now happily away on holiday, and hence might even have the time to read them!

• Penicillin reduces the risk of recurrent cellulitis. In many ways this is an ideal clinical trial. It takes a highly relevant clinical question — should patients with recurrent cellulitis take daily penicillin? — and then answers it in a double-blind, randomized study. The results showed that the penicillin treatment group had nearly a two-fold reduction in the risk of subsequent cellulitis, with no major drug toxicity. This is a particularly useful strategy for patients with recurrent cellulitis due to lymphedema, venous insufficiency, or obesity, infections which are mostly caused by beta strep.
• The optimal duration of therapy for gram-negative bacteremia remains unclear. Amazing how many ID consults focus on this how long should treatment continue question, and also amazing how few controlled studies answer it. So we’ll have to revert to observational studies. Here’s one paper that says 7-9 days is fine for gram negative bacteremia; but here’s another paper that says two weeks is better. Oh well, better consult the rules! And on this topic of treatment duration …
• Four days of antibiotics is just as good as eight for intraabdominal infection, with one big caveat. In contrast to the first study cited above (the penicillin one), this trial is of relatively little use to us ID doctors. And here’s the reason — it included only patients if “they had undergone an intervention to achieve source control.” In other words, these are emphatically not the sort of patients with abdominal infections who need ID consults, and the surgeons understandably rarely ask for our input. Oh well.
• Two-drug treatment with dolutegravir and rilpivirine maintains virologic suppression as well as 3-drugs. This is a particularly useful regimen for hospitalized HIV patients who develop acute renal issues, as both drugs are hepatically metabolized. Importantly, we need to check first that they’re not also receiving PPIs, which are contraindicated with rilpivirine, and that they’ve not failed treatment in the past with NNRTI resistance. And while it’s now available as a single pill, I doubt most hospital formularies are stocking this as of now. The two little separate pills will be just fine until then.
• Mycoplasma has many extra-pneumonic complications. Encephalitis, transverse myelitis, hemolytic anemia, myopericarditis, erythema multiforme, Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis — you name it. Apparently, mycoplasma-related SJS has more prominent mucosal and eye involvement and frequently milder skin findings, prompting the designation of “Mycoplasma-induced rash and mucositis” or “MIRM”. Who knew?
• Oxacillin/nafcillin vs cefazolin for serious Staph aureus infections:  The Debate Continues. On the one hand, there is the “cefazolin inoculum effect” of the staph beta lactamases, which theoretically could reduce cefazolin activity more than oxacillin/nafcillin in high-burden infections. Certain cases suggest this might be clinically relevant. On the other hand, there are several uncontrolled studies (here and here for example) showing that outcomes of long-term cefazolin treatment is better than oxacillin/nafcillin. Plus, cefazolin is better tolerated, and much easier to administer. Randomized clinical trial, anyone? Until then, perhaps the optimal approach is to use oxacillin initially, then switch to cefazolin once the infection is controlled.
• Primary prophylaxis for M. avium complex is still recommended in the DHHS Guidelines, but not the IAS-USA Guidelines. My take? There has never been a study of primary MAC prophylaxis in the ART era, and furthermore we want to avoid azithromycin monotherapy in someone with undiagnosed MAC, right? So count me on the IAS-USA Guidelines side. More on this issue here.
• There is still no better paper on ICU Infectious Diseases than “Fever of Too Many Origins.” I’ve covered it before, but it’s worth revisiting this outstanding perspective every so often. It brings some sanity to this challenging endeavor of seeing febrile patients in the ICU, or at least provides a group therapy session. It’s brilliant, so read it!

Happy Holidays! Please enjoy my favorite seasonal song that, in contrast to many other of the other ubiquitous holiday tunes, does not grow tiresome on repeated hearing.