HIV and ID Observations

Sam approaching a “scent detection box.”

As an infectious diseases specialist attending on the general medical service each year, I am the beneficiary of a wonderful knowledge exchange.

The smart house staff and my generalist co-attending teach me the latest about hyperkalemia, anticoagulation, anemia, alcohol withdrawal, acute renal injury, COPD, atrial fibrillation, pancreatitis, asthma, diabetes, and congestive heart failure — to name a few of the non-infectious issues that come up routinely during inpatient care.

For example, I am now quite comfortable saying HFpEF — which, if you haven’t done inpatient medicine in a while, is pronounced “HEF-PEF,” and most certainly did not get mentioned a single time during my residency training.

And what do they get in return? A bunch of infectious diseases snippets, factoids, random comments, and (I hope) clinical pearls, such as the following:

• A shorter course of antibiotics should in many conditions become standard of care. In addition to the linked review, two studies at the current ECCMID meeting in Madrid also showed that shorter is just as good as longer — or even better! There’s less drug exposure, less chance for toxicity, and a faster return to usual activities. The studies were: 1) Three versus eight days for community-acquired pneumonia, and 2) Seven versus fourteen days for gram-negative blood stream infections. We will obviously need to see the full details of these studies once published, but it looks like the antibiotic “course” has had its day.
• Guidelines for treatment of uncomplicated lower UTI in women recommend nitrofurantoin, trimethoprim-sulfamethoxazole, or fosfomycin. And hot off the presses — nitrofurantoin for 5 days is better than single dose fosfomycin. Note that quinolones are not included due to concern about “collateral damage,” specifically in this paper their effect on antibiotic susceptibility. See below for an additional concern about quinolones we discussed on rounds this week.
• The guidelines for diagnosis and treatment of C. diff have been updated. Among the highlights:  vancomycin or fidaxomicin (not metronidazole) for first-line therapy; vancomycin taper or fidaxomicin for first recurrence (if vancomycin used as initial therapy); for more than one recurrence, vancomycin followed by rifaximin; and for patients with multiple recurrences, referral for fecal microbiota transplantation (FMT). There’s also an acknowledgement that nucleic acid testing alone (without the proper clinical correlation) has an unacceptably high false-positive rate.
• The Advisory Committee on Immunization Practices (ACIP) now includes the new hepatitis B vaccine.  The vaccine (called HepB-CpG or “Heplisav-B”) is indicated for HBV-seronegative individuals over 18. Given as two doses separated by 1 month (rather than three doses over 6 months), HepB-CpG is both easier to give and more immunogenic, yielding protective antibody responses in 90.0%–100.0% of recipients vs. 70.5%–90.2% with the older vaccine. As with the other recently approved “adjuvanted” vaccine for zoster, postmarketing safety data will be important, as will data on its efficacy in prior non-responders.
• The price of linezolid has plummeted — but you’d still better shop around. I’ve mentioned this price drop before — but it’s worth repeating since linezolid was so notoriously expensive for so long that many clinicians might not realize the price has changed. How about fidaxomicin, mentioned above in the C. diff guidelines? No such luck.
• The most important risk factors for cefepime neurotoxicity are older age and decreased renal function. Encephalopathy and delirium, sometimes associated with myoclonus, are the most common manifestations; seizures may rarely occur.
• An interferon gamma release assay (IGRA) is now the preferred test in most settings for latent TB. Tuberculin skin tests (TSTs) continue to be used for “budgetary reasons,” or in the settings where both an IGRA and a TST would be useful. Indications for both IGRA and TST would be a high-risk setting where either test being positive would prompt treatment (e.g., prior to receiving TNF-blockers in a patient from a TB-endemic region), or in a low risk setting where either being negative would mean deferring therapy. Pet peeve: It’s better to say IGRA (“ig-rah”) than either of the brand names. Thank you.
• Doxycycline may have anti-inflammatory activity. This property, independent of its antibacterial effect, is the reason some dermatologists choose very low doses for treatment of acne, and why they sometimes continue it for ulcerative or bullous disease even in the absence of infection. Note that this ancillary effect was not mentioned by Rebeca Plank in our antibiotic draft, even though she chose doxycycline first. Maybe I should get it on a technicality?
• Fluoroquinolones should be avoided for acute sinusitis, acute bronchitis, and uncomplicated urinary tract infections unless there are no other treatment options. The reason — “fluoroquinolone toxicity syndrome,” which consists of “disabling and potentially permanent serious side effects … that can involve the tendons, muscles, joints, nerves, and central nervous system.” This FDA action in 2016 has substantially changed clinical practice, as previously these drugs were used like water — in other words, excessively.
• Dogs have been used to diagnose both C. diff and urinary tract infections. The best part about these papers are the videos (here and here) that cover them! The pictures are cute too (see above).

Meanwhile, in other news, there’s this podcast — highly recommended and entertaining!

https://www.facebook.com/andyborowitz/posts/10156754879150681

And note, not a single mention of an antibiotic.