January 11th, 2021
After Ivermectin Controversy, A COVID-19-Free ID Link-o-Rama
Field Cricket, from Fabre’s Book of Insects (1921)
Wow, quite the week for this country of ours. We’re all deeply saddened by the events, very hopeful that the transition in leadership will be peaceful.
And also an eventful week for this little blog. When I wrote “
Enter ivermectin — and let the controversy begin,” little did I know.
Amazingly, this is
already the second-most widely read post on this site over the past 365 days, and it’s been out less than a week. It’s closing in on number one, which came in early March — that’s when I not-so-boldly predicted we’d see a big increase in COVID-19 cases. Quite the visionary, wasn’t I?
(That was a rhetorical question.)
Anyway, who knew this obscure antiparasitic agent would capture so much attention?
With that controversy out of the way (ahem), allow me to return to non-COVID-19 ID/HIV for a brief time. I’ve been doing inpatient ID consults quite a bit recently, and here are a few of the interesting things that popped up:
In addition to liver abscesses, it frequently causes metastatic infection elsewhere, including septic arthritis, meningitis, and endophthalmitis. Hypervirulent Klebsiella pneumoniae is a nasty, nasty bug.
Not all PCP presents with diffuse ground-glass infiltrates — and yes, I still abbreviate it PCP ( Nodular “granulomatous” pneumocystis pneumonia is an unusual radiographic presentation of PCP. Pneumo Cystis Pneumonia). Note that sputum induction and BAL may have lower sensitivity in granulomatous PCP, which will warrant other diagnostic strategies. For example …
Disseminated A markedly elevated beta-glucan in a person with HIV and respiratory symptoms is PCP until proven otherwise. Talaromyces marneffei and histoplasmosis can also greatly increase beta-glucan in people with HIV, but PCP is way more common. (Should I change to saying PJP? It’s Pneumocystis Jirovecii Pneumonia, after all.)
Many of the “false positive” beta-glucan results are not very high, or represent testing done in low pre-test probability settings. ID fellows will recognize that fact instantly! This is also true with non-HIV related immunosuppression, where a high beta-glucan and a compatible clinical syndrome are all but diagnostic. (Seems that switching to PJP is just a matter of time. Oh well. I’ll live.)
This is why it’s so critical that our heavily treatment-experienced patients with HIV/HBV receive tenofovir-based regimens — many received lamivudine for years before we knew about this issue of HBV cross-resistance. Prior treatment failure of hepatitis B with lamivudine may induce entecavir cross-resistance.
Optimal dosing is unclear, though our crack ID pharmacy team recommend 12 mg/kg/day of the TMP component. (12? Not 10 or 15?) And yes, this is one of those fabulous ID tongue-twister bugs — one of the more common ones. The preferred treatment of Stenotrophomonas maltophilia is TMP/SMX.
Certainly it’s TMP/SMX is probably as effective as pyrimethamine plus sulfadiazine for CNS toxoplasmosis. way less expensive (pyrimethamine, ouch), and much easier to take. It’s already standard of care in most of the rest of the world. Will make this the case here in the USA as well? At least list it side-by-side with pyrimethamine and sulfadiazine, rather than listing it as an alternative? our HIV opportunistic infection guidelines
This review notes that 40% are cryptogenic, 20% come from a dermal sinus, and 20% from bacteremia. High incidence of permanent neurologic sequelae. Intramedullary spinal cord abscess is a rare CNS infection that may be complicated by spinal artery occlusion.
Anecdotally I’ve seen this most commonly in those being treated for candida endocarditis, cryptococcal meningitis, and osteomyelitis. I’m sure it’s true for coccidioides, too, but we don’t see much of that in Boston. It slowly improves after stopping therapy, or decreasing the dose. In a similar theme … Hair loss is a well-recognized complication of prolonged fluconazole use.
Most cases do resolve over time after cessation of the drug, but sometimes it can be permanent. And it’s not just the skin — here’s a Blue skin is a well-recognized complication of prolonged minocycline use. blue aorta!
The problem is that assessing whether positive urine cultures are symptomatic — especially in older adults with cognitive impairment and multiple comorbidities — is an enormous challenge. While UTIs in older adults no doubt are overdiagnosed (and overtreated), this paper hints that undertreatment may be a problem too.
The dogma has always been to use a fluoroquinolone or TMP/SMX. This study suggests beta-lactams may be a good option, provided it’s a urinary source and that initial treatment is parenteral. Oral beta-lactam antibiotics might be a reasonable option for treating gram-negative bacteremia after all.
The critical thing is that the lab does this testing — some don’t. Anecdotally, penicillin is better tolerated than nafcillin and oxacillin, too. Penicillin-susceptible Staph aureus can be treated with penicillin — provided the microbiology laboratory confirms it’s truly sensitive.
Generally no, argues this persuasive paper. And this question comes up Should osteomyelitis complicating sacral pressure ulcers be treated with antibiotics? all the time on inpatient ID services.
This contemporary series cites low body mass, low hemoglobin, and elevated alkaline phosphatase as readily available predictors. Note that the literature on management of HIV-related MAC IRIS is badly out of date. When should steroids be started? How long should they be continued? What are the side effects? A good project for a large cohort study. Certain clinical and laboratory features are predictive of immune reconstitution inflammatory syndrome (IRIS) due to M. avium complex (MAC) in people with HIV.
Many thanks to ID fellows Drs. Susan Stanley, Alex Tatara, and Zach Nussbaum for providing some of these references. And remember all you fellows out there, you’re more than halfway done with your first year of fellowship!
For next week? Maybe I’ll write about albendazole. Or praziquantel. Or nitazoxanide. Or some other antiparasitic agent. They seem to be quite popular!
Or maybe I’ll just watch this baby bear playing on this golf green.