In the beginning we played a word association guessing game related to microbio — currant jelly and rust colored sputum, target lesions, descending maculopapular rashes, etc. On the topic of viral rashes, the table on page two of this paper might be useful (or, y’know, use the table on page 183 of First Aid, 2018). The “lacy” appearing rash I mentioned is parvovirus (aka fifth disease, aka erythema infectiosum) and is not know to descend (the buzzword to know is “slapped cheeks,” although much like “target lesions,” examiners may find some slightly obfuscated way to say ‘slapped cheeks’ so as not to make the question too easy).
Alex talked a little about malaria and tonic water, as well as relapsing fever in the NPS. Below are a couple of articles he wanted to pass along:
https://academic.oup.com/jme/article/50/2/221/851614 (Relapsing fever)
We also talked about various methods of malarial prophylaxis and I mentioned that mefloquine is associated with psychosis. Here’s a 2016 review paper. Note, “while psychiatric symptoms from mefloquine were previously considered reversible and self-limiting, the US product label for mefloquine was recently updated to include a boxed warning (or “black box”) that psychiatric effects from mefloquine could last years after use. A recent follow-up study has found a sizeable proportion of those previously reporting adverse events from the drug complain of long-term psychiatric symptoms including cognitive dysfunction years after use.”
Our vocab word for this show was shibboleth.
Antibiotic prophylaxis before surgery
Alex raised the concept of cefazolin prophylaxis before surgery, and wanted to pass along this link to guidelines for preventing surgical site infections. I mentioned that I’d heard about cefazolin prophylaxis in The Checklist Manifesto by Atul Gawande. Here’s a paper from Gawande and several other authors talking about cefazolin and the use of checklists before surgery. And here’s a short excerpt from his book:
Infection is one of the most common complications of surgery in children. And the most effective way to prevent it, aside from using proper antiseptic technique, is to make sure you give an appropriate antibiotic during the sixty-minute window before the incision is made. The timing is key. Once the incision is made, it is too late for the antibiotic. Give it more than sixty minutes before the procedure, and the antibiotic has worn off. But give it on time and studies show this single step reduces the infection risk by up to half. Even if the antibiotic is squeezed into the bloodstream only thirty seconds before the incision is made, researchers have found, the circulation time is fast enough for the drug to reach the tissue before the knife breaches the skin. Yet the step is commonly missed.
In 2005, Columbus Children’s Hospital examined its records and found that more than one-third of its appendectomy patients failed to get the right antibiotic at the right time. Some got it too soon. Some got it too late. Some did not receive an antibiotic at all.
I mentioned that my read of the evidence surrounding wound sterilization before sutures is that tap water is just fine (maybe even superior once you factor in the likelihood that the wound will be flushed better due to the volume and pressure). Here are just a few studies on this, including a Cochrane review:
- Water is a safe and effective alternative to sterile normal saline for wound irrigation prior to suturing: a prospective, double-blind, randomised, controlled clinical trial (2013) [Pubmed]
- Water for wound cleansing (2012) [Cochrane Database]
- Tap water for irrigation of lacerations (2002) [Pubmed]
- Common questions about wound care (2015) [Pubmed]
- A Multicenter Comparison of Tap Water versus Sterile Saline for Wound Irrigation (2007) [PDF]
- Comparison between sterile saline and tap water for the cleaning of acute traumatic soft tissue wounds (1992) [Pubmed]
The seminal paper on early goal-directed therapy for sepsis came out in 2001, and found a 40% reduction in mortality using EGDT. In recent years, two influential trials — ARISE and ProCESS — have failed to show any mortality benefit to early goal-directed therapy (let alone the 40% reduction reported in the Rivers trial linked above). A few years before ARISE and PROCESS, Marik and Varon published a paper, “Early goal-directed therapy: on terminal life support?” in which they argue that the promises of early goal-directed therapy are simply too good to be true:
Although the 3 major pillars that form the basis of EGDT [early goal-directed therapy] are not supported by evidence-based medicine and are potentially harmful, what is more troubling is that the results of the EGDT study are “just too good to be true” and would appear to be scientifically implausible.
It is also hard to view the newly revised guidelines from the Surviving Sepsis Campaign as being sound when they are actively opposed by the AAEM, ACEP, and SSCM (the three groups that represent the vast majority of physicians in the US who care for septic patients). The journal Chest hosted a point-counterpoint debate on retirement of the guidelines in January 2019 → argument in favor, argument opposed. Also worth linking is this article, “The 2018 Surviving Sepsis Campaign’s Treatment Bundle: When Guidelines Outpace the Evidence Supporting Their Use.”
We also discussed lactate as a marker for sepsis. In the Surviving Sepsis protocols, serial lactate values can be used in place of the requisite central venous pressure monitoring. How sensitive are WBC and temperature for detecting sepsis? Not great (sensitivities around 50%).
- Criteria for SIRS:
- Temperature either > 38.5 or < 35
- HR > 90
- RR either > 20 or PCO2 < 32 mm Hg
- WBC > 12000, < 4000, or > 10% immature bands
- Criteria for SIRS:
Also, I mentioned that I recalled a lecture where a “within so many hours” rule was mentioned regarding antibiotic administration (in a situation other than sepsis). I gave this as an example of the law of unintended consequences; how cookbook medicine can lead to harms — in this case the lecturer had given an anecdote about antibiotics being administered to patients at triage to ensure Medicare would pay. I listened to this lecture last year and can’t remember what conference it came from, but I am almost certain it was referencing the “4 hour rule” for pneumonia that Medicare implemented in the early 2000s. Here’s a 2007 study that shows how this rule made no change on mortality or other significant outcomes at a particular hospital, yet led to a 1.6x per-patient usage of antibiotics when compared to a prior year. Here’s another interesting article that points out several potential unintended consequences. CMS has now relaxed the timing of the rule to 6 hours, with a number of exceptions including for patients for whom there was diagnostic uncertainty.
UTIs, asymptomatic bacteriuria, and cranberries
I mentioned that in WA a pharmacist can be licensed to prescribe drugs for common conditions such as UTI. It turns out that WA was the first state to pass such a law, in 1979! There are a number of studies showing patients are competent at self-diagnosing their UTIs, particularly of note is a JAMA paper that says: (dysuria and frequency) + absence of vaginal discharge/irritation = LR of ~25, with greater than 96% posttest probability of UTI.
We talked about cryptogenic UTIs causing confusion in older adults. On the flipside, we also talked about asymptomatic bacteriuria and the risks of treating based on tests that may not have been indicated. A 2017 paper in Current Opinion in Urology says, “Available evidence only supports the need for screening and treatment of ABU in pregnant women and prior to urological procedures breaching the mucosa. In all the other conditions the treatment of ABU is not only useless but also harmful.” Furthermore, the 2017 paper above says:
“Several authors have demonstrated that ABU may protect against super-infecting symptomatic UTI, therefore, treatment of ABU should be performed only in cases of proven benefit for the patient to avoid the risk of selecting antimicrobial resistance”
Even pyuria isn’t necessarily cause for treatment. Another paper from 2017 states: “Pyuria is sensitive but not specific for UTI, particularly among catheterized patients in whom its presence is ubiquitous. Reliance on pyuria alone for the diagnosis of UTI would lead to widespread antibiotic over-treatment, particularly because pyuria accompanies asymptomatic bacteriuria.” The IDSA, for example, says that: Pyuria accompanying asymptomatic bacteriuria is not an indication for antimicrobial treatment (evidence level A II).
If you’re interesting in reading RCTs on cranberry juice and UTIs, here are three you might check out:
Red flags in back pain
Back pain is a frustrating MSK issue for many patients, but for the occasional patient, it’s something even more insidious. Keeping with the infection theme, we took a moment to talk about spinal epidural abscesses. Here’s a quote from a 2014 systematic review of SEA: “In 1901, the first successful decompressive laminectomy for an SEA was performed by Barth on a patient with a thoracic abscess. Since then, urgent surgical intervention with systemic antibiotics has been the gold standard of SEA treatment, especially for patients presenting with evolving neurological deterioration, spinal instability, or persistence of infection despite antibiotic treatment.” Note that this review does go on to discuss that a growing number of these cases are being managed medically rather than surgically, although to some controversy.
- Presentation: back pain (67%), motor weakness (52%), fever (44%), sensory abnormalities (40%), and bladder/bowel (27%).
- Risk factors: Intravenous drug use was the most frequently seen risk factor (in 22% of patients). Diabetes (27%) and hepatic disease (14%) were #2 and #3, respectively.
- Pathogen findings: S. aureus (64%), negative culture (14%), gram negative (8%), coagulase negative staph (7.5%), and strep (7%).
Congenital syphilis on the rise in US
First, I want to cite a comment made in the “buzzword game” at the beginning of the show where I said I thought the peg-shaped teeth (Hutchison teeth, aka “saber teeth” if you’re Addie) were apparent as the child grows; FPnotebook says it is indeed permanent teeth and not deciduous. I checked a number of other sources to verify this and most are ambiguous, but at least two do say that ‘Hutchinson triad’ (deafness, teeth deformities, and interstitial keratitis) develop after age 2.
Second, here’s the JAMA paper regarding dramatically rising incidence of congenital syphilis in the US.
Shared decision making
In 2014 Rafael Nadal developed appendicitis during a tennis tournament and elected to use antibiotics over surgery in order to continue playing on subsequent days. Here’s the AHRQ page on shared decision making. As evidence of its growing importance in medicine, it might be worth mentioning that one of the ABEM LLSA articles for 2018 was a paper on shared decision making.
— Episode credits —
Hosted by Addie, Kim, and Alex. Audio production and editing by Addie. Show notes written by Addie. Theme music (Too Cool, and Laserpack) by Kevin MacLeod of incompetech.com, licensed under Creative Commons: By Attribution 3.0 License.