Friday, March 23, 2018

Mechanisms of sudden cardiac death related to cigarette smoking

This study focuses on repolarization abnormalities, particularly prolongation of the Tp-e.

Thursday, March 22, 2018

Animations in cell biology

Free educational resources here.

Wednesday, March 21, 2018

Should patients admitted with inflammatory bowel disease exacerbation be tested for C diff?

The American College of Gastroenterology guidelines (which as of a few weeks ago are no longer the newest ones) recommend testing. More recently there was this study:

To evaluate the frequency, possible risk factors, and outcome of Clostridium difficile infection (CDI) in inflammatory bowel disease (IBD) patients.

There has been an upsurge of CDI in patients with IBD who has been associated with increased morbidity and mortality. Various risk factors have been found to predispose IBD patients to CDI.

A retrospective case–control study on IBD patients admitted with exacerbation and tested for CDI at the Tel Aviv Medical Center in 2008 to 2013. Epidemiologic, laboratory, and prognostic data were retrieved from electronic files and compared between patients who tested positive (CDI+) or negative (CDI−) for CDI.

CDI was identified in 28 of 311 (7.31%) IBD patients hospitalized with diarrhea. IBD-specific risk factors (univariate analysis) for CDI included: use of systemic steroids therapy (odds ratio [OR] = 3.6, 95% confidence interval [CI] 1.2–10.6) and combinations of ≥2 immunomodulator medications (OR = 2.6, 95% CI 1.1–6.3). Additional risk factors for CDI that are common in the general population were hospitalization in the preceding 2 months (OR = 6.0, 95% CI 2.6–14.1), use of antacids (OR = 3.8, 95% CI 1.7–8.4), and high Charlson comorbidity score (OR = 2.5, 95% CI 1.1–5.7). A multivariate analysis confirmed that only hospitalization within the preceding 2 months and use of antacids were significant risk factors for CDI. The prognosis of CDI+ patients was similar to that of CDI− patients.

Hospitalized IBD patients with exacerbation treated with antacids or recently hospitalized are at increased risk for CDI and should be tested and empirically treated until confirmation or exclusion of the infection.

Tuesday, March 20, 2018

White board notes: Sjogren’s syndrome

Below are key points drawn from a recent NEJM review on the topic as well as E Medicine’s chapter.

Of related interest: pulmonary manifestations of rheumatic diseases [1] [2]

Types of AV block that can cause syncope, and their characteristics

Current literature reveals three types of paroxysmal atrioventricular block (AVB) that can cause syncope:

Intrinsic paroxysmal atrioventricular block is due to an intrinsic disease of the AV conduction system; this type of “cardiac syncope” is also called Stokes-Adams attack;

Extrinsic vagal paroxysmal atrioventricular block is linked to the effect of the parasympathetic nervous system on cardiac conduction and is one of the mechanisms involved in “reflex syncope.”

Extrinsic idiopathic paroxysmal atrioventricular block is associated with low levels of endogenous adenosine and is supposed to be one of the mechanisms involved in “low-adenosine syncope.”

These three types of paroxysmal AVB present different clinical and electrocardiographic features. Additionally, the efficacy of cardiac pacing and theophylline therapy to prevent syncopal recurrences is also different for these three types of AVB.

Also noteworthy:

Intrinsic AVB, they type we are most familiar with, can take the form of either phase 3 or, less commonly, phase 4 block. Vagally mediated AVB is characterized by sinus slowing leading up to and during the AVB, and evidence that pacing is helpful is lacking. Extrinsic idiopathic paroxysmal AVB due to low baseline adenosine levels is a more recently described entity.

Monday, March 19, 2018

Antidepressants really do work after all

The narrative for the last decade was that they didn’t, and that their use was a pharma conspiracy. Nice post at SBM. (Oh, but wait! One of the authors of the primary source is John Ioannidis! Does that make this paper one of the few research reports that’s actually true?).

Sunday, March 18, 2018


Here is another free full text review.

Saturday, March 17, 2018

An interesting paper about antibiotic stewardship

This review sets out to evaluate the current evidence on the impact of inappropriate therapy on bloodstream infections (BSI) and associated mortality. Based on the premise that better prescribing practices should result in better patient outcomes, BSI mortality may be a useful metric to evaluate antimicrobial stewardship (AMS) interventions. A systematic search was performed in key medical databases to identify papers published in English between 2005 and 2015 that examined the association between inappropriate prescribing and BSI mortality in adult patients. Only studies that included BSIs caused by ESKAPE (Enterococcus faecium/faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) organisms were included. Study quality was assessed using the GRADE criteria and results combined using a narrative synthesis. We included 46 studies. Inappropriate prescribing was associated with an overall increase in mortality in BSI. In BSI caused by resistant gram positive organisms, such as methicillin resistant S. aureus, inappropriate therapy resulted in up to a 3-fold increase in mortality. In BSI caused by gram negative (GN) resistant organisms a much greater impact ranging from 3 to 25 fold increase in the risk of mortality was observed. While the overall quality of the studies is limited by design and the variation in the definition of appropriate prescribing, there appears to be some evidence to suggest that inappropriate prescribing leads to increased mortality in patients due to GN BSI. The highest impact of inappropriate prescribing was seen in patients with GN BSI, which may be a useful metric to monitor the impact of AMS interventions.

Yeah, well, we already knew that antibiotic delay makes things worse. What’s interesting about this report is that it’s way, way worse for gram negative bacteremia. But what does this have to do with antibiotic stewardship? Promptness of antibiotic administration is a concept that was around long before “antibiotic stewardship” became a buzzword.

Webster defines stewardship this way:

the conducting, supervising, or managing of something; especially : the careful and responsible management of something entrusted to one's care

To the uninitiated, antibiotic stewardship might just mean optimal use of antibiotics but to those in the know special meanings apply. Given the narrative of the day that we’re headed for a gram negative antimicrobial apocalypse many stewardship programs emphasize restriction of gram negative drugs. If front end restrictions delay first dose administration that might be a bad thing according to this report.