Negative CT to rule out SAH?

We were optimistic, but not so fast according to this study.

Masquerading bundle branch block: what is it?

Quite often one encounters a wide QRS in the dominant rhythm of the electrocardiogram which may have features of either or both bundle branch blocks but is typical of neither. It is often referred to as nonspecific intraventricular conduction delay (IVCD). If the condition is chronic and stable (that is, not due to external factors such as drug effects or hyperkalemia) it generally represents diffuse myocardial scarring and it's a sure bet the patient's ejection fraction will be reduced.

One such pattern, recently described in this paper which caught my eye, is characterized by the RBBB pattern in the precordial leads but with the LBBB pattern in the limb leads and has been termed masquerading BBB. It has been conceptualized in various ways but represents bilateral conduction system disease as a reflection of multifocal myocardial scarring, reflecting extensive damage. It tends to be a poor prognostic sign.

One of the early papers on this topic, back in the days of physician-scientists when autopsies were done and doctors were actually interested in clinicopathological correlations, is here and it is a fascinating read.

Overuse of PICCs in CKD patients

PICCs (or PICC lines to those suffering from the redundant acronym syndrome) have become popular because they offer a convenient option for IV access and blood sampling. They are becoming the default option for patients who are a “tough stick” or have special IV therapy needs. These are usually the sicker patients who are likely to have CKD. But there's a problem in CKD patients. PICC use may jeopardize future dialysis access and current guidelines discourage the practice.

But a recent study presented at the National Kidney Foundation meeting (via Medpage Today) showed that the practice is common in advanced CKD patients. According to one of the discussants:

She explained that at her institution, they have started a program to reduce PICC placement in CKD patients. "For anyone with a glomerular filtration rate of less than 30 mg/L, you cannot just order a PICC. You have to go through an algorithm where you consider other line placements."

Long term central venous catheter related infections: what to do?

Remove? Treat through? Antibiotic lock?

A practical review is presented here and the IDSA guidelines for IV catheter related infections in general are here.

H7N9 influenza: the next pandemic?

NEJM report and Medscape update.

Cerebral vein thrombosis review

From the paper:

Dural sinus or cerebral venous thrombosis (CVT) is a frequently unrecognized cause of stroke affecting predominantly young women. Typical clinical signs include headache, visual problems and seizures.

Fairly easy to diagnose and treat once you think of it.

Alcoholic hepatitis

An update. Free full text via Medscape.

Non-evidence based use of IVC filters

Recent paper here in JAMA Internal Medicine. Variability may be driven by the paucity of high level data, variable resources at different hospitals and marked variations in current guidelines.

Perspective offered here in Medpage Today.

Does widespread ertapenem use breed resistance to the broader spectrum carbapenems?

That's a popular concern but available evidence suggests it doesn't.

What makes a great diagnostician?

Pause for a little metacognition by reading these tips. None of them will do you any good, of course, if you don't have enough time to spend with patients.

Idiopathic ventricular tachycardias

Most are outflow tract tachycardias and most of those are right ventricular. They are unique in that while they tend to be benign they may cause tachycardia mediated DCM and are amenable to ablation. (They may respond to calcium blockers too but leave that to the experts). Also don't forget that right ventricular cardiomyopathy may manifest as RV tachycardia. This review focuses on RVOT.

Aspirin: should we add it to our pneumonia order sets?

It has been known for a while now that pneumonia is a short term risk factor for acute coronary syndrome. So it recently occurred to some investigators to see if adding an aspirin a day to the regimens of pneumonia patients would help. The results were startling:

..the rates of ACS at 1 month were 1.1% (n=1) in the aspirin group and 10.6% (n=10) in the control group (relative risk, 0.103; 95% confidence interval 0.005–0.746; P=0.015). Aspirin therapy was associated with a 9% absolute reduction in the risk for ACS. There was no significant decrease in the risk of death from any cause (P=0.151), but the aspirin group had a decreased risk of cardiovascular death (risk reduction: 0.04, P=0.044).

Budd–Chiari update

New review here (free full text provided by Medscape).

Points of interest:

Budd–Chiari syndrome is a rare disorder caused by hepatic venous outflow obstruction and resulting hepatic dysfunction....

BCS is defined as hepatic venous outflow obstruction at any level from the small hepatic veins (HV) to the junction of the IVC and the right atrium, regardless of the cause of obstruction. Outflow obstruction caused by the sinusoidal obstruction syndrome (formerly 'veno-occlusive disease') and cardiac disorders is excluded...

Hepatic venous outflow obstruction caused by external compression or invasion of the venous lumen is termed secondary BCS and is seen with malignant tumors or large cysts...

B-C can be considered a disease of thrombophilia:

At least one thrombophilic disorder is identifiable in 84% of patients and multiple disorders are found in 46%...

Myeloproliferative disorders (MPD) deserve specific mention due to their high frequency in BCS. MPD result in excess cell production by the bone marrow and include: chronic myeloid leukemia, primary myelofibrosis, polycythema rubra vera and essential thrombocytosis. These disorders are particularly common in patients with BCS and may be overt or occult (occurring with normal peripheral blood counts). MPD is found in 49% of BCS cases who undergo a bone marrow examination.

The importance of JAK 2:

In the setting of BCS or splanchnic thrombosis, the positive predictive value rises further and JAK2 (V617F) mutation is a very reliable marker for MPD. A recent meta-analysis of 23 studies reported a pooled prevalence of 37 and 24% of patients with BCS and portal vein thrombosis respectively.

That said, virtually all the other thrombophilias have been associated with B-C.

The clinical presentation can be acute (with abdominal pain) or chronic, and range from asymptomatic to acute liver failure and include encephalopathy, variceal bleeding and splenomegaly.

In addition to treatment of any underlying diseases and general supportive management of the liver disease anticoagulation, shunting, vascular stenting and transplant are discussed as treatment options. There is very limited experience with thrombolysis.

Precious bodily fluids honors William Stone

Bill Stone is another member of that dying breed of physician-scientists and master clinicians. He was a nephrology attending at the Nashville VA and Vanderbilt Hospital across the street when I was a medical student there. He had a superficial reputation for being a bit malignant but to those who knew him well he was a dedicated physician and teacher who cared greatly about the students and house staff. He was a walking encyclopedia of internal medicine. I was too intimidated to fully appreciate his teaching gifts.

Joel Topf at Precious Bodily Fluids has recently written a post in his honor which lists his 23 “rules of Stone” and mentions his research. Among many other things he discovered beta-2 microglobulin amyloidosis in hemodialysis patients.

Another of his research accomplishments impressed me as a med student. Back then IV penicillin G was used to treat a lot of serious infections. Every now and then patients with renal impairment would experience penicillin neurotoxicity and seize. Thus was born the notion that doses of pcn that were appropriate for normal renal function were “comparably massive” in patients with renal failure. Stone and one of the ID fellows got together, looked at the pharmacokinetics and worked out a method for “renal dosing” of pcn.

Of his 23 rules I like #18: “If an older doctor writes an axiom or a diagram on a piece of paper, ask if you can have it.” (Now some EBM apologists who decry experience and expertise as a basis for learning won't like this).

Sometimes I feel a little worn down by the legal and administrative baggage I face in practice. Reflecting on the legacy of the exemplars of internal medicine is therapy for me.

The asthma-COPD overlap syndrome

ACOS, reviewed here. From the review:

ACOS accounts for approximately 15–25% of the obstructive airway diseases and patients experience worse outcomes compared with asthma or COPD alone. Patients with ACOS have the combined risk factors of smoking and atopy, are generally younger than patients with COPD and experience acute exacerbations with higher frequency and greater severity than lone COPD.

It is not yet a well defined clinical entity, but is a useful construct.

Safe drug use in long QT and Brugada syndromes

A review of two popular websites with links.

Patent foramen ovale in patients with obstructive sleep apnea

According to this study it is common in patients with OSA and its coexistence is associated with more profound nocturnal desaturation. In the small number of patients in the study, closure did not help.

The fragmented QRS

It indicates myocardial scar no matter what the underlying cardiac disease.

I first blogged it several years ago and the field has since seen further clarification as documented in this review.

FFR guided PCI: does it really matter?

We know it makes sense physiologically but does it make a difference in outcomes? A recent study suggests it does.

D-dimer testing and aortic dissection

How useful is it to exclude the diagnosis?

According to one recent review:

The sensitivty of D-dimer test for AD diagnosis is reported as close to 100% in the literature and has a negative predictive value between 92% and 100% [5, 6]. Two meta-analyses confirmed that D-dimer testing is useful for the diagnosis of suspected acute aortic dissection [2, 3].

Additional references here and here.

D-dimer testing combined with the ADD score might be a useful approach.