Thursday, February 28, 2013

In which I ponder the antecedents of quackademic medicine

For some time now bloggers who share a concern about quackademic medicine (a term referring to the pervasive infiltration of quackery into the curricula of American medical schools which I coined here) have pondered the reasons. Indeed the reasons are multiple and complex. But I believe there is a causal chain and if you trace back far enough along the chain you land here: the American Medical Student Association (AMSA).

In the past I’ve blogged a great deal about their woo promoting agenda. Moreover, in considering this agenda alongside AMSA’s PharmFree initiative I have previously noted, in less PC terms, a certain lack of internal consistency.

But over time my enthusiasm for calling out the quack promoting activities of the AMSA waned; despite multiple attempts of myself and others in the blogosphere to raise awareness the problem continued unabated. Among the many folks in high places in the world of medical education few people seemed concerned enough to do anything to try and stem the tide.

I recently ran across two wonderful blog posts (here and here) that rekindled my interest. These bloggers have succeeded in probing the extensive AMSA site and unpacking the woo promoting content better than I ever did. Both posts are worth the read. Great exposure!

Monday, February 25, 2013

Breath acetone as a biomarker in heart failure

It performed comparably to BNP/proBNP in this study, both in diagnosis and severity assessment.

The incredible and never adequately explored potential of breath acetone (BA) analysis for clinical application has long been a pet interest of mine. As a medical student I got to spend my summers playing with the gas chromatograph machine in Oscar B. Crofford's lab. Although the focus of that research was diabetes and obesity BA has potential application as a biomarker in a variety of disease states. This is best appreciated by understanding that BA reflects lipolytic activity; it is, as Dr. Crofford was fond of saying, the “smoke of burning fat.” That in turn reflects the balance between insulin and counter regulatory hormone activity on hormone sensitive lipase located in adipose tissue cells. The counter regulatory hormones are the stress hormones: epinephrine, norepinephrine, growth hormone, glucagon and cortisol. So elevated BA reflects the catabolic state and/or the ratio of activities of stress hormones to insulin.

The methodology is simple, specimen collection is easy (the patient can exhale into a syringe) and turn around is instantaneous. BA analysis deserves further study in a variety of clinical situations.

Sunday, February 24, 2013

HIV disease as a powerful risk factor for lung cancer

A recent commentary in Chest notes a marked increased risk. Age of onset and tobacco burden are much lower than in the general population and presentation with advanced disease is common. Histologic type is similar to the general population.

Saturday, February 23, 2013

ICU delirium

Here's a nice review and it's free full text.

Nonpharmacologic modalities are preferred by far over drugs though the latter are popular and sometimes necessary when the delirium is agitated. Data to support the use of drugs are sparse. Antipsychotics tend to be preferred over benzos except for alcohol withdrawal delirium, in which benzo therapy is the treatment of choice and antipsychotics are avoided. There is little to recommend second generation over older (e.g. haldol) agents. Dexmedetomidine has promise and is popular, but evidence in favor of its use is weak.

Extreme hypertriglyceridemia

Extreme hypertriglyceridemia can cause acute pancreatitis. It can also wreak havoc on the management of hospitalized patients by interfering with their lab tests. Management is a challenge, as it often responds inadequately to conventional measures. This article discusses two under appreciated (and off label) tricks of the trade: insulin infusion and heparin infusion. These treatments rapidly clear triglycerides and work about as well as plasmapheresis. They work by facilitating lipoprotein lipase. In the case of insulin, hark back to basic biochem and note an important distinction which is an apparent paradox: while insulin facilitates the action of lipoprotein lipase to clear triglycerides from the circulation it also inhibits hormone sensitive lipase in adipose tissue, the rate limiting enzyme for lipolysis and one of the two on-off switches for ketosis.

Monday, February 18, 2013

ACEI/ARB plus diuretic plus NSAID: the renal triple threat

----for AKI, as reported in BMJ and summarized here. Then again I worry about the renal risk from NSAIDs whether or not they are combined with other drugs.

Sunday, February 17, 2013

Endovascular repair of abdominal aortic aneurysm: where we've come in 20 years

Now, more endo repairs have been done than open repairs. Over 70% of repairs now are endo repairs. The history and current status of the procedure are discussed in this review.

Saturday, February 16, 2013

Wednesday, February 13, 2013

Administration of NAC for prevention of contrast nephropathy: what's the latest?

The evidence is mixed and weak and the guidelines (AHA/ACCF vs nephrology) are conflicting. Here's what the authors of a recent CCJM mini-review recommend:

Clarify whether contrast is truly needed
When possible, limit the volume of contrast, avoid repeated doses over a short time frame, and use an iso-osmolar or low-osmolar contrast agent
Discontinue nephrotoxic agents
Provide an evidence-based intravenous crystalloid regimen with isotonic sodium bicarbonate or saline
Although it is not strictly evidence-based, use NAC in patients with significant baseline renal dysfunction (glomerular filtration rate < 45 mL/min/1.73 m2), multiple concurrent risk factors such as hypotension, diabetes, preexisting kidney injury, or congestive heart failure that limits the use of intravenous fluids, or who need a high volume of contrast dye
Avoid using intravenous NAC, given its lack of benefit and risk of anaphylactoid reactions.

Monday, February 11, 2013

ITP update

The topic is reviewed in a recent issue of CCJM.

Key points:

The old name for the disease, idiopathic thrombocytopenic purpura, is a misnomer. The disease is not idiopathic and most patients do not have purpura.

Though no longer idiopathic its pathogenesis is more complex than once thought. It is a disorder of both peripheral destruction and under production:

ITP is a complex immune process in which cellular and humoral immunity are involved in the destruction of platelets3 as well as impaired platelet production. Several theories have emerged in the last decade to explain this autoimmune process...

The triggering event for antibody initiation in ITP is unknown.3 Autoantibodies (mostly immunoglobulin G [IgG] but sometimes IgM and IgA) are produced against the platelet membrane glycoprotein GPIIb-IIIa. The antibody-coated platelets are rapidly cleared by the reticuloendothelial system in the spleen and liver, in a process mediated by Fc-receptor expression on macrophages and dendritic cells. Autoantibodies may also affect platelet production by inhibiting megakaryocyte maturation and inducing apoptosis.

The review had this updated information on the H pylori association:

The association between H pylori infection and ITP remains uncertain. Eradication of infection appears to completely correct ITP in some places where the prevalence of H pylori is high (eg, Italy and Japan) but not in the United States and Canada, where the prevalence is low.20 The different response may be due not only to the differences in prevalence, but to different H pylori genotypes: most H pylori strains in Japan express CagA, whereas the frequency of CagA-positive strains is much lower in western countries.

Treatment is summarized here.

Sunday, February 10, 2013

Aldosterone receptor antagonists in heart failure management

Here is a superb update in CCJM. These things are clear:

The indications for the use of ARAs in heart failure are expanding since the publication of RALES.

ARAs are underutilized.

When they are used patients are not monitored well enough for hyperkalemia.

Tuesday, February 05, 2013

ABI testing in the office

A CCJM review makes this strong statement:

The ankle-brachial index is valuable for screening for peripheral artery disease in patients at risk and for diagnosing the disease in patients who present with lower-extremity symptoms that suggest it. The ankle-brachial index also predicts the risk of cardiovascular events, cerebrovascular events, and even death from any cause. Few other tests provide as much diagnostic accuracy and prognostic information at such low cost and risk.

Sunday, February 03, 2013

Continuous infusion Zosyn (Pip/Tazo)

It makes pharmacodynamic sense, it is gaining in popularity and there is evidence that it is superior, but the evidence is low level. We need better clinical trials.

Saturday, February 02, 2013

Should we skip SCIP?

One by one the core measures (now known by the feel-good term “value based purchasing”) are letting us down. Add SCIP to that list.

Friday, February 01, 2013

Short QT syndrome: what the hospitalist needs to know

CCJM has a nice nuts-and-bolts review. It contains new updates on the nuances of diagnosis and treatment. Simple reliance on the QT (or Qtc) is beset with difficulty, just as it is in the LQTS. I have blogged previously about SQTS here and here.

And remember, when it comes to the QT interval it's best to be average.