Friday, January 31, 2014

Management of patients hospitalized with asthma exacerbation

This post draws from a talk given by Prescott Woodruff, MD, MPH at UCSF's 17th annual hospital medicine conference.

Asthma subtypes

There are numerous classifications of asthma and they overlap somewhat. A useful one for the hospital presentation of asthma is type 1 versus type 2. Type 1 is by far the most common and is mediated by inflammatory cell infiltration and mucus plugging. As such it is gradual in onset and slow to resolve. Type 2, sometimes referred to as “sudden asphyxic asthma,” has a more rapid onset but also responds more rapidly to treatment. It is characterized by intense bronchospasm and less of an inflammatory component. Review here.

Corticosteroids: Dose? Route?

High level evidence to guide clinicians is lacking. The “official” recommendation is to start with oral and switch to IV if poor response. The speaker initiates IV therapy in critically ill patients.

Levalbuterol versus albuterol

Evidence mixed, controversy unresolved. It may not matter.


Not generally recommended for asthma per se but indicated if specific signs/sx of infection e.g. fever, purulency. Don't forget sinusitis.


Forget about it.


Probably helpful as an adjunct.


No evidence that it impacts hard clinical outcomes but works fast and may buy time initially until other therapies take effect. [1] [2] If FiO2 of over 40% is required it's not a good option (you can't mix in enough helium).

IV magnesium

2 grams IV may help as an adjunct to improve pulmonary function during the initial management of severe attacks.

Destructive games involving doctors and patients

I found particularly interesting in this review the list of destructive games played between doctors and patients:

Wooden leg Possessing a disability as a justification for choices or behavior which in the average person may be considered unacceptable.
Why don't you… Yes, but  The player reports a problem despite having been presented with solutions to it, to gain confirmation that his/her issue is “insoluble.”
Now I've got you If one party of a usually not-clearly-defined contract even slightly exceeds its boundaries, the other party, the player, thinks he/she is permitted to react in a forceful way, possibly with full rage.
How do you get out of here? In case of failure of repeated mock efforts the player can avoid a possible consequence of achieving success and feel “justified” in this situation.
Clinic Because both parties of a contract benefit from it they do not want to give it up, even if there is really no need to continue it.

The doctor can be a passive or active participant in the games. Elaboration is found in the body of the paper which is free full text.

Mortality and choice of oral hypoglycemic

Metformin wins, sulfonylureas lose. From a recent study:

We identified new users of oral hypoglycaemic medication monotherapy between 2004 and 2009 who received care for at least 1 year from the Veterans Health Administration. Patients were followed until initial monotherapy discontinuation, addition of another diabetes pharmacotherapy, death or end of follow-up. Mortality HRs were estimated using Cox regression adjusted for potential confounding factors.

Among new users of metformin, sulfonylureas and rosiglitazone (185,360 men, 7,812 women), 4,256 (2.2%) died during follow-up. Average duration of medication use ranged from 1.4 to 1.7 years. Significantly higher mortality risk was seen for glibenclamide (known as glyburide in the USA and Canada) (HR 1.38, 95% CI 1.27, 1.50) or glipizide (HR 1.55, 95% CI 1.43, 1.67) compared with metformin monotherapy, and for glipizide compared with rosiglitazone (HR 1.27, 95% CI 1.01, 1.59) or glibenclamide monotherapy (HR 1.12, 95% CI 1.02, 1.23). A significant sex–rosiglitazone interaction was seen (p = 0.034) compared with metformin monotherapy, with women having a higher HR (HR 4.36, 95% CI 1.34, 14.20) than men (HR 1.19, 95% CI 0.95, 1.49).

Significantly higher mortality was associated with glibenclamide, glipizide and rosiglitazone use compared with metformin, and with glipizide use compared with rosiglitazone or glibenclamide. The potential for residual confounding by indication should be considered in interpreting these results.

Thursday, January 30, 2014

The Berlin definitions for ARDS

Here is a recent review.

The new classification removes the category formerly known as ALI. The definition also removes the quantitative assessment for cardiogenic pulmonary edema, thus relying on clinical circumstances and assessment. The addition of minimum PEEP levels to satisfy the definition would exclude non intubated ward patients who were included under the old definition.

Takotsubo cardiomyopathy due to inhaled beta agonists

Takotsubo cardiomyopathy (TC), in our current understanding, is a disorder of catecholamine myocardial toxicity. Early descriptions attributed it to endogenous catecholamine excess triggered by emotional stress. Over time physical stressors, especially acute illnesses, were recognized as triggers. Exogenous catecholamines as triggers are supported by animal data and have been only occasionally reported clinically.

Here [1] [2] are two reports of TC complicating acute exacerbations of asthma and COPD, triggered by inhaled beta agonists. Arrhythmia and hypokalemia are additional complications of beta agonists. This alongside the considerable overlap between COPD and CAD highlights the importance of cardiac precautions in appropriate patients.

Wednesday, January 29, 2014

Venous thromboembolism in cancer patients

Though there is a relative lack of high level evidence regarding this condition we do know that it differs in important ways from VTE in the general population. Below are some key points from a recent review.

Initial treatment

Acceptable alternatives include low molecular weight heparin (LMWH), unfractionated heparin (UFH), and fondaparinux. LMWH seems to be associated with a mortality benefit and is favored over the other two.


Little evidence exists to guide clinicians. Though special vigilance is needed to exclude patients with cancer associated bleeding risks (eg CNS involvement) patient selection in general is similar to that in the general population.

Continued management after the first few days

Here is where we have the best evidence. Several open label RCTs and a meta-analysis favor LMWH over warfarin for the next 3 to 6 months at least if the patient has normal renal function.

Duration of treatment

Cancer patients have an increased risk of recurrent VTE on and off treatment. They also have an increased risk of anticoagulant related bleeding in many circumstances. The review states that extended anticoagulation (beyond 3-6 months) “be considered” in this population. So just as with the ACCP guideline recommendation on this question for the general VTE population, considerable wiggle room is given for clinician judgment and patient preference.

IVC filters

IVC filters are thrombogenic and even more so in cancer patients. The review authors recommend against IVC placement unless there is an acute VTE with contraindication to anticoagulation, which is consistent with the more conservative of the various guidelines for the general population.

Management of recurrent VTE while on treatment

True anticoagulant failure is believed to be rare in the general population but according to the review is common in the setting of cancer. Strategies to deal with this situation involve first ruling out HIT, non compliance or subtherapeutic anticoagulation. In the event of true anticoagulant failure increasing the intensity of anticoagulation is recommended, either by switching to a superior anticoagulant or increasing the dose of the existing anticoagulant. An algorithm is presented in the review.

Novel oral anticoagulants

The authors recommend against the use of these agents in cancer associated VTE until more research evidence is available.

Approach to the hospitalized patient with altered mental status

These are a few pearls from a talk by S. Andrew Josephson MD at UCSF's 17th annual hospital medicine conference.

Dementia with Lewy bodies (DLB)

Associated with parkinsonism.

Visual hallucinations.

Has a fluctuating course so may present as delirium.

Antipsychotics contraindicated. Cholinergics help.

Here are some links [1] [2]

HSV-1 meningoencephalitis

Tests may be negative initially. Speaker's comment: “We start a lot of confused patients on acyclovir.” (IV).


Triad: confusion, ataxia, occulomotor.

Alcoholism no longer the leading risk factor!

Low threshold to give IV thiamine in confused patient.

Agitated delirium

Non pharmacologic modalities are the treatment of choice. Drugs as a last resort (exception: ETOH withdrawal).

Benzos make it worse (exception: ETOH).

Antipsychotics may be necessary but contraindicated in some patients (e.g. Lewy body).

Tuesday, January 28, 2014

The peri go-live period and patient safety risk

It's something people don't want to talk about. For that matter neither do I, so just go and read this.

Noninvasive ventilation for acute severe asthma: is it appropriate?

There are limited data, summarized in a recent review:

Purpose of review
The use of noninvasive positive pressure ventilation (NPPV) is often employed for the management of acute respiratory failure as an alternative to endotracheal intubation and mechanical ventilation. However, evidence to support the application of NPPV use in patients with acute severe asthma is less known.

Recent findings
A paucity of evidence is available to support the use of NPPV as part of clinical care in patients with acute severe asthma. A number of small studies in adult and paediatric populations suggest that NPPV may have a beneficial role through improving respiratory rate and reducing the need for more invasive alternatives. Overall NPPV use appeared to be well tolerated with few reports of adverse events.

Monday, January 27, 2014

Hantavirus twenty years later

We've learned a great deal since the outbreak in the Four Corners region in 1993. Full text here.

Drug culprits in ANCA associated vasculitis

It is increasingly appreciated that a positive ANCA and various associated clinical manifestations can be associated with certain drugs. From a recent review:

Hydralazine, minocycline, propylthiouracil and levamisole-adulterated cocaine use should be closely considered in any patient where ANCA vasculitis is entertained given the wide use of these drugs in the community. Furthermore, medical practitioners should test urine for the presence of cocaine in any patient with presumed ANCA vasculitis, and if positive, then urine should also be tested for levamisole. Clinical features can be severe requiring not only drug cessation and supportive care, but also immunosuppression, plasma exchange in severe cases and dialysis as needed. Clinical trial investigators should strongly consider excluding patients with drug-induced forms of disease and mechanistic inroads are greatly needed in these secondary forms of disease to help elucidate the underlying cause and pathogenesis of ANCA vasculitis.

Sunday, January 26, 2014

Drug induced channelopathies

Long QT, Brugada syndrome and short QT can be induced by drugs and the topic is covered in this review. Both cardiac and non cardiac drugs are on the list. Long QT inducing drugs are primarily potassium channel blockers but there are other mechanisms. Brugada pattern inducing drugs are sodium channel blockers and include class 1 antiarrhythmics, TCAs and other psychiatric drugs. The list of drugs inducing short QT is short but likely to expand. Many of the short QT inducing drugs were discovered and removed in preclinical development. Patients who experience drug induced channelopathies may be genetically susceptible and have a forme fruste of the condition. The paper, which is available as free full text at the link above, contains links to web resources for drugs to avoid as well as other precautions in syndromic patients.

Chemistry videos

An assortment of videos generated automatically by You Tube's video discovery system.

Saturday, January 25, 2014

Takayasu arteritis

Here's a Mayo Clinic series. The disease is rare. Diagnostic delay is characteristic because when the disease is encountered it tends to be attributed to the ordinary atherosclerotic process. The patients tend to have the traditional risk factors. Think of it in those youngish patients who present as “vasculopaths.”  

Incidentally discovered pulmonary nodules

Hospitalists encounter this situation all the time when chest CTs are done for other reasons. A nice summary post at ERCAST addresses the topic. The emergency physician's perspective on this is pretty much the same as the hospitalist's. Informing the patient and documenting it in the medical record (including stating in the record what the patient was told) is our responsibility, not long term follow up and definitive evaluation. The post has some tips and scripts for how to have the conversation, some pearls about pulmonary nodules and a link to the Fleischner Society recommendations.

Friday, January 24, 2014

Propofol infusion syndrome (PRIS)

This is actually a case report of PRIS treated with ECMO but attached is a nice mini-review of the condition.

The pathophysiology is complex but apparently involves, among many other things, impaired ability of FFA to enter the mitochondria for oxidation (as in Reye's syndrome or carnitine deficiency?) and impaired electron transport.

The association of inflammatory myopathy with underlying malignancy

Understanding of this association has increased in recent years. Here is an update, which contains several pearls. Free full text.  

Thursday, January 23, 2014

Extended infusion cefepime

As compared to conventional dosing it appears to be associated with a marked reduction in mortality in Pseudomonas aeruginosa infections:

We evaluated the clinical and economic outcomes associated with extended-infusion cefepime in the treatment of P. aeruginosa infections. This single-center study compared inpatients who received cefepime for bacteremia and/or pneumonia admitted from 1 January 2008 through 30 June 2010 (a 30-min infusion of 2 g every 8 h) to those admitted from 1 July 2010 through 31 May 2011 (a 4-h infusion of 2 g every 8 h). The overall mortality was significantly lower in the group that received extended-infusion treatment (20% versus 3%; P = 0.03). The mean length of stay was 3.5 days less for patients who received extended infusion (P = 0.36), and for patients admitted to the intensive care unit the mean length of stay was significantly less in the extended-infusion group (18.5 days versus 8 days; P = 0.04). Hospital costs were $23,183 less per patient, favoring the extended-infusion treatment group (P = 0.13). We conclude that extended-infusion treatment with cefepime provides increased clinical and economic benefits in the treatment of invasive P. aeruginosa infections.

Over the last few years a number of publications [1] [2] [3] raised safety concerns regarding cefepime, noting a poorly understood association with increased mortality. Neurotoxicity was cited as a possible mechanism. Extended-infusion dosing might mitigate toxicity by means of lower maximum blood levels.

Via Hospital Medicine Virtual Journal Club.


Learn all about it. Lots of resources here.

Wednesday, January 22, 2014

JNC 8: the minority opinion

Several members of the panel disagreed with portions of the JNC 8 guidelines and expressed their concerns in this article in the Annals of Internal Medicine. It is available as free full text. From the introduction:

The “2014 Evidence-Based Guideline for the Management of High Blood Pressure In Adults: Report From the Panel Members Appointed to the Eighth Joint National Committee (JNC 8)” recommends several major changes from the JNC 7 report (1–2). The 2014 guideline is based on a systematic review of randomized, controlled trials (RCTs) by a multidisciplinary panel using a process informed by Institute of Medicine recommendations for guideline development (3). Although there was almost unanimous agreement on nearly all recommendations, a minority of the panel (the authors of this commentary) disagreed with the recommendation to increase the target systolic blood pressure (SBP) from 140 to 150 mm Hg in persons aged 60 years or older without diabetes mellitus (DM) or chronic kidney disease (CKD). This target guides both the initiation of therapy and treatment goals. Although this issue has major clinical and public health implications, the guideline only briefly summarized the concerns underlying the minority opinion to maintain the target of less than 140 mm Hg. The Institute of Medicine recommendation for guideline development encourages guidelines to provide “a description and explanation of any differences of opinion regarding the recommendation” (3). This article summarizes the evidence and rationale underlying the minority opinion to maintain the SBP target of 140 mm Hg or lower in persons aged 60 years or older until there is greater certainty of the risks and benefits of a higher target.

The authors make a strong case. The more clinical trials published on a topic the more ways there are to combine and interpret the findings. And in hypertension the number of trials is very large. It rivals all of medicine in the number of trials published. There will be much more discussion about this. Guidelines from ACC/AHA are due out soon I'm told.

More from Medpage Today.

Houston Resus

Podcasts and teaching slides on topics in critical care medicine. Early in development and off to a slow start but looks promising.

Tuesday, January 21, 2014

Mini lectures

---in a variety of topics from CrashCourse.

Methadone's cardiotoxicity

When I first wrote about methadone's proarrhythmic effects the connection was well established but ignored by many clinicians and denied by many others. In fact, I was attacked at one point for my postings. But the evidence continued to mount and it soon became apparent that the proarrhythmic effect (torsades) occurred not just in cases of overdose or abuse but in therapeutic use. When the FDA came out with its alert on methadone in 2006 I recommended taking it a step further and proposed protocols for cardiac safety testing for patients given methadone. It may have seemed excessive at the time but sure enough two years later the American College of Physicians followed suit and published guidelines for methadone cardiac safety monitoring.

Some of my other postings on the topic can be found here, here and here.

Now we have new data published in the Annals of Internal Medicine from the FDA's adverse event reporting system. From the report:

Results: 1646 cases of ventricular arrhythmia or cardiac arrest and 379 cases of QTc prolongation or torsade de pointes were associated with methadone. Monthly reports of QTc prolongation or torsade de pointes increased from a mean of 0.3 (95% CI, 0.1 to 0.5) before the 2002 publication to a mean of 3.5 (CI, 2.5 to 4.8) after it. After 2000, methadone was the second-most common primary suspect in cases of QTc prolongation or torsade de pointes after dofetilide (a known proarrhythmic drug) and was associated with disproportionate reporting similar to that of antiarrhythmic agents known to promote torsade de pointes. Antiretroviral drugs for HIV were the most common coadministered drugs.
Limitation: Reports to FAERs are voluntary and selective, and incidence rates cannot be determined from spontaneously reported data.
Conclusion: Since 2002, reports to FAERS of methadone-associated arrhythmia have increased substantially and are disproportionately represented relative to other events with the drug. Coadministration of methadone with antiretrovirals in patients with HIV may pose particular risk.

A few observations:

It is worth repeating that methadone was the second-most reported cause of QT prolongation or torsades after dofetilide. The use of dofetilide may be decreasing nowadays and it is mainly in the hands of cardiologists, so methadone is likely the most important proarrhythmic drug handled by hospitalists.

As evidenced by this and other reports the rise in methadone related deaths began in the year 2000 which is right after the launch of the pain-as-the-fifth-vital-sign movement, promulgated by Joint Commission and various advocacy groups.

According to the above referenced paper reports of arrhythmic events with methadone outpaced reports of other adverse events. The threat of proarrhythmia with methadone is insidious. Pharmacodynamic tolerance to the analgesic and respiratory depressant effects of the drug may enable gradual increase in blood levels as the dose is increased. But there is no reason to think, nor is there evidence that I know of, that similar tolerance to the electrophysiologic effect occurs.

Monday, January 20, 2014

Handwritten tutorials

---in the basic medical sciences.

What is double diabetes?

In patients with DM 1 it's the coexistent development of DM 2 traits including weight gain, high insulin requirements and metabolic syndrome. This may occur because a person genetically predisposed to DM 2 independently develops DM 1, or because exogenous insulin used to treat DM 1 causes weight gain leading to insulin resistance and other manifestations of the metabolic syndrome. Review here.  

Sunday, January 19, 2014

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF)

According to a recent review AE-IPF is characterized by:

..worsening dyspnea with new ground glass opacities superimposed upon a radiographic usual interstitial pneumonia (UIP) pattern. It is a diagnosis of exclusion.

AE-IPF is an emerging clinical entity. Traditional thinking has been that IPF progresses as a continuum but it is increasingly recognized that it often does so in stepwise fashion with acute on chronic episodes.

New antibiotics

What's here, what's in the pipeline? This list is pretty exhaustive.  

Saturday, January 18, 2014

A New Mexico district court legislates assisted suicide

Leslie Smith, author of the Human Exceptionalism blog, brought this to my attention. He opened his post on the subject with this:

If you ever wonder why there are so many radical and extreme lawsuits, wonder no more. As I have often said about a variety of issues, it only takes one judge to break down the walls of democratic governance and impose an ideological view.

Such a judge, once again, has been found. If you're finding it as difficult to believe as I did, that a district court could legislate assisted suicide, go and read the decision. It's right here.

Here's the short and simple version as I understand it. Assisted suicide is prohibited by New Mexico law. One of the plaintiffs, a patient currently in remission from cancer, wants the future option of assisted suicide should the cancer return. According to Smith the lawsuit is backed by Compassion and Choices, a group formed out of a merger with the former Hemlock society. Defendants in the suit were state officials whom the plaintiffs were asking the courts to prohibit from prosecuting any health care provider involved in medically assisted suicide.

As Smith points out the judge seems to have a profoundly misinformed view of terminal illness:

First, Judge Nan G. Nash finds that terminal illness is nothing but suffering–despite the great advances of hospice and the meaning many find in that time of life.  From the decision:
Once diagnosed, these patients are subjected to invasive medical tests and procedures, loss of autonomy and control, extreme pain and other equally insidious indignities. When given their terminal diagnosis, they must say good bye to friends and loved ones, put their affairs in order, come to terms with their imminent death and await the inevitable. The activities which give their lives meaning are stripped away, one after the other, as their disease progresses
Having painted the bleakest and most pessimistic picture possible, she ignores that not all people diagnosed as “terminal,” actually die from their condition.

The court's ruling tends to avoid use of the term “assisted suicide” in favor of “aid in dying” to describe the process as applied to a patient with terminal illness. No matter what it's called the judge acknowledges repeatedly in her decision that the process is clearly in violation of New Mexico's statute against assisted suicide. But then she goes on to say that to deprive a terminally ill patient of such an option would violate New Mexico's constitutional guarantee of the right to “enjoy life and liberty and to seek and obtain safety and happiness.” It's a stretch, I know. And so from the concluding statements:

For the reasons stated herein, the Court grants Plaintiffs the requested injunctive relief prohibiting Defendants from prosecuting physicians who provide aid in dying to mentally- competent, terminally-ill patients.
The Defendants, their agents, employees, representatives, and all those acting in concert with them, shall be permanently enjoined from prosecuting any physician for providing aid in dying to a mentally-competent, terminally-ill individual.

JNC 8 hypertension guidelines

The full text of the original document is here and a concise summary was recently posted here at the Clinical Correlations blog.

The less aggressive BP targets recommended by JNC 8 represent a major shift in the approach to treatment of hypertension. I wonder if they'll change practice all that much, though, because hypertension tends to be under treated and uncontrolled BP levels in hypertension are widely ignored. Traditional thinking about hypertension has been that, down to some theoretical point where autoregulation fails and the patient experiences light headedness or other symptoms, the lower the BP is, the better. The new guidelines don't challenge the physiologic basis for that thinking but acknowledge that lower BP targets are not supported by high level evidence. The authors sought to be more strictly evidence based than JNC 7, relying solely on RCTs. (In the field of hypertension there have been a lot of them). The guideline did not draw on any meta-analyses or systematic reviews. The guideline authors did their own. So the paper is actually a guideline and a systematic review all in one document.

Friday, January 17, 2014

Where do (KPC)–producing Enterobacteriaceae hang out?

In the LTAC hospitals according to this study:

Results. We surveyed 24 of 25 eligible short-stay acute care hospitals and 7 of 7 eligible LTACHs. Among LTACHs, 30.4% (119 of 391) of patients were colonized with KPC-producing Enterobacteriaceae, compared to 3.3% (30 of 910) of short-stay hospital ICU patients (prevalence ratio, 9.2; 95% confidence interval, 6.3–13.5). All surveyed LTACHs had patients harboring KPC (prevalence range, 10%–54%), versus 15 of 24 short-stay hospitals (prevalence range, 0%–29%). Several patient-level covariates present at the time of survey—LTACH facility type, mechanical ventilation, and length of stay—were independent risk factors for KPC-producing Enterobacteriaceae colonization.
Conclusions. We identified high colonization prevalence of KPC-producing Enterobacteriaceae among patients in LTACHs. Patients with chronic medical care needs in long-term care facilities may play an important role in the spread of these extremely drug-resistant pathogens.

That's astounding. Take home lesson? You might want to check the antibiograms of the LTACs in your area to guide initial antibiotic therapy should a recent LTAC patient present septic to your hospital.

Left atrial appendage closure device likely to be approved by the FDA

Via Cardiobrief.

Thursday, January 16, 2014

Blog hiatus

Yes things have been quiet around here for the past week. During the time off from posting I've been working on a few tweaks to make the site more useful as a clinical and educational resource. The labor of love continues and posting is about to resume apace.

Wednesday, January 08, 2014

Subtleties in the electrocardiographic diagnosis of pericarditis

This post from Dr. Smith's ECG blog discusses some quantitative aspects of the electrocardiographic evaluation of possible pericarditis including the ST/T ratio and the magnitude of PR segment depression (not all PR depression is due to pericarditis!).

A case presentation of a patient repeatedly misdiagnosed as having pericarditis discusses some cognitive traps along the way. One that I was intuitively aware of but had never seen mentioned in print before was referred to by the presenter as overconfidence inspired by scientific intrigue. You could also call it the “hey, I just made a really cool diagnosis” heuristic. If you think you've just made a cool diagnosis, watch out. It's emotionally intoxicating and further thinking tends to stop.

Monday, January 06, 2014

We are not choosing wisely in the diagnosis of pulmonary embolism

The hope of finding an alternative diagnosis is often cited as justification for choosing CTA over VQ scanning to evaluate patients for PE. In this study the yield of finding an alternative diagnosis was poor.

Saturday, January 04, 2014

Thiamine administration as a treatment for heart failure with reduced ejection fraction

This systematic review and meta-analysis found two placebo controlled randomized trials. Both showed that thiamine administration was associated with improvement in EF but the numbers were small. The review cites this paper which reports an alarming prevalence of thiamine deficiency in heart failure patients.

Here is another systematic review supporting thiamine administration. Its selection criteria for included studies were broader. Larger studies are needed.

Friday, January 03, 2014


A key point in this review is that acromegaly may not present the way we were taught:

Patients with longstanding disease commonly present at advanced stages with striking physical characteristics (eg, enlarged hands, feet, lips and tongue; prominent supraorbital ridges; and lower jaw protrusion) (Table 1).11 However, the onset of physical changes is insidious (Figure 3) and patients are unlikely to present with complaints relating directly to these distinguishing signs of acromegaly;5 rather, they are more likely to present with complaints typical of other conditions (eg, cardiovascular disease, diabetes, hypertension, and sleep apnea) more commonly seen in primary care.

You see this type of patient every day.

Thursday, January 02, 2014

Hyperkalemia causing pseudoSTEMI

Hyperkalemic electrocardiographic changes can occasionally be mistaken for STEMI. Dr. Smith at his ECG blog presents a case here and links to several others, in which recognition of the hyperkalemia was delayed by a trip to the cath lab (none of the patients presented turned out to have ACS) resulting in a bad outcome.

Instance after instance has been reported in which hyperkalemic ECG changes were initially interpreted as STEMI. The differentiation is a little tricky but there are always clues to point to the correct diagnosis, among them wide QRS and peaked T waves.

It is helpful to look at a lot of these tracings and as you do a more easily recognizable pattern emerges. To me, in many examples, there is something about the way the terminal up or down stroke of the wide QRS heads into the T wave that gives the appearance of ST segment displacement. Also, though the T waves are high in amplitude they are peaked rather than rounded and broad based as in true STEMI. Apparently, according to Dr. Smith's post, the pattern has not been studied very systematically but there are many anecdotal reports.

The recognition of this phenomenon is not new. It was first reported in the early 1950s and was termed “the dialyzable current of injury.” One of those early papers is linked here. It is available as free full text and is well worth the read.

A word of caution.  Today's performance driven world is hazardous to the diagnostic process.  Once a STEMI alert is called all diagnostic reasoning tends to stop.  Be aware that hyperkalemia is a great electrocardiographic imitator.