Thank-you from the BoringEM.org

Hey everyone,

This is Teresa Chan writing on behalf of the BoringEM team to wish everyone a very happy Canadian thanksgiving today!  We would like to thank all of our readers for their clicks, follows, reads, and shares.  It has been very exciting to help to grow this blog in these past few months.

First, I would also like to thank our fearless leader, Dr. Brent Thoma, without whom BoringEM would not exist.  We are very proud to announce that Dr. Thoma will be in Toronto next weekend to receive a much deserved leadership award.  On behalf of the whole BoringEM team, we salute you good sir, and thank you for all the work you have done (and will continue to do) in the future.

Next, I would like to thank the tireless Associate Editors that we have had this past year – Dr. Sarah Luckett-Gatopoulos and Soon-To-Be-Dr. Eve Purdy.  Without all of their work, we would be lost.

Finally, we would like to thank all of the writers who have submitted pieces (whether they are posted or still undergoing peer review.  Your pieces are what bring BoringEM to life.

Therefore, in alphabetical order, we would like to thank:

Writers:

Jacob Avila, Chris Byrne, Erin Dahlke, Danica DeJong, Anton Gervaiev, Alana Hawley, Chris Hicks, Andrew Petrosoniak, Eve Purdy, Romesa Khalid, Heather Murray, Rob Woods,Ross Morton, Aaron Sibley, Brent Thoma, Corey Veldman, Ping Yu Xiong, Amna Zaki.

Attending Reviewers:

Alim Pardhan, Andrew Petrosoniak, Dan Kim, Heather Murray, James Ahn, James Huffman, Joanna Bostwick, Nadim Lalani, Paul Olzynski, Ross Morton, Seth Trueger.

Thank-you to everyone who has made BoringEM a great place to volunteer and contribute.

Yours truly,
Teresa M. Chan
Managing Editor,
BoringEM.org

p.s. If you would like to contribute to BoringEM, please click here to find out how!

Author information

Teresa Chan
Managing Editor at BoringEM
Emergency Physician. Medical Educator. #FOAMed Supporter, Producer and Researcher. Assistant Professor, Division of Emergency Medicine, Department of Medicine, McMaster University. + Teresa Chan

The post Thank-you from the BoringEM.org appeared first on BoringEM and was written by Teresa Chan.

#TipsforEMexams: The Psychological Science of Exams

So, I ran into my friend Meghan McConnell the other day and we got chatting about how to make examinations less of a horrible experience. Dr. McConnell is a PhD researcher in the world renowned Program for Education Research & Development at McMaster University. Her research interests are in the area of how emotions influence training, assessment and performance of healthcare professions.

Considering her interests and expertise, I thought it would be great to interview her for the BoringEM blog, and get some insights into how we might actually harness our own psychology to conquer the exams.

You can listen to our conversation here:

But, for all of busy residents ACTUALLY studying for your exams, here is a summary so you can quickly gleam all the info quickly.

Transcript of Podcast (The Psychological Science of Exams)

TC: What are some things that we can do as people challenging exams to not “psych ourselves out”?

MM: So, a big thing in the emotions research is what we refer to as appraisal. So you can look at an event as stressful or …you can appraise it as a positive or a negative thing. So, classic example is they did this research where they looked at the effects of stress, so if you found that stress had a negative impact on your life then when you followed these people forward you found that they died a lot sooner. If you found that you had a stressful life, but you viewed the stress as a positive thing, then the[se people] actually out performed a lot of their peers. So the idea is that by looking at stress as a positive thing, so it oxygenates your blood, helps focus your attention …

TC: You’re riding an adrenaline high, right?

MM: Exactly. Stress has developed and evolved for a reason, so if you can appraise it as a positive thing – sure, you’re a little antsy, but you know what? That’s going to likely enhance your performance, and that’s really it.

TC: So in other words, don’t let stress get to you, but rather ride that adrenaline high.

MM: Exactly. Ride the wave.

TC: And considering that we’re talking to emerg residents that’s very applicable because, I mean, we ride the adrenaline high all the time, right? Like, in the emergency department … I mean who doesn’t get super psyched up for a really extra interesting case, right? Someone patches in, and needs our help, and is there…

MM: Yup.

TC: So it’s just channelling that …

MM: Well it’s finding that excitement.

TC: So can you get excited about the exam in the same go-getter way that we do every day in the department. Okay. Perfect.

MM: Yeah.

TC: What about [memorization]. There’s a lot of stuff we’ve got to cram in our brains. Honestly, it’s the biggest complaint I hear about the exam. So what can we do to better cram stuff into our brain?

MM: Best thing that I can think of – and I tell everybody this – is …. Testing, testing, testing. It’s not about different ways of encoding the information, which is what studying does, but retrieving information – because that’s what you have to do when you’re testing. You actually have to access the information.

TC: You mean, like, quizzing yourself? Is that what you mean?

MM: Yup. So flash cards – that was my go-to for all of school, and it was really great. Even just, a big part is – and I haven’t go to test this (and I would love to study it) would be to use different parts of your brain. Speaking is one thing, versus reading, versus writing – all of these are accessing different neural networks. And the more accessible this information is, the less stressful it’s going to be, and the easier it is going to be to come out.

TC: Do you think that if you’re going to be challenging a multiple-choice exam, then you should probably try to do as much multiple choice as possible?

MM: Yes. Although research has suggested that even if you … the more elaborate the processing is the better. So it’s just as efficient to test yourself using short answer questions and things like that. Because if you’re making your own quizzes, it’s kinda hard to come up with alternative options.

TC: Yeah. It’s really hard to make up multiple-choice questions.

MM: Right. They have experts on these committees that spend years doing that.

TC: We hope so, anyways!

MM: But even just doing short answer questions still shows an enhancement [in performance] in multiple-choice tests. And even, [with] Meredith Young and Christine St. Onge recently, [I’ve] published something that testing [can have an effect on] a mock licensure exam with multiple-choice questions

TC: In other words, just practice pulling this stuff out of your brain.

MM: Exactly. In as many different ways as you possibly can. Pretend you’re giving a lecture. It doesn’t have to be just be cue cards. Pretend you’re explaining it to someone.

TC: Exactly…

MM: Call up your mom like we were talking about, say: “Okay mom, I’m going to explain this to you. You’re probably not going to understand it… but…”

TC: If your mom is a doctor then she can correct you!

TC/MM: Laughter.

TC: As yours is! And my dad is… so… Obviously, that makes sense. And you can explain things to your learners, if you’re a senior in the department. Finding a learner and tell them you’re going to tell them about some esoteric thing that I need to know for myself. Think of it as both teaching and learning at the same time.

MM: Exactly, it’s about accessing that information. Retrieval practice.

TC: So you want to retrieve things out of your brain. Dust of the cobwebs and really just take it out as much as possible. Alright. And then, my final question to you would be: What do you think are things you can do for mock oral exams? Now, those are a slightly different technique, they tend to be a bit more grounded in reality – most people find them more user friendly. Obviously, it’s not quite like an OSCE – it’s more about your cognition. So, any insights on how to optimize that?

MM: So, I think, if you’ve got the knowledge base so use your testing… Well, you’ve got your comfort there, practice has to be one of the most beneficial things. Again, if you just read over the text, that’s great, but you have to – in the context of an oral exam – actually verbally access [read: represent] that information. You have to also practice the process of speaking and articulating that. And I think a lot of the time, [it’s how you get] more comfortable with it. And if you get stuck in a moment, just take two seconds – remember it’s just ride that adrenaline. So practice, and if you get stuck, it’s not [the end of the world].

TC: Like, do you think it matters if you practice with a faculty member or just with one of your buddies?

MM: I think you could practice in the mirror. I think you could practice on your cat!

TC: Laughs.

MM: The point is getting that information to flow verbally, because a lot of the time you can access it, but being able to say it is a whole other ballgame.

TC: Yeah. It’s kinda like you can watch and know how to do a dance routine but until you actually dancing… Or we’ve all been there, and on platform speeches. Where you have to give a speech – I may know the words but it’s not the same as being on stage. And I guess in some of my earlier days, I may have done some acting… And so memorizing the speech – you know a monologue from Shakespeare -is not the same performing it really well. So that performance part is what you’re talking about. It’s the practicing of that performance. You may know your stuff, but you need to practice performing.

MM: And, you even the bonus of doing it with yourself is that you need to come up with your own questions. It makes you think critically about the same material. And again, variety is the spice of life. Practice with a senior colleague, a junior colleague – they’re all going to ask different questions, and it’s all about accessing that information.

TC: And one of the things that I found was that doing those practice exams, honestly, the quizzes that my friends gave me – some of them have actually impacted on patient care. They didn’t immediately interact on it, but for sure I found that there were some mock oral exams that my friends gave me that resonated with me so much that a couple months later when I was first year staff, it probably saved someone’s life.

MM: Huh!

TC: So, I think that is worth it all. So practicing mock oral exams, learning the material… it’s all important! Well, thank you very much – this is Teresa. And…

MM: Meghan!

TC: Meghan… And thanks for tuning in! Bye!

References:

1.  TED Talk by Kate McGonigal.

2.  McConnell, M. M., St-Onge, C., & Young, M. E. (2014). The benefits of testing for learning on later performance. Advances in Health Sciences Education, 1-16.

Other Resources

1.  Strategies that Make Learning Last 

3.  To remember a lecture take notes by hand 

 

Author information

Teresa Chan
Managing Editor at BoringEM
Emergency Physician. Medical Educator. #FOAMed Supporter, Producer and Researcher. Assistant Professor, Division of Emergency Medicine, Department of Medicine, McMaster University. + Teresa Chan

The post #TipsforEMexams: The Psychological Science of Exams appeared first on BoringEM and was written by Teresa Chan.

Posterior Shoulder Dislocation: Radiographic Evidence

The Case

You’re in the final stretch in an overnight fast track shift at your local emergency department andsleepily contemplating whether to invest in another energy drink when you glance over at the triage desk and your natural endorphins kick in.

A 25-year-old male with the presenting complaint of left shoulder pain is being seen – and the dude has obvious pathology.

shoulder dislocation

(Not actual file photo – this image shows similar patient with pathology on opposite arm – From Imagine courtesy: http://thesportsphysio.wordpress.com/2013/08/20/shoulder-instability-part-2-trauma/)

You immediately suspect an anterior shoulder dislocation and gleefully attempt a Cunningham reduction while taking your history. The patient notes a one-week history of increasing left shoulder instability. His past medical history is significant for previous dislocations of both shoulders. He is otherwise well and takes no medications. He awoke with the shoulder discomfort and came in straight away.

Unfortunately, your reduction is not successful and you start thinking about that energy drink again. You slink off to order a series of shoulder films. 

Play along! For the following images (actual file photos), name the view and note the presence of any abnormalities. Discussion below.

What is this view? Any abnormalities?

What’s this view? What bony anatomy comprises the important landmarks?

What’s this view called? How do we know which direction is anterior and which is posterior?

Acute Posterior Dislocations of the Shoulder

This patient presents with an acute posterior shoulder dislocation.

General Information & Incidence

Posterior shoulder dislocations are rare, accounting for only 2-4% of all shoulder dislocations (anterior dislocations make up the vast majority). The shoulder support provided by the scapulae and their thick muscular associations is what makes this type of dislocation so uncommon. Posterior shoulder dislocations are generally associated with the ‘3 Es’: ethanol, epilepsy, and electricity. The mechanism of injury is nearly always indirect traumatic force, such as a fall or seizure.

Delays in the diagnosis of posterior shoulder dislocation are common due to subtle clinical and radiographic findings. ED physicians must be vigilant and look for them.

Clinical Assessment & Presentation

This patient presented classically, with an internally-rotated arm held in adduction, with reluctance and pain on external rotation.

Image courtesy Roberts & Hedges Clinical Procedures in Emergency Medicine (6th ed) 2014. Philadelphia. Elsevier Saunders Inc. – Chapter 49

Other findings in posterior dislocation may include:

  • Anterior contour of the shoulder absent (flattened anterior shoulder),
  • Prominent coracoid and acromion,
  • Rounded posterior shoulder,
  • Palpable posterior humeral head

Radiographic Examination

In the setting of a suspected posterior shoulder dislocation, radiographs should be surveyed for several subtle findings. In particular, a full shoulder series (anterior-posterior (AP), scapular ‘Y’, and axillary views) is an essential part of the diagnostic workup. Occasionally, a patient’s inability to externally rotate for the ordered views (as noted by the radiology tech) may be a helpful clue in the case of a unsuspected posterior dislocation.

AP View

Subtle signs on the AP radiograph include:

  • ‘Light Bulb sign’
    • Internally rotated humeral head appears symmetric on AP film (due to rotation of the greater tuberosity).
  • ‘Empty glenoid sign’
    • Widened space between articular surface of humeral head and anterior glenoid rim.
  • Trough sign
    • Dense vertical line on AP indicating compression fracture of medial aspect of humeral head.
Abnormal Image A
Normal AP View
Un-Boring Finding
Empty glenoid fossa and widened joint spaceHumeral head well-positioned and overlaps with glenoid fossa'Lightbulb Sign' due to rotation of greater tuberosity of humeral head; 'Trough Sign' on humeral head

Scapular View

The scapular view is generated by superimposing the humeral head over the coracoid, acromion, and scapular body and spine. A posterior dislocation is represented by the humeral head lying posterior to the glenoid fossa.

Abnormal Image B
Normal Scapular 'Y' View
Un-Boring Finding
Humeral head appears misleadingly well-positioned in this view - this is why multiple views are essential!Humeral head overlying intersection point of coracoid, acromion, and scapular spinePosterior dislocation of humeral head (HH - humeral head; G - glenoid, SP - scapula)

Axillary View

Abnormal Image C
Normal Axillary View
Un-Boring Finding
Posteriorly displaced humeral head with reverse Hill-Sachs lesionHumeral head well-positioned in relation to the glenoid fossaCoracoid process points anteriorly; note posterior displacement of humeral head; arrow shows reverse Hill-Sachs lesion

The axillary view is generated by placing the arm in abduction, with the image taken through the axilla at 45 degrees. This is arguably the most important view for posterior dislocations, as it easily visualizes a posteriorly situated humeral head. It may also reveal the presence of a reverse Hill-Sachs lesion (also known as a McLaughlin defect), which is an impaction fracture of the humeral head following posterior dislocation.

Tip: Use the coracoid process to orient yourself to the anterior direction on the film!

Reduction Technique

picture15

From Roberts & Hedges Clinical Procedures in Emergency Medicine (6th ed) – Chapter 49

As with any dislocation, be sure to check neurovascular status prior to reduction! Fortunately, neurovascular injury is rare in posterior dislocation because the nerves and vessels serving the area are protected due to their anterior location. Consider ortho involvement as posterior dislocations are rare and they may want to be involved in the reduction. Reverse Hill-Sachs lesions occur in >20-25% of posterior dislocations and may require open reduction and internal fixation (ORIF) under general anaesthestic, which is another good reason to consult orthopaedic surgery. Patients in whom you suspect a reverse Hill-Sachs lesion may require further imaging (CT) prior to reduction.

To reduce a posterior dislocation, apply traction to the internally-rotated and adducted arm in conjunction with direct pressure on the posterior aspect of humeral head. The mechanics are relatively similar to the traction-countertraction technique sometimes used to reduce an anterior dislocation.

Analgesia

Consider procedural sedation with or without an intraarticular block for adequate muscle relaxation and patient anxiolysis.

Post-reduction care

Repeat neurovascular examination and post-reduction radiographs are key. On assess of shoulder ROM the patient should now be able to place palm of injured arm on the opposite shoulder. The patient will require post-sedation monitoring, shoulder immobilization, and follow-up with ortho.

Case Resolution

After your refreshing energy drink, you review the case with your attending. You note the presence of a subtle empty glenoid sign on AP film, and posteriorly displaced humeral head with a reverse Hill-Sachs lesion on axillary view. You suspect a posterior shoulder dislocation.

After further discussion with the patient, he confides that he is worried that he may have seized prior to presentation because when he awoke with the shoulder pain he felt groggy and his bedding and bedside items were on the floor. Apparently he’s had a few of these before with unremarkable neurology workups.

The shoulder reduced without issue and the patient is referred to neurology for further workup of for his possibly recurrent seizures.

Peer reviewed by Dr. Sarah Luckett-Gatopoulos (@SLuckettG) and staff reviewed by Dr. Heather Murary (@HeatherM211)

References

  1. Roberts & Hedges Clinical Procedures in Emergency Medicine (6th ed) 2014. Philadelphia. Elsevier Saunders Inc. – Chapter 49
  2. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide (7th ed) 2011. New York. McGraw Hill Companies Inc. – Chapter 268
  3. Rosen’s Emergency Medicine: Concepts and Clinical Practice (8th ed) 2014. Philadelphia. Elsevier Saunders Inc. – Chapter 53

More Posterior dislocations on FOAMed..

  1. Life in the Fast Lane – Posterior Shoulder dislocation (Great images of the radiographic signs mentioned above)
  2. The Blunt Dissection – ‘In or Out?’
  3. EM Resident Blog – Case Discussion
  4. Radiopaiedia – Posterior Shoulder Dislocations

Author information

Corey Veldman
Corey Veldman

The post Posterior Shoulder Dislocation: Radiographic Evidence appeared first on BoringEM and was written by Corey Veldman.

#TipsforEMexams: Aaron Sibley presents his EM Exam Tips

The snowball nomination fun has begun!  Originally I nominated Rob Woods, when then nominated Aaron Sibley from Dalhousie University (Halifax, NS).  Rob is currently an examiner for the RC exams, but he has kindly sent along some really good tips for studying that do not violate the terms of his confidentiality re: the exams.

- TChan
p.s. Also, we are still waiting on previous nominees…
Heather Murray
Chris Hicks

***

Name:  Aaron Sibley, Survivor of the 2008 RC emergency medicine exam. (I graduated from the U of A in 2008, the year behind Rob.)

Where are you now?   I am currently an Assistant prof at Dalhousie University and a member of the emergency dept. at the Queen Elizabeth Hospital in Charlottetown. I am also an examiner for the Royal College in Emergency Medicine.

My List:

  1. Create a study plan early (in late August or early September). Set weekly and monthly goals for reading/covering the information. Meet with colleagues regularly to ensure you are keeping on track and to reaffirm your retention.
  2. Take a break.  Studying everyday for months on end can be mentally and physically exhausting. A night out with a significant other or friends, exercising, or even watching a favourite TV show can be rejuvenating and give you the needed energy to make it for the long-haul. Think about taking a longer break in the winter.
  3. Reach out to others.  This is a difficult year.  Use the support of others in your program who have gone before you.
  4. Practice makes permanent. Do as many mock written and oral exams as you can. Perfect you “spiel” of how you would like the patient managed initially and what tests/investigations you would like performed.
  5. Keep track of important articles during the year prior to the exam.  Use a resource such as “Journal Watch” or McMaster ACCESSSS federated search to do the grunt work for you, ask one of the EBM gurus at your institution for their top articles.
Hope this helps,
Aaron
My nomination is:
Anthony Chahal at UBC

Author information

Teresa Chan
Managing Editor at BoringEM
Emergency Physician. Medical Educator. #FOAMed Supporter, Producer and Researcher. Assistant Professor, Division of Emergency Medicine, Department of Medicine, McMaster University. + Teresa Chan

The post #TipsforEMexams: Aaron Sibley presents his EM Exam Tips appeared first on BoringEM and was written by Teresa Chan.

Counterpoint: Don’t use Steroids for Tinea!

I received a message from an old friend from medical school about our recent Tinea Piece.  Dr. Erin Dahlke FRCPC is a dermatologist in Toronto.  She wrote me the following piece when I invited her to comment back!
I now invite our community to join in on the discussion.  What do you think?
- TChan

Don’t use Steroids in Tinea!

by Dr. Erin Dahlke
Note: Dr. Dahlke was invited to review the topic and the Cochrane review from her point of view as a Dermatologist and provide her perspective.  Please give her a warm BoringEM welcome and perhaps drop your comments below.  Let’s have some frank discussions about how and if we should do things differently – based on the info below.
My criticism is twofold.
Firstly, treating blindly is poor medicine.
What if you have the wrong diagnosis?
When presented with an annular erythema with scale a number of diagnoses run through my mind.  Tinea corporis, psoriasis, erythema annulare centrifugum, allergic contact dermatitis, lichen planus, cutaneous T-cell lymphoma, eczema, subacute cutaneous lupus erythematosus, discoid lupus erythematosus, pityriasis rosea, secondary syphilis, polymorphous light eruption, annular seborrheic dermatitis, erythrokeratodermia variabilis, leprosy, etc.
Yes, tinea corporis is one of these diagnoses, but very often the diagnosis is unclear.
In these cases I will do a fungal scraping, sometimes a KOH examination, often a skin biopsy, and will wait for the results before initiating treatment.
Often Cutaenous T-Cell lymphoma is treated as tinea or psoriasis for many years before an accurate diagnosis is made.
Occasionally there is an obvious diagnosis of a dermatophyte infection – ie- horrific onychomycosis, tinea pedis and then a new annular erythema with a characteristic leading edge of scale in the groin.  This is tinea cruris and the differential diagnosis is short. Even then – I will always do a fungal scraping, and have the patient follow up to ensure treatment is effective.
Secondly, combination steroid/antifungal products should not be used for superficial dermatophyte infections.
There is no doubt industry-sponsored evidence to support the use of these lucrative combination products.  Short term clinical cure is an easy endpoint to achieve when you add an anti-inflammatory agent, but raises the question – what is the risk of rebound upon discontinuation?  This can force a steroid dependency to quell inflammation caused by a dermatophyte infection.
The use of even mid-potency topical steroids can have serious consequences if used chronically, and sometimes even from short term use.
There is a real risk of atrophy, telangiectasia, striae, purpura, bruising and hair growth.  There is also a risk of HPA axis suppression, growth retardation, immunosuppression and impaired wound healing, although perhaps this is more theoretical.
A product like lotriderm (topical azole and betamethasone diproprionate) is often prescribed by primary care docs unsure of how to treat a rash.
Betamethasone diproprionate is a class 1/2 steroid (meaning highest potency), very different from betamethasone valerate, an entirely different, milder, medication.
I recently reviewed a case of a teenage girl with horrific striae, erythema, and telangiectasia between her breasts.  She had been prescribed lotriderm for a presumed fungal infection, and as the area continued to be red (which was, in fact, atrophy from the treatment) she continued to use it.  Unfortunately for her (and the prescribing doctor), her disfiguring stretch marks are permanent.  This is not a unique story.

In summary:

  • If a fungal infection is suspected, confirm the diagnosis prior to initiating treatment.
  • If the scraping is negative and the diagnosis is unclear, consider referral to dermatology for a skin biopsy for diagnosis (+/- repeat scraping).
  • If the fungal scraping is positive, treat with antifungal therapy, monotherapy.
  • Do not use corticosteroids on dermatophyte infections.
  • Use caution when prescribing strong topical steroids.

 

Suggested Papers for Further Reading:

1.  Greenberg, H. L., Shwayder, T. A., Bieszk, N., & Fivenson, D. P. (2002). Clotrimazole/betamethasone diproprionate: a review of costs and complications in the treatment of common cutaneous fungal infections. Pediatric dermatology,19(1), 78-81. DOI: 10.1046/j.1525-1470.2002.00027.x

2. Alston, S. J., Cohen, B. A., & Braun, M. (2003). Persistent and recurrent tinea corporis in children treated with combination antifungal/corticosteroid agents. Pediatrics, 111(1), 201-203. doi: 10.1542/peds.111.1.201

 

Author information

Teresa Chan
Managing Editor at BoringEM
Emergency Physician. Medical Educator. #FOAMed Supporter, Producer and Researcher. Assistant Professor, Division of Emergency Medicine, Department of Medicine, McMaster University. + Teresa Chan

The post Counterpoint: Don’t use Steroids for Tinea! appeared first on BoringEM and was written by Teresa Chan.

Management of Hyperkalemia with ECG Changes

Editors Note: We are very excited to have our first professor of Nephrology guest blog with us here at BoringEM.  He kindly asked one of his residents to write up the “C BIG K DROP” mnemonic (see Tiny Tip from September 22, 2014), but he also obliged us with an expert review of the topic. 

The association of electrocardiogram (ECG) changes in the setting of hyperkalemia is a medical emergency.  As with most emergent situations, the management strategy is to alleviate the consequences and then deal with the cause of the emergency.

The major consequence of acute hyperkalemia is cardiac standstill which results from reduction of the natural myocyte excitability with loss of spontaneous pacemaker activity and marked conduction delay. The ECG changes reflecting this usually follow a progressive pattern of symmetrical T wave peaking, PR interval prolongation, reduced P wave amplitude, QRS complex widening, sine wave formation, fine ventricular fibrillation and asystole. There is frequently a background progressive bradycardia. (See http://lifeinthefastlane.com/ecg-library/basics/hyperkalaemia/ for some excellent examples.) However, these changes are unpredictable and unreliable.

In the presence of ECG changes and hyperkalemia, intravenous calcium (usually as gluconate, since chloride is chemically more toxic if extravasated) results prompt reversal of ECG changes. The effect is transient, but the calcium injection can be repeated until measures to correct the hyperkalemia are undertaken.

The two main methods of lowering the potassium are by shifting the potassium from the intravascular to the intracellular space, and by eliminating potassium from the body via the urine, feces, or extracorporeally by dialysis.

By its nature, shifting of potassium is a temporizing measure and needs to be followed by an elimination process.

Shifting

Both intravenous insulin (followed by glucose to prevent hypoglycemia) and nebulized beta agonists produce similar (and synergistic) lowering of the potassium level by about 1 mmol/L by about one hour. The effect of insulin appears more predictable and robust (reviewed in [1]), and should probably be used first.

Intravenous sodium bicarbonate has been part of the “shifting” armamentarium for many years. By lowering the extracellular [H+] this favours export of protons from and influx of sodium to the cells via the Na+ / H+ exchanger (NHE). The extra sodium is then exported by the Na-K-ATPase and causes influx of potassium lowering the extracellular [K+]. While good in theory, it transpires that the NHE is probably inactive in the non-acidotic state, therefore this mechanism would be expected to work only if the patient were academic prior to the administration of the bicarbonate (reviewed in [1]). Certainly sodium bicarbonate is commonly used for patients with low pH (< 7.1 in my practice), but its effects in non-acidotic patients have not been shown to be great.

Eliminating

In patients with good urine output, intravenous furosemide can enhance elimination of potassium. The onset of action is fairly rapid in patients with normal renal function and can last for up to six hours.

The most controversial agent in the management of acute hyperkalemia is the ion exchange resin sodium polystyrene sulphonate (Kayexelate). This agent acts in the colonic and rectum, so any effect of oral administration is hampered by delays in gut transit time. This led to the combined use of Kayexelate with a cathartic such as sorbitol. Current warnings suggest an increased risk in colonic perforation in this setting. In the acute phase, there is non role for this oral agent (reviewed in [2] and [3].) The use of Kayexelate as a retention enema makes more intuitive sense, but there remains the concern of bowel wall necrosis. It is fair to say, that there is no role for this agent in the acute management of severe hyperkalemia.

Hemodialysis provides prompt reduction and elimination of potassium. There is the need for the patient to be at a facility which offers this treatment, central venous access has to be obtained, and the machine and staff have to be made available. The delay to starting dialysis de novo is usually in the order of 1 – 2 hours (longer if the patient has to be transferred.)

After the emergent situation is under control, attention needs to be directed at the cause of the hyperkalemia. For an excellent review of potassium disorders see [3].

 References:

1. Kamel, KS, Wei C. Controversial issues in the treatment of hyperkalaemia. Nephrol Dial Transplant 2003;18:2215 – 2218

2. Kamel, KS, Schreiber M. Asking the question again: are cation exchange resins effective for the treatment of hyperkalaemia? Nephrol Dial Transplant 2012;27:4294 – 4297

3. Medford-Davis L, Rafique Z. Derangements of potassium. Emerg Med Clin N Am 2014;32:329-347

 

This piece has been peer reviewed by Dr. Teresa Chan (@TChanMD), Managing Editor.

Author information

A. Ross Morton
A. Ross Morton
Dr. A. Ross Morton is an Educator and Clinician Scholar at Queen's University. He is a Professor of Medicine and the Chair of the Division of Nephrology at Queen's University, Kingston, ON, Canada.

The post Management of Hyperkalemia with ECG Changes appeared first on BoringEM and was written by A. Ross Morton.