The Yellow Stone Ultrasound Course

Are you going to SMACC – flying all that way for 4 days – well why not kill 3 birds with 1 Stone!

(1) Attend SMACC

(2) get some awesome pre-SMACC ultrasound and airway training

(3) help save one of FOAMed’s great teachers from a dark, yellow side

Here is how:
Register for the Yellow Stone Ultrasound Course

Check out the Promo here 


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Or hear it from the boys at the Ultrasound Podcast here:

See you there in June 2015

It will be AWESOME!
Casey

Apologies: we are back online

Hi All

Just a quick note to let you know that the blog and comments are now back up and online.

We did have a bit of drama with some seriously heavy spam traffic and had to put a block up to keep it sane. Now back up and functioning.

Apologies if you wrote some really long and insightful comments on the last few posts only to have them blocked by the spam filter…. super annoying I realise!

But now it is up and going – so please share your collective wisdom with us all.

Thanks Casey

Clinical Case 106: The mysterious Pink Lady

Time for another quick clinical case

Your next patient is Joan – a semi-regular attender to your family practice.

Joan is a 67 yo woman who is usually reasonably well.  She works as a book keeper in a small business.

She has been troubled by some gastro-oesophaeal reflux symptoms over the last few years and has been taking some omeprazole “most days” for symptom relief.

Today she presents with a sheaf of discharge letters from the local ED.  7 in total!  She has been seen in the ED 7 times in the last 6 weeks with “chest pain – non-specific”.

She tells you that she has been experiencing dull, spasms of pain in her substernal area that sometimes radiate to her back.   They are not really like her usual ‘heartburn’ symptoms.  She doesn’t feel sick or sweaty.  Just worried.

These are quite unpleasant and stop her from working at her computer.  The last couple of episodes have occurred at night and woken her from sleep – her husband has called the ambulance service twice in the last fortnight!  On each attendance to the ED she has been “fast tracked” into the chest pain protocolised management.  And spent a few uncomfortable nights on a stretcher in the corridor of the ED…..  awaiting a second  troponin.

Amidst the paperwork there are formatted letters from ED interns, Registrars and even one from a consultant ED Physician.

There are a batch of plumb normal ECGs and photocopies of many negative troponin results.  She even stayed in for an exercise stress test one day – which was non-suggestive of ischemia.

She has been diagnosed consistently with:  “Chest pain – non-specific.”  or “Chest pain, not cardiac.” on each occasion.  On the latest visit the senior Doc has ventured a positive diagnosis – “Probable Oesophageal spasm.”

Interestingly there have been a number of therapeutic trials of “Pink Lady” i.e.. the Mylanta & Xylocain viscous cocktail so loved by triage nurses the world over!  Joan says that the pain is usually short-lived – coming in spasms. It seems to go away after a few minutes then return.  She says a lot of the doctors ordered the Pink stuff and when her pain got better…  told her it was from her oesophagus. [ see this post from Dr Seth Trueger on this topic. ]  Maybe best left until after the troponin has settled the question!!

She has received advice to take her omeprazole twice a day and to follow up with her GP.  OK, here she is….

So, it seems clear that she is in the low-risk group for cardiac disease as a cause of her chest pain.  Let us assume that the ED Docs have excluded ACS as a cause.

SO, if you are the GP how do you go about making an actual diagnosis in this scenario?

Is a therapeutic trial of PPIs a reasonable strategy?

Depends…. are you trying to give relief to the patient or make a diagnosis? After searching through the databases I found this decent sized trial from Flook et al, in Amer Journal of Gastroenterology (January 2013)

It looked at 600 patients with reflux symptoms giving chest pain.  A placebo, RCT (esomeprazole 40 mg BD for 4 weeks) They found a significant improvement in symptoms at the end – but this was really only for patients with less frequent reflux sx at the outset.  Not so effective for the pts with more than 2 days a week of symptoms.

There is also a meta-analysis [Wang et al, JAMA, June 2005 ] looking at 6 papers ( only 220 pt in total) which tried to answer the question about the diagnostic characteristics of a “trial of PPI” for reflux-related chest pain in patients with “non-cardiac chest pain” .  The conclusion of the authors was that is was an acceptable “test” with a sensitivity of 80% and specificity of 74% roughly.  So – it might help – but to my mind those are not stellar numbers.  I would want a reasonable high or low pretest probability of “GORD” before hanging my patient’s hat upon those figures.

Should she have endoscopy to look for serious upper GI problems?

Well that is a tricky one.  Not a lot of data.  Just opinion.  The surgeons that I work with would suggest everyone with severe enough , persistent symptoms should probably have a scope to exclude malignancy or other correctable lesions in the oesophagus.  In the good old days we would send them for a Barium swallow.  But nowadays it seems easy to get a scope, and then you have the option of a CLO, biopsy or whatever else they need on the day.

So I think it is reasonable to get a scope if you have persisting symptoms or severe symptoms so that you know what you are dealing with.  It would be disastrous and unfortunate to treat a malignant process for months and months with symptomatic care.

What is the role of manometry or pH monitoring to try and correlate her symptoms with  events in her oesophagus?

This is not something that I really see much of – but I work a long way from any Gastroenterolgists!  Certainly I have seen this done in patients with bad GORD – i.e.. those whom are contemplating a fundoplication procedure.

Found this paper in the BMJ – Barham et al from Gut, 1997. [Diffuse oesophageal spasm: diagnosis ] It is old – but suggests that for intermittent symptoms like our patient is suffering – you really need to get continuous outpatient / 24 hour ambulatory monitoring of pH and pressure in order to make this diagnosis.  Diffuse oesophageal spasm is also known as “nutcracker oesophagus” or “corkscrew oesophagus” as it has characteristic appearances on imaging.  However – you would be lucky to see this phenomenon as it is fleeting!  IN order to correlate symptoms with measured anomalous peristalsis or pH spikes – you would need ambulatory monitoring.  I guess it is like the Holter of the gut?

http://download.figure1.com/broome

Image courtesy of Figure 1

Clinical Case 106: The mysterious Pink Lady

Time for another quick clinical case

Your next patient is Joan – a semi-regular attender to your family practice.

Joan is a 67 yo woman who is usually reasonably well.  She works as a book keeper in a small business.

She has been troubled by some gastro-oesophaeal reflux symptoms over the last few years and has been taking some omeprazole “most days” for symptom relief.

Today she presents with a sheaf of discharge letters from the local ED.  7 in total!  She has been seen in the ED 7 times in the last 6 weeks with “chest pain – non-specific”.

She tells you that she has been experiencing dull, spasms of pain in her substernal area that sometimes radiate to her back.   They are not really like her usual ‘heartburn’ symptoms.  She doesn’t feel sick or sweaty.  Just worried.

These are quite unpleasant and stop her from working at her computer.  The last couple of episodes have occurred at night and woken her from sleep – her husband has called the ambulance service twice in the last fortnight!  On each attendance to the ED she has been “fast tracked” into the chest pain protocolised management.  And spent a few uncomfortable nights on a stretcher in the corridor of the ED…..  awaiting a second  troponin.

Amidst the paperwork there are formatted letters from ED interns, Registrars and even one from a consultant ED Physician.

There are a batch of plumb normal ECGs and photocopies of many negative troponin results.  She even stayed in for an exercise stress test one day – which was non-suggestive of ischemia.

She has been diagnosed consistently with:  “Chest pain – non-specific.”  or “Chest pain, not cardiac.” on each occasion.  On the latest visit the senior Doc has ventured a positive diagnosis – “Probable Oesophageal spasm.”

Interestingly there have been a number of therapeutic trials of “Pink Lady” i.e.. the Mylanta & Xylocain viscous cocktail so loved by triage nurses the world over!  Joan says that the pain is usually short-lived – coming in spasms. It seems to go away after a few minutes then return.  She says a lot of the doctors ordered the Pink stuff and when her pain got better…  told her it was from her oesophagus. [ see this post from Dr Seth Trueger on this topic. ]  Maybe best left until after the troponin has settled the question!!

She has received advice to take her omeprazole twice a day and to follow up with her GP.  OK, here she is….

So, it seems clear that she is in the low-risk group for cardiac disease as a cause of her chest pain.  Let us assume that the ED Docs have excluded ACS as a cause.

SO, if you are the GP how do you go about making an actual diagnosis in this scenario?

Is a therapeutic trial of PPIs a reasonable strategy?

Depends…. are you trying to give relief to the patient or make a diagnosis? After searching through the databases I found this decent sized trial from Flook et al, in Amer Journal of Gastroenterology (January 2013)

It looked at 600 patients with reflux symptoms giving chest pain.  A placebo, RCT (esomeprazole 40 mg BD for 4 weeks) They found a significant improvement in symptoms at the end – but this was really only for patients with less frequent reflux sx at the outset.  Not so effective for the pts with more than 2 days a week of symptoms.

There is also a meta-analysis [Wang et al, JAMA, June 2005 ] looking at 6 papers ( only 220 pt in total) which tried to answer the question about the diagnostic characteristics of a “trial of PPI” for reflux-related chest pain in patients with “non-cardiac chest pain” .  The conclusion of the authors was that is was an acceptable “test” with a sensitivity of 80% and specificity of 74% roughly.  So – it might help – but to my mind those are not stellar numbers.  I would want a reasonable high or low pretest probability of “GORD” before hanging my patient’s hat upon those figures.

Should she have endoscopy to look for serious upper GI problems?

Well that is a tricky one.  Not a lot of data.  Just opinion.  The surgeons that I work with would suggest everyone with severe enough , persistent symptoms should probably have a scope to exclude malignancy or other correctable lesions in the oesophagus.  In the good old days we would send them for a Barium swallow.  But nowadays it seems easy to get a scope, and then you have the option of a CLO, biopsy or whatever else they need on the day.

So I think it is reasonable to get a scope if you have persisting symptoms or severe symptoms so that you know what you are dealing with.  It would be disastrous and unfortunate to treat a malignant process for months and months with symptomatic care.

What is the role of manometry or pH monitoring to try and correlate her symptoms with  events in her oesophagus?

This is not something that I really see much of – but I work a long way from any Gastroenterolgists!  Certainly I have seen this done in patients with bad GORD – i.e.. those whom are contemplating a fundoplication procedure.

Found this paper in the BMJ – Barham et al from Gut, 1997. [Diffuse oesophageal spasm: diagnosis ] It is old – but suggests that for intermittent symptoms like our patient is suffering – you really need to get continuous outpatient / 24 hour ambulatory monitoring of pH and pressure in order to make this diagnosis.  Diffuse oesophageal spasm is also known as “nutcracker oesophagus” or “corkscrew oesophagus” as it has characteristic appearances on imaging.  However – you would be lucky to see this phenomenon as it is fleeting!  IN order to correlate symptoms with measured anomalous peristalsis or pH spikes – you would need ambulatory monitoring.  I guess it is like the Holter of the gut?

http://download.figure1.com/broome

Image courtesy of Figure 1

Relative Absolute Risk

Gday!  This post is inspired by a few things:

A. Dr Andre Bonney (@keeweedoc) who tweeted earlier this week - 

B. This article that came out in the Lancet August 16th 2014 on Blood pressure-lowering treatment based on cardiovascular risk: a meta-analysis of individual patient data

The bottom line is:

“Lowering blood pressure provides similar relative protection at all levels of baseline cardiovascular risk, but progressively greater absolute risk reductions as baseline risk increases. These results support the use of predicted baseline cardiovascular disease risk equations to inform blood pressure-lowering treatment decisions.”

C.  A few discussions I have had with the male members of my family (I have 2 brothers, 3 sisters and 2 parents!) about the advice / prescriptions that they had received when undergoing cardiovascular preventative screening by their local GPs.  For the record – none have had any previous cardiovascular disease / events.

So let me introduce the 3 “cases” for this weeks discussion about risk.  For reference I have included a copy of the Australian Heart Foundation’s 

Use this to work out a basic risk of 5-year major cardiovascular event.  aust-cardiovascular-risk-charts .

“The Old Boy” – 73 yo retired farmer / amateur share-trader.  He has let himself go a bit – now 105kg, and has been shown to be “borderline T2DM” with a penchant for jam & cream on his scones!  He is a non-smoker, has a pretty healthy total: HDL cholesterol ratio of 6 and a BP of 145/90.

“Tootie” is now 45 years old and is a smoker.  He has been screened and has a cholesterol ratio of 5.5.  He doesn’t have diabetes  but his BP is a bit high for a ‘young’ active guy at 145/90.

“Trick” – he was unfortunately given this moniker after suffering with enuresis to a late age. “Trickle” being shortened to “Trick” later in his teens.  Like any good nickname in Australia – hard to shake if off!  Trick is only 30, he is fit, active and slim.  Non-smoker, no diabetes.  But he does eat a lot of junk – crazy amounts of bachelor food!  His cholesterol is high – with a TC:HDL ratio of 7.5.  His BP was also a bit up at 145/90.

So – there you go – 3 blokes with a set of traditional CV risk factors plotted out.  All of the same genetic stock basically.

Imagine that you are their GP.  Have a read through the Lancet paper above.

Now answer me these questions.

(Q1)  For each family member – would you commence an antihypertensive medication for primary prevention (assume no renal disease/albuminuria )?

(Q2)  For each family member what would you target as a single “intervention” to try and achieve in order to reduce each fellows’ absolute risk.

(Q3) Assuming no signs of malignant hypertension or end-organ dysfunction – at what blood pressure would you treat purely to reduce the BP – rather than aiming to reduce the longer term CV disease risk?  Name a number X/Y?

OK

Food for thought.  Looking forward to hearing your thoughts.

From my favourite comic: XKCD – risk is always conditional! 
Casey

 

Risk and Uncertainty – part 1

Gday.
It has been a quite month on the blog as I have started paternity leave and have been redressing the work-life balance scales – very much in the family direction.

Not doing any clinical work has given me time to pause and ponder a few of the more abstract ideas that we often brush over in the daily grind of clinical medicine. So this month I am going to explore a few of these.

The themes are all interrelated and quite broad – from understanding risk, dealing with uncertainty, shared decision making, communication about risk and consent.

So what has prompted me to ponder such ideas? Well, a few things really. I have been reading some wonderful books by Gerd Gigerenzer – and his ideas have really resonated with my beliefs and how I practice.   I have also had a few interesting interactions with medicine on the “patient side” – and seen things from a patient perspective first hand – and this has left me feeling somewhat dissatisfied.  Now – where to start this extended rant….

In the last few years the work of the Nobel laureate Dr Danial Kahneman has become very sexy in the world of medical education and thinking about doctors’ psychology.  His book Thinking Fast and Slow has become a staple of the medical metacognitive types [me included].  Chris Nickson gave a great talk on this at SMACC 2013 [All Doctors are Jackasses]

Kahneman explores the biases and cognitive errors that creep into our practice.  His basic premise is that heuristics [simple 'rules-of-thumb'] can lead us to incorrect decisions and error.  He asserts that our human brains are not well equipped to deal with probability and as such we often make errors when dealing with relatively simple statistical calculations.  Some true experts with many ( ? > 10,000 hours) of experience may develop useful intuition in practice…. but mostly our “fast-thinking” brain gets it wrong a lot of the time.  The solution is to adopt a more analytical approach and try to recognise these traps, slow down and do some deliberate calculation and weighing in order to get a more realistic assessment of the situation before making a call, decision, cut, burr hole etc.

When I first read “Thinking Fast and Slow” it made a lot of sense.   I could certainly recall serious errors that I had made where I was following biased, rapid-fire thought processes.  But… I never really thought it explained the whole picture.  As a GP I work in a world of uncertainty.  There are few patients with a statistically describable problem.  There are a lot of unknown, unknowns.  So the cold analytical “slow brain” approach didn’t really seem to be a viable option either.  I even wrote quite a long essay on this entitled “On Evidence, Education, Errors, Ego and Expert intuition“.   I felt that there was a need to balance careful analysis where viable against simple, dumb rules where there was no clear, simple and safe path forward.

So when I started reading Gerd Gigerenzer’s Risk Savvy I felt a strong resonation with what I had learned the hard way over the last dozen years.  Gigerenzer disagrees with Kahneman to some extent.  They both conclude that we are basically innumerate when it comes to simple risk calculations.  Gigerenzer feels that these skills are imminently teachable though.  The main way that Gigerenzer diverges from Kahneman is that he distinguishes “risk” and “uncertainty”.  And suggests that we need different toolboxes to deal with each of these.

So – what is the difference between “risk” and “Uncertainty” ?

Gigerenzer describes risk as the way to describe systems where the numbers are known.  For example, the lottery – we know the risk or chances of winning.  They are low but calculable from the data available.  Sure, humans are terrible with statistics – and we are soften biased towards irrational optimism.  This is the basis of the modern lottery, casino, poker machine etc.  When it comes to dealing with “risk” we need to adopt a solid, carefully analytical mindset and not fall victim to our inherent biases.  Simple heuristics may lead us astray as they may not be subtle or sophisticated enough to cope with the situation.

Now here is the problem…  modern medicine is far from statistically describable.  It is just plain dirty.  We read a lot of papers with fancy statistics.  Clinical decision aids are all the rage – but these are really just crude approximations.  They are population-based tools which are tough to apply to the patient sitting in front of us.  The overwhelming majority of what we do falls clearly into the realm of Uncertainty.  The numbers are not known, and tend to move with alarming frequency!

So Gigerenzer would argue that in this situation, an uncertain world, we ought to use heuristics – smart ones.  In fact he has described an “adaptive toolbox”, a repertoire of heuristics which we have at our disposal.  He argues that the trick is to choose the right heuristic (rule) to use in the right situation.   Attempting to “calculate” risk in an unknowable environment is both slow and often inferior to following a simple heuristic.  He and his colleague Daniel Goldstein have describe a series of “smart heuristics” which have worked pretty well in the right context – often outperforming complex models based on available data.

OK.  That is a quick introduction to the current state of play in my mind.    I will be back soon with a few examples and scenarios to illustrate how I think we can use this theory to do better in the workplace and improve our communication with patients.

In the mean time I highly recommend reading anything by Gigerenzer – e.g..

- Better Doctors, Better Patients, Better Decisions: Envisioning Health Care 2020

- Risk Savvy

- Reckoning with Risk: Learning to Live with Uncertainty

He also has a few cool TED talks that you can check out:  Simple Heuristics that make us smart,  Risk literacy

OK, enough homework.  Will be back soon to explore a few real world examples closer to home.

Casey