Can't beat videos for learning...

So my part C revision is difficult... having been practicing with colleagues I have found I have developed some very lazy habits since med school!

In order to counter some of these I have gone back to videos produced for medical students, after all no point in knowing clever stuff if the basics elude you.

The following are some videos I have round useful:

http://www.youtube.com/watch?v=MZKSkVSbH8k

http://www.youtube.com/watch?v=k3MlxdTWihM

There are also some good podcasts on iTunes if you search for clinical examination.

B is done... on to Part C

So results are out and despite some controversy over the fire alarm at one venue I have passed part B, so the focus for this blog may change a little bit to part C, I still have some draft posts for part B topics and they will also find their way out in the next couple of weeks.

A Bolus is a bonus - fluid management in children

So fluids in kids is an easy topic for an exam as it follows clear rules, however it is tricky for ED doctors as most of us have limited paediatric exposure and it has some important differences to the management of adults. Children are far more prone to fluid shifts and the therefore poor fluid management of children can kill.

Below are a few simple rules aimed at giving safe answers that are suitable for an exam, the reality of the matter in the ED is that if you are in doubt there are all sorts of useful resources that can guide you e.g. your boss or the paediatric reg/ PICU. There are even apps to help with the calculations.

For the purposes of the below assume I am referring to 0.9% sodium chloride unless stated otherwise.

Step 1:

Know the child's weight, you cannot proceed without this, but you may have to work it out:

• 0-12  months: weight = (0.5 x age in months) + 4
• 1-5 yrs: weight = (2x age in years) + 8
• 6-12 years: weight = (3x age in years) + 7

Step 2:

Bolus for the shocked child: know the cause of shock

• Sepsis: 20ml per Kg
• Hypovolaemia/ trauma: 10ml per kg
• DKA: 10 ml per kg - do not exceed 30ml per kg in total - 
• and if you are managing a child with DKA and needing fluid boluses you should probably not be managing them on your own!!!

Step 3:

Maintenance fluids: "4-2-1 rule"

• 4mls per Kg for the first 10 kgs
• 2mls per Kg for 10-20 kgs
• 1mls per Kg for 20+ Kg

Worked example:

22kg child =

4mls x 10 +

2mls x 10+

1ml x 2 = 22 ml/ hr

Don't forget that maintenance will need to consider potassium and dextrose to be included in regime.

Step 4:

Special circumstances:

• DKA: can't stress this one enough - cautious fluid is the order of the day and rehydration may be undertaken over a 48 hr period!!!
• Burns: remember Parkland 4x %BSA X Weight - give half over first eight hours from injury and then second half over next sixteen hours.
• Dehydration: similar to burns you can calculate the deficit by working out the %dehydration x weight.
• Hypoglycaemia - weight x 2mls - here the fluid is 10% dextrose

Questions:

1) What is your estimated weight for a seven year old boy?

2) What would be a suitable maintenance fluid regime for this child?

3) He has sustained 6% partial thickness burns, what are his fluid requirements over the first 24 hours.

4) How much dextrose would a hypoglycaemic 6 month old require?

Diabetic Ketoacidosis- Glucagon is the Problem!

Another common topic and also a frequent presentation to the ED is DKA. On the whole I think of this as straight forward ie bang up some fluids and insulin and it'll sort itself out! That being said when you actually read about it things are a little bit more complicated.

Your hospital will have it's own policy and approach, but a nice little guide has been produced by the Joint British Diabetes Societies Inpatient Care Group:

http://www.bsped.org.uk/clinical/docs/DKAManagementOfDKAinAdultsMarch20101.pdf

Let's start with some background to put things in perspective:

• It is potentially life threatening, although mortality rates have fallen in the last 20 years from 7.96% to 0.67%!
• Cerebral oedema especially in children and adolescents is the most serious complication.
• The typical fluid deficit in DKA may be 100 ml/kg!
• It is now possible to measure blood ketones at the bedside.
• The treatment of DKA has developed and will continue to develop as our understanding increases.

The rest of this post is about adults, there are key differences in the management of children/ adolescents.

Definition:

1. Blood glucose >11
2. Ketones > 3 (or 2+ on urine)
3. pH <7.3 or bicarb <15

Pathophysiology:

Its a lack of insulin, right? Well yes and no.

Type one diabetics have impaired insulin production and therefore cannot bring their sugars down, but Insulin also acts to oppose other hormones (glucagon). It is this lack of opposition that causes the metabolism of fatty acids which in turn produces the ketones. So it is good to think of it as unopposed gluconeogenesis: the production of ketones lowers the pH and therefore gives us the acidosis ie. not a sugar problem.

Bang up some fluids and give insulin:

Treatment is aimed at correct the abnormalities and these patients are certainly dry and in need of lowering their blood sugars, but actually we need to think of treatment goals as switching off the gluconeogenesis and ketone production.

1. Fluid resuscitation - the link at the top contains a bit of debate as to the fluid to give, but essentially 0.9% Chloride is the answer because you can add potassium when it is needed.
2. Insulin- fixed rate infusion based on weight (0.1 units/kg/hr) - this corrects the sugars but also suppresses ketogenesis!
3. Monitor K+ and add it to fluids given - remember insulin will push it into intracellular space.
• hypokalaemia is a complication of treatment.
4. Give glucose when blood glucose is <14 - DKA is not a sugar problem but the production of ketones driven by glucagon, what we don't want is the sugar to fall and the gluconeogenesis to begin again!!!

What should I be worried about?

Things to worry about are the complications mentioned above: cerebral oedema and hypokalaemia.

Other things that warrant a higher level of care (HDU/ ITU) include:

• pH <7.1
• bicarb <5
• cardiovascular compromise
• Blood ketones >6
• Hypokalaemia on admission
• Anion gap >16
• Reduced GCS

Question:

A 36 year old lady who frequently attends the department with diabetic problems presents with a three day history of abdo pain and vommiting. She ways 65kg. Her observations are as follows: HR 117, Bp 109/76, RR 30, Sats 99% (21%). The results of her blood gas are as follows:

• pH: 7.23,
• Pa O2: 10
• Pa CO2: 1.4
• HCO3: 11.2
• Glucose: 36

a) What are the diagnostic criteria for Diabetic Ketoacidosis (DKA)? (3)

b) Write an appropriate prescription for an insulin regime in this patient. (2)

c) Give three features that should trigger discussion with critical care? (3)

d) What would be an appropriate fluid regime for this patient? (2)

Clever Marks:

Another question could quite easily ask you to calculate the anion gap - I have left this out of the gas information as I intend to do another medical maths entry on this topic.

Completely unpredictable...

So sometimes the exam just contains weird and wonderful things that you wouldn't expect - innervation of the female genital tract being an often quoted example. Then again other questions that come out of left field can with hindsight be identified as a popular issue around the time the exam was set. Another example that fits this is a major incident question following the 7/7 bombings.

So in light of that what sort of sort things have sprung to my mind? (if you can think of others please post in the comments).

1. Measles- recent outbreak in Wales. Questions could easily cover rashes/ other child infections and vaccination schedules. Also could be extended to meningitis or other infections amongst students
2. Over crowding: http://www.bbc.co.uk/news/health-24432072 a BIG issue at the moment, CEM have released a statement this week and did you know they have a document detailing their recommendations for dealing with over crowding (released approx a year ago!) www.collemergencymed.ac.uk/code/document.asp?ID=6296
3. Paracetamol - recent guideline change (again about a year ago).

Other things to think about:

• Capacity
• Consent
• DVLA guidance
• Child protection.

Question:

a) What markers indicate a department is overcrowded?

b) What steps can be taken in the ED to facilitate flow?

c) Define boarding.

d) At what point does the ED become responsible for a patient?

e) What steps can be taken to improve output problems?

Bloodbourne Infections and Needlestick Injury

Needlestick injuries and other exposures are a risk that all healthcare workers are exposed to. Out of hours they may easily present to the ED and are therefore on the syllabus for CT3 - they have also appeared in part B. Questions around rates of seroconversion, vaccinations and risks could easily appear in part A.

The Syllabus includes the following:

The health protection agency have a useful tutorial/ elearning http://www.health-protection-update.org.uk:8100/tutorials/needlestick/

Points to consider:

Risks:

Donor - Known blood HIV, Hepatitis B/C or High risk group - IVDU/ High prevalence Country

Fluid- Blood/ CSF/ Peritoneal or Pleural Fluid/ Breast Milk

Mechanism- hollow needles/ visible blood/ needle that has been in vein or artery/ deep wound/ not --------------------- through gloves/ injection of contaminated material

Disease Specifics:

The risks of transmission differ for the 3 main infections:

Hep B (30%) > Hep C (3%) > HIV (0.3.%)

Management:

It is necessary to take a relevant history including the risk factors and the vaccination status of the patient. The main point of management is to make a risk assessment and decide of post-exposure prophylaxis (PEP) is needed - you will have a local policy for this and it may well involve your oncall microbiologist. Follow up will be necessary however this is likely to be by occupational health rather than the ED.

• HIV - PEP available to high or unknown risk - many side effects and interatctions to consider
• Hep B - need to know immunisation status - immunoglobulin available
• Hep C - no PEP available

Acute Kidney Injury (& Hyperkalaemia)...

Whilst revising this I couldn't stop myself seeing how easy it is to turn into a part B question, the stem could begin with an ecg and ask you to describe the changes and give the diagnosis. Then ask you to list causes and describe the treatments. Alternatively you could be given a blood gas result including a sodium, potassium and glucose with an Addissonian picture and be asked to list what changes you would look for on the ECG, then to describe your management. Worst case scenario could even be to define an Acute Kidney Injury. Given it lends itself so well it is little wonder that it is a previous part B question!

Acute Kidney Injury:

Definition:

Stage 1: 
- creatinine rise >26 from baseline over 48 hrs
- creatinine rise x1.5 from baseline over 1 week
- Urine output <0.5 ml/kg/hr for 6 hrs

Stage 2:
- creat 2-3x baseline
- urine output <0.5ml/kg/hr for 12 hrs

Stage 3:
- creat >3x baseline
- <0.3ml/kg/hr for 24 hrs or anuria

The Causes are summarised in the following diagram borrowed from the wonderful Sketchy medicine

Investigation in the ED can help pin down the cause: protein on urine dip suggests glomerular disease, blood on dip think TINS (Trauma/ infection/ neoplasm/ Stones). However by far the commonest cause is pre-renal ie poor perfusion (sepsis/ hypovolaemia/ etc).

Management in the ED involves: catheter and hourly urine output, IVI bolus and response monitoring, treat the cause!

Hyperkalaemia

The most significant complication of AKI from an ED perspective is the potential for an increased serum potassium, as this can by imminently life threatening!

• Mild: 5.5-6 mmol/l
• Moderate 6.1-6.9 mmol/l
• Severe >7 mmol/l

See raised K+ think ECG:

• Tall t-waves (easy)
• short QT
• prolonged PR
• wide QRS
• flat p waves
• VT  (may be pulsed)

Treatment:

1. Calcium Chloride 10mls 10% IV - cardioprotective
2. Insulin - shifts potassium intracellular (remember to give with glucose!)
3. Salbutamol neb.

Clever Marks:

Marks may be available for recognising an addisonian crisis (hyponatraemia, hyperkalaemia and hypoglycaemia) and treatments including hydrocortisone.

Bad to Worse... SIRS, Sepsis and Shock...

The bread and butter of Resus, there are certain things you will see at work time and time again and this is one of the them. However it is not always something we manage as well as we should. Here is a three step approach to recognising sepsis:

Step 1:

The first concept you have to get your head round is the the Systemic Inflammatory Response Syndrome (SIRs)... Which requires two or more of the following:

• Hr >90
• RR >20
• Temp >38.3, <36
• WCC >12 or <4

SIRs does not mean sepsis but it does mean the patient is unwell (seems obvious), however it just means the body is reacting to an insult. This could be trauma/ post surgery/ PE/ infection/ autoimmune. I find my self documenting explicitly the sirs criteria present before my diagnosis for all my patients and this makes it easier to remember the exact criteria.

Step 2:

Does the patient have an infection or do you suspect they might? This deliberately includes the suspicion of infection as you may not have proof straight away but this should not delay treatment. It obviously requires you to have examined the patient and consider basic investigation. If the answer is yes the patient has sepsis.

Step 3:

Is there end organ dysfunction? Easy ones to quickly measure are renal function (urine output) and brain function (GCS).  If the answer is yes the patient has severe sepsis. You can also measure liver function (INR), Lactate, etc.

The final thing to know is the definition of SHOCK- which is inadequate tissue perfusion given end organ dysfunction and this clearly overlaps with our severe sepsis definition. The magic number to remember is a MAP <65.

What Next?

Its all good and well recognising SIRs/ Sepsis/ Shock but actually that is only half the story as we need to be able to treat these patients as well. Guidance exists on this from the surviving sepsis campaign: http://www.sccm.org/Documents/SSC-Guidelines.pdf

This can be summarised into initial management steps and some physiological targets:

Decussation is the key to the infamous Brown Seqard...

Well this one always gives me a headache... spinal cord syndromes! No matter how hard I try I can't keep these in my head, however the video podcasts http://emergencymedicineireland.com/anatomy-and-em/ always make it easy to refresh my knowledge:

AFEM 06.1 - anterior cord syndrome
AFEM 06.2 - central cord syndrome
AFEM 06.3 - brown seqard

This is a pet topic made for exams as it includes anatomy and specific clinical findings matched to that anatomy, it can be linked to a variety of clinical cases/ images. It could also quite easily be tied into a question about c-spine clearance, management of suspected spinal injury or SCIWORA.

My summary of Brown Seqard is below (the colour scheme and concept are borrowed from AFEM):

Can't Pee...

Another of the CT3 additional presentations:

Urinary retention is a fairly common presentation, but it is not the most glamorous of topics, there is however a CEM standard for its management and it easily could make an SAQ.

There is a nice summary article on the BMJ website http://www.bmj.com/content/318/7188/921

Question:

A 72 year old man presents with increasing lower abdominal pain and the inability to pass urine for the past 24 hours. He is in obvious distress and is tachycardic and hypertensive, a bladder scan is performed and shows in excess of 800mls. You successfully pass a urethral catheter and the patient is quickly relieved.

1) List 3 differentials for this man's problem. (3)

2) What clinical features would suggest a history of prostatism? (2)

3) Following insertion of a urethral catheter list three things you should document. (3)

4) Give two features that would require hospital admission. (2)

Blood Pressure is a GP thing right?

So we spend a lot of our time worrying about shock/ hypotension and are probably better at putting people's blood pressure up (white coat hypertension). Just occasionally though you will meet somebody whose blood pressure is too high and needs to come down.

What constitutes a hypertensive emergency? The section in the BNF is rather good for this and was my go to resource for part A.

Important numbers are 180/ or /110, the second step is to decide if there is end organ dysfunction:

1. Hypertensive encephalopathy
2. Acute LVF
3. Acute MI
4. Aortic Dissection
5. Intracranial Haemorrhage
6. AKI
7. Eclampsia

The presence of any of the above is hypertensive emergency.

Without them it is hypertensive urgency.

Remember BP = CO x SvR

Treatment options mostly cause some form of vasodilatation: sodium nitroprusside/ labetalol/ nitrates.

Another review of a course...

So I recently attended the Bromley Mcem Part B course (http://www.mcemcourses.org).

The course itself is two days in the clinical education centre of the Princess Royal hospital in Orpington. It includes 4 practice papers (with one sent out before the course) and lectures on some common topics that come up frequently.

The course faculty admit that they cannot cover the whole syllabus but they do try to flag up common things. It also includes so good tips on exam technique and how to approach the paper. I'm am not going to go into detail on what they say as I don't want to steal their content. However I will say I found the course useful and came away feeling better prepared to tackle the paper.

Another useful thing they encourage is to mark other people's papers to recognise how to make the examiner's life easier.

Their website's free resources include cases of the week, these make good practice questions.

All in all I would definitely recommend the course.

Decompression, Drain or not to drain...

Tension pneumothorax... every one knows how and where to decompress (https://www.youtube.com/watch?v=PblI70wkpjg - you only have to watch the first three minutes but I recommend the whole episode).

However what if it is a primary pneumothorax, measured at 3cm and no features of a tension? Fortunately the BTS are there to help: http://www.brit-thoracic.org.uk/Portals/0/Guidelines/PleuralDiseaseGuidelines/Pleural%20Guideline%202010/Pleural%20disease%202010%20pneumothorax.pdf

The Takeaway points can be summarised in the following flow chart and diagram

Another nice easy stem would be to describe the anatomical landmarks for the safety triangle:

Question...

(this should be easy after reading the above)

A skinny 24 your old presents with shortness of breath and reduced air entry on auscultation of the left chest.

1) Describe your management of this condition.

2) What features would suggest a tension pneumothorax?

3) Give the land marks of the "safe ares" for chest drain insertion, and why is it "safe"?

4) List three predisposing factors for this condition.

5) What advice would you give before discharge?

College Standards...

Found another wonderful little document on the college website (actually discovered it quite by accident preparing for a CBD on urinary retention). It summarises the standards set by CEM for the timings of certain investigations and interventions for various conditions, including:

• Asthma
• Dislocated shoulders
• Feverish Children
• Fractured Neck of femur
• Head injury in Adults
• Hand Injury
• Mental Health
• Pain
• Paracetamol OD
• Radiology
• Recording vital signs in Majors and Resus
• Renal Colic
• Retention of Urine
• Safeguarding Children
• Sepsis and Meningitis in Children
• Severe Sepsis and Septic Shock in adults
• Spontaneous Pneumothorax in Adults

This has to be mandatory reading for PART B, it is like a one stop shop for writing SAQs! These are basic standards that lend themselves so well to examination.

The document above: Download the clinical standards

Then CEM guidance in general: http://www.collemergencymed.ac.uk/Shop-Floor/Clinical%20Guidelines/

Bazzet's Formula and QTC...

So this will be the first of a few posts on ecgs (this will be a new label on the blog). I am going to start with one of the things I hate... calculating the QTC.

Without devolving into a massive rant knowing how to calculate this is relatively straight forward and there are some good apps that can do it for you, rather than doing the math itself. It is also one of the weaknesses of the automated ecg interpretations. However it is also of great clinical importance i.e.. sudden cardiac death and has been a previous question.

Hopefully the following is not new to you:

I don't think I can do a better job of explaining than the following: http://lifeinthefastlane.com/ecg-library/basics/qt_interval/

If that doesn't clear things up the only thing I can suggest is to work it out every time and ecg is thrust under your nose - if you work anywhere like where I do this will mean after one shift you will be an expert!

ACS Risk scoring

All scoring systems make good SAQs as there are different things to ask such as components, what carries more weight and asking why is it useful.

Both TIMI and GRACE help predict the mortality/ further consequences in patients with suspected or confirmed ACS. In the ED perhaps they are most useful for helping to support a safe discharge of a person with trop negative chest pain. After all a STEMI will be referred regardless of their GRACE score.

Nice recommend the GRACE score which is worked out via normograms and therefore usually computer generated after the inputs are entered. It is also worth knowing the Khilip classification of heart failure (an easy SAQ: outline the Khilip classification of heart failure)

1. No heart failure
2. Mild- moderate heart failure
3. Pulmonary oedema
4. Cardiogenic Shock

The Timi Score has come up in previous questions and lends it self very well as one point is assigned to each feature making it easy it calculate. The risks range from 5% for 1 point, up to 41% for 6/7 points.

Question:

A 54 year old male smoker presents with an episode of central chest pain whilst walking his dog. He felt sweaty, clammy and nauseous at the time.

1) What are the indications on ECG for PCI? (3)

2) What initial treatments should be given in the ED? (3)

3) List three  further features of history you would like to enable you to calculate his risk of death and name the scoring system you would use. (4)

DVLA and illness.

So you've seen a patient, sorted them out and now it's time for discharge... they take their car keys out of their pocket and then you remember does the DVLA have something to say about their diagnosis?

Never fear, the college has a nice little summary of conditions that lead to restrictions on driving.

CEM summary of DVLA fitness to drive medical standards

Conditions restricting driving:

Things that do

1. Seizure- 6 months
2. LOC with high risk factors- 6 months unless cause identified
3. Cough syncope- 6 months
4. CVA - 1 month
5. Angina- driving must stop with symptoms at rest/ emotion/ at wheel
6. Arrhythmia - stop driving if arrhythmia incapacitates
7. Diabetes- only if awareness of hypoglycaemia is lost
8. Attacks of disabling giddiness - stop driving

Things that don't

1. Hypertension
2. Single episode of syncope.

Copycat or Inspired By...

Inspired by the previous post about sketchy medicine I have scanned in one of my revision "post-it" notes that I have up around my desk. It's my summary of common organisms causing illness in adults...

Brilliant little find...

I stumbled upon this little gem of a website with fantastic cartoon summaries of various topics... perfect for a quick revision bite...

http://sketchymedicine.com

Also some of the images are for sale on etsy.

Here's an example for toxidromes:

Another Post about Burns...

Found this article on BMJ whilst trying to find an learning module on burns (for CT3 curriculum), contains an SAQ style question.

http://www.bmj.com/content/341/bmj.c4485