drugs in society part 1

have been to 2 very interesting events about drugs this week

one was the high society exhibition at the wellcome collection

very well put together, thought provoking and, in places, really beautiful

the exhibit is not too large but does contain a good chunk of material

i would strongly encourage you to go

it is just round the corner & public science does not get much better than this

there are several associated events, one, a tour with the curator is on this evening (dec 16 @ 1800-1845)

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my highlights:

1) the home-made crack pipe & the crack pipe art by keith coventry

have never come across a crack pipe before & the delivery device is ingenious

the thinking behind one of keith coventry's pieces was to do with the user's experience of the pipe - they cannot experience any part of the 'moment' except where they are in relation to the pipe - serious addiction

2) drug use through history

cannabis has been used in india for thousands of years

the british used opium (which contains 12% morphine) to gain advantage over other colonising powers in china

the opium was grown (forcibly) in places like bengal & trafficked by the east india company

rich chinese smoked it using beautiful expensive pipes, the poor using simple apparatus (partly to reduce hunger)

there were also interesting insights into the tribal use of various compunds eg peyote cactus

famous users were also detailed, eg freud, coleridge & sherlock holmes (who injected opium until he was weaned by watson)

currently the (illegal) global cannabis industry ($113bn per year) is worth more than coffee ($98bn) or porn ($95bn)

3) animals on drugs

the animal experiments shown were great

NASA gave various substances to spiders & recorded their subsequent webs

the caffeine web is shoddy-looking & full of holes, the cannabis web is meticulous & unfinished

bruce alexander's 'rat park' experiments are also shown

his hypothesis was that well housed rats will be less 'addicted' to morphine

to test this he did a series of experiments comparing rats living in 'rat park', a 200 sq foot rodent paradise with play areas, privacy areas & lots more besides to similar rats living in cages

the 'free' rats were 16 times less likely to drink morphine water compared to caged rats when given a free choice

fascinating stuff!

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lots to think about as we (collectively) will consume large quantities of drugs over the holidays (alcohol, caffeine, whatever ...)

Salaam

learning neurology

hello


i have talked about my favourite neuro learning resources before

here is an update

do add your suggestions / opinions
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1) neurological exam made easy by geraint fuller

great book - short, readable, nice pictures, clinical

2) neurological differential diagnosis by john patten

brilliant book - the best anatomical drawings of neurology (done by the author), clinical, practical
not so short, but all you will ever need to know about neurological examination (unless you become a neurologist)

3) neuroanatomy through clinical cases by hal blumenfeld

great book - very sensible way to learn neuroanatomy, lots of cases, good pictures, associated website
not short, but very readable

4) neuroanatomy: draw it to know it by adam fisch

great book - teaches anatomy by way of staged diagrams illustrating all the major neuro systems
good text too
not short, but nicely 'chunked'

5) neurologic examination website by university of utah

excellent website - videos of normal & abnormal findings for all major components of neuro exam, downloadable (with permission)

6) the neurological exam website by university of toronto

good site - not as comprehensive as utah site, but well laid out with nice tables
videos only with healthy volunteers

7 eyevideos.blogspot.com

good site made by a young ophthalmologist with videos detailing neuro-ophthalmology examination & investigations

Salaam


s

a 20-year-old woman with slurred speech and weakness

yesterday we briefly examined a very pleasant university student who has been unwell since earlier this year

she was alert - we did not test her higher order cognitive function

she had obvious slurring of her speech, which had been present for a month or so

we concentrated on examining her arms

we talked (again) about the importance of INSPECTION

fasciculations can be quite hard to see, especially if the light is poor and the muscles involved are small, so really have a good look - make sure you turn the lights on & adequately expose the patient (which can be done comfortably and with dignity)
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as an aside, i wanted to mention motor neurone disease - i know very little about this condition; it results in upper and lower motor neurone signs; it must be one of the worst diseases and there are no treatments, riluzole, the only drug available increases life expectancy by a few months at best (miller et al, 2007);

here is link to a video of the historian tony judt talking about the disease

he died in august
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we went on to test tone and then power

this is often done quite badly

my most useful tip (after practise a lot) would be to slow down & think about what you are doing

use the MRC grading scale

if a patient uses their muscles to move their arm (or leg) into the correct position against gravity, then they have already scored 3/5
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here is a link to another website showing you how to do a neuro exam

i particularly like the muscle action & innervation chart in the motor section

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we talked about the decreased utility of testing for inco-ordination in the context of muscle weakness
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this lady has a diagnosis of multiple sclerosis

she has had several clinical events and has had a full diagnostic work up including MRIs, LP, VEP

the visual evoked potential involves being shown a visual stimulus, eg a pattern, and then measuring electrical responses primarily from the occipital lobe using EEG

[why the occipital lobe?]

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she was actually admitted for episodes of loss of consciousness, the cause of which is not entirely clear

interestingly she is due to have a tilt table test - i mentioned my ignorance of the effects of MS on the autonomic nervous system

she is in the midst of a relapse affecting her speech, face, right arm & leg, and is due to start steroids this week

Salaam

a 48-year-old woman with breathlessness and difficulty walking

on monday we saw a very pleasant middle-aged woman, a pretty heavy smoker, with a history of COPD

she had had multiple courses of oral steroids in the past but no previous admissions until last week when she had a short stay for an infective episode

she become breathless enough to significantly restrict her activity around 24 hours post discharge

we focused on examining her so did not talk much about her symptoms

we could have explored possible reasons why she deteriorated

what do you think?

possibilities that spring to my mind are:

- ineffective treatment for respiratory infection (eg resistant organism)
- PE
- pneumothorax
- heart failure
- something else
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thanks to our patient's forbearance, we examined her chest & legs (neuro) in detail

thoughts:

- make an effort to really stand at the end of the bed and LOOK:
you can determine asymmetry, depth of breathing, colour, adjuncts and much more; in this case we would have been able to get the diagnosis from just looking without doing anything else

- practise percussing things: in the experience the key is having a very stiff middle finger of the left hand, and a very floppy right wrist; you can percuss lots of things (eg walls to see where joists are, barrels to see how full they are)

- most medical students find neurological examination hard - so you are not alone!

- knowing some neuroanatomy helps, as does giving clear instructions

- i have mentioned my favourite neuro learning resources before

our patient had weakness of left ankle dorsiflexion and a lost left ankle jerk, suggesting an S1 root lesion; her sensory loss was patchy

her leg symptoms are long-standing; we did not look at previous spinal imaging -we should have done!
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Salaam

s

blood

i gave blood a couple of weeks ago

i am ashamed to say it was only my second time

it was pretty painless & the actual blood-letting took 4 and a half minutes to take 468mL

[the ultra-rapid haemoglobin estimate is a thing of beauty - how does it compare to a lab test?]
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only 4% of the population are blood donors and as of today, stocks of O- blood will last just over 4 days

i am constantly amazed by the dedication and community spirit of the students i meet, so if you have ever thought about giving blood, but never quite got round to it, take the chance now

call 0300 123 23 23 or use the blood.co.uk website


Salaam

a young man who ingested 4.5g of cocaine

we did not see this gentleman and only discussed his case very briefly

however, as a clinical pharmacologist, this was too interesting not to share

we did not get onto signs, symptoms and treatment of cocaine toxicity, but it is an important clinical issue and is worth knowing something about

eMedicine has a decent review

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this gentleman swallowed 4.5g of 'cocaine' wrapped in cling film

my first question was: what is a lethal dose?

we discussed ways of answering this question in the UK, namely toxbase, and the national poisons information service

it turns out that there is a great deal of variability as to what a lethal dose might be, and it depends on the route of administration - IV as little as 20mg, orally or intranasally 500mg-1.4g

another key issue is the purity of the cocaine - most cocaine on sale in the UK is heavily 'cut' for example with lactose, mannitol, baking powder

average purity in the UK around 34%, price £30-50 per gram (data from drug scope)

one 'line' might contain 50-200mg (depending on how big the line is)

one cocaine cigarette might contain 300mg & is more commonly associated with myocardial infarction
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the clinical pharmacology of cocaine is fascinating

cocaine powder is often the hydrochloride salt which is snorted (white lines)

it is made by pulverising coca leaves, then mixing with an alkaline substance and organic solvent and removing leaves to produce coca paste

this paste is often smoked in south america

for transport, the paste is usually converted to cocaine salt (powder) via the addition of hydrochloric acid

this chloride salt has a boiling point of 190+ degrees which means it cannot be inhaled

however it is water soluble, and thus can be absorbed through mucous membranes
_ _ _

freebase & crack cocaine are made by removing the chloride to leave the base alkaloid

cocaine base sublimates at around 90 degrees - it is thus smokeable
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we did not get onto signs, symptoms & treatment of cocaine toxicity, but it is an important clinical issue and is worth knowing something about

eMedicine has a decent review



Salaam

a new AAU firm

we had another firm of students join the acute admissions unit today

as usual we introduced ourselves, briefly mentioning our genetic inheritances

this time the group's knowledge of what a SNP is was good, thanks to the presence of a geneticist

i have written about SNPs before - it is an area of such growing importance that i would strongly recommend you find out something about them
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our case discussion, truncated because of time was again centred around 'dizziness'

while we did not go through things in great detail, the importance of disentangling the terminology was highlighted (see previous post)

the other thing that struck me was the need for detail when it comes to the history in this presenting problem

you really do need to find out everything you can about the circumstances of what happened

eg, where: which shop? which department? having just done what? carrying what? wearing what?

all these details will help you to build up a picture of 1) what this lady's cognitive function is like and 2) clues that point to a specific diagnosis (eg fast onset-fast offset for arrhythmia)
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we also mentioned how to start a case presentation well (content - the right amount of data & process - a positive, professional dialogue)

'framing' the problem is key, because without asking the right question, you cannot hope to find the right answer

i would encourage you to watch how real doctors present cases

how many of them need the notes to present? not many i suspect

could you present without your notes?


Salaam


sabih