Thursday, 31 December 2015

High Voltage - What the diagnosis plus severity means for management of viral wheeze


In the previous post, I concentrated on giving the correct label to the child under the age of five with recurrent episodes of wheeze.  I'd like to pretend that that makes the management simple but I just can't do that.  Not only are the diagnoses confusingly difficult to tell apart sometimes but there are overlaps with treatment options.  So are there actually distinct clinical entities at all?

There are important differences between the two main groups: viral wheeze and asthma/ multi-trigger wheeze.  Once again though, I have to emphasise that viral wheeze is not a lesser diagnosis and can cause life-threatening exacerbations.   It is possible that there are just these two entities and that the viral wheezers need different treatment at the more severe end of the spectrum.  After all, high voltage can do bad things to a circuit.


What is particularly confusing for the generalist is seeing children with a diagnosis like viral episodic wheeze being given a steroid inhaler.  You might be excused for exclaiming WTF!  (Wheeze Treatment Freestyle!)  Surely the whole point is to avoid giving steroid inhalers when the diagnosis is viral wheeze.  Well, as is often the case, yes and no.  Yes, most of the time but no, not always.


The vast majority of children who only get wheeze during a viral illness will do so relatively infrequently.  Also, the episodes in most cases will be mild or moderate and (more importantly) respond well to decent doses of bronchodilators.  The key differences between these children and the smaller number of children who have an atopic cause to their wheeze are that preventative steroid inhalers are not at all likely to prevent or blunt exacerbations of viral wheeze, and the evidence is that systemic steroids do not work for acute episodes.

However, not all viral wheezers were created equally.  Some get frequent exacerbations and some get frequent and severe exacerbations.  There is much debate about phenotypes, genotypes and other big words that don't mean much to the poor three year old who is getting the symptoms.  There is genuine uncertainty about whether there are multiple entities or overlaps and polymorphism.  My  hope is that the paediatric respiratory world find a way to identify the subgroups without over-complicating the list of possible diagnoses.

What we have at the moment is two main groups, with the more severe end of the viral wheeze group being treated in ways that look remarkably similar to the asthma group.  Similar, but not the same.

With the child under five who has an asthma pattern of wheezing, steroid preventer inhalers are a cornerstone of management.  If the diagnosis is recurrent viral wheeze, steroid inhalers are an option when exacerbations are very frequent, especially if severe.  The current advice is that a trial of steroid inhalers should be evaluated and should be stopped if not helpful.  How one knows whether the trial has worked is another question.  If anyone knows a cast iron way of deciding this please get in touch or post a comment.

Edward Snelson
@sailordoctor

Disclaimer: I am not a Respiratory Paediatrician, but sometimes I see so many children with wheeze, it feels like I should be.



Tuesday, 15 December 2015

How is your wheezer wired? Asthma vs Viral wheeze in the under 5 year old.

This week, I was asked a very good question by one of my colleagues in primary care: Why are children under the age of five who have recurrent wheeze and who are clearly atopic not given a diagnosis of asthma?  It's a question I have been asked many times before before, often accompanied by a frustrated and confused expression.

Are paediatricians allergic to diagnosing asthma in under five year olds?  It might seem like it.  The answer is no, but the diagnosis is avoided by most paediatricians and some have stopped using that term altogether (preferring multi-trigger wheeze for the under five year olds).  So when is it asthma?

Some children under the age of five with atopy and wheeze are asthmatic (or have multi-trigger wheeze if you like) but most are not.  Most have recurrent viral wheezing.  The difference is all in the circuitry. Remember circuit diagrams?  You may have intentionally blocked them out from your memory but for the purposes of this explanation it will be helpful, especially for the visual/ special learners, of which I am one. 

The thing is that lots of children have viral wheezing episodes and lots of children have atopy, usually in the form of eczema.  To find them both in the same child is reasonably common so association does not prove causation.  For that you need to establish whether the two things are happening in series or parallel.  This is where my circuit diagrams come in.

Fig 1. When a child has episodes of wheeze that are not related to anything other than viral illnesses, then any co-existing atopy is not thought to be part of the problem.  In these cases the diagnosis remains recurrent viral wheeze.

Fig 2. If there are episodes of wheeze that are unrelated to viral illnesses then coexisting atopy is the likely cause and these children are diagnosed with asthma.

Why does it matter what label we give this?  The main reason is that the chronic treatment is different.  In a review article in the BMJ, the evidence is summarised for treating acute episodes of viral wheeze with bronchodilators only, without either acute or prophylactic steroids.
When it comes to knowing whether your patient’s wheeze and atopy are wired in series or parallel, it all comes down to precipitants and interval symptoms.  If the precipitant is always a viral illness and there are no interval symptoms, then the wiring is in parallel (recurrent viral wheeze).  If there are episodes in the absence of viral illness, or there are interval symptoms (usually frequent cough or wheeze) then the wiring is in parallel (asthma).

Are there any drawbacks to having this separate diagnosis?  I can think of a few.  Firstly, having seen life-threatening exacerbations of viral wheeze I know that the acute episodes are just as capable as asthma attacks of becoming severe and deteriorating rapidly.  Recurrent viral wheeze is not a benign condition and children do die from it.

My next concern is whether or not these children get themselves into the system properly in primary care.  I know that with the current systems in place, children with asthma will be easily identified in a General Practice setting and thus get an annual review, inhaler technique checked and an invitation for an annual influenza vaccination.  Children with recurrent viral wheezing should probably also get these, but there is little guidance and no quality framework for recurrent viral wheezing. 

So how do we make sure that these children are managed appropriately?  The separate label of viral wheezing allows us to treat them consistently without giving treatments that are not going to help.  The same label risks putting these children on one side or implying that they are not at risk of severe episodes.
It does however make me wonder if the label of 'multi-trigger wheeze' is a step too far.  The European Respiratory Society Task Force defines a clinical entity "as a cluster of associated features that are useful in some way, such as in managing the child or understanding the mechanisms of disease."  Since the majority of these children are managed by general practitioners I would argue that the diagnosis of multi-trigger wheeze should be useful to them.  I am struggling to see a clear benefit.  Having labels that change and multiply can have a detrimental effect by confusing clinicians and parents alike.  In the pursuit of purism, we can end up with nomenclature which is more academic than practical.

So, let's stick with the terms recurrent viral wheeze and asthma for now.  That still leaves us with the need to ensure that the recurrent viral wheezers get treated as children with a debilitating and potentially dangerous respiratory problem.  So, can General Practitioners come up with solutions to this?  Part of the answer will be awareness and I hope that this little update has helped.  I suspect there is also a need for coding ingenuity.  It may be that others have recognised this conundrum and come up with novel solutions.  If so, please comment below and share your ideas.

Edward Snelson
Medical polyglot
@sailordoctor

Disclaimer: I fear change

References
  1. Andrew Bush, Managing wheeze in preschool children BMJ 2014; 348 
  2. Brand PL et al. Definition, assessment and treatment of wheezing disorders in preschool children: an evidence-based approach. Eur Respir J2008;32:1096-110




Thursday, 10 December 2015

Is your wheezer happy or are they waving a red flag?

Once you have decided that a child has bronchiolitis, there is only one real decision to be made*: home or hospital?  In some cases this decision will be made clear but for others the clues may be more in need of detective work.

*Decisions re antibiotics, inhalers and steroids are easy: don't give them!

If possible, babies with bronchiolitis should be kept well away from hospital.  Nothing quite makes bronchiolitis worse than catching rotavirus gastroenteritis from the nice family in the waiting room, while you are waiting for your mother to see the paediatrician who will send you home.  But, if you need to go you need to go.  There are three main categories of things that necessitate admission:
  • Inadequate feeding
  • Ineffective breathing or excessive work of breathing
  • A red flag symptom
Although they do not necessarily mandate referral, a risk factor that makes a sudden collapse more likely is the fourth factor in the referral risk assessment.

Inadequate feeding was covered in the last post.  Feel free to do the maths, work out what the baby is getting, look at the baby or all of the above.  For me, how alert and hydrated the child is will always be a better measure of adequacy.

Ineffective breathing or excessive work of breathing is based on many factors.  It is important to assess respiratory rate, intercostal recession and how loud the breath sounds are on auscultation.  I would say that it is even more important to look at the baby and get a gut feel for how they are coping.

The term "happy wheezer" has been around for as long as I can remember.  A happy wheezer is a baby with bronchiolitis who, often despite an impressively audible wheeze, looks ridiculously happy.  It's funny that none of the official guidelines legislate for the happy wheezer who is above the 91st centile for weight (catchy eh?).  I think that they deserve a pathway of their own.  They seem to cope well and manage far better than equivalent skinny babies with bronchiolitis.

There are two other considerations which affect the level of clinical concern.  These are risk factors and red flags.

Risk factors are important to ask about and will often not be volunteered unless the right questions are asked.  Risk factors in children with bronchiolitis include:
  • Ex-prematurity
  • Underlying respiratory problems e.g. chronic lung disease
  • Age under three months old
  • Underlying cardiac problem
  • Underweight
  • Known immunodeficiency
  • Neurological problems
The presence of risk factors presents an interesting conundrum.  Take the baby with mild bronchiolitis who is two months old.  They do not currently need nasogastric feeding nor do they need supplemental oxygen.  So why refer?  The argument for is that they are more difficult to assess and they will decompensate more rapidly.  The argument against is that being at risk and in hospital can actually be a bad thing.



The presence of a risk factor does not change the clinical assessment of the child (they still have mild bronchiolitis after all) but it sometimes changes the decision to refer or get advice from an experienced paediatrician.  If in doubt, discuss.



The well baby with mild bronchiolitis and a risk factor is better not sent to the emergency department for all the reasons above.  If they need to come in they should be referred directly to paediatrics.

Finally, there are red flags.  These are great because they make the decision easy.  If a child with bronchiolitis has a red flag, they must be referred for observation as a minimum.  Most will need intervention.  Red flags include:
  • Increasing pauses in breathing
  • Grunting
  • Refusing feeds
  • Head bobbing
  • Not waking for feeds
  • Floppy
  • Pale or cyanotic episodes
  • Episodes which alarm parents
Some red flags tell you what you already know - bad things are happening for this baby.  Some red flags tell you that bad things are happening even when it is not obvious from looking at the baby.

So the decision to bounce a bronchiolitic in the direction of a paediatrician is usually straightforward.  If they're need help feeding or support with breathing then the paediatricians need to have them.  Also refer if there are red flag signs or symptoms.  If they are mild but have a risk factor, then either refer or discuss them with an experienced paediatrician.

If the episode is mild and there are no risk factors or red flags, keep them well away from hospital.  They are not good places to be.

Edward Snelson
@sailordoctor

Disclaimer:  If the baby is waving an actual red flag, they are probably fine.



Friday, 4 December 2015

Enough already! Adequate Feeding in Bronchiolitis

It can be difficult to know whether a child with bronchiolitis is best managed in the community with advice, or is one of the small proportion that should be referred for possible admission.  When NICE produced NG9 "Bronchiolitis in Children" there was a number put on how much feed a baby with bronchiolitis should be taken in order for that to be considered adequate.  Well, that's not quite true.  The guideline uses two numbers and a few words.  So how much do the guidelines say is enough?

The first number is "difficulty with breastfeeding or inadequate oral fluid intake (less than 75% of usual volume)" (1) which is listed as an indicator that the baby may need referral to secondary care.  Two pages later a similar but slightly different description of what inadequate feeding looks like is used: "difficulty with breastfeeding or inadequate oral fluid intake (50- 75% of usual volume, taking account of risk factors and using clinical judgement)" (2)


Unsurprisingly, the fact that these numbers are rather tidy and there is a little uncertainty expressed is due the the fact that they are based on expert opinion.  Fair enough but my question is, are we measuring the right thing?

There are lots of variables in the mix here.  Firstly, in breast fed babies, we have to guess what is going in.  As well as what is going in, there is the issue of what comes straight back out.  Finally, what is being used up in terms of calories and water depends on the work of breathing and other factors such as pyrexia.  It will also probably be affected by the amount of subcutaneous fat and renal function.  What is going in is only part of the equation and the formula looks much more like algebra than simple maths to me.  So, why don't we cheat and look at the answers?


The answers that I like to look at are energy levels and hydration.  Assessing a baby's energy levels will be easy in most cases.  If a baby is alert and smiling, it is probably safe to assume that a good supply of calories and water is reaching the most frivolous part of the baby's brain.  If that is the case, then the baby's carbohydrate economy is buoyant.  If this is not the case then something is wrong and whether inadequate feeding is an issue or not, a subdued or tired looking baby with bronchiolitis should be referred.

Assessing hydration is done the old fashioned way as well.  I look for wet mucous membranes in the mouth, good skin hydration, and wet nappies.  If I am really lucky I might have a weight from a couple of days ago to compare to.

The overall appearance, wellness and alertness of the child are always going to be a more valid assessment than comparing an uncertain number (how much we think the baby is getting) to a made up number (how much we think the baby needs).  So, once again, a victory for old school paediatrics and an adage which should never get old: "Look at the child."

Edward Snelson
Uncertaintologist
@sailordoctor

Disclaimer: If none of this makes sense, the NICE bronchiolitis guidelines are actually very good in my opinion.

References
  1. Page 16, Full guideline NG9 Bronchiolitis in Children, NICE
  2. Page 18, Full guideline NG9 Bronchiolitis in Children, NICE

Friday, 27 November 2015

Fairy logic - how to avoid the understanding gap

I recently realised that my medical advice is not as good as it could be.  I tell parents and young people what will help their treatment have the maximum chance of success, but I do so without always thinking about how the advice might fall into an understanding gap.  From now on I am going to try to apply fairy logic whenever I give my explanation of what to do next.

Fairy logic?  Let me explain: In popular mythology, fairies are often need permission from people to do things.  As a result they look for opportunities to interpret what is said to them in inventive ways.  For example if a fairy wants to enter your abode, they need permission.  If they are told, "You can't come in my house" they may see the loophole and go into the garage instead.  In consultations, I think that this misunderstanding of convenience happens often, albeit unintentionally.

For example, with eczema treatment, I will advise that soap should be avoided.  I should probably include shampoo and shower gel in that to avoid misinterpretation.

Other examples include

  • "Stopping milk" when cow's milk protein allergy is suspected (should be stopping milk and anything containing milk, milk products like cheese or having these as an ingredient)
  • "Smoking in the house is associated with chest problems in children" (should be that having a smoker who lives in the house is associated with chest problems in children.  Avoiding smoking in the house and car is good, but quitting is better.)

I know that time is at a premium when there are lots of patients to be seen.  However to avoid that misinterpretation you have to be specific and be comprehensive.  If you have examples of circumstances which benefit from this, why not post them in the comments section?  I suspect that there will be plenty of times that I am not aware of when I need to apply fairy logic to avoid the gap.

Edward Snelson
@sailordoctor

Disclaimer: I am largely basing my knowledge of fairies and their way of thinking on the writings of Eoin Colfer, but I'm not even sure he's ever really met a fairy.


Friday, 20 November 2015

Outside-in or Inside-out? Top tips for making childhood eczema better

In developed countries the incidence of eczema has been increasing for several decades.  At the same time, children are tending to take longer to grow out of having eczema, leading to an even greater prevalence.  While it can be difficult to treat in a General Practice setting, eczema treatment is ripe for Primary Care expertise to make a big difference to a group of children who have an unpleasant but treatable condition.

Recently, I heard an experienced paediatric dermatologist try to squeeze all his eczema wisdom into about an hour long session.   What I learned was that by understanding the way that eczema works, I can be better at treating eczema.

There are many proposed models for what causes and perpetuates eczema.  Two of these are the ‘inside out’ and the ‘outside in’ models.  If you are interested in these things, there is much debate about whether eczema is caused by allergy and perpetuated by damaged skin versus being caused by a defective skin barrier which then leads to allergens penetrating the epidermis.  If you don’t care and just want to treat the eczema effectively, the answer is simple: do something about all the factors involved regardless of which is chicken or egg.
Here's how to do that:

1. Restoring the skin barrier
Think of the epidermis as being a brick wall.  In eczema all the mortar is falling apart and there are gaps between the bricks.  That means that the wall is leaky and does not protect the house from the elements.  What is needed is to repair the mortar.  In eczema, repairing the skin barrier requires oil.  This can be achieved in several ways.  The first thing that is needed is to use emollients. 

Of course there are many emollients available.  Whatever the treatment is, it needs to be one that the family will use often enough.  This requires the provision of large amounts so that the parents will be liberal in using it.  They need to be told to apply it often enough to keep the skin feeling greasy all the time.  Some creams are greasier than others.  Bigger is not always better though.  Sometimes families find the greasiest creams to be too oily and so they apply them less often.  It is important to make sure that they are happy with the cream prescribed.

As well as replacing oils, we need to make sure that whatever is there is not being taken away.  Soaps, shampoos and detergents need to be avoided.   Instead, encourage the use of water alone or with bath oils.  Aqueous cream contains sodium lauryl sulfate which is a mild detergent.  Aqueous cream should not be used as an emollient but can be used as hand soap (1).

2. Treating the inflammation
Returning to the inside out/ outside in way of thinking about eczema, restoring the barrier is not going to be effective on its own when there is inflammation present.  Inflammation requires steroid creams.  How strong a cream and how long it should be given depends on the severity of the eczema and how well it responds.  In short, the steroid cream should be prescribed at a strength that treats the eczema and for as long as necessary to resolve the inflamed skin.  It is very important to attack the eczema from every other angle at the same time so that the steroid cream is given the best possible chance to work and be stopped.

3. Addressing the itch
Treating eczema does not stop at using emollients and steroids.  The next issue to consider is the itch-scratch cycle.  Inflamed skin is itchy and scratched skin makes eczema worse.  Antihistamines can make a big difference during an exacerbation of eczema, not just to help with symptoms but also to speed recovery.

4. Treating drivers of inflammation
Another consideration is the possibility of something driving the inflammation.  Bacterial infection may be manifested as exudative or golden crusted areas.   Herpes virus infection will usually be evident either by the characteristic vesicles or the ulcerated lesions left behind.  Treatment of bacterial infection with oral antibiotics is sometimes needed.   Topical treatment with fucidic acid cream is often the preferred option.  Topical antibiotics must not be continued long term as this simply promotes resistant bacteria colonising the skin. 

Besides infection, there may be allergens that are identifiable.  Avoiding (e.g. specific foods) or minimising (e.g. house dust mite) these precipitants is important, though often difficult.



Having this four pronged approach is much more likely to be effective than being overly simplistic such as by just prescribing a steroid cream for a flare up of eczema.  Good explanation of the treatment and being supportive are both essential to the success of any plan.

I am told by paediatric dermatologists that they often don't use special secondary care treatments when they see children with eczema.  What they do is to use the same treatment that are available in primary care but use these treatments differently.  That sounds like an opportunity for us to make these dermatologists a bit more redundant.

Edward Snelson
@sailordoctor


Disclaimer: Other models of eczema pathogenesis are also available

References


  1. National Eczema society - "Why Aqueous Cream is Bad for Eczema" http://www.eczema.org/aqeous
  2. Drug Safety update - aqueous cream may cause irritation https://www.gov.uk/drug-safety-update/aqueous-cream-may-cause-skin-irritation



Saturday, 14 November 2015

When it walks like a duck- Do I give salbutamol to this 11 month old?

This year saw the arrival of the NICE Bronchiolitis guidelines.  Like many guidelines, this requires the clinician to know that the problem that the child has is bronchiolitis. The trouble is that there are times when there is uncertainty.  It is an important distinction to make since bronchiolitis is best left well alone.  You should not prescribe inhalers, antibiotics or steroids.  Viral wheeze on the other hand requires the liberal use of inhalers for appropriate to the severity of the exacerbation.

As a medical student I was taught that beta-agonists such as salbutamol don't tend to work under the age of one.  That is only partly true.  Beta-agonists don't work for bronchiolitis and most children under 12 months with wheeze have bronchiolitis.  However when the problem is a viral induced wheeze the inhaled Beta agonist is exactly what is needed even if they child is below a year old.

Bronchiolitis and viral induced wheeze have a similar presentation but very different mechanisms which is why one responds and the other doesn't.  Bronchiolitis is essentially a problem of wetness.  The viral lower respiratory tract infection causes the airways to be constricted by the accumulation of secretions.  With viral induced wheeze, the infection has induced bronchospasm.

In both cases there will be a cough, coryza, wheeze and possibly some respiratory distress.  Only one needs inhalers or nebulisers to be given.  So how do I tell them apart?

The easiest way is to look at the child's age.  There seems to be a fairly good split between the typical age groups of the two conditions.  Bronchiolitis tends to affect those under 12 months old while viral induced wheeze tend to be seen in the over 12 month olds.  Using that as a cut off will leave you being correct a lot of the time.  Of course there are exceptions and they will usually be those children a few weeks or a couple of months either side of that cut off.

So for those who are well before their first birthday you can assume they have bronchiolitis.  If the child has already started to outgrow the clothes that they were given for their first birthday, you can assume they have a viral induced wheeze.  But what about the ones who are too close to call?

One thing that helps is the prodrome.  Typically, children with bronchiolitis have a few days of being snotty before the cough develops.  Then there is a daily worsening of cough followed by feeding difficulties.  By day 3 of the cough there may be fast breathing and an audible wheeze.

With viral induced wheeze there is a variable length of coryzal illness from a day to a week.  What is noticeably different is the onset of the wheeze and respiratory distress.  This will usually happen over the space of hours, not days.


The other factor that helps is the severity of the symptoms.  Consider our 11 month old with wheeze: If bronchiolitis affects children from birth to about 15 months of age, the most severely affected will be the littlest babies.  Wet lungs when you are a few weeks old is no walk in the park.  So by the time you are 11 months old, bronchiolitis is less likely to be severe.

Why not just try inhalers with all wheezers?  The answer is that it is possible that this might make the child worse.

If an infant has bronchiolitis, they fight the good fight against wet lungs.  They succeed against the odds since they are less able too feed and use more energy in the effort of breathing.  What we must do as clinicians is avoid making this worse.  Don't give unnecessary antibiotics that will fill and irritate their stomachs.  Don't send them home with ineffective inhalers which will result in a routine of upsetting and tiring out the child.

Conversely, make sure that children with viral induced wheeze get enough beta-agonist.  This might be quite a lot (the salbutamol paradox).

So, because it is an important distinction, use age, then prodrome and then severity in that order to decide if it is bronchiolitis or viral induced wheeze.

Edward Snelson
@sailordoctor




Wednesday, 4 November 2015

Hot topic - Should children who develop a rash while taking antibiotics be re-challenged in primary care?

These are the facts:

  • The vast majority of children who have been labelled as allergic to penicillin have no evidence of allergy on patch-testing, prick testing or oral challenge.  
  • The most common cause of acute urticaria in childhood is viral illness.
  • For various reasons, many children are prescribed antibiotics for viral illnesses.  During the time that they are taking antibiotics they may develop a  rash (urticarial or non-specific) which might lead to the conclusion that the child is reacting to the antibiotics when in fact the rash is due to the viral illness.
  • Anaphylaxis kills around 20 people per year in the United Kingdom.

In this post I would like to debate the pros and cons of what should happen next when a child has been labelled as allergic to penicillin.

The clinical scenario is this: While taking penicillin for an upper respiratory tact infection, a child develops an urticarial rash.  There are no other symptoms such as wheeze associated with the onset of the rash.  The rash settled after a few days.  The child has been labelled as penicillin allergic on the basis of this episode.
The child then presents three months later with an acute otitis media and fulfils the criteria for a prescription of amoxicillin.  What should you do?

One option is to prescribe an alternative antibiotic.  The argument for this is that there is a possibility that the urticaria was due to the penicillin.  Why take a risk?  Although the likelihood of a further reaction is small there is such a thing as penicillin allergy.  Furthermore the child could have a more significant reaction this time.  They could have an anaphylaxis or develop Stevens-Johnson syndrome.  Despite the small chances, the potential severity of the possible reaction makes avoidance of penicillin the best way forward.

The second option is to prescribe amoxicillin.  The attribution of the label 'allergic to penicillin' was not justified.  The vast majority of children who develop an acute episode of urticaria do so in response to the viral illness.  If anything, the appearance of such a rash probably indicates that the antibiotics were unnecessary rather than problematic.  Research has shown that only about 1 in 20 children labelled as allergic to penicillin actually have evidence of a reaction.  Furthermore, the fear of a more severe reaction is probably unfounded.  The only factors known to increase the severity of an allergic reaction are dose and route.  So if the same dose and route are used, the worst that should happen is a recurrence of the rash.  When compared to the increased probability of side effects with an alternative antibiotic, prescribing amoxicillin is the least harmful option.  It is simply a question of amoxicillin being the best drug for the job.

The third option is to prescribe amoxicillin but to have them take the first dose in your clinical setting and wait for up to an hour before leaving.  If the child has a label of penicillin allergy which we know is likely to be wrong, this option somewhat addresses the issues of having been told that they are allergic to penicillin.  The parents are likely to be anxious about giving the medicine.  If there is a reaction to the medicine then this can be assessed as it occurs so that there is no future doubt.  In most cases the reaction will again be mild.  If respiratory or systemic features occur then all of the drugs needed for the initial treatment of allergy and anaphylaxis can be given in Primary care.  In short, it is unlikely that a reaction will occur.  If it does it can be assessed.  It is very unlikely that the reaction will be anaphylaxis but if that occurs it can be treated and the child sent immediately to secondary care by ambulance.

So having heard the arguments, what do you think?  It's time to choose.  Here is the link to the poll: Click here
Alternatively you can join the debate and post a comment below.

Edward Snelson
Notanallergologist
@sailordoctor

Disclaimer:  I never prescribe antibiotics.  I use antibionics (much stronger)

References:


  1. The role of penicillin in benign skin rashes in childhood: a prospective study based on drug rechallenge, J Allergy Clin Immunol. 2011 Jan;127(1):218-22
  2. Penicillin Allergy in Children  Current Allergy & Clinical Immunology, June 2009 Vol 22, No. 2


Wednesday, 21 October 2015

It's all about the wave - An expert's tip for recognising seizures in children

I was recently picking the brains of a paediatric neurology colleague and discussing how they distinguished epileptic seizures from other events.  I already knew that it wasn't through the black arts of EEG (electroencephalogram) interpretation.  I'm sorry to be the bearer of bad news but EEG has a very poor sensitivity and specificity for epilepsy (1).  By the time an EEG is requested, a diagnosis should already have been made on clinical grounds.  The EEG is then useful as part of deciding how to manage the epilepsy, not to screen for epilepsy.


Why do we front line clinicians need to be able to tell the difference?  There are so many things that children present with that could be seizures but probably are not.  One good example of this is absence seizures.

Absence seizures (no longer called petit mal) account for 10% of epilepsy in children.  The incidence of epilepsy in childhood is not well described but is probably about 1/2000 making absence seizures about 1/20,000.  Staring episodes are very common in children and if these occur frequently, it is understandable that parents or teachers want to know if this is a form of epilepsy.  Not all of these need to be referred.

If a paediatric neurologist makes the diagnosis from the history, then so can any clinician.  All we need is to know what their secret is.  It turns out that they are riding a wave.

The characteristic feature of absence seizure is the abrupt and brief impairment of consciousness with a complete inability to intrude on the episodes.  (2) What this means to the observer is that they will notice a sudden onset and then notice the event suddenly finish.

 Fig 1. If you were to plot the change over time, an inattentive staring episode would be like a sine wave.
Fig 2. The typical abrupt onset and cessation of an absence seizure gives a square wave.

It may just be that simple.

Of course, I am not suggesting that no examination is needed.  There are also other features of absence seizures that may be helpful:
  • The episodes occur during any activity and in any environment
  • There may be subtle muscle twitches or lip smacking (automations)
  • There may be a slight loss of tone leading to slumping of the head or trunk

There are two ways that you can get to see the episodes for yourself.  If they happen frequently then, through the magic of smartphones the parents will be able to capture an episode for you.  There is a better way though, as almost all absence seizures can be provoked through hyperventilation as demonstrated beautifully in this video:

So, I have to give thanks to Tony for telling me about the wave thing.  I find pictures are a great way to help me understand things that I know, when I don't necessarily know them well enough.

Edward Snelson
Wave junky
@sailordoctor

References
  1. EEG in the diagnosis, classification, and management of patients with epilepsy, S J M Smith, J Neurol Neurosurg Psychiatry 76:ii2-ii7 doi:10.1136/jnnp.2005.069245
  2. Typical absence seizures and their treatment, C P Panayiotopoulos, Arch Dis Child 81:351-355 doi:10.1136/adc.81.4.351




Tuesday, 13 October 2015

Reverse Engineering - Feeding Problems in the Under-One-Year-Old



What's in a name?  When it comes to the medical conditions affecting babies, there is so very much to be confused about.

Whatever your reaction to that, you are probably aware that the terminology used to describe infant feeding problems is confusing and inconsistent.  I have spent a little time recently looking at the relevant websites, guidelines and journal review articles available to professionals on this subject.  So far I have not found two that use exactly the same terminology to categorise the various clinical entities that exist.  I also know from professional experience that understanding varies and even conflicts between clinicians.

Let me give you an example: reflux.  "Reflux" in babies means to many doctors that a child has a problem with bringing up milk that needs treating.  However, bringing milk up is normal for babies, so many encourage the use of the words posseting or regurgitation to describe harmless reflux.  Many academic papers and guidelines use the medically correct term of gastro-oesophageal reflux (GOR) for the harmless type but distinguish this from gastro-oesophageal reflux disease (GORD) when there is a significant problem.  So there we have five different ways to describe just two clinical entities.  Two of those terms might be used interchangeably to describe either entity.

The conditions involving any sort of reaction to milk are even more confusing.  Some try to simplify things by insisting on having just two diagnoses- cow's milk protein allergy or lactose intolerance.  This goes a long way to help clinicians to avoid getting confused between the two, but then many children who are having a reaction to cows milk do not have lactose intolerance, and do not have any evidence of allergy to cow's milk protein either.  For this reason, the term Milk Intolerance is used by some including NHS choices.  Some feel that this helps to distinguish children who have a proven allergy, and so need to be managed as such, from those who do not.  The term milk intolerance does however confuse us again by it's vagueness.  Intolerance to what?  There is now a growing consensus that there is only milk protein allergy or lactose intolerance.


When you can't get started because nothing makes sense, the process that will get you there is called reverse engineering.  Start with the end point and work backwards.  So, lets have a go at this for the infant with feeding problems.  There is one outcome that we are aiming for: a well child.  There are only a few treatment options, so lets start with those and describe the children who should be having that treatment.  All scenarios rely on a thorough history and examination.  One of the most important parts of this is to take a feed history.

Lets start with my favourite outcome and reverse engineer that:

How to get there: reverse engineering option 1 - doing as much nothing as possible

Babies who regurgitate feeds without choking, gagging frequently, faltering growth or being significantly distressed during or after feeds do not require intervention.   It is important to safety-net so that parents know to return if problems such as feed refusal develop.

How to get there: reverse engineering option 2 - reducing the feeds

The baby that vomits and cries a lot may be over-feeding.  This is because, while most babies determine their own requirements, some get stuck in a loop called the feed-cry cycle and need to have their feeds restricted to something more sensible.  Take a feed history in any baby presenting with vomiting and distress and limit the feed to 150ml/kg/day.  If that doesn't work, look at the other options.
How to get there: reverse engineering option 3 - thickeners and alginates

This is where to start with the infant who fits these characteristics:

  • Onset of vomiting before the age of three months old
  • Gagging, choking or significant distress
  • Symptoms are not progressive over a few days and no signs of other illness
  • Adequate weight gain and still taking a sensible amount of feed

Thickened milks are the recommended first line of treatment in the NICE guideline for GORD in children.  If thickened feeds do not help or if the baby is breastfed then an infant alginate preparation is a thickener as well as an antacid.

How to get there: reverse engineering option 4 - what am I missing?

This is not really a feeding problem treatment option but an important reminder that we all need to re-think when a child does not improve.  Even if the initial assessment was reassuring, by the second or third visit we should always be asking "what am I missing?"  One thing not to miss is a urinary tract infection.  These low-grade UTIs may be sub-clinical apart from symptoms indistinguishable from GORD.  Other conditions such as pyloric stenosis should be considered if the vomiting escalates over the space of a few days.

How to get there: reverse engineering option 5 - acid suppression

H2 receptor agonists (H2RAs) and proton pump inhibitors (PPIs) are an option for the child who has not responded to option 3 and does not have anything to suggest a hidden diagnosis (option 4).  As long as there is a re-evaluation of the pathway, acid suppression is the next step assuming that the infant does not have sever symptoms or signs of an allergy.

How to get there: reverse engineering option 6 - try an extensively hydrolysed feed (EHF) (or revert to breastfeeding)

There are a few scenarios which might benefit from EHF.  These milks have the proteins broken down so that the feed is very unlikely to trigger an allergic reaction.  
If treatment option 5 has been tried then this is one possible way to go next when there is no response.  In this context the EHF is a trial to see if the child is reacting to the milk with a reaction that only manifests as symptomatic vomiting or distress around feeds.
If an infant who is initially treated with thickeners goes onto develop signs of atopy (such as severe eczema) or fails to improve and has a very strong family history of atopy, EHF can be tried earlier.  Most likely this will be after option 3 in an infant under three months old.
In an infant who presents later in the first year of life, the odds of the problem being a reaction to the milk increase.  In such children, ECF could be tried even without trying options 3 or 4.
The main differences from option 6 are that with option 5 you do not need to refer.  There are a variety of ways to go next.  NICE recommends re-challenging after 2-6 weeks (in this scenario) while local guidelines vary.


How to get there: reverse engineering option 7 – start an extensively hydrolysed feed (EHF) (or revert to breastfeeding) and refer to a specialist

In an infant who has a clear allergic reaction (e.g. develops urticaria after weaning from breast milk) then there is an urgent need to remove cow’s milk protein from the baby’s diet.  This can be done by using EHF or by returning the infant to being fully breastfed.  In these cases the next steps require the input of a specialist so they will need to be referred.  Breastfeeding mothers should exclude milk from their diet until a dietician can fully advise.

How to get there: reverse engineering option 8 – start a lactose free milk (or add lactase for breast feeding mothers)

In the UK, lactose free milk is usually needed when a child has partially recovered from a gastroenteritis,  The unwellness and vomiting settles but they have persistent and often explosive loose stools.  In these cases, it is likely to be the case that the child will dramatically improve with a trial of lactose free milk.  Once symptoms have been resolved for two weeks, the child can return to normal milk products.
For breast feeding mothers, there is no point excluding lactose from their diet as the breast naturally produces lactose anyway.  One option is to add lactase to the feeds in the form of drops.
Note: EHFs tend to be lactose free (because lactose also causes problems for babies reacting to the proteins in cow's milk) but this is a very expensive option if the problem is purely the lactose. Choose a simple lactose free milk in this scenario.

So, I have managed to describe the various options and the patients who should benefit from them, yet I only mentioned a diagnosis once (in the context of a NICE guideline).  When it comes to feeding problems in the under one year old, the diagnosis matters little and may never be known.  What really matters is to know what has the best chance of success for a given clinical entity and what to do next if that intervention does not work.

Having said all that, if you want to know how the names match up to the scenarios, here's a simplistic table that pretty much does that as well:

Edward Snelson
Paediatrician with sub-specialty training in having a short attention span
@sailordoctor

Disclaimer: I could have just given you the last picture, but what would be the fun in that?




Monday, 14 September 2015

Paracetamol as an anti-emetic

Now that children have returned to school you may have notice something new in your consulting room: the smell of stale vomit.  I think that I have a fairly protected professional life but puke is not one of those things that I mention when extolling the virtues of my (eventually) chosen career.  As winter approaches, the number of children with viral gastritis and gastroenteritis will go up and up until one day before Christmas, I will have a loved one ask me to shower before supper so that I can be in polite company.

Perhaps there is one good thing to come out of all this though.  I think that all these vomiting children have taught me something that not everyone else knows: For the child with viral vomiting who will not drink, paracetamol is an accidental anti-emetic.  (I am also fairly sure that there is no medical evidence for it, having done a literature search.)
Anti-emetics are traditionally avoided in  viral vomiting due to the possibility of side effects which might complicate what should be a self-limiting illness.  In the UK, most children with viral gastritis/ gastroenteritis do not become significantly unwell. However it is unpleasant and occasionally causes a child to become severely unwell.

I know that I can’t prove my belief but I can tell you this: I frequently see children who seem unwilling to drink and incapable of appropriate onwards gastric peristalsis (AOGP, as well as a new acronym, happens to be the sound made just before an almighty puke).   Parents bring their children in the hope that we will help.  These children seem beyond simple measures and yet almost without fail, an hour after a dose of paracetamol they are drinking, soon to be followed by appropriate discharge.

Why haven’t they been give paracetamol already?  That’s easy.  It is counter-intuitive to give slimy medicine to a child who vomits every few minutes.  It stand to reason that it will come straight back or precipitate a puke.  The child may not be febrile and even if they are it seems a waste of good medicine.

When I sit down to write these posts, I enjoy the fact that FOAMed allows the writer to be free of the normal constraints of traditional forms of publications.  I am keen, however to make sure that I don’t write anything that is dangerous or wrong.  As mentioned above, I really did do a literature search on this.  You may have noticed that I never sport a serious disclaimer.  This is for two reasons.  Firstly, a disclaimer is no defence against wrongness.  Secondly a lack of a disclaimer is no excuse for you to go and jump off a bridge just because I said so.  We have an understanding, you and I.  I will make this as good as I can make it and you will be professional, question my advice and apply what you get from it in the context of everything else that you know about clinical medicine.  That said, paracetamol really is an anti-emetic when a child has viral gastritis.

In the absence of a randomised controlled trail (that will probably never be done) one needs a plausible explanation for one's claim.  It works like this: When you feel unwell and have abdominal pain you do not want to drink.  Pain and malaise are both emetic in their own right.  Paracetamol reduces pain and feelings of malaise, helping a child to vomit less and drink more.


There are two caveats with this.  Firstly, I would be against giving repeated doses paracetamol too readily to a child who is dehydrated.  Secondly, remember that many paracetamol suspensions contain sugar substitutes which are hyper-osmolar.  Sugar is preferable in vomiting children since they need to energy and don’t need the diarrhoea that can be made worse by sugar free suspensions. 

I know that just because it makes sense doesn't mean it is true, nor does an observed association prove causation. (1)  In this case I have been convinced of an association because it seems to work and it makes sense.  If that’s good enough for you, then great.   There are plenty more like this to come in future posts.

Edward Snelson
Statistical Sceptic when it suits me
@sailordoctor

Disclaimer: Were you even paying attention?  I covered this.



Tuesday, 1 September 2015

How special is your patient? (recognising the unwell child with a difference)


The previous GPpaedsTips was all about deciding when a child does not have sepsis. The hierarchy of evidence was put forward as a model for determining what information is most helpful in this process.  Those of you who take the time to read the terms and conditions will have noticed the "this rule does not always apply" clause.

Fig 1 - The hierarchy of evidence used in most cases to determine whether a child does not have a serious infection

The reason that the rules do usually apply is that the majority of children are unlikely to have a serious infection (one that has a reasonable chance of causing morbidity or mortality).  Also, they will usually have some sort of red flag to alert the clinician to serious infection when they are really unwell.

The reason that the rules do not always apply is that some children are special.  They might be special because they are much more likely to have a serious infection.  They might be special because they do not readily alert the clinician when they are significantly unwell.  If they are really special they will do both.

Fig 2 - Legolas from the Lord of the Rings
As explained to me by my daughter, a 'Special'  in a book or film is a character that can only really be taken on by another 'Special'.  Hundreds of unnamed characters might try to kill them without any hope of success.


Contrary to what parents think, most children are not special, at least not in this context.  Most children are predictably ordinary.  They probably have a viral upper respiratory tract infection and if they are developing a more significant infection they will have the courtesy to look and behave as though they are unwell.  Hopefully they will do so enough to convince a clinician that this is the wrong time to assume that the red throat is all the explanation that is needed for the fever.

Fig 3 -  In the Star Trek universe, 'Red Shirts' were never special and had a tendency to be killed off each episode.

So, how do you know when you have a special patient?  You know because they come with labels such as:
  • Neonate
  • Immunosuppressed
  • Immunodeficient
  • Pre-existing neurological or muscular disorder
  • The child with chickenpox
Neonates (or to be honest, all sprogs under 3 months old) are the biggest group of specials in primary care.  Due to their maternally donated immunity, new-born babies tend to have a few months free of common viral infections.  When infection does occur, the likelihood of bacterial infection and sepsis is therefore much greater. In addition to this they are to give clear signs of illness.  More often the indicators are vague and come in the form of a subtle change in behaviour such as sleeping excessively or feeding poorly.

Children are rarely immunosuppressed but it is increasingly common for a child to be treated with immunosuppressant medication if they suffer from any chronic autoimmune condition.  Ideally these families have direct access to specialist advice when their child becomes even slightly unwell.

Thankfully and despite parental concerns, congenital immunodeficiency is very rare in children.  Having frequent self-limiting viral illnesses is normal as long as the child is otherwise thriving and developing normally.  When a child does have a congenital problem with their immune system they are usually prone to rapid deterioration into serious infections.  One of the best ways of establishing a child’s tendency to do this is to ask what has previously happened in similar circumstances.

If the child has a neurological or muscular disorder they may not be able to look unwell in a way that you will easily recognise.  If in doubt, ask the parents.

Which brings me onto my surprise witness: the child with chickenpox.  Large numbers of children with varicella are seen in primary care every minute of every day.  The vast majority have a self-limiting illness which causes more annoyance than unwellness.  A small proportion of children with chickenpox get secondary infection.  The danger is that someone will assume that this is caused by the logical staph aureus and prescribe flucloxacillin.  In fact Streptococcal infection is the greater risk and infection may be invasive and severe.  Any child who has chickenpox and goes onto be unwell (especially when this occurs late in the usual 7 day course of the illness) has to be presumed to have streptococcal sepsis.

The bottom line is that special children must be treated in special ways.  They are dangerous patients for the unwary clinician.  I have listed the groups that I think might come your way but there will be others.


Fig 4 - Dumbledore could only be taken on by other special characters.  Special children need special doctors when they are unwell.

What does special treatment look like?  It does not comprise giving them all amoxicillin “just to be on the safe side.”  It is useful to go into more detail about past illness in the history and be extra thorough when examining.  It might involve a discussion with a specialist and often requires referral.  Just like in the movies, a special character needs another special character to take them on.  I, like you, am a generalist.  I don’t fancy my chances if I start to free-style the management of a special patient so I phone a friend so that I survive another episode.

Edward Snelson
Fellow Red Shirt
@sailordoctor

 Disclaimer: I am told I am a very, very special doctor.  All generalists are specialists but that is another blog.

 If you found this helpful, you might also like:  The TPR paradox - how do I know if a child might have sepsis?

Sunday, 16 August 2015

The TPR paradox - how do I know if a child might have sepsis?


When I assess an ill child, I am primarily making a decision about whether the child has possible sepsis.  To a certain extent, everything else is detail.  The sepsis question determines which door the child leaves through.  Just like in primary care, I send the vast majority of children presenting to the ED back out the way they came, whether they have pneumonia, urinary tract infection or just a cold.  A small number of ill children are admitted, with the possibility of sepsis as the primary reason.  The question is: How do I decide which door to send each child through?  Once you answer that, I believe that you can begin to understand how to use the many guidelines and decision tools designed to help us make this choice.

In 1935, Einstein and two of his buddies published a paper detailing some problems with quantum physics theories.  In effect they were saying that their own advances had explained a lot about how physics worked, but that there were some things that they could not explain.  Specifically, when two particles went through two doors, one of them did something that didn't make sense.  You could do something to one of the particles and the other reacted even though they are not connected.  This is called the EPR paradox, after Einstein, Podolsky and Rosen.  These three were the best scientific minds in the world and yet they had a missing piece of the jigsaw so big that it called everything else into question.

I believe that we are in a similar place in medicine when it comes to recognising possible sepsis in children.  Once again we have two doors and sending children through these is not as straightforward as it should be.  We all do our best to send each child through the correct door.  There is a big piece of the jigsaw missing though and that’s got us all scratching our heads.  The missing bit is knowing how to go from considering possible sepsis to diagnosing probable sepsis without resorting to reading tea leafs or other substitutes for a valid test.  Most of the time we do our best and accept that in the absence of a good test all we have is good judgement.  The problem comes when a child dies of sepsis and that gap in the process comes under scrutiny.  I'm all for completing the puzzle but I am suspicious that we are trying to put the wrong piece into the gap.

If I asked you to create a decision tool for clinicians to move from considering sepsis to a provisional diagnosis of sepsis, what would you choose as predictors?  You could use the appearance of the child but that is difficult to quantify.  What seems far more reliable is TPR (temperature, pulse and respiration) since these can be measured.  The trouble is that the most measurable features of your assessment are the least reliable.


Before I get a rush of people saying that I think that you should ignore tachycardia and high temperature, please be clear that I don’t think that.  It is just that I think that there is a much better category of evidence and that numbers are not as reliable as we want them to be.

There are plenty of reasons to mistrust numbers.  For starters we have a lack of reliable reference ranges.  There is a good reason why no-one has started making a lot of money out of selling centile charts of paediatric heart and respiratory rates.  They don't exist.  There is not enough evidence to produce such a thing.  The variables are just too many.  Is it age that determines heart rate or your weight?  If it is weight then is it lean weight?  What is the effect of anxiety on heart rate?  How different is a normal heart rate in a resting child to that of a playing child or a screaming child?

What about those normal ranges that you have somewhere when you need to check?  Aren't they evidence based?  You could try to find out what their evidence base is but I could probably save you a lot of hassle by telling you that all the normal ranges that I know of are based on consensus, which is why they are all slightly different from each other. In the past few years, two large analyses have shown that some of the most commonly available reference ranges map poorly to population studies.  Even then, these publications acknowledge that the populations studied are never truly normal. (1,2)

However, I think that this whole issue is much simpler than all of that, because the wrong question is being asked.  The question is not, “Does this child have sepsis?”  The question is, “Can I say with confidence that this child does not have sepsis?”  When we use the rule out rather than rule in approach, everything starts to fall into place, including the value of numbers.

I said before that there is more reliable evidence than temperature and pulse.  That evidence is something that you rely on every time you assess a child and it is the thing that makes sense of the numbers for you: activity.   What we really want to know about the heart rate and capillary refill is not the absolute number but the effect that these are having.  What we need to assess is oxygen and glucose delivery to the organs and there is no better measure of this in a child than what the child can do once these get there.

There is one more variable which complicates the TPR paradox, which is the up and down nature of the illness.  You may see the child at their worst or possibly their best.  In any viral illness the likelihood is that the child will have extremes of activity making nonsense of the assessment.  Thankfully we have two saving graces here.  The first is that we can hear about what has gone before.  The second is that we are able to continue the assessment either by observing, referring or safety netting.

So let’s bring all of this together.  There are two simple elements to recognising serious infection in children.  The first is a hierarchy of evidence.  The second is a rule-in/ rule-out approach.


The hierarchy of evidence is logical.  If I see a child in a playground climbing up to go on the slide and their parent mentions that they have had a temperature, I don’t worry that they may be septic.  I do imagine that they have a significant tachycardia but this will be a result of their activity and possibly their temperature.  I see with my eyes both the activity and the vigour with which it is undertaken.  I don't need to ask any questions or measure any physiological parameters because I have all the evidence that I need.

If I was giving telephone advice and I hear that a child is sat playing on a tablet I now have some very useful information about the adequacy of their brain’s perfusion and oxygen/glucose supply.  It's not as good as what I see because I can't scrutinise what I am being told with my own experienced eye.

Finally if I measure a child’s heart rate and capillary refill, I have information but it needs to be put into context.  Was it cold outside?  Have they just been upset by something?  So the numbers are important but I need what I see and hear to make sense of them.


In any acute assessment of an unwell child this hierarchy can be combined with a rule-in/ rule-out approach to answer the question, “Am I certain that this child does not have sepsis?”

If what you see, hear and measure is all reassuring then the answer is yes, they do not have sepsis.  If what you see, hear and measure are all concerning then the answer should be no, they could well have sepsis.  If what you see, hear and measure give a mixed message then the question remains open and there are various ways to answer it.  Using the hierarchy of evidence above, I feel confident to give paracetamol and wait when a child looks well and behaves well even if they are febrile and tachycardic.  The options are always the same: discharge with safety netting advice, observe, discuss or refer.

Just like the scientists of 1935, none of us has all the answers.  None of the decision tools available is even close to perfect and all of them rely on someone at some point taking responsibility for making a decision about which door the child will go through.  Thankfully the majority of children answer the question for you.

Edward Snelson
@sailordoctor



If you liked this you might also like:

In Praise of Doing Nothing (Easter Egg – good safety-netting and saving lives)

Or How special is your patient? - (Neonates and other patients who don't follow the rules)

References: