Wednesday, 29 May 2019

Should I prescribe antibiotics for a child with otitis media and discharge from eardrum rupture?

The answer to that question is much more complicated than most guidelines will lead you to believe.
The headline statement recommending the use of antibiotics in this scenario has buried the evidence in multiple layers of interpretation.  To get to the truth, we have to look at the lierature ferred to in the decision to make that recommendation.

Guideline writers put in huge amounts of work looking at all the available evidence and then turning that into simple statements.  When these recommendations are truly simple and make sense in clinical practice, we tend to just follow them.  In a recent Twitter poll of over 600 people, this was far from the case.
If over half of clincians would avoid treatment, that suggests that there is something about the recommendation that is misaligned with our front-line work.  When you deconstruct the recommendation, it becomes clear why that is.

First of all though, let’s look at simple otitis media without rupture of the eardrum (tympanic membrane).

Otitis media is a common childhood infection.  It starts off with a cold and then progresses to an infected middle ear.  It is important to be aware that neither ear pain nor a red tympanic membrane is diagnostic of otitis media.
  • An inflamed tympanic membrane is a common finding in uncomplicated viral upper respiratory tract infections (URTI).  In such cases the tympanic membrane is red but not bulging.
  • Ear pain (otalgia) may be caused by eustachian tube blockage even when there is no middle ear infection.  In these cases the tympanic membrane is typically retracted.
  • A painful ear with a red bulging tympanic membrane is the usual presentation of otitis media.
The evidence for antibiotics being effective in the treatment of otitis media is pretty poor.  In a Cochrane review of this subject (1) it is reported that antibiotics have no effect on pain at 24 hrs and that you need to treat 16 children in order to see one of those children having less pain at 2-3 days.  In line with previous discussions re antibiotics, the same review noted that antibiotics had no effect on the rate of complications.  With a similar number of children being made unwell by the antibiotics, it is questionable what their role is at all in uncomplicated otitis media.
Many guidelines list exceptions to this rule.  One that often confuses clinicians is the scenario of the child who presents with a sudden onset of purulent discharge from the ear.  In these circumstances, there is often a recommendation to treat with antibiotics.

So where does this recommendation come from?  Peeling back the layers is quite interesting and what lies beneath the recommendation shows that it is far from a straightforward "must do" for antibiotics in children when the otitis media bursts the tympanic membrane.

Starting with a commonly cited recommendation, the NICE CKS for acute otitis media (2) states "...immediate antibiotic prescription could be considered in children... ...of any age with both AOM and ear discharge..."  The basis for this recommendation is cited as the aforementioned Cochrane Review (1).  This Review states "Antibiotics are most useful in children under two years of age with bilateral AOM, or with both AOM and otorrhoea. For most other children with mild disease in high-income countries, an expectant observational approach seems justified."

The Cochrane Review conclusion itself is based on a paper (3) that looked at the features that made it more likely that antibiotics would have an effect.  In the case of otitis media with otorrhoea, it found that the NNT improved to 3.  That sounds good, so why would most people avoid treating?

The answe is simple.  In the published evidence, the effect of antibiotics was still to do with symptom (mainly pain) improvement.  That is clinicaly important because in many cases pain is resolved when the discharge occurs.  Presumably this is because the pain was due to the stretching of the tympanic membrane rather than due to the inflammation of soft tissues.

If the pain is resolved, the NNT to treat becomes irrelevant.  How can you improve pain that has gone away? Even if there is still some discomfort, if this is controlled by analgesia, isn't that a better option than antibiotics?

Therefore, when a child presents with otorrhoea due to otitis media, rather than faithfully following a recommendation to give antibiotics, we consider the applicability to the child in front of us.  If the pain has gone or is easily controlled with analgesia, we can hold off.  The appearance of the discharge may be alarming but it is often the beginning of the end of the illness.

What about topical antibiotics?  These are also frequently recommended.  In answer to these recommendations I would point out that neither the NICE CKS nor the Cochrane review have recommended antibiotic ear drops for this clinical scenario.  In addition, there is BMJ paper (4) that states "Topical antibiotics are associated with fewer systemic side effects and a lower risk of antibiotic resistance than oral antibiotics, but there is no strong direct evidence to support their use in this condition."

So there you have it - the bottom line:
Once the recommendation to treat is deconstucted, it all makes sense.  In this case, it seems that taking it apart and looking inside reveals why most of us still don't give antibiotics when nasty green stuff starts pouring out of a child's ear.

Edward Snelson
Guideline Deconstrucivist
@sailordoctor

Disclaimer - One time I took a guideline apart and couldn't work out how to put it back together. It's still in my cellar.
References
  1. Cochrane Database of Systematic Reviews Antibiotics for acute otitis media in children
  2. Acute Otitis Media Clinical Knowledge Summary, NICE
  3. Rovers M at al, Antibiotics for acute otitis media: a meta-analysis with individual patient data, The Lancet, Vol 368, Issue 9545, 21–27 October 2006, Pages 1429-1435
  4. P Venekamp et al, Are topical antibiotics an alternative to oral antibiotics for children with acute otitis media and ear discharge?, BMJ 2016; 352 doi: https://doi.org/10.1136/bmj.i308

No comments:

Post a Comment