Category: Pediatrics

A Little Proof of Harms from CTs

It is popular to worry about the harms of CT scans in small children.  A retrospective Swedish study suggests decreased intelligence.  And, our models based on nuclear weapon exposure data combined with dummy CT exposure suggest these scans are likely to result in an increased risk of malignancy.

This is another retrospective study in the National Health Service of Britain comparing malignancy outcomes with their exposure to CT in childhood.  The scary headline: CT scan radiation triples the risk of leukemia and primary brain malignancy.  Of course, triple the risk is essentially 1 additional case of leukemia and 1 additional case of primary brain malignancy in the first 10 years after exposure.  So, this is potentially another study you can use to discuss the Number Needed to Harm with families when discussing the need for CT radiation in pediatric cases.

Now, whether articles like this trigger a wave of legal trolling for malignancies preceded by CT remains to be seen….

“Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours:  a retrospective cohort study”
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(12)60815-0/abstract

Plain C-Spine Radiography in Children

In adults, the use of plain radiography has largely been replaced in the U.S. by computed tomography over concerns regarding missed injuries – and some literature even argues that, given the right clinical circumstances, even a normal CT scan is inadequate.  But, in children, the harms of radiation exposure are greater, so pediatrics has been more hesitant to move to CT as the first imaging study of the cervical spine in blunt trauma.

Unfortunately, this retrospective PECARN study of children with cervical spine injuries isn’t as helpful as one would hope.  The authors identified 204 children, 58 of whom were aged less than 7 years, who sustained a CSI and had plain radiographs of the cervical spine performed.  Of these patients, 127 patients had a definite injury on plain radiography.  41 additional patients had “possible” abnormalities.  Then, 20 films were judged to be inadequate by technique.  And, finally, there were 18 adequate radiographs with normal findings who subsequently had a CSI identified.  The overall sensitivity, then, was 90% (CI 85-94%) – which compares very similarly to the sensitivity in adults from the 34,000 patients in the NEXUS study.
The authors note that most missed injuries fell into two general categories: they were either subtle and non-morbid, or the patients were altered/intubated/focal neurologic findings.  It is probably still reasonable to start with screening plain-film radiography and use clinical judgment to determine when CT may be necessary, but if you’re looking for airtight evidence to guide your decision-making, CSI in children is too rare to generate that sort of data.
“Utility of Plain Radiographs in Detecting Traumatic Injuries of the Cervical Spine in Children”

Codeine, Potentially Unpredictably Lethal

Frequently used in the pediatric population, codeine is a narcotic analgesic in prodrug form.  In the body, codeine is metabolized to morphine through the CYP2D6 pathway.  In the general population, it is estimated that approximate 10% of codeine undergoes conversion to morphine.

We’re generally familiar with the concept that a certain percentage of the population is ineffective at metabolizing codeine, and therefore receives no additional analgesic effect.  However, the flip side, as these authors report, is a CYP2D6 genotype of over-metabolizers.  In this case series, the over-metabolism of codeine in three post-surgical children likely resulted in supra-therapeutic conversion to morphine, leading to respiratory arrest.

The short summary – when possible, avoid medications that are unpredictably metabolized – such as codeine.

“More Codeine Fatalities After Tonsillectomy in North American Children”
www.ncbi.nlm.nih.gov/pubmed/22492761

Suprapubic Tap Should Be Used for Urinalysis in Children?

“Ideally, SPA should be used for microbiological assessment of urine in young children,” states the abstract conclusion for this article from Australia.


Looking retrospectively at urine samples from 599 children with an average age of 7 months, these authors conclude that suprapubic aspiration is superior to all other methods of obtaining urine samples for contamination rates.  Contamination rates were 46% with bag urine, 26% for clean catch, 12% for catheterization, and 1% for suprapubic aspiration.


We generally rely on catheterized urine samples in our Emergency Departments – and we even have difficulty convincing some parents that this is required, let alone a suprapubic aspiration.  In fact, I’m rather surprised they had 84 patients (14%) in their cohort receiving suprapubic aspiration, considering I have never seen it performed.


While I have no issue with their conclusion from a microbiologic accuracy standpoint, I’m not so sure such an invasive and painful procedure has a place in routine practice.


“Contamination rates of different urine collection methods for the diagnosis of urinary tract infections in young children: An observational cohort study.“
www.ncbi.nlm.nih.gov/pubmed/22537082

Hopping To Rule Out Appendicitis

The “Best Evidence Topic” reports from the Manchester Royal Infirmary are published in the Journal of Emergency Medicine.  Overall, they are meant to summarize evidence regarding more practical, clinical applications.  One of the recent summaries focuses on appendicitis, and whether eliciting pain during coughing, percussion, or hopping is useful in ruling in or out disease.
For this topic, they summarize a few articles – mostly following a prospective derivation study in which hopping/percussion/coughing was 93% sensitive and 100% specific for appendicitis.  Unfortunately, the test performance didn’t quite hold up – sensitivity ranging from 72% to 89%, depending on age group, and highly variable specificities.
So, unfortunately, somewhat like the “hamburger test,” you won’t be able to base the entirety of your clinical disposition on this, but it’s not an irrelevant input into your general clinical gestalt.
“BET 1: Is abdominal pain when asked to hop suggestive of appendicitis in children?”

Most Severe Mechanism Children Don’t Need Head CTs

The PECARN group has published a set of criteria that identify children at very low risk for significant traumatic injury.  This is publicly available and an excellent decision instrument to enhance your clinical judgement.  But, the problem is, with excellent sensitivity, the specificity is weak – such that a great number of patients who fail to meet low-risk criteria will still have good outcomes.

So, this is a follow-on study attempting to determine whether the severe mechanism portion of the decision instrument was predictive of significant TBI, or whether scans could be avoided if mechanism was the only positive feature in their decision instrument.  And, yes, a severe injury mechanism in isolation – at least in the 35% of their cohort who received a head CT – had only a 0.3% chance of significant injury in age <2 years and 0.6% chance of significant injury in age >2 years.  Severe injury mechanisms associated with additional PECARN criteria, however, had 4% and 6% incidence of TBI, depending on age.

Probably the most important aspect of these numbers is they allow for a better discussion of risks with parents and families.  While 1 in 150 or 1 in 300 sound like pretty good odds, when you practice long enough, those odds will catch up with you.  Even with severe mechanism and additional features, 19 of 20 CTs will be negative – you can still make a reasonable case for observation rather than knee-jerk scanning.

“Prevalence of Clinically Important Traumatic Brain Injuries in Children With Minor Blunt Head Trauma and Isolated Severe Injury Mechanisms”

“Malodorous” Urine Isn’t Necessarily a UTI

Which is to say, when a parent brings in a child with a fever and the urine “smells bad”, plenty of those kids have normal urine cultures and plenty of children with Febreeze for urine have a urinary tract infection, regardless.


This is a prospective cohort study enrolling children receiving a urine culture as part of an evaluation for fever without a source in the Emergency Department – and then they went back and data mined for associations between the group diagnosed with UTI and not.  The overall incidence of UTI was 15%.  The overall incidence of UTI in those with “malodorous” urine was 24%.  It was the most significant contributing factor they found, but it’s still not sensitive or specific enough to use in isolation to change management.


Other interesting tidbits:  no circumcised male had a UTI, known high-grade vesicoureteral reflux predicted UTI.


“Association of Malodorous Urine With Urinary Tract Infection in Children Aged 1 to 36 Months”
http://www.ncbi.nlm.nih.gov/pubmed/22473364

The Dexamethasone Dose for Croup is 0.15mg/kg

Unfortunately, this is still probably not the trial that convinces everyone.  In fact, it’s been over 15 years since the original single-center trials/reports showing that 0.15mg/kg of dexamethasone was every bit as effective as 0.6mg/kg of dexamethasone.  This makes intuitive sense, considering the steroid equivalencies, and the doses used in studies that have established prednisolone as an adequate treatment for croup, as well.

Regardless, this is a very small – 30-odd patients – with mild croup, randomized to dexamethasone at 0.15mg/kg vs. placebo.  The point of this study was not to test the efficacy of dexamethasone, but rather to show that, despite it’s long half-life, it had immediate effects.  And, I think it’s fair to say this study demonstrates those significant effects in reduction in croup score, gaining statistical significance by 30 minutes.

I don’t know where the attachment came from in terms of the 0.6mg/kg dose of dexamethasone, but it’s just preposterously high.

“How fast does oral dexamethasone work in mild to moderately severe croup? A randomized double-blinded clinical trial.”
http://www.ncbi.nlm.nih.gov/pubmed/22313564

Early Steroids Probably Better for Asthma

Not sure if this is the study that proves it – since due to ethical considerations it’s simply observational, and doesn’t control for confounders and introduces a lot of bias – but, it’s a small piece of the puzzle.

This is a cohort in a Montreal pediatric emergency department in which they prospectively collected data on moderate and severe asthma exacerbations as patients progressed through their care pathway.  They see, essentially, a nonsignificant trend in increased odds of hospital admission for patients in whom administration of systemic steroids was delayed.  This is mostly a data mining exercise, so any significant associations should be considered hypothesis generating.  However, considering the patients who received delayed steroids had milder exacerbations overall – yet still seemed to go on to have higher admission rates – it might be tempting to interpret these findings as appropriately confirmatory of physiologic foundations of treatment.

At least, there’s no suggestion of harm from early steroid administration in asthma with exacerbation in children.  Perhaps some prospective interventional data with patient-oriented outcomes will surface in response.

“Early Administration of Systemic Corticosteroids Reduces Hospital Admission Rates for Children With Moderate and Severe Asthma Exacerbation”
http://www.ncbi.nlm.nih.gov/pubmed/22410507

Please Stop Using Azithromycin Indiscriminantly

There is a time and a place for a macrolide with a long half-life, and it is not empirically for pharyngitis.

And, it’s even less appropriate empirically for pharyngitis now that it’s been overused to the point where it’s nearly in the drinking water – because it can no longer be considered second-line for group A streptococcus for your penicillin allergic patients.

This is a case report and evidence review from Pediatrics that discusses two cases of rheumatic fever, both of which presented after treatment of GAS pharyngitis with azithromycin.  While rheumatic fever has been almost completely wiped out – there are so few of the RF emm types in circulation, that it’s almost nonexistent in the United States – there are still sporadic cases.  Macrolides are listed as second-line therapy for GAS, but single-institution studies have shown macrolide resistant streptococcus in up to 48% of patients.  Macrolide resistance varies greatly worldwide, from a low of 1.1% in Cyprus to 97.9% in Chinese children.

Why is macrolide resistance so high?  Azithromycin is the culprit; because it has such a long-half life, it spends a long time in the body at just below its mean inhibitory concentration, and preferentially selects for resistant strains.

Please stop using azithromycin.  Use doxycycline, or another alternative, when possible.  There has never been reported resistance to pencillin in GAS.

“Macrolide Treatment Failure in Streptococcal Pharyngitis Resulting in Acute Rheumatic Fever”
http://www.ncbi.nlm.nih.gov/pubmed/22311996