Pediatric Pneumonia in the ED

OK, we’ve finished reading the Feb 2011 edition of @EBMedicine‘s Pediatric Emergency Medicine Practice article on pneumonia:

Jadavji T (2011). An Evidence-Based Review Of Pediatric Pneumonia In The ED. Pediatric Emergency Medicine Practice, 8(2). [Abstract and subscription link]

Let’s not muck around — here are 8 Q-and-As to test whether you’re a (wo)man or an amoeba when it comes to childhood pneumonia…

Questions

Q1. From a global perspective, how important is childhood pneumonia?

Pneumonia is the no. 1 killer of children worldwide.

There are over 2 million deaths per year from pneumonia, accounting for 1 in 5 deaths of children under 5 years of age. This is more than AIDS, malaria and measles combined.

Q2. How is pneumonia diagnosed?

Definitions of pneumonia are hard to pin down!

In the simplest clincal terms, pneumonia is simply an infection resulting in lower respiratory tract dysfunction in the presence of radiographic abnormalities on chest x-ray.

A chest radiograph should be considered in children with prolonged cough, high or prolonged fever and in the presence of focal respiratory signs other than wheeze (especially if there are multiple signs and symptoms).

In resource poor settings, WHO guidelines for pneumonia in children aged 2 months to 5 years states that a clinical diagnosis can be made if the child has a cough and fast or difficult breathing. Tachypnea according to age is defined as:

  • RR>60 if <2 months, RR>50 if 2 months to 12 months, and RR>40 if 12 months or older.

Q3. How should respiratory rate be measured?

Respiratory rate should be measured by observation of an awake child who is not crying over 60 seconds.

Measurement of respiratory rate will vary according to:

  • method of measurement: lower respiratory rate for observation than electronic measurement, which are both less than for measurement by auscultation.
  • duration of measurement: increased RR if measured over 15 seconds rather than 60 seconds.
  • child activity: respiratory rate is increased if crying or active, decreased if asleep.

Q4. What is occult pneumonia?

Occult pneumonia refers to the presence of CXR abnormalities consistent with pneumonia in a febrile child with no evidence of tachypnea or focal respiratory signs. In the current post-vaccination age, about 5-7% of cases of diagnosed pneumonia are occult.

Q5. How can viral pneumonia be distinguished from bacterial pneumonia?

Viral and bacterial causation cannot be reliably distinguished in usual clinical practice.

In modern times, even with a comprehensive search for a cause, the underlying etiology of pneumonia remains unknown in over 20% of cases. Furthermore, viral and bacterial causes may coexist.

Traditionally the appearance of the chest radiograph was felt to help distinguish between viral and bacterial causation:

  • Viral pneumonias classically show perihilar bronchial thickening, interstitial opacities and hyperinflation.
  • Bacterial pneumonias classically cause lobar consolidation.

In reality, either radiographic appearance may be seen in viral or bacterial causes.

Age is the best predictor of the likely cause of pneumonia in children.

Q6. What is the likely cause of pneumonia in the following age groups (in order!):

Neonates

Group B streptococci, Escherischia coli, Listeria monocytogenes, Staphylococcus aureus

1 month to 2 years

Respiratory syncytial virus, parainfluenza virus, metapneumovirus, influenza virus, adenovirus, Streptococcus pneumoniae
(NB. 3 weeks to 3 years: pneumonitis syndrome may be caused by: Chlamydia pneumoniae, RSV, parainfluenza virus, Bordetella pertussis)

2 – 5 years

Respiratory syncytial virus (RSV), Streptococcus pneumoniae, non-typeable Haemophilus influenzae, Group A Streptococcci, Mycoplasma pneumoniae, Chlamydia pneumoniae

6-18 years


Mycoplasma pneumoniae
, Chlamydia pneumoniae, Streptococcus pneumoniae, non-typeable Haemophilus influenzae, influenza A, other respiratory viruses

The choice of antibiotics depends on the likely cause, and the severity of illness, and should be guided by local practice guidelines and sensitivity patterns.

Q7. Which children with pneumonia require admission?

There is little evidence to guide us in deciding who to admit to hospital.

Hospitalisation should be considered when:

  • age < 6months (more likely to rapidly deteriorate)
  • hypoxemia (Sp02 <92% OA)
  • toxic appearance or severe respiratory distress
  • suspected complications (e.g. empyema)
  • immunocompromise
  • vomiting, dehydration or not tolerating oral intake
  • social circumstances

Q8. How has the epidemiology of pneumonia in children changed since the introduction of pneumococcal vaccination?

The introduction of pneumococcal vaccination has decreased the rates of pneumonia, and in particular has reduced rates of pneumococcal hospitalisations. However, the rates of empyema complicating pneumonia have increased, although pneumococcal disease is now less likely to be the cause. MRSA should be considered in this setting, along with the administration of vancomycin.

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  1. says

    An article in the Jan 2011 edition of the Journal of Medical Microbiology ( Gladstone R.A., Jefferies, J.M., Faust, S.N., Clarke, S.C. Cont. Ctrl. of Pneomococcal Dis. in the UK, -The Impact of Vaccination. JMM, P60) interestingly highlighted the problem of serotype and strain replacement in a vaccinated population.

    As different strains correlate with different regions of the world (perhaps adapting to receptors present in different ethnic groups), elements of the community who remained unvaccinated compounded the problem by allowing for the further evolution of new serotypes.

    The difference in the serotypes capsids were such that the 12 valent vaccine was no longer effective at creating immunity in the individual, subsequently no herd immunity, and therefore the same amount of community spread as observed prior to the vaccination campaign, with the same associated conditions. It highlights the need to have a strong vaccination campaign, and perhaps rather than just one vaccine, there should be several developed for use in different geographical regions to prevent such disease re-emerging in 1st world communities.

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