Pediatric Case of the Week #5: Late night breathing

Pt: Warren Peace

Age: 8 mos
CC: "gasping for air"

During your first overnight at West Health (somewhere in the foggy nether-region of 4am), a new mother is  concerned that her precocious child has been "gasping for air."  The is infant is noted to have had a runny nose, cough, and low grade temp for a few days.  (The infant is generally disgreeable but his mother assures you that this component of his history is not related to his medical state.) Tonight, mom notes that he is breathing more rapidly and wheezing.  Mom asks if the infant might have asthma because, "he has had wheezing in the past."  You astutely ask about feeding and mom offers that he has not taken his usual amount of fluids over the past day. 



VS: T 99.3 HR 140 BP 97/55 RR 55 Sats 87% on RA

PE:

Gen: Alert 8 month old with wry look on his face
HEENT: mucous membranes are dry
CV: no murmurs, normal pulses
Lung: diffuse expiratory wheezes, no rales, lower intercostal retractions
Skin: normal, no tenting
Extremities: Right middle finger appears fixed in extension

Any immediate actions?

Which of these vitals are abnormal?

Is this asthma?

What is your differential diagnosis?

Do you administer a neb?

If so, what do you put in it?

Steroids?

Would you get a chest xray? 

Would Dave Peterson get a chest xray?

How would you decide disposition?

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Bronchiolitis is the most common lower respiratory tract infection in infants and young children less than 2 years of age.  More than 200,000 annual ED visits in the US.  Admission rates are roughly 19% which makes bronchiolitis the leading cause of hospitalization for infants.  The definition of bronchiolitis, the clinical scoring systems, and outcome measures vary significantly, complicating the interpretation of this disease.  Even the 2006 AAP definition is confusing. They note that signs and symptoms often include, "rhinitis, tachypnea, wheezing, cough, crackles, and use of accessory muscles and/or nasal flaring."

http://pediatrics.aappublications.org/content/118/4/1774.full.pdf

I like to think of bronchiolitis as AIRWAY SLUDGE followed by inflammation.  The infection produces increased mucous secretion, cell death, and sloughing of the respiratory epithelium.  This is followed by peribronchiolar lymphocytic infiltrate and submucosal edema which leads to airway narrowing and obstruction.  The final result is ventilation/perfusion (V/Q) mismatch.  The most current important pathophysiologic point to remember is that unlike asthma smooth muscle constriction seems to have a limited role. (This is important to remember when we consider treatment of the disease.)

A number of viruses are known to cause bronchiolitis but the most common is RSV which accounts for some 50%-80% of the cases. The disease tends to peak in January and February.

The differential diagnosis of wheezing in infancy:

Life threatening causes of infant wheezing:

  Infections: pneumonia, chlamydia, pertussis
  Foreign body: aspirated or esophageal
  Cardiac anomaly: CHF, vascular ring
  Allergic reaction
  Bronchiopulmonary disorder exacerbation

Non Life threatening causes of infant wheezing:

  Congenital anomaly: tracheoesophageal fistula, bronchogenic cyst, laryngeotracheomalacia
  Gastroesophogeal reflux disease
  Mediastinal mass
  Cystic fibrosis

Bronchiolitis is very common and we will need to identify who is at risk for severe disease.  Obviously any congenital disease or history of immune deficiency increases a child's risk of severe disease.  Less obvious risk factors associated with severe presentation include a history of premature birth <35-37 weeks and kids <6-12 weeks of life.

Similarly, we have to assess risk of apnea which includes history of full term birth < 1 month of age; preterm birth <37 weeks gestation and age <2 months; history of apnea of prematurity; ED presentation of apnea or apnea witnessed by caregiver.

Bronchiolitis is primarily a clinical diagnosis.  CXR, Viral testing (RSV), CBC, and UA are not routinely recommended for infant bronchiolitis evaluation.  (Xray may be helpful to evaluate for foreign body, pneumonia, or CHF if these are clinically suspected.)

Treatments: 

Nasal suction should be used to clear secretion particularly if they exhibit difficulty with feeding or sleeping.

It is reasonable to try a bronchiodilator and, if there is a positive clinical response, continue bronchiodilator therapy.  However, if no clinical response, then bronchiodilators should be discontinued.  A recent Cochrane review of bronchiodilators showed only epinephrine to be effective over time. B-Agonists had no effect on hospitalization or hospital stay. 

http://archpedi.jamanetwork.com/article.aspx?articleid=485625#qundefined

A meta-analysis of nebulized epinephrine suggested a decrease in clinical symptoms when compared with placebo or albuterol.  The dose was 0.9 mg/kg racemic or 0.03 mL/kg of the 2.25% solution (diluted with 3 ml NS.)  A more recent Cochrane review showed that inhaled epinephrine affected day 1 admission rates but not day 7 admission rates.

http://archpedi.jamanetwork.com/article.aspx?articleid=481450 http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003123.pub3/abstract

The main finding of the 2011 Cochrane review was that COMBINED EPINEPHRINE and DEXAMETHASONE (1 mg/kg in ED and 0.6 mg/kg/day for and additional 5 days) showed a lower admission rate over 7 days.

This was initially reported in a NEJM article from 2009:

http://www.nejm.org/doi/full/10.1056/NEJMoa0900544




Disposition:

Most children with bronchiolitis have mild disease and are discharged home.  Infants with bronchiolitis are frequently hospitalized for respiratory distress, hypoxia, or dehydration due to inability to take in fluids secondary to increased work of breathing.  Additionally, concerns of apnea should direct decisions to admit.

The AAP recommends judicious O2 when SpO2 falls below 90%.  As a general rule infants with SpO2 <92% on RA require close observation and (in my opinion) hospitalization should be strongly considered.  For patients with SpO2 between 92%-94% you will need to make a detailed clinical assessment and consider the phase of the illness along with social factors.