Episode 163.0 – Croup

May 20, 2019

Croup is a common viral infection that strikes children, leading to a barking cough and inspiratory stridor. The hosts unpack its causes, primarily the parainfluenza virus, and discuss the typical presentation of croup, including the alarming 'steeple sign' seen on X-rays. They also emphasize the critical importance of assessing symptom severity through tools like the Westley Croup Score and offer management strategies for mild to severe cases. Learn how to navigate this challenging condition in young patients!

Ask episode

AI Snips

Chapters

Transcript

Episode notes

INSIGHT

Pathophysiology of Croup

Croup is caused by viral infection leading to subglottic narrowing and dynamic airway obstruction.
This causes the hallmark barking cough and sometimes inspiratory stridor in children.

INSIGHT

Causes and Age Range of Croup

Parainfluenza virus is the most common cause of croup, with others like rhinovirus and RSV contributing.
It mainly affects children aged 6 to 36 months, rarely affecting children over 6 years old.

INSIGHT

Seasonality and Differential Diagnosis

Croup has a seasonal peak in mid-fall to early winter and is more common in odd years.
It can mimic severe infections like bacterial tracheitis, epiglottitis, or inhaled foreign body, requiring careful differential diagnosis.

Get the Snipd Podcast app to discover more snips from this episode

Get the app

A look at one of the most common and potentially concerning upper respiratory infections in children.

Host:
Brian Gilberti, MD

Download One Comment Tags: Airway, Infectious Diseases, Pediatrics

Show Notes

Background

Croup is a viral infection starts in the nasal and pharyngeal mucosa but spreads to the larynx and trachea
- Subglottic narrowing from inflammation
- Dynamic obstruction
- Barking cough
- Inspiratory stridor
Causes:
- Parainfluenza virus (most common)
- Rhinovirus
- Enterovirus
- RSV
- Rarely: Influenza, Measles
Age range: 6 months to 36 months
Seasonal component with high prevalence in fall and early winter
Differential
- Bacterial tracheitis
- Acute epiglottitis
- Inhaled FB
- Retropharyngeal abscess
- Anaphylaxis

Presentation & Diagnosis

Classically a prodrome of nonspecific symptoms for 1-3 days with low grade fevers, congestion, runny nose.
Symptoms reach peak severity on the 4^th day
“Steeple sign” on Xray (subglottic narrowing) present in only 50% of patients with croup
Assess air entry, skin color, level of consciousness, for tachypnea, if there are retractions / nasal flaring (if present at rest or with agitation) & coughing
“Westley Croup Score” (https://www.mdcalc.com/westley-croup-score)
- Chest wall retractions
- Stridor
- Cyanosis
- Level of consciousness
- Air entry

Management

Mild Croup
- Occasional barking cough, but no stridor at rest and mild to no retractions
- Tx: Single dose of dex
  - Has been shown to improve severity and duration of symptoms
  - Route is not particularly important, whether it’s PO, IV or IM
  - Chosen route should aim to minimize agitation in the patient that might worsen their condition
- May be managed at with supportive care
  - Humidifiers (NB: there isn’t good evidence supporting the use of humidifiers)
  - Antipyretics
  - PO fluids
- Moderate Group
  - May have stridor at rest, mild-moderate retractions but no AMS and will not be in distress.
  - Tx: Dex + Racemic Epinephrine
    - Racemic epinpehrine will start to work in about 10 minutes
    - Effects last for more than an hour
  - Severe group
    - Receives the same initial therapy as the moderate group with dex and race epi
    - Pts with worrisome signs: stridor at rest, marked retraction, cyanosis and/or lethargy
    - Heliox (a combinations of 70-80% helium + 20-30% oxygen) may be attempted
      - There is limited evidence to support the role of heliox in croup,
      - NB: Pt may require higher levels of oxygen than the 20-30% mixture may provide
    - Intubation
      - Anticipate edema narrowing the airway
      - Consider starting with a tube that is 0.5 to 1 mm smaller than size typically used

Disposition:

Patients without stridor at rest or respiratory distress can be generally discharged from the ED
If epinephrine is given, patients should be monitored for 2-4 hours for reemergence of symptoms as the medication wears off

Take Home Points

Croup usually affects children within the age range of 6 months to 36 months with the most common cause being parainfluenza virus
Given the symptom overlap, we must consider more concerning diagnoses, including bacterial tracheitis, in these patients, especially if they are ill appearing or traditional therapies are ineffective
All patients benefit from a one-time dose of dexamethasone and, if racemic epinephrine is given, the patient should be observed for at least 3 hours
If intubation is required, anticipate a narrowed airway

Parent Article: https://coreem.net/core/croup/ by Dr. Pankow