Croup 

Key Points

• young age: uncommon <6 months old, rare <3 months of age.

• Consider alternative diagnosis and causes of upper airway obstruction

• Minimise distress to the child, as this can worsen upper airway obstruction. 
• Note: Swabbing for COVID-19 or other viruses should not be performed until deemed safe to do so by a senior clinician
• Consider early transfer and involvement of senior staff if concerns regarding worsening upper airway obstruction
• For severe and life-threatening croup, use nebulised adrenaline
• Less severe cases can be managed with corticosteroids alone

Pathophysiology

• Viral infection

1. most prevalent autumn / spring
2. most common aetiological agents
   1. Parainfluenza type 1 – approx 50%
   2. Parainfluenza type 2
   3. Influenza A
   4. Adenovirus
   5. RSV
   6. enterovirus
3. 6 months to 6 years, mean age 18 months
4. may be seen into teenage years

• Recurrent spasmodic croup

1. occurs in older children
2. associated with asthma / atopy
3. management similar

Pathology

1. viral replication causes oedema of larynx and trachea
2. luminal narrowing of vocal cords and subglottis
3. causes stridor, hoarseness and characteristic barking cough
4. acute and transient higher degree of obstruction may occur due to
   1. mucous plugging
   2. distress and agitation
   3. Poiseuille’s Law: resistance to flow is inversely proportional to the fourth power of the radius

Assessment

History

1. 1-2 day prodrome of URTI
2. Cough: “Barking” OR “seal-like”
3. hoarse voice
4. +/ stridor / retractions
5. worsening symptoms at night and when recumbent
6. worsening of obstruction usually takes hours to progress
7. history of previous croup, preexisting airway narrowing
8. immunisation history – esp diphtheria and Hib
9. Risk factors severe croup
   1. known narrowing
   2. previous admission very young (consider alternatives)
10. Classify severity
    1. Loudness of stridor not a good indication
    2. Don’t need to measure sats if mild-moderate
    3. GCS, agitaiton, stridor, resp rate, accessory msucles, cyanosis/pallor, oxygen saturation
    4. Not necessary to measure sats in mild-moderate

Examination

• Minimise distress to the child, as this can worsen upper airway obstruction 
• Children with croup should have minimal examination so as not to upset the child further. Throat examination is rarely required
• Swabbing for COVID-19 should not be performed until deemed safe to do so by a senior clinician

Investigations

1. oximetry
   1. of limited value as will remain in high 90’s even when badly obstructed
2. lateral soft tissue XR of neck
   1. rarely helpful
   2. requires child moved from resus area and hence disturbing precarious airway
   3. in general risk of procedure outweighs any benefits

Minimal Wheezing (Inspiratory Stridor instead), Minimal rhonchi and no rales

Assessment

“Sound worse than they look” (Opposite of Epiglottitis) – However, severe croup can cause complete airway obstruction

	Mild	Moderate	Severe
Behaviour	Normal Able to talk normally	Some / intermittent irritability  Some limitation of ability to talk	Increasing irritability and / or  lethargy Marked limitation of ability to talk or unable to talk
Tachypnoea* (at rest – ie not crying)	Normal or mildly increase respiratory rate (normal values by age)	Increased respiratory rate	Increased or markedly reduced respiratory rate as the child tires.
Signs of  increased work of breathing Retraction (intercostal, suprasternal, costal margin)Paradoxical abdominal breathing Accessory muscle use Nasal flaring Sternomastoid contraction (head bobbing) Forward posture	None or minimal	Moderate retractions and / or accessory muscle use	Marked increase in accessory muscle use with prominent chest retraction.
Oxygenation Oxygenation is only of limited utility in judging severity in many paediatric respiratory conditions. Don’t just focus on the SaO2 monitor. Look at the other signs.			O2 saturations less than 90% (in room air)Any O2 requirement in croup is classed as severe Cyanosis
Heart Rate	Normal or slight increase	Mildly increased	Significantly increased or bradycardia
Blood Pressure	Normal	Increased	Increased or decreased late.

Management

General supportive

1. Minimal handling, reduce distress
2. Keep children with carers to reduce distress
3. Children will adopt a position of comfort that minimises airway obstruction, do not change this
4. nurse in upright position
5. Treat mild croup with steroids alone. 
6. Barking cough with no other symptoms does not always require steroids 
7. increased respiratory effort increases degree of obstruction in extrathoracic airway obstruction
8. O2 – is not usually required. If needed, treat for severe upper airway obstruction/hypoxic
9. no scientific evidence of benefit of steam or mist therapy
10. Consider a longer period of observation than 4 hours for a child who:
    1.     presents overnight
    2.     lives far from medical care
    3.     presents with stridor more than once during the same illness
    4.     has risk factors for severe croup

Specific

• Corticosteroids

1. used in all severities
2. emerging evidence of effectiveness within one hour
3. usually one dose only required
4. routes of administration
   • oral
   • nebulised
   • IM/IV
5. options
   • dexamethasone 0.15 mg/kg oral
   • prednisolone 1 mg/kg oral
   • budesonide 2 mg nebuliser
6. oral glucocorticoids inexpensive and easier to administer

• Other therapies

1. NO place for antibiotics in the treatment of croup
2. heliox insufficient evidence of benefit in reducing respiratory distress

Moderatesevere croup

• Nebulised adrenaline

1. 0.5 mL/kg of 1:1,000 (up to 5 mL dilute to this volume with Normal saline)
2. racemic adrenaline (mixture of dextro and levo isomers) is no more effective than normal adrenaline
3. recent studies have failed to demonstrate any rebound phenomenon following the administration of adrenaline
4. length of illness is not affected
5. most centres now use nebulised adrenaline in patients with moderate and severe croup
6. if no improvement admit to ICU
7. if improved – admission for several hours observation as may have further need for adrenaline nebs

Admission criteria

1. persistent stridor
2. < 6 months of age
3. factors that do not allow observation at home or rapid return to hospital if condition worsens

Safety Netting

1. 000/QAS if any of the following
   1. Is going blue around the lips
   2. A harsh breath noise as they breathe in (stridor) present all of the time (even when they are not upset)
   3. Has pauses in their breathing (apnoeas) or has an irregular breathing pattern
   4. Is too breathless to talk / eat or drink
   5. Becomes pale, mottled and feels abnormally cold to touch
   6. Becomes extremely agitated (crying inconsolably despite distraction), confused or very drowsy (difficult to wake)
   7. Develops a rash that does not disappear with pressure (the ‘Glass Test’)
   8. Is under 3 months of age with a temperature of 38°
2. Urgent GP review if any of the following
   1. Has laboured/rapid breathing or they are working hard to breathe – drawing in of the muscles below their lower ribs, at their neck or between their ribs
   2.  A harsh breath noise when they breathe in (stridor) present only when they are upset
   3. Seems dehydrated (sunken eyes, drowsy or no urine passed for 12 hours)
   4. Is becoming drowsy (excessively sleepy)
   5. Drooling and has difficulty swallowing saliva
   6. Is 3-6 months of age with a temperature of 39°C or above (but fever is common in babies up to 2 days after they receive vaccinations)
   7.  Seems to be getting worse or if you are worried

Prognosis

1. 85% of patients with mild moderate croup can be managed as outpatients
2. stridor usually lasts 12 days
3. cough may last for 1 week
4. glucocorticoids have significantly reduced need for intubation

Other causes of upper airway obstruction

1. angioedema
2. diphtheria
3. laryngospasm
4. anterior mediastinal tumour

Management of critical upper airway obstruction

1. avoid upsetting child
2. minimal handling / investigation
3. secure airway
   1. initial orotracheal intubation
   2. use most experienced airway doctor – preferably anaesthetist
   3. sevoflurane/halothane induction preferred
   4. surgical backup for tracheostomy if needed
4. antibiotics if bacterial cause suspected e.g. epiglottitis, bacterial tracheitis, retropharyngeal abscess, severe tonsillitis
   1. IV ceftriaxone (50 mg/kg/day up to 2 g) or IV cefotaxime (50 mg/kg 8 hourly)
   2. chloramphenicol if severe penicillin hypersensitivity
   3. consider metronidazole
5. antibiotic prophylaxis if epiglottitis
   1. rifampicin to index case and contacts
6. if diagnosis unclear a lateral neck Xray
   1. may reveal a markedly swollen epiglottis (thumb sign)
   2. slough for tracheitis
   3. retropharyngeal swelling
   4. interpretation of these films may be very difficult

Additional notes

• Antibiotics have no role in uncomplicated croup as it has a viral aetiology
• Anti-tussives such has codeine, have no proven effect on the course or severity of croup, and may cause respiratory depression and increase sedation
• Humidified air has not been proven to change the severity of croup 
• Heliox has not been shown to be better than nebulised adrenaline in severe croup