Croup

Aka: Croup, Laryngo-tracheo Bronchitis, Laryngotracheal Bronchitis, Laryngotracheitis, Laryngotracheobronchitis, Laryngotracheobronchopneumonitis, Spasmodic Croup

1. See Also
   1. Croup Score
   2. Dexamethasone in Croup
   3. Stridor
   4. Epiglottitis
   5. Bacterial Tracheitis
2. History
   1. Word "Croup" derived from Scottish for raven's "croak"
3. Epidemiology
   1. Incidence
      1. Overall Incidence: 6 cases per 100 children <6 years
      2. Accounts for 15% of pediatric respiratory visits to the emergency department
      3. Hospitalizations: 1-8% of US cases (20,000 per year)
      4. Intubation: 1-5% of cases hospitalized
   2. Boys affected more than girls by ratio of 1.5 to 1
   3. Outbreaks and epidemics occur in autumn to early winter
      1. Can occur year round sporadically
   4. Affects ages under 12 years
      1. Most common cause of Stridor in children 6 months to 3 years of age
      2. Typical age 6 months to 36 months of age (peaks between 12 and 24 months)
      3. Rare before 3 months of age
4. Pathophysiology
   1. Subglottic infection
5. Etiology
   1. Parainfluenza virus (50-75% of cases)
      1. Type 1 (18% of cases)
      2. Type 2
      3. Type 3 (more common in younger children)
   2. Adenovirus
   3. Respiratory Syncytial Virus (RSV)
   4. Influenza A and Influenza B
   5. Rhinovirus
   6. Enteroviruses
   7. Human Bocavirus (spring and fall)
   8. Mycoplasma pneumoniae (uncommon)
6. Symptoms
   1. Low grade fever
      1. High grade fever suggests other diagnosis (see differential diagnosis)
   2. Prodrome of initially mild upper respiratory symptoms or Coryza (first 1-2 days)
      1. Nasal Congestion
      2. Rhinorrhea
   3. Upper respiratory symptoms rapidly develop
      1. Hoarseness
      2. Cough: "Barking" OR "seal-like"
      3. Inspiratory Stridor
      4. Expiratory Wheezing
      5. Dyspnea
   4. Symptoms worse at night
   5. Symptom duration <1 week (peaks at 2-4 days)
      1. Cough may persist up to 1 week
7. Signs
   1. "Sound worse than they look" (Opposite of Epiglottitis)
      1. However, severe croup can occur
   2. Minimal Wheezing (Inspiratory Stridor instead)
   3. Mild to Moderate respiratory distress
      1. Nasal flaring
      2. Respiratory retractions
      3. Inspiratory Stridor
8. Labs
   1. Avoid labs unless diagnosis unclear
      1. Blood draws cause worsening distress and do not add to diagnosis in typical croup
   2. Complete Blood Count
      1. May show mild Leukocytosis
9. Diagnosis
   1. See Croup Score
10. Differential Diagnosis (Croup is diagnosis of exclusion)
    1. Angioedema
    2. Epiglottitis
       1. Less common in U.S. now since HaemophilusInfluenzae type B Immunization
    3. Bacterial Tracheitis
    4. Ludwig's Angina
    5. Peritonsillar Abscess
    6. Diphtheria
    7. Paraquat Poisoning (Herbicides)
    8. Foreign-body obstruction
       1. History of Choking episode (88%)
       2. Neck XRay PA and Lateral if object is radiopaque
    9. Gastroesophageal Reflux
       1. Common cause of recurrent croup
11. Imaging
    1. Avoid imaging (as with labs) unless diagnosis is unclear
       1. Typically worsens distress and does not add to diagnosis in typical croup
    2. Lateral Neck XRay
       1. Findings suggestive of croup
          1. Subglottic Narrowing
          2. "Steeple" sign on PA Neck XRay (40-50% of croup cases)
          3. Narrowing of subglottic region from mucosal edema
          4. Images
             1. From MedPix with permission.
       2. Findings suggestive of alternative diagnosis
          1. Epiglottitis: Thickened epiglottis
          2. Retropharyngeal Abscess: Widening retropharyngeal soft tissue
          3. Bacterial Tracheitis: Thickened trachea
    3. Chest XRay
       1. Does not diagnose croup (will not demonstrate steeple sign)
       2. Indicated only to evaluate differential diagnosis (e.g. Pneumonia) where the diagnosis is unclear
12. Management: Home Therapy
    1. Maintain adequate Ambient humidity in house
    2. Cool mist may decrease subglottic edema
       1. No studies to support this
       2. May make Asthma worse due to irritation
       3. Options
          1. Cool-mist humidifier
          2. Cold weather
             1. Bundle child warmly
             2. bring outside for 15 minutes
          3. Closed bathroom with cold shower mist
    3. Maintain adequate hydration
       1. Offer child favorite drink every 10 minutes
       2. Consider crushed ice drinks or other frozen treats
    4. Corticosteroids
       1. See Dexamethasone in Croup
13. Management: Emergency Department and Inpatient
    1. Primary tenet
       1. Do not distress a child with croup
       2. Avoid unnecessary procedures
       3. Position child as they are most comfortable
    2. Humidified Oxygen
       1. Indicated for Hypoxia or moderate to severe respiratory distress
       2. Blow-by oxygen is preferred to avoid distressing child
       3. Do not use heated humidification due to risk of burns
    3. Nebulized racemic epinephrine
       1. Indicated in moderate to severe emergency department cases
       2. Nebulizer Dose
          1. Racemic Epinephrine 0.05 ml/kg (maximum 0.5 ml) of 2.25% via nebulizer or
          2. Standard L-Epinephrine 0.5 ml/kg (maximum 5 ml) of 1:1,000 via nebulizer
       3. Effect onset within 30 minutes and lasts up to 2 hours
       4. Observe at least 2-4 hours after administration
       5. Typically admit patient if requires a repeat Epinephrine neb
    4. Corticosteroids
       1. See Dexamethasone in Croup
       2. Dexamethasone 0.15 to 0.6 mg/kg orally (maximum 10 mg)
          1. Onset of action in 6 hours and effect lasts for 72 hours
    5. Antibiotics
       1. Not indicated unless concurrent bacterial infection
    6. Helium added to Oxygen (Heliox)
       1. May prevent intubation in borderline patients
    7. Intubation
       1. Indicated less frequently now with above management
       2. Significant risk of Subglottic Stenosis
       3. Use ET Tube at least 1 size smaller than predicted
14. Management: Outpatient Management Indications
    1. Non-toxic appearance
    2. Well hydrated and taking oral fluids
    3. Minimal or no Stridor or retractions at rest
       1. At presentation or 2 hours after Epinephrine
    4. Reliable parents
15. Management: Inpatient Observation Indications
    1. Persistent moderate to severe symptoms despite above management
       1. Dexamethasone 0.6 mg/kg and
       2. Epinephrine nebulizer treatment with observation for 2 hours
    2. Signs of respiratory distress or respiratory failure
    3. Cyanosis
    4. Tachypnea
    5. Agitation or Fatigue
    6. Stridor severity
    7. Accessory muscle use
       1. Intercostal retractions
       2. Neck or abdominal muscle use
    8. Rising arterial PCO2
16. Management: Recurrent Croup
    1. Consider esophageal reflux
    2. Consider referral to pulmonology for bronchoscopy (especially age under 3 years old)
       1. Higher Incidence of findings such as Subglottic Stenosis or cyst
17. References
    1. Cherry (2008) N Engl J Med 358(4): 384-91
    2. Folland (1997) J Postgrad Med 101(3): 271-8
    3. Geelhoed (1997) Pediatr Pulmonol 23:370-374
    4. Klassen (1994) N Engl J Med, 331: 285-9
    5. Knutson (2004) Am Fam Physician 69(3):535-42
    6. Quan (1992) Am Fam Physician 46(3): 747-55
    7. Sobol (2008) Otolaryngol Clin North Am 41(3): 551-66
    8. Wald (2010) Pediatr Ann 39(1): 15-21
    9. Zoorab (2011) Am Fam Physician 83(9): 1067-73