Croup Vs Epiglotitis

Croup-Acute Laryngotracheobronchitis: inflammation of the glottic & subglottic region (narrowest part)

1. Viral Croup - parainfluenzae viruses
- occasionally RSV, rhinoviruses, or measles
- coryzal prodrome, low grade fever
- rare < 6/12, consider ? underlying lesion - commonest obstruction at 6/12 to 6 yrs - median age of presentation 18/12 - more common in autumn & winter - <5% require intubation 2. Spasmodic Croup - children with an allergic nature
-? spectrum of asthmatic population
- no coryzal prodrome / fever

3. Bacterial Tracheitis - usually Staph. aureus ± H. influenzae, group A Strep.
- high fever, WCC, purulent secretions
-* risk of sudden obstruction

Varied Clinical Presentation
a. signs of mild croup
- URTI preceding 2-3 days
- loud barking "croupy" cough
- gradual onset inspiratory stridor which is high pitched
- hoarse voice
- no postural preference
- mild fever
- often a past history of croup

b. moderate
- stridor on inspiration & expiration
- tachypnoea
- flaring alar nasae
- suprasternal/intercostal retractions

c. severe - restlessness caused by hypoxia
- exhaustion & listlessness
- deteriorating conscious state
- cyanosis on air

Differential diagnosis
- epiglottitis
- aspiration of foreign body
- bacterial tracheitis
- retropharyngeal abscess
- peritonsillar abscess

Diagnosis
i. history and examination * mainstay of diagnosis
ii. radiology of the larynx (ESS or ICU) ®
"steeple" sign - AP view
widened hypopharynx - lat. view, only ~ 40-50% of cases
iii. direct laryngoscopy under GA

Management
a. minimal disturbance - VM & VO2,nursed by parent
b. adequate hydration,but propensity for pulmonary oedema; hypo-Na+ & convulsions have occurred 2° to SIADH with airway obstruction
c. oxygen therapy ® SpO2 > 90%- hypoxia from parenchymal infection ± increased interstitial water
d. humidification - mainstay for years but studies showing efficacy are lacking now abandoned by many centres but anecdotal evidence ? otherwise
e. steroids - dexamethasone ~ 0.6 mg/kg (= 12 mg) stat., then 0.15 mg/kg q6h.
Given on admission - decreases intubation rate & duration of stay
Failed extubation rate - administer 24 hrs pre & 12 hrs post-extubation
May also be of use in spasmodic croup
f. nebulized adrenaline - 1:1,000 ~ 0.5 ml/kg £ 5 ml of 0.1% solution, nebulised 2 hrly, this dose is effective, has little systemic effect, and is less than the recommended dose for the racemic solution -subsequent doses ® less effective. The obstruction may be more severe after the effect has worn-off ® rebound phenomenon ? progression of the disease process.
-In Acute LTB - lasts ~ 1-2 hrs,doesn't alter course but may allow secretion expectoration and prior to intubation, enhances induction
-In spasmodic croup - may obviate need for intubation
- Post ETT / endoscopy oedema where effect is often dramatic
- prior to transfer if not for intubation
- prior to anaesthesia & intubation if tolerated
g. Antibiotics - only for proven bacterial infection
h. Intubation ~ 2-5% of cases, nasotracheal,use 1 mm less than "size for age"

Indications for Intubation NB: essentially subjective assessment
a. ­ respiratory rate, HR, and chest wall retractions
b. cyanosis not responsive to oxygen
c. exhaustion and/or confusion
d. increased use of, and failure to respond to, nebulised adrenaline
e. need for transport to another hospital

Method
-spontaneously breathing,
-inhalational anaesthetic induction is prolonged
-ETT ~ 1 size smaller for age to minimise trauma
-most safely passed orally, then changed to a nasal
-small tubes are shorter and may be difficult to secure
-sedation ± arm splints to prevent self extubation
-stomach should be emptied with a nasogastric tube
-CPAP or IPPV with PEEP to maintain oxygenation
- size limited to > 3.0 mm, due to requirement to pass a suction catheter to clear secretions

Extubation
-can be attempted when a leak is present with positive pressure or coughing,
- or when the disease has run its course at 5 to 7 days
Reintubation may be required, but the incidence is reduced by administration of steroids prior to extubation ® prednisolone ~ 2 mg/kg/day.
Prior to steroid therapy intubation duration was average 5 days, but now reduced to 2-3 days.

Bacterial Tracheitis
-results in purulent secretions, pseudomembranes and ulceration of epithelium within the trachea
-death can result from upper airway obstruction, endotracheal tube blockage, and toxic shock
-either a primary bacterial infection or a superinfection on primary viral illness
-the causative organisms are,
a. Staphylococcus aureus
b. Haemophilus influenza type B
c. Streptococcus pneumoniae
d. Branhamella catarrhalis

Clinical Presentation
a. fever & toxaemia
b. respiratory distress
c. similar to epiglottitis except for
- the presence of a cough
- a subjective difference in quality of the stridor

Diagnosis
i. CXR - may show tracheal membranes
- narrowing & "fuzziness" are variable
ii. ETT - absence of epiglotitis
- suction following intubation ® pus and membranes in the trachea

Management - similar to that for epiglottitis (see over)
- if intubation is required, the ETT may block acutely with secretions ® aggressive tracheal suction ± reintubation
- bronchoscopy to clear tracheal pus should be considered where the airway remains compromised after intubation, suction and reintubation
- initially, there may not be a leak around an appropriately sized endotracheal tube
- sputum should be sent for gram stain and culture, and urine for rapid antigen identification
- extubation is best performed when, the fever and secretions have settled, and a leak is present around the endotracheal tube
- initial antibiotic therapy ® cefotaxime ~ 50 mg/kg q6h for 10/7, then by MC&S

Epiglottitis: supraglottic, infective inflammatory lesion, caused almost exclusively by Haemophilus influenzae - type B ± occasionally streptococci, staphlococci, or pneumococci
a. acute onset - short history (hrs) with no preceding URTI
b. high fever & toxaemia
c. stridor - low pitched, inspiratory ± expiratory snore, usually constant in nature
d. absence of cough and reluctance to talk
e. characteristic posture - sitting forward,mouth open, drooling & dysphagia
f. diagnosis
- direct laryngoscopy
- urine latex antigen agglutination
- ~ 80% blood culture (+)'ve
- lateral XRay ® "thumb print"

Most commonly children from 2 to 7 years but the disease can involve adults and infants due to septicaemia. The severity of the illness is often out of proportion to the airway obstruction.Children less than 2 years of age may present with airway obstruction atypically accompanied by apnoea, URTI, low grade fever, and/or cough and sudden total obstruction may be precipitated by,
a. instrumentation of the pharynx
b. painful stimuli - eg. IV insertion
c. supine posture

Management
a. minimal disturbance - nurse in mothers arms, etc.
b. ready access to intubation equipment
c. oxygenation - mask or nasal cannulae, if obstructs ® CPAP/assist by bag
d. antibiotics
- cefotaxime ~ 50 mg/kg q6h ± chloramphenacol ~ 25 mg/kg q6h or
- ampicillin was used but high percentage of resistant strains
e. intubation - all but the mildest cases, average duration ~ 18 hours but may be required for longer in cases with,
- pulmonary oedema
- pneumonia
- cerebral hypoxia
f. racemic adrenaline is of no use in this condition and can precipitate obstruction

Epiglottitis - Intubation Indications
1. severe or progressive respiratory distress
2. prior to transportation to a tertiary centre
3. following diagnosis by direct laryngoscopy under GA

- Patients can be managed without intubation if they remain in an area where appropriate personnel, equipment and supervision is available. Such patients are generally older, co-operative and are seen early in the day with minimal signs of obstruction. Diagnosis in these cases is made by lateral neck XRay
- An IV line can be inserted before anaesthesia, but should be delayed until after induction when the patient is distressed or obstruction is severe in order to avoid sudden obstruction.
- In spontaneously breathing, inhalational GA is best tolerated in the sitting position.
- Agitation and distress at induction may be due to acute hypoxia.
- The patient can be laid flat on loss of awareness, and airway obstruction overcome by application of CPAP or assisted ventilation.
- Laryngospasm may be precipitated if laryngeal stimulation occurs prior to surgical anaesthesia being achieved.
- Copious and persistent pulmonary oedema fluid may obscure the larynx, making intubation difficult.
- An ETT of normal size for age or one size smaller should be inserted orally then changed to the nasal route once the child has settled
- Positive pressure should demonstrate a leak around the tube.
- The patient can be sedated ± restrained to prevent self-extubation.
- Muscle relaxants are not routinely required unless IPPV/PEEP is required to overcome hypoxia and hypoventilation from pulmonary oedema.

Complications
a. respiratory failure / obstruction
b. pulmonary oedema ~ 7-10% of cases and is precipitated by intubation
- hypoxia & SNS discharge - ­ PAP
- vascular - endothelial injury & capillary permeability
- decreased intrathoracic pressure after intubation, augmenting venous return, and increasing transmural pulmonary vascular hydrostatic pressure gradients
c. barotrauma
- pulmonary interstitial emphysema (PIE)
- pneumothorax
- pneumomediastinum
d. septicaemia / pneumonia

Extubation Criteria
a. when the fever has settled
b. signs of inflammation subside ® usually ~ 18 hours
- pain subsided
- able to swallow
- free movement of the larynx

NB: exceptions are where hypoxia and reduced lung compliance persist direct laryngoscopy prior to extubation is not required

Thanks to Dr Anuj Clerk for this wonderful article.