Viral Croup

Also known as: Croup, Laryngotracheobronchitis

Acute laryngotracheobronchitis, an inflammatory narrowing of the subglottis producing the characteristic barking cough and inspiratory stridor. It is the commonest cause of acute upper airway obstruction in children.

Why the subglottis

The subglottis is the narrowest part of the paediatric airway and is the only part completely encircled by rigid cartilage, that is the cricoid ring, so mucosal oedema cannot expand outward and instead encroaches directly on the lumen. In a 1 year old the subglottic diameter is around 5 mm.

Poiseuille law dictates that resistance to laminar flow is inversely proportional to the fourth power of the radius, so 1 mm of circumferential oedema reduces the cross sectional area by around 60 percent and increases resistance approximately 16 fold. This is why a small amount of oedema produces dramatic obstruction in a young child and none at all in an adult, and it is the single physiological fact that explains the entire disease.

Epidemiology and aetiology

Peak age 6 months to 3 years, with a peak at 18 to 24 months.
Male predominance of around 1.5 to 1.
Autumn and early winter seasonality.
Parainfluenza virus types 1, 2 and 3, causing around 75 percent, with type 1 the commonest.
Influenza A and B, which cause more severe disease.
Respiratory syncytial virus, adenovirus, rhinovirus, human metapneumovirus, coronavirus and SARS-CoV-2.
Measles in unvaccinated populations, which causes severe croup.

Variants

Spasmodic or recurrent croup: sudden nocturnal onset without a viral prodrome or fever, resolving rapidly, recurring, and associated with atopy and reflux. It is thought to have an allergic or hyperreactive rather than a purely infective basis.
Bacterial tracheitis, that is bacterial laryngotracheobronchitis, in which a viral croup is complicated by bacterial superinfection with Staphylococcus aureus, Streptococcus pyogenes, Moraxella or Haemophilus, producing thick purulent membranous secretions, high fever, a toxic child and a poor response to adrenaline. It is a distinct and dangerous entity requiring intubation in a high proportion.

Westley croup score, used to grade severity and guide management:

Level of consciousness: normal 0, disoriented 5.
Cyanosis: none 0, with agitation 4, at rest 5.
Stridor: none 0, with agitation 1, at rest 2.
Air entry: normal 0, decreased 1, markedly decreased 2.
Retractions: none 0, mild 1, moderate 2, severe 3.

Total score: 0 to 2 mild, 3 to 5 moderate, 6 to 11 severe, 12 or above impending respiratory failure.

Coryzal prodrome of 12 to 72 hours with low grade fever, rhinorrhoea and mild cough.
Barking, seal like cough, which is the characteristic feature.
Inspiratory stridor, initially only with agitation, then at rest as obstruction worsens.
Hoarseness, since the vocal folds are involved.
Symptoms characteristically worse at night and worse with crying and agitation.
Low grade fever, usually below 38.5 degrees Celsius.
Duration of 3 to 7 days with peak severity on days 2 to 3.

Assessment of severity

Mild: barking cough, no stridor at rest, no or mild retractions, the child is playful and feeding.
Moderate: stridor at rest, visible retractions, but no agitation and no significant distress.
Severe: stridor at rest, marked retractions with tracheal tug and sternal recession, agitation, distress, tachycardia, tachypnoea.
Impending respiratory failure: fatigue, decreasing stridor which paradoxically indicates reducing air movement rather than improvement, decreased air entry, cyanosis, drowsiness, and a falling respiratory rate. A quiet chest in a tiring child with croup is a preterminal sign and is the finding most often misread as improvement.

Red flags indicating a different diagnosis

Drooling, absence of cough and a toxic appearance, indicating epiglottitis.
High fever with a toxic child and poor response to adrenaline, indicating bacterial tracheitis.
Sudden onset without a prodrome in a child who was previously well, particularly with a witnessed choking episode, indicating an inhaled foreign body.
Neck stiffness, torticollis and refusal to move the neck, indicating retropharyngeal abscess.
Age under 6 months or over 6 years, in which croup is less likely and a structural cause should be considered.
Recurrent croup, particularly more than twice, which requires airway endoscopy to exclude subglottic stenosis, subglottic haemangioma, a laryngeal cleft, papillomatosis or a vascular ring.
Persistent stridor between episodes.
Failure to respond to standard treatment.
Facial or lip swelling and urticaria, indicating anaphylaxis or angioedema.

Clinical. Investigations are unnecessary in typical croup and risk distressing the child, which worsens obstruction.

Do not examine the throat with a tongue depressor in a child with stridor, and do not perform painful procedures such as cannulation or venepuncture unless the airway has been secured or the child is clearly stable, since agitation precipitates deterioration.
Pulse oximetry, which is normal until late and which therefore provides false reassurance. Hypoxia in croup is a late sign.
Anteroposterior neck radiography may show the steeple sign of subglottic narrowing, but it is neither sensitive nor specific, adds nothing to management in typical croup, and requires the child to leave a safe area. Reserve it for atypical presentations where a foreign body or another structural cause is suspected, and only in a stable child.
Lateral neck radiography where epiglottitis or a retropharyngeal collection is considered, with the same caveats.
Viral polymerase chain reaction on a nasopharyngeal swab where the result affects infection control or cohorting.
Full blood count, blood cultures and inflammatory markers where bacterial tracheitis or an alternative diagnosis is suspected.
Direct laryngotracheobronchoscopy under general anaesthesia for recurrent croup, atypical presentation, failure to respond, suspected foreign body, or suspected structural airway abnormality. This is both diagnostic and therapeutic.

General principles

Keep the child calm and with the parent. Agitation increases turbulent flow and worsens obstruction, and the single most useful intervention early on is to leave the child undisturbed on the parent's lap.
Avoid unnecessary examination, cannulation and separation from the parent.
Position the child as they are comfortable, which is usually sitting upright.
Humidified air and steam, despite being traditional, have no demonstrated benefit in controlled trials and carry a scald risk. They should not be relied upon.
Oxygen only where there is hypoxia, delivered in the least distressing way, such as blow by oxygen held by the parent.

Corticosteroids, which are given to every child with croup regardless of severity

Dexamethasone 0.15 mg/kg orally as a single dose, which is as effective as 0.6 mg/kg and is the dose increasingly used. The traditional 0.6 mg/kg dose, to a maximum of 16 mg, remains widely used and is appropriate for severe disease.
Onset of clinical benefit within 30 minutes to 2 hours, with the effect lasting 24 to 48 hours given the long half life. A single dose is therefore usually sufficient.
Oral administration is as effective as intramuscular or intravenous, and is far less distressing. Use the oral route unless the child cannot tolerate it.
Prednisolone 1 to 2 mg/kg is an alternative but has a shorter duration and higher rates of representation, so a second dose the following day is often needed. Dexamethasone is preferred.
Nebulised budesonide 2 mg is an alternative where oral administration is impossible, such as in persistent vomiting, and is equally effective but considerably more expensive and requires a mask that may distress the child.
Corticosteroids reduce symptom severity, hospital admission, length of stay, the need for adrenaline and the rate of return visits. Even mild croup benefits, which is why treatment is universal.

Nebulised adrenaline, for moderate to severe croup

Nebulised adrenaline 1 in 1000 solution at 0.5 mL/kg to a maximum of 5 mL, or 5 mL of 1 in 1000 undiluted in most protocols. Racemic adrenaline 2.25 percent at 0.05 mL/kg to a maximum of 0.5 mL, diluted in saline, is used where available and is equivalent in effect.
Acts through alpha adrenergic vasoconstriction of the subglottic mucosa, reducing oedema.
Onset within 10 to 30 minutes, with peak effect at 30 minutes and duration of around 2 hours.
The effect wanes, and the child may return to the pretreatment state. This is a return to baseline rather than true rebound, but the practical consequence is the same: any child who receives nebulised adrenaline must be observed for at least 2 to 4 hours afterwards before discharge is considered, and must have received a corticosteroid.
May be repeated as required. A child requiring repeated doses at short intervals requires admission to a high dependency setting.

Heliox

A helium oxygen mixture reduces the density of the inspired gas, converting turbulent to laminar flow through a narrowed segment and reducing the work of breathing. It is a temporising measure in severe croup while corticosteroids take effect, and it is limited by the fact that it cannot deliver a high inspired oxygen fraction.

Antibiotics

Not indicated in viral croup. Reserve for bacterial tracheitis and for documented secondary bacterial infection.

Bacterial tracheitis

Suspect in a child with croup like features who is toxic, has a high fever, and responds poorly to nebulised adrenaline.
Admit to intensive care. Intubation is required in a high proportion, both to secure the airway and to permit removal of the thick purulent membranous secretions, which obstruct the tube and require repeated suction and sometimes rigid bronchoscopic clearance.
Intravenous ceftriaxone 50 mg/kg every 12 to 24 hours plus flucloxacillin 25 mg/kg every 6 hours, or vancomycin where methicillin resistant Staphylococcus aureus is a concern, adjusted to culture.
Rigid bronchoscopy for diagnosis, culture and clearance of membranes.

Indications for admission

Moderate or severe croup, or a Westley score of 3 or above.
Stridor at rest persisting after treatment.
Requirement for nebulised adrenaline, with observation of 2 to 4 hours minimum before considering discharge.
Hypoxia.
Poor oral intake or dehydration.
Age under 6 months.
Significant comorbidity: prematurity, chronic lung disease, congenital heart disease, neuromuscular disease, Down syndrome, or a known airway abnormality.
Toxic appearance or diagnostic uncertainty.
Social factors, distance from hospital, or parental inability to return, which are legitimate and frequently decisive.
Represented after an earlier assessment in the same illness.

Intubation

Required in around 1 percent of hospitalised children. Perform in theatre or intensive care by the most experienced operator available, using a tube 0.5 to 1 mm smaller than predicted for age to avoid further subglottic trauma. Extubation is guided by the development of an audible leak around the tube, usually at 2 to 5 days. Prolonged intubation and the use of an oversized tube are the principal causes of acquired subglottic stenosis, which is why tube size selection matters.

Discharge and safety netting

Discharge when there is no stridor at rest, normal oxygen saturation, adequate oral intake, and a period of observation after any adrenaline.
Explain the natural course: symptoms are worse at night and typically last 3 to 7 days.
Advise return immediately for stridor at rest, difficulty breathing, chest recession, drooling, poor colour, unusual drowsiness or reduced fluid intake.
Advise against steam inhalation over hot water, given scald injuries.
No antibiotics are needed and this should be stated explicitly, since parents commonly expect them.

Recurrent croup

More than two episodes, or croup outside the usual age range, requires flexible and rigid airway endoscopy to exclude subglottic stenosis, subglottic haemangioma, a laryngeal cleft, recurrent respiratory papillomatosis, a vascular ring or tracheomalacia. Assess for reflux and atopy, which are associated with spasmodic croup.

Clinical toolsCalculators

BMI GCS EDD Parkland Formula

Corrected Sodium Corrected Calcium Anion Gap Creatinine Clearance Insulin Calculations qSOFA Wells PE Wells DVT CHA₂DS₂-VASc HAS-BLED CURB-65 Centor/McIsaac

Nasal Fracture

The commonest facial fracture, involving the nasal bones, the frontal processes of the maxilla, and frequently the septum. The nasal bones are thin, prominent and unsupported, and fracture with relatively low force.

Mechanism and resulting pattern

Lateral impact, which is the commonest, produces depression of the ipsilateral nasal bone with outward displacement of the contralateral bone, giving a deviated dorsum.
Frontal impact produces flattening and splaying of both nasal bones with telescoping, and frequently a comminuted septal fracture.
Higher energy frontal impact produces nasoethmoidal fracture with telecanthus, which is a different injury requiring different management.

Septal involvement, which determines outcome

The septum is fractured in a large proportion of nasal fractures and is the single most important determinant of long term functional and cosmetic outcome. Two classical patterns occur:

Chevallet fracture: a vertical fracture of the quadrangular cartilage from the dorsum to the maxillary crest, from a frontal blow.
Jarjavay fracture: an oblique fracture running from the anteroinferior septum backward, from a lateral blow.

Failure to recognise and correct septal deformity is the commonest reason for persistent obstruction and deviation after nasal fracture reduction, and is the reason so many patients require later septorhinoplasty.

Injuries that must be excluded before attending to the nose

Septal haematoma, which requires immediate drainage.
Cerebrospinal fluid rhinorrhoea, indicating cribriform plate or skull base fracture.
Nasoethmoidal fracture with telecanthus and medial canthal tendon disruption.
Orbital fracture with entrapment.
Cervical spine injury and significant head injury.
Other facial fractures, particularly Le Fort patterns.

Timing, which governs everything

Assess at presentation for haematoma and other injuries.
Reassess at 5 to 7 days in adults, and 3 to 5 days in children, once oedema has settled, to determine whether reduction is needed.
Reduce within 10 to 14 days in adults and 7 to 10 days in children, before fibrous union occurs. After 3 weeks, closed reduction is no longer feasible and formal septorhinoplasty is required, deferred by 3 to 6 months.

Epistaxis at the time of injury, usually self limiting.
Pain, tenderness and swelling.
Visible deformity, which is frequently obscured by oedema in the first days.
Nasal obstruction, which may be from oedema, clot, septal deviation or septal haematoma.
Crepitus and mobility of the nasal bones.
Periorbital ecchymosis and subconjunctival haemorrhage.
Anosmia, which may indicate cribriform plate injury with olfactory nerve shearing.

Examination

Inspect from the front, the side and from above looking down over the brow, which is the best view for detecting dorsal deviation.
Compare with pre injury photographs, which is essential, since many patients have pre existing deviation and will otherwise expect an outcome that never existed.
Palpate for step, mobility, crepitus and tenderness.
Anterior rhinoscopy after suctioning clot and after decongestion, examining the septum specifically for haematoma, deviation, dislocation from the maxillary crest, and mucosal laceration. This step is not optional.
Assess for clear rhinorrhoea, particularly increasing on leaning forward, and for the halo or double ring sign on a tissue.
Measure the intercanthal distance. Normal is approximately 30 to 32 mm in adults, or roughly half the interpupillary distance. Telecanthus above 35 mm indicates a nasoethmoidal fracture.
Bimanual examination of the medial canthal tendon, palpating the tendon while pulling laterally on the eyelid, to detect avulsion.
Assess eye movements, acuity, diplopia and pupils.
Assess the dentition, occlusion and facial buttresses.
Full neurological and cervical spine assessment where indicated by the mechanism.

Nasal fracture is a clinical diagnosis. Plain radiography of the nasal bones has poor sensitivity and specificity, does not change management, and should not be requested. Old fracture lines and normal suture lines produce false positives, and undisplaced fractures produce false negatives.
Computed tomography of the facial bones is indicated for suspected nasoethmoidal, orbital, zygomatic or Le Fort fractures, for suspected skull base injury, for significant head injury, and when the examination is limited by swelling in a high energy mechanism.
Beta 2 transferrin or beta trace protein testing of nasal fluid where cerebrospinal fluid leak is suspected. Glucose testing of nasal fluid is unreliable and should not be used.
Photographic documentation at presentation and at review, which is valuable both clinically and medicolegally.
Consider a coagulation screen where bleeding is disproportionate.
In children, consider non accidental injury and follow safeguarding procedures where the history is inconsistent.

At presentation

Control epistaxis with first aid measures, topical vasoconstrictor and, where necessary, cautery or packing.
Drain any septal haematoma immediately, as an emergency, with a drain or quilting sutures and antibiotic cover.
Analgesia with paracetamol 1 g every 6 hours and a nonsteroidal anti inflammatory drug, avoiding the latter if bleeding continues.
Ice packs for the first 24 to 48 hours and head elevation to reduce swelling.
Advise against nose blowing, which risks surgical emphysema and, with a skull base fracture, pneumocephalus.
Tetanus prophylaxis where there is an open wound.
Antibiotics only for open fractures, contaminated wounds, or where packing is in place. Co amoxiclav 625 mg three times daily is appropriate.
Refer for review at 5 to 7 days for reassessment once swelling settles.
Give clear safety netting advice: return immediately for increasing nasal obstruction, pain or swelling, which indicates a developing septal haematoma, and for clear nasal discharge.

Reduction

Indications: a cosmetically or functionally significant displacement confirmed at the 5 to 7 day review.

Closed reduction under local anaesthesia with topical cocaine or lidocaine with adrenaline pledgets plus infiltration, or under general anaesthesia, which is required in children and preferred for comminuted fractures.
Use Walsham forceps for the nasal bones and Asch forceps for the septum. Digital pressure alone suffices for simple laterally displaced fractures.
Disimpact the fracture first by elevating the depressed side, then mould the dorsum.
Address the septum at the same sitting where it is deviated or dislocated. Reposition a caudal dislocation onto the maxillary crest. Where the septal fracture is significant, a limited septoplasty at the time of reduction improves outcomes and reduces the need for later revision, though some surgeons prefer to defer formal septoplasty.
Apply an external thermoplastic or plaster splint for 7 to 10 days, and internal silastic splints where the septum has been manipulated.
Warn the patient before the procedure that closed reduction produces a satisfactory result in around 60 to 90 percent, that some residual deviation is common, and that a proportion require later septorhinoplasty. This conversation before rather than after the procedure prevents most dissatisfaction.

Nasoethmoidal fracture

A different injury requiring open reduction and internal fixation with transnasal wiring or plating of the medial canthal tendon, performed by an appropriate facial trauma surgeon.
Delayed or inadequate treatment produces permanent telecanthus, a flattened nasal dorsum, epiphora from lacrimal obstruction, and a result that is very difficult to correct secondarily.
Assess and manage the lacrimal system.

Cerebrospinal fluid leak

Most traumatic leaks close spontaneously within 7 to 10 days with conservative management: bed rest with head elevation, avoidance of straining, nose blowing and Valsalva, and stool softeners.
Avoid nasal packing where a skull base fracture is present.
Prophylactic antibiotics for cerebrospinal fluid leak are not routinely recommended, since they do not reduce meningitis and select resistant organisms.
Pneumococcal vaccination is appropriate.
Persistent leak beyond 7 to 14 days requires localisation with high resolution computed tomography and magnetic resonance cisternography, and endoscopic repair with a multilayer technique and a vascularised nasoseptal flap where the defect is large.

Children

Reduce earlier, within 7 to 10 days, since bone heals faster.
Use general anaesthesia.
Drain any septal haematoma immediately, since cartilage necrosis in a growing nose produces progressive midface hypoplasia and severe deformity through adolescence.
Defer definitive septorhinoplasty until facial growth is complete, around 16 to 18 years, except where obstruction is severe.
Arrange long term follow up through the growth period.

Late presentation and revision

Fractures presenting after 3 weeks with fibrous union cannot be reduced closed. Defer for 3 to 6 months and perform formal septorhinoplasty with osteotomies, septal correction, and grafting as required.
Persistent obstruction after reduction requires assessment for septal deviation, nasal valve collapse and turbinate hypertrophy, each of which needs its own solution.
Persistent deformity requires septorhinoplasty, and it should be made clear that this is a reconstructive procedure with its own risks and a revision rate of its own.

Follow up

Review at 1 week after splint removal and again at 6 to 12 weeks with photographic comparison and assessment of nasal airflow. Document the outcome objectively with a validated obstruction score where symptoms persist.

Viral Croup

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management