Epiglottitis

Acute inflammation of the epiglottis and adjacent supraglottic structures, that is the aryepiglottic folds, arytenoids, false cords and vallecula. Supraglottitis is the more accurate term, since the inflammation is rarely confined to the epiglottis. It is an airway emergency in which death results from sudden complete obstruction.

Epidemiological shift

Before routine Haemophilus influenzae type b conjugate vaccination, this was predominantly a disease of children aged 2 to 7 years with an incidence of around 5 per 100000 children. Vaccination reduced paediatric incidence by more than 95 percent, and the disease is now predominantly one of adults, with an incidence of 1 to 4 per 100000 adults which has been rising. The consequence is that adult supraglottitis is now the presentation clinicians encounter, and it is less often recognised because it does not fit the paediatric picture taught traditionally.

Why the adult presentation differs

The adult supraglottic airway is larger, so obstruction develops more slowly and the classical paediatric picture of a toxic drooling child in a tripod position is often absent. The adult presents with severe sore throat and odynophagia with an unremarkable oropharynx, and the disparity between the severity of the symptoms and the paucity of visible findings is the diagnostic clue. Adults nevertheless obstruct, and around 10 to 20 percent require airway intervention.

Microbiology

• Haemophilus influenzae type b, which remains the commonest organism in unvaccinated children and still occurs in adults.
• Non typeable Haemophilus influenzae and other Haemophilus species.
• Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus including methicillin resistant strains, Moraxella, Klebsiella and Pseudomonas.
• Viral: herpes simplex, parainfluenza, varicella zoster, Epstein Barr virus.
• Candida in the immunocompromised.
• Non infective causes: thermal injury from inhaled steam, hot food or crack cocaine; caustic ingestion; foreign body; angioedema, both hereditary and angiotensin converting enzyme inhibitor induced; post radiotherapy oedema; and trauma.

Risk factors in adults: diabetes, immunosuppression, HIV, hypertension, smoking, and previous head and neck radiotherapy.

The four Ds of severe disease: dysphagia, dysphonia, drooling and distress.

In children

• Rapid onset over hours, with high fever and toxicity.
• Severe sore throat and refusal to eat or drink.
• Drooling, from inability and unwillingness to swallow saliva.
• Muffled hot potato voice rather than hoarseness, since the supraglottis rather than the vocal folds is swollen.
• Absence of a barking cough, which distinguishes it from croup.
• Tripod or sniffing position: sitting upright, leaning forward on outstretched arms with the neck extended and the chin thrust forward. A child who will not lie down has an airway problem.
• Stridor, which is a late sign indicating critical narrowing. Its absence is not reassuring, and its appearance is an emergency.
• Anxiety, restlessness and a still, quiet demeanour with minimal movement.
• Cyanosis, exhaustion, reduced consciousness and bradycardia, which are preterminal.

In adults

• Severe sore throat and odynophagia, often described as the worst sore throat ever experienced.
• Odynophagia disproportionate to the appearance of the oropharynx, which is the key diagnostic feature.
• Muffled voice.
• Anterior neck tenderness over the hyoid and thyrohyoid membrane, which is a useful and simple bedside sign.
• Fever, though a proportion are afebrile.
• Dysphagia and drooling in more advanced disease.
• Stridor and respiratory distress in a minority, indicating imminent obstruction.

The diagnosis is made by direct visualisation of the supraglottis, but the manner and setting of that examination is itself a critical clinical decision.

In children

• Do not examine the oropharynx with a tongue depressor, do not attempt cannulation, do not take blood, do not lie the child down, and do not send the child unaccompanied for imaging. Any of these can precipitate complete obstruction through laryngospasm in a critically narrowed airway.
• Keep the child upright, calm and with a parent. Give humidified oxygen if tolerated without distress.
• Summon senior anaesthetic, otolaryngology and paediatric intensive care support immediately.
• The airway is examined and secured in theatre under inhalational induction with maintained spontaneous ventilation, with a rigid bronchoscope and tracheostomy set open and the surgeon scrubbed.
• Lateral soft tissue neck radiography showing the thumb sign of a swollen epiglottis and thickened aryepiglottic folds is supportive but has a false negative rate of around 20 percent, requires the child to leave a safe area, and should not be obtained where suspicion is high. If it is obtained, the child must be accompanied by someone able to manage the airway.

In adults

• Flexible nasolaryngoscopy performed carefully by an experienced operator in a setting with airway support available is the diagnostic test and is safe in the cooperative adult. Perform it with the patient sitting upright, with minimal topical anaesthesia to avoid impairing the airway reflexes.
• Findings: a swollen erythematous epiglottis described as cherry red or, in more advanced disease, pale and oedematous, with swollen aryepiglottic folds and arytenoids, and a narrowed supraglottic inlet. Assess the size of the residual airway.
• Full blood count showing neutrophilia, C reactive protein, blood cultures which are positive in 10 to 25 percent, and glucose.
• Culture of the supraglottic surface at intubation.
• Contrast enhanced computed tomography of the neck only once the airway is secure or clearly safe, to identify an epiglottic abscess or deep neck space collection requiring drainage. Never send an unstable patient to a scanner.

Differential diagnosis

• Croup: age 6 months to 3 years, barking cough, inspiratory stridor, coryzal prodrome over days, and a child who is generally less toxic and who has hoarseness rather than a muffled voice.
• Bacterial tracheitis: brassy cough with high fever and thick purulent secretions, and a toxic child who does not respond to nebulised adrenaline.
• Retropharyngeal abscess: neck stiffness, torticollis, preference for lying supine with the neck extended, and posterior pharyngeal wall bulging.
• Peritonsillar abscess: trismus, uvular deviation.
• Inhaled foreign body: sudden onset with a choking episode.
• Angioedema: lip, tongue and facial swelling, urticaria in allergic types, an angiotensin converting enzyme inhibitor history, or a family history in hereditary angioedema, and the absence of fever.
• Diphtheria: an adherent grey membrane, bull neck, and systemic toxicity, in an unvaccinated patient.
• Infectious mononucleosis with airway obstruction.
• Anaphylaxis.

Airway first, always. Everything else follows.

Airway management

• Assess urgency: stridor at rest, drooling, inability to lie flat, use of accessory muscles, exhaustion, cyanosis and reduced consciousness all indicate imminent obstruction.
• Assemble the team before intervening: the most experienced anaesthetist available, an otolaryngologist, and in children a paediatric intensivist.
• Keep the patient upright and calm. Do not administer sedation outside a fully prepared environment.
• Humidified oxygen.
• Nebulised adrenaline 1 mg/kg of 1 in 1000 solution to a maximum of 5 mL in children, or 5 mL of 1 in 1000 in adults, as a temporising measure that buys time but does not treat the disease and whose effect wanes within 2 hours, with the possibility of rebound.
• Intravenous dexamethasone 0.6 mg/kg in children to a maximum of 10 mg, or 8 to 10 mg in adults, repeated 8 hourly. Evidence of benefit is limited but it is widely used to reduce supraglottic oedema.
• Heliox, that is a helium oxygen mixture, reduces turbulent flow resistance and may improve gas flow through a narrowed airway as a bridge to definitive management.

Securing the airway

• Children: intubate in theatre with inhalational induction using sevoflurane in oxygen, maintaining spontaneous ventilation, with the surgeon scrubbed and prepared for rigid bronchoscopy and tracheostomy. Use a tube one to two sizes smaller than predicted. Avoid muscle relaxants until the airway is secured, since loss of spontaneous ventilation in a critically narrowed airway that then cannot be intubated is catastrophic.
• Adults: awake fibreoptic intubation is often the preferred technique in a cooperative patient, or inhalational induction with a prepared surgical airway. Tracheostomy or cricothyroidotomy under local anaesthesia is the fallback and must be planned and prepared, not improvised.
• The single most dangerous action in this condition is administering a muscle relaxant or sedative to a patient with supraglottic obstruction outside a prepared environment.
• Not every adult requires intubation. Around 80 percent are managed with close observation in a high dependency setting with antibiotics and steroids, with a clearly documented escalation plan and immediate access to airway expertise. Observation is only safe where that access genuinely exists at all hours.

Antibiotics

• Intravenous therapy immediately after the airway is addressed.
• Ceftriaxone 2 g every 12 to 24 hours in adults, or 50 mg/kg every 12 to 24 hours in children, or cefotaxime 2 g every 8 hours in adults or 50 mg/kg every 8 hours in children. These cover Haemophilus influenzae and pneumococcus.
• Add vancomycin with a target trough of 15 to 20 mg/L, or clindamycin, where methicillin resistant Staphylococcus aureus is prevalent or suspected.
• Add metronidazole where an abscess or anaerobic infection is suspected.
• Duration 7 to 10 days, converting to oral therapy such as co amoxiclav once improving.
• Antifungal therapy in immunocompromised patients with candidal supraglottitis.

Supportive care

• Intravenous fluids.
• Analgesia.
• Nurse in a high dependency or intensive care setting.
• Sedation and appropriate ventilation for the intubated patient.
• Extubation is generally possible at 24 to 72 hours, guided by resolution of oedema on direct inspection and by an audible leak around the tube. Direct laryngoscopy before extubation to confirm resolution is good practice.

Epiglottic abscess

Occurs in a minority and is suspected where there is failure to improve within 48 hours. It requires contrast imaging and needle aspiration or incision and drainage under controlled airway conditions.

Complications

• Complete airway obstruction and hypoxic brain injury or death, which is the outcome that all of the above is designed to prevent.
• Epiglottic abscess.
• Deep neck space infection, mediastinitis and necrotising fasciitis.
• Pneumonia, meningitis, septic arthritis and pericarditis from haematogenous spread of Haemophilus influenzae type b.
• Sepsis.
• Complications of intubation including subglottic stenosis.
• Negative pressure pulmonary oedema after relief of obstruction.

Prevention and public health

• Haemophilus influenzae type b conjugate vaccination, which is the reason this disease has largely disappeared in children in vaccinated populations.
• In confirmed Haemophilus influenzae type b disease, rifampicin prophylaxis for household contacts where there is an unvaccinated or incompletely vaccinated child under 4 years, or an immunocompromised child of any age: rifampicin 20 mg/kg once daily to a maximum of 600 mg for 4 days. Notify public health.
• Vaccinate the index case after recovery, since natural infection does not confer reliable immunity in young children.

Follow up

Review after discharge with laryngoscopy to confirm resolution, particularly where intubation was prolonged, and assess for subglottic or supraglottic stenosis. Screen adults for diabetes and immunodeficiency, since these are common and frequently first identified in this setting.