Bacterial Tracheitis

Bacterial tracheitis is a severe, potentially life threatening bacterial infection of the trachea, most commonly caused by Staphylococcus aureus. It occurs predominantly in young children, either as a primary infection or, more often, as a bacterial superinfection complicating a viral illness (classically viral croup).

Severe, purulent, exudative tracheal inflammation produces thick, adherent mucopurulent membranes and debris. These can cause significant, sometimes critical, upper airway obstruction that may progress rapidly.

The condition overlaps clinically with viral croup and epiglottitis, but management differs, so careful distinction is required. Methicillin resistant strains are an important consideration for empirical antibiotic selection.

Pathophysiology

• Secondary bacterial invasion of the tracheal mucosa, usually after viral tracheitis or laryngotracheobronchitis (viral croup), causes severe exudative inflammation. Tracheal epithelium sloughs, and thick, adherent mucopurulent membranes and debris form within the lumen.
• Mucosal oedema plus luminal debris can produce critical, rapidly progressive airway obstruction. This is the key distinguishing feature from simple viral croup, where obstruction reflects predominantly subglottic mucosal oedema without a purulent membrane and debris component.
• Staphylococcus aureus is the commonest identified organism. Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae are further recognised causes.
• The organism profile overlaps with that of epiglottitis, but bacterial tracheitis involves the tracheal mucosa rather than the supraglottic structures characteristically affected in epiglottitis.

• A biphasic pattern is frequently, though not universally, seen. An initial period consistent with uncomplicated viral croup or upper respiratory tract infection is followed by abrupt, marked deterioration with high fever, toxic appearance and rapidly progressive respiratory distress. This pattern should raise suspicion of bacterial superinfection.
• Compared with viral croup, children with bacterial tracheitis appear significantly more unwell and toxic, with high fever. They are generally able to lie flat and tolerate supine examination, in contrast to the tripod positioning and refusal to lie flat classically associated with epiglottitis.
• A harsh, brassy cough is typical. As the condition progresses, stridor and respiratory distress increase, reflecting progressive luminal obstruction from mucopurulent debris and membrane formation.
• Viral croup generally shows some response to corticosteroids and nebulised adrenaline. Bacterial tracheitis characteristically shows poor or absent response to these measures. A child with apparent croup who fails to respond as expected should prompt reconsideration of the diagnosis and targeted intervention.
• Progressive respiratory distress, with potential for rapid deterioration and complete airway obstruction if the diagnosis is not promptly recognised and treated, is the most serious, life threatening complication.

• Diagnosis is predominantly clinical. The key combination is toxic appearance, high fever and poor response to croup treatment in a child with an apparent croup-like picture. A high index of suspicion is essential because of the potential for rapid, critical deterioration.
• Direct laryngoscopy and bronchoscopy provide definitive confirmation through direct visualisation of purulent tracheal exudate and membrane formation. They also allow therapeutic removal of the obstructing material and collection of microbiological samples to guide targeted antibiotic therapy.
• The procedure carries significant airway risk, so it is generally performed under controlled, appropriately prepared conditions in an operating theatre or equivalent setting.
• Plain neck radiography, where obtained, may show subglottic narrowing similar to croup and, in some cases, irregular tracheal wall contour or visible intraluminal membrane or debris. Findings can be non-specific and should never delay airway assessment and management in a child with significant, progressive respiratory distress.
• Blood cultures and, where obtained at laryngoscopy and bronchoscopy, direct tracheal culture confirm the causative organism. Results guide targeted narrowing of the initial empirical antibiotic therapy.

• Urgent, senior-led airway assessment and management is the essential, immediate priority, given the potentially rapidly progressive airway risk. It generally involves close collaboration between anaesthesia, otolaryngology and paediatric intensive care specialists.
• Keep a low threshold for controlled intubation, given the risk of sudden, critical deterioration. Intubation is generally performed in an operating theatre with full airway rescue capability immediately available, because it is recognised to be difficult in the presence of significant tracheal debris and membrane formation.
• Direct laryngoscopy and bronchoscopy under controlled conditions allow definitive diagnostic confirmation and therapeutic removal of the obstructing purulent membrane and debris. This is a central component of management, because the material directly and mechanically contributes to obstruction, unlike the predominantly mucosal oedema based obstruction of simple viral croup.
• Start empirical broad spectrum intravenous antibiotics promptly, covering Staphylococcus aureus and the other relevant organisms. Where methicillin resistant strains are locally prevalent, consider vancomycin or clindamycin according to local resistance patterns. Narrow therapy once culture results are available. Treatment typically extends to ten to fourteen days according to clinical response.
• Close intensive care monitoring and support are essential throughout acute management, with full supportive care. Once the airway is secured, manage it carefully, with repeated bronchoscopic reassessment and, where required, further removal of reaccumulating debris or membrane.
• Consider extubation once there is clear, objective evidence of clinical improvement and bronchoscopic confirmation that tracheal inflammation and debris have resolved. Plan extubation carefully in stages and monitor closely for recurrent respiratory distress, because residual airway inflammation and oedema may persist despite apparent improvement.
• Prompt recognition of the features distinguishing bacterial tracheitis from simple viral croup, with immediate escalation to senior specialist airway support when the diagnosis is suspected, is the single most important element of safe management of this uncommon but potentially life threatening condition.