Tracheitis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Dushka Riaz, MD

Tracheitis is the bacterial infection of the trachea. It is also known as bacterial croup or acute laryngotracheobronchitis. It results in airway inflammation with mucosal edema, tracheal ulceration and thick membranous exudates. It is most commonly caused by a superimposed bacterial infection following a viral upper respiratory tract infection. Common bacterial pathogens include Staphylococcus Aureus, Haemophilus Influenza, Streptococcus Viridans and Moraxella Catarrhalis. It is a disease most commonly encountered in the pediatric age group, between 2-10 years of age. However, mechanical ventilation can also cause tracheitis as it allows colonization of the trachea through endotracheal tube. Clinical features include cough, hoarseness, stridor which can rapidly progress into respiratory distress within 36 to 72 hours. Acute airway obstruction can also develop due to rapid formation of tracheal exudates. Securing airway by endotracheal intubation is therefore crucial in management of tracheitis along with early initiation of empiric antibiotics. Rigid endoscopy is performed to remove thick membranous exudates, known to cause significant tracheal lumen obstruction. Complications of tracheitis include airway obstruction, acute respiratory distress syndrome, toxic shock syndrome, septic shock and multi organ failure. ^{[1] [2] [3] [4] [5]}

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dushka Riaz, MD

Tracheitis means inflammation of the trachea. It is a rare disease. Tracheitis appeared in medical history in 1920s. It was commonly named as acute laryngotracheobronchitis, non diphtherial laryngitis with marked exudates, bacterial croup, pseudomembranous croup, purulent tracheobronchitis and membranous laryngotracheobronchitis. It was not until 1979, when Jones et al reported case series on bacterial tracheitis in children. It was then recognized as an infectious disease of the trachea, involving bacteria either as a primary or as a secondary source of infection. ^{[1] [2]}

• Tracheitis is a rare disease.
• There is limited information about the historical perspective of tracheitis.
• In 1920, it first began to appear in literature. ^[3]
• It was initially known as acute laryngotracheobronchitis due to inflammation involving the trachea, larynx and bronchi.
• In 1979, Jones et al reported case series on this disease entity in children.^[4][5]
• After 1979, it was commonly referred to as Bacterial tracheitis in medical literature.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dushka Riaz, MD

Trachea connects larynx with the bronchi and conducts air to the lungs. The mucus membrane of trachea is lined by pseudostratified ciliated columnar epithelium. The goblet cells in the epithelium secrete mucus which captures inhaled pathogens. The cilia propagate the movement of the mucus towards the larynx and pharynx. Bronchial associated lymphoid tissue further augments the defensive system by providing humoral and cellular immunity. The tracheal mucosa therefore serves as a protective barrier to all inhaled pathogens. Tracheitis means inflammation of the trachea. . As tracheal inflammation occurs the mucosal edema significantly constricts the tracheal lumen. This increases the airflow due to Venturi effect. The decrease in luminal diameter generates negative pressure which increases the propensity for airway collapse. This causes turbulent airflow which can be heard as a stridor. Tracheal inflammation further reduces the luminal diameter which causes difficulty in breathing. Tracheitis is caused by a secondary bacterial inflammation which follows a prodromal viral illness. Viral pathogens include Influenza A and B, Parainfluenza, Respiratory Syncytial Virus, Adenovirus and Herpes Simplex Virus. Viruses enter the body through inhalation and damage the mucosal lining of the trachea. They induce local inflammation which impairs the host defenses making bacterial invasion more likely. Bacterial pathogens include Staphylococcus Aureus, Haemophilus Influenza, Moraxella Catarrhalis, Klebsiella Pneumonia. They infiltrate the epithelial lining causing mucosal edema, mucopurulent exudation and necrosis of the tracheal wall. A systemic inflammatory response develops due to cytokine release, causing septic shock. The exudates adhere to the tracheal wall causing narrowing of the tracheal lumen. The necrotic debris and purulent membranes can slough off into the trachea, causing acute obstruction. ^{[1] [2] [3]}

Trachea connects larynx with the bronchi and conducts air to the lungs. It is made of C shaped rings of cartilage. Muscles and fibers connect the tracheal rings together. This structural strength enables the trachea to withstand the variations in air pressure during each breathing cycle. The mucus membrane of trachea is lined by pseudostratified ciliated columnar epithelium. The goblet cells in the epithelium secrete mucus which captures inhaled pathogens. The cilia propagate the movement of the mucus towards the larynx and pharynx. It is either swallowed or expectorated as phlegm out of the body. Bronchial Associated Lymphoid tissue further augments the defensive system by providing humoral and cellular immunity. As tracheal inflammation occurs the mucosal edema significantly constricts the tracheal lumen. This increases the airflow due to Venturi effect. The decrease in luminal diameter generates negative pressure which increases the propensity for airway collapse.^[4] This causes turbulent airflow which can be heard as a stridor. Children have a narrower subglottic region compared to adults. Tracheal inflammation further reduces the luminal diameter which causes difficulty in breathing. Therefore, patients with tracheitis present with tachypnea, tachycardia, respiratory fatigue and stridor. ^{[5] [6] [7]}

• The tracheal mucosa serves as a protective barrier to all inhaled pathogens
• Tracheitis means inflammation of the trachea. The larynx and bronchi can also be involved in the inflammatory process, causing laryngotracheobronchitis.
• Viruses enter the body through inhalation and damage the mucosal lining of the trachea.
• Viral pathogens include Influenza A and B, Parainfluenza, Respiratory Syncytial Virus, Adenovirus and Herpes Simplex Virus.^[8]
• Viruses cause desquamation of the pseudostratified columnar epithelium.
• The epithelium regenerates into stratified non keratinized epithelium through metaplasia.^[9][4]
• As host defenses become weak, bacterial invasion becomes more likely.
• Bacterial pathogens include Staphylococcus Aureus, Hemophilus Influenza, Moraxella Catarrhalis, Klebsiella Pneumonia
• They infiltrate the epithelial lining causing mucosal edema, mucopurulent exudation and necrosis of the tracheal wall.
• A systemic inflammatory response develops due to cytokine release, causing septic shock.
• The exudates adhere to the tracheal wall causing narrowing of the tracheal lumen.
• The necrotic debris and purulent membranes can slough off into the trachea, causing acute obstruction.
• S. Aureus is the most common etiology. ^{[4] [10] [9]}

There is no known genetic cause.

There is usually a prior viral infection that causes airway mucosal damage that leads to the bacterial infection. ^{[11] [12] [13]}

On gross pathology, mucosal edema, ulceration, and exudates with thick membranes are characteristic findings of tracheitis. ^[14]

On microscopic histopathological analysis, microabscesses and mononuclear inflammatory cells in the tracheal wall are characteristic findings of tracheitis. Bacterial tracheitis is generally polymicrobial. ^{[15] [1]}

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dushka Riaz, MD

Bacterial tracheitis is most often caused by the bacteria Staphylococcus aureus. It frequently follows a recent viral upper respiratory infection. Common causes include Streptococcus Pyogenes, Haemophilus Influenza, Moraxella Catarrhalis, Mycoplasma Pneumonia, Echoviruses, Klebsiella Pneumonia, Adenovirus, Rhinovirus, Coxsakievirus and Influenza virus. ^[1]

Bacterial tracheitis is most often caused by the bacteria Staphylococcus aureus. It frequently follows a recent viral upper respiratory infection. Common causes include Staphylococcus Aureus, Streptococcus Pyogenes, Haemophilus Influenza, Moraxella Catarrhalis, Mycoplasma Pneumonia, Echoviruses, Klebsiella Pneumonia, Adenovirus, Rhinovirus, Coxsakievirus and Influenza virus. ^[2]

Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated. There are no life-threatening causes of tracheitis itself, however, complications resulting from untreated tracheitis can occur. Acute airway obstruction can occur due to rapidly developing exudates and thick membranes in the trachea which requires emergency intubation to maintain airway. ^[3]

Common causes of tracheitis may include: ^{[2] [3] [4]}

• Staphylococcus Aureus, this is the most common.
• Haemophilus Influenza
• Streptococcus Viridans
• Streptococcus Pyogenes
• Moraxella Catarrhalis
• Mycoplasma Pneumonia
• Parainfluenza 1
• Influenza A and B
• RSV
• Adenovirus
• Rhinovirus
• Coxsackievirus
• Paramyxovirus

Less common causes of tracheitis include: ^[5]

• Pseudomonas Aureginosa
• Acinetobacter baumannii,
• Klebsiella Pneumonia
• Escherichia coli
• Enterobacter cloacae
• Aspergillus
• Histoplasma
• Cryptococcus Neoformans

• There are no known genetic causes for tracheitis.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Prince Tano Djan, BSc, MBChB [2], Dushka Riaz, MD

Tracheitis means inflammation of the trachea. It presents with cough, fever and sore throat. Sudden deterioration can occur within few days due to superimposed bacterial infection. High fever, tachypnea, stridor and hoarseness develop. Differential diagnosis include viral croup, epiglottitis, pharyngitis, retropharyngeal abscess, diptheria, angioneurotic edema and subglottic stenosis. The table below explains the differentiation in detail.

Bacteria tracheitis must be differentiated from other causes of airway disease such as croup, epiglottitis, pharyngitis, tonsillitis, retropharyngeal abscess and subglottic stenosis.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dushka Riaz, MD

Tracheitis is a rare disease with incidence of 0.1 per 100,000 individuals worldwide. It is not associated with mortality now due to understanding of the disease process, immediate intubation of the airway and prompt use of antibiotics. It commonly affects children, median age reported as 5.2 years. Males are reported to have a higher incidence compared to females. There is no regional or racial predilection for the disease till date. ^[1]

• The incidence of tracheitis is approximately 0.1 per 100,000 individuals worldwide. ^[2][1]
• In North West of England the incidence was reported 0.09/100,000 children per year.
• In Victoria (Australia) the incidence was reported 0.08/100,000 children per year
• It is an uncommon disease with limited data available for reporting.
• The incidence rises more in the winter months because of virus epidemics such as influenza and RSV.

• Mortality rate was high when the disease was not well understood. It was reported to be 10% to 40%. ^[3] Now it is not associated with mortality likely due to the immediate use of antibiotics and mechanical ventilation. ^[4]

• Tracheitis commonly affects children younger than 10 years of age. The median age at diagnosis is 5.2 years. The peak incidence is between ages of 3 to 8. ^[5]

• There is no racial predilection to tracheitis.

• Males are more commonly affected by tracheitis than females. The male to female ratio is approximately 1.3 to 1. ^[1]

• Tracheitis is a rare disease. No regional association has been reported

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dushka Riaz, MD

Common risk factors in the development of tracheitis include pediatric age group, prior viral upper respiratory tract infection, mechanical ventilation and immunocompromised state. ^{[1] [2]}

The individuals most likely to be affected are between 2-10 years of age. Staphylococcus Aureus is the most commonly cultured organism on tracheal aspirate. Mechanical ventilation allows easy colonization of the trachea by bacteria and cause tracheitis. Invasive fungal infections commonly develop among immunocompromised individuals and can cause tracheitis. ^{[3] [4] [2] [5] [6]}

• Common risk factors in the development of tracheitis include:
  • Paediatric age group (because their airways are smaller)
  • Viral upper respiratory tract infection
  • Airway Intubation
  • Long term presence of tracheostomy

• Less common risk factors in the development of tracheitis include:
  • Immunocompromised state
  • Lack of immunization e.g Heamophilus Influenza B

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dushka Riaz, MD

Tracheitis is caused by inflammation of the trachea. Initial presentation is characterized by cough, fever, shortness of breath and hoarseness of voice. Thick exudates develop in the trachea which increase tracheal obstruction and can cause severe respiratory distress. Common complications of tracheitis include hypotension, acute renal failure, septic shock, acute respiratory distress syndrome, toxic shock syndrome and pulmonary edema. ^[1]

• The symptoms of tracheitis usually develop in the first and second decade of life, and start with symptoms such as cough, change in voice quality and difficulty in breathing.
• The symptoms of tracheitis typically develop after exposure to viruses e.g parainfluenza, rhinovirus, metapneumovirus, adenovirus. After the prodromal viral illness develops, superimposed bacterial infection can occur and cause even more severe disease.
• Mild upper respiratory tract symptoms predominate in the initial 3-7 days. As the secondary bacterial infection develops the symptoms worsen with marked respiratory distress and stridor. In some individuals, sudden deterioration can occur within 24-48 hours of initial presentation requiring airway intubation. ^[2]

Common complications of tracheitis include: ^[3]

• Airway obstruction — can lead to death
• Toxic shock syndrome — caused by the bacteria Staphylococcus Aureus
• Acute Respiratory Distress Syndrome
• Septic Shock^[4]
• Pulmonary Edema^[5]
• Acute Renal Failure
• Pneumonia^[6]
• Pneumothorax
• Pneumomediastinum
• Lobar atelectasis

With prompt treatment, the child should recover. Presentations and severity are less so in adults. ^[7]

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