Theory · 1. Acute tracheobronchitis and bronchitis;

Acute Tracheobronchitis

Definition

• Acute tracheobronchitis is inflammation of both the trachea and bronchi, often caused by viral infections.
• Cause: Tracheal inflammation typically occurs after upper respiratory viral infections that descend into the airways. The inflammation of the mucosa leads to bronchial irritation and pain when coughing.

Etiology

• Viruses (most common):
• Influenza, Parainfluenza, RSV, Adenovirus
• These viruses inflame both the upper (trachea) and lower (bronchi) airways, making both areas susceptible to coughing and pain. Tracheal irritation is the reason behind retrosternal chest pain.

• Bacteria (less common):
• Mycoplasma pneumoniae, Chlamydia pneumoniae
• These can cause secondary infections in already inflamed airways. They attach to the airway epithelium and compromise ciliary clearance, which leads to mucus accumulation and worsens symptoms.
• Irritants (pollution, smoke):

Symptoms

• Dry Cough (becoming productive):

• Initially, the cough is dry due to the inflammation of the mucosa, which triggers the cough reflex. As inflammation persists, the glands produce mucus leading to productive cough.
• Duration: symptoms usually last less than 10 days, but the cough may persist for up to 3 weeks, especially post-viral.
• Retrosternal Chest Pain:
• The trachea is richly innervated. When inflamed, it causes pain, particularly during coughing (which creates a mechanical pressure on the trachea).
• Low-Grade Fever & Malaise:
• These are systemic signs of the body’s immune response to viral infection. Fever occurs as a result of pyrogenic cytokines released during infection, while fatigue is due to systemic inflammation.
• Hoarseness:
• Laryngeal involvement can occur if the inflammation spreads upward toward the larynx, causing voice changes or hoarseness.
• Burning/Scratchy Chest Sensation:
• Caused by the direct irritation of the tracheal lining and the cough reflex.

Physical Examination

• Harsh Breath Sounds or Coarse Rhonchi:
• The trachea is inflamed, which can extend to the bronchi. Rhonchi are heard due to mucus in the bronchi and trachea, leading to obstruction.
• Retrosternal Tenderness:
• This is due to tracheal inflammation, which is often palpable in the lower part of the trachea and exacerbated by coughing.
• Wheezing:
• If the bronchial involvement leads to spasm or narrowing of the airways, wheezing may be present, especially if there is bronchospasm or mucus accumulation.

Lab Tests

• ↑ WBC, CRP, ESR:
• These markers indicate systemic inflammation. In bacterial causes, these would be more elevated than in viral infections. CRP is a reactive protein that increases with inflammation, and WBC count rises due to immune cell activation.

• Sputum Culture:
• Used to identify if bacteria are involved (rare), such as Mycoplasma pneumoniae or Chlamydia pneumoniae.