Occupational Pulmonary Fibrosis

Full Answer Section

• • Bronchoconstriction: Contraction of the smooth muscles surrounding the airways, leading to narrowing of the bronchial tubes. This is the primary cause of wheezing and shortness of breath.
  • Airway edema: the inflammation causes swelling of the airway tissue, which also narrows the airway.
  • Increased mucus production: The inflammatory process stimulates goblet cells to produce excessive mucus, which further obstructs the airways and contributes to coughing.
  • Airway hyperresponsiveness: The airways become overly sensitive to various triggers (e.g., allergens, irritants, exercise), leading to exaggerated bronchoconstriction.
• In this patient, the 3 week long cough, and the recent onset of shortness of breath, points to a prolonged inflammatory response.

2. Airway Obstruction and Air Trapping:

• The combination of bronchoconstriction, edema, and mucus plugging leads to significant airway obstruction.
• This obstruction causes air trapping in the lungs, especially during exhalation, resulting in pulmonary hyperinflation, which was observed on the chest X-ray.
• The reduced FEV1 (forced expiratory volume in 1 second) of 75% indicates significant airflow limitation, confirming the presence of airway obstruction.

3. Symptoms Explained:

• Wheezing: The whistling sound during breathing is caused by turbulent airflow through the narrowed airways.
• Nonproductive cough: The cough is often dry (nonproductive) because it's primarily triggered by airway irritation and inflammation, rather than excessive mucus production (though some mucus is produced).
• Shortness of breath (dyspnea): The difficulty breathing arises from the increased resistance to airflow and the increased work of breathing required to overcome the obstruction.
• Pulmonary hyperinflation: This is the lungs attempt to compensate for the air trapping, and to try to keep the alveoli open for gas exchange.

In summary:

The patient's symptoms and findings are consistent with an asthma exacerbation, driven by airway inflammation, hyperresponsiveness, and obstruction. The inflammatory process causes bronchoconstriction, mucus production, and airway edema, leading to wheezing, coughing, shortness of breath, and pulmonary hyperinflation. The reduction in FEV1 confirms the presence of significant airflow limitation.

Sample Answer

To explain the pathophysiologic mechanisms responsible for the patient's symptoms, we need to refer back to the patient profile you provided earlier:

• Patient: 16-year-old female
• Symptoms: Wheezing, nonproductive cough (lasting 3 weeks), shortness of breath (past 3 days)
• Findings: Pulmonary hyperinflation on chest X-ray, reduced FEV1 (75%)
• Diagnosis: Asthma exacerbation

Here's a breakdown of the pathophysiology:

1. Airway Inflammation and Hyperresponsiveness:

• Asthma is characterized by chronic inflammation of the airways. This inflammation involves various inflammatory cells (e.g., eosinophils, mast cells, lymphocytes) that release mediators (e.g., histamine, leukotrienes) that cause: