Definitions

OBSTRUCTIVE VERSUS RESTRICTIVE LUNG DISEASE

Pulmonary function tests (PFTs) place patients in 1 of 3 categories--normal lung function, obstructive disease, or restrictive disease--to help guide treatment and management.

Obstructive lung disease: Patients have decreased airflow (decreased FEV1/FVC ratio) and usually have normal or above-normal lung volumes. COPD (emphysema, chronic bronchitis, asthma, cystic fibrosis, and bronchiectasis) encompasses this category.

Restrictive lung disease: Patients have decreased lung volumes or TLC (total lung capacity) with normal airflow (normal FEV1/FVC ratio but with reduced values for both FVC and FEV1 individually). There are five primary types:

  • Pleural--diseases of the pleura that restrict lung expansion and decrease lung volumes (eg, pleural effusions or pleural thickening).
  • Alveolar--diseases of alveolar spaces that prevent air from filling those same spaces (eg, pneumonia, cancer, and pulmonary edema).
  • Interstitial--various diseases contracting the space in the lung parenchyma between the alveoli (interstitium), reducing lung volumes (eg, sarcoidosis, pulmonary fibrosis, silicosis, and pneumoconiosis).
  • Neuromuscular--Normal lung parenchyma with an inability to take a deep breath (eg, diaphragmatic paralysis, Guillain-BarrŽ syndrome, myasthenia gravis, and amyotrophic lateral sclerosis).
  • Thoracic cage--Skeletal abnormalities with normal lungs (eg, kyphoscoliosis, obesity).

Tuberculosis: Pulmonary tuberculosis is a contagious bacterial infection caused by Mycobacterium tuberculosis (TB). The lungs are primarily involved, but the infection can spread to other organs.

Cough: Coughing is an important way to keep your throat and airways clear. However, excessive coughing may mean you have an underlying disease or disorder.

Some coughs are dry, while others are productive. A productive cough is one that brings up phlegm (also called sputum or mucus). Coughs can be either acute or chronic:

  • Acute coughs usually begin suddenly. They are often due to a cold, flu, or sinus infection. Typically, they do not last longer than two to three weeks.
  • Chronic coughs last longer than two to three weeks.
 

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