The student will be able to describe the symptoms and signs of patients presenting with restrictive lung diseases.
The student will be able to define the pathophysiological mechanisms of specific restrictive lung diseases.
The student will be able to use clinical, physiological, and chest imaging data to differentiate patients with various forms of restrictive lung diseases.
The student will be able to provide a stepwise approach to the diagnosis and treatment of patients with selective restrictive lung diseases.
Restrictive lung diseases comprise a heterogeneous group of >100 different respiratory disorders whose common denominator is a pathological reduction in lung volume. The reduced volume may result from diffuse inflammatory injury, as well as abnormal fibrotic proliferation and repair within alveolar walls and the lung's interstitial structures. Such disorders are collectively designated interstitial lung diseases (ILDs). Many ILDs not only lead to thickening of alveolar walls and septal interstitium, but also of the lumina and walls of small airways (alveolar ducts, respiratory bronchioles, and terminal bronchioles) and the pulmonary capillary network. Chest wall disorders and certain neuromuscular diseases that adversely influence the mechanical efficiency of the muscles of respiration also culminate in pulmonary restriction, albeit without ILD-like pathophysiological features in the lung parenchyma. Regardless of the specific etiology of an ILD and its pathophysiological mechanisms, the presenting clinical manifestations usually include three hallmark features: (1) progressive dyspnea on exertion; (2) restrictive physiology on pulmonary function tests; and (3) diffuse reticular infiltrates or ground-glass opacities on chest radiographs or thoracic CT imaging studies.
INTERSTITIAL LUNG DISEASES
To facilitate a differential diagnosis of ILD, it is helpful to view the condition as associated with ten broad disease categories affecting the respiratory system (Table 24.1). These general categories will be considered in turn.
Table 24.1General categories of interstitial lung diseases ||Download (.pdf) Table 24.1 General categories of interstitial lung diseases
|Idiopathic interstitial pneumonias ||Sarcoidosis |
|Connective tissue diseases ||Eosinophilic lung disorders |
|Hypersensitivity pneumonitis ||Pulmonary vasculitides |
|Pneumoconioses ||Alveolar hemorrhage syndromes |
|Drug-induced pulmonary disease ||Miscellaneous disorders |
IDIOPATHIC INTERSTITIAL PNEUMONIAS
Idiopathic interstitial pneumonias are a group of lung disorders comprised of: idiopathic pulmonary fibrosis (IPF); nonspecific interstitial pneumonia (NSIP); cryptogenic organizing pneumonia (COP); acute interstitial pneumonia (AIP) or Hamman-Rich syndrome; respiratory bronchiolitis-interstitial lung disease (RB-ILD); desquamative interstitial pneumonitis (DIP); and lymphoid interstitial pneumonia (LIP). Each of these disorders has characteristic histopathological features which permit their presumptive distinction (Table 24.2; see Chap. 23).
Table 24.2Classification of idiopathic interstitial pneumonias ||Download (.pdf) Table 24.2 Classification of idiopathic interstitial pneumonias
|Histological pattern ||Clinical/Radiologic/Pathologic Diagnosis |
|Usual interstitial pneumonia ||Idiopathic pulmonary fibrosis |
|Nonspecific interstitial pneumonia ||Nonspecific interstitial pneumonia |