INTERSTITIAL AND INFLAMMATORY

1. BRONCHIOLITIS OBLITERANS  A fibrotic lung disease that primarily affects the small conducting airways and spares most of the interstitium.
   1.     Pathology: epithelial injury with a repair process causing an excessive proliferation of granulation tissue which compromises or completely obliterates the airway lumen.
   2.     Physiology: obstructive or restrictive ventilatory defect.
   3.     CXR: show more
2. COLLAGEN VASCULAR DISEASES    Pleuropulmonary Manifestations
   Rheumatoid Arthritis
   • Pleuritis with or without effusion
   • Rheumatoid effusion
   • Cholesterol effusion
   • Necrobiotic nodules
   • Caplan's syndrome (rheumatoid show more 
3. IDIOPATHIC PULMONARY FIBROSIS    Idiopathic pulmonary fibrosis is a disease characterized by diffuse interstitial fibrosis of unknown etiology and frequently occurs between the ages of 50-70.
   Clinical Picture
   • Patients present with dry cough and shortness of breath and sometimes with fever, arthralgias and Raynaud's phenomenon.
   • Clubbing (40-70%) tachypnea and persistent coarse basal crackles are encountered on physical exam. Often they are using accessory muscles of inspiration for tidal show more 
4. SARCOIDOSIS   A multisystem granulomatous disorder of unknown etiology.
   Clinical manifestations
   a.      Mostly young adults.
   b.     Any organ may be involved with the lungs, lymphatics, skin, liver, eyes most commonly affected in decreasing order. Some manifestations to watch for:
   - Myocardial involvement (possible conduction disturbances)
   - Uveitis
   - Cranial nerve VII show more
5. HYPERSENSITIVITY PNEUMONITIS                 HYPERSENSITIVITY PNEUMONITISA type III and IV hypersensitivity reaction to microbial spores, animal proteins and chemicals.
   
   a.      Farmer's lung is the prototypic disease caused by a reaction to Micropolyspora faeni.
   b.     Fever, chills, dyspnea, leukocytosis may occur 4-6 hours after exposure and eventually resolve; symptoms and signs may recur on re-exposure.
   c.      CXR: Acute - normal to reticulonodular pattern; Chronic - progressive fibrosis, show more
6. Diagnostic Criteria For Hypersensitivity Pneumonitis (Extrinsic Allergic Alveolitis)?                                                                Always think of HP in patients with a working diagnosis of asthma whose symptoms do not improve, and there are infiltrates on CXR. The terms hypersensitivity pneumonitis (HP) and extrinsic allergic alveolitis (EAA) are used interchangeably.
   
   Several different diagnostic criteria for HP have been proposed. All have problems that limit their utility, for example:
   
   - All were developed before the common use of high resolution CT scanning and bronchoalveolar lavage
   - Most apply only to typical, acute cases
   - No clear diagnostic criteria exist for show more