Interstitial lung diseases
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1. Interstitial lung diseases (ILDs) involve the lung parenchyma including the alveoli, capillaries, and spaces between. 2. ILDs are classified based on known causes, idiopathic forms, and granulomatous types. Idiopathic pulmonary fibrosis is the most common idiopathic form. 3. Clinical presentation involves breathlessness, cough, and reduced lung function. Investigations include chest imaging showing infiltrates and fibrosis, and lung biopsies to determine classification. Treatment focuses on removing exposures, suppressing inflammation, and palliating symptoms primarily using corticosteroids.
Interstitial lung diseases
- 1. Interstitial Lung Diseases Dr. Rahul Magazine M.D.(Medicine), D.T.C.D. Department of Pulmonary Medicine
- 2. Definition The interstitial lung diseases (ILDs) represent a large number of heterogeneous disorders that involve the parenchyma of the lung -- the alveoli, the alveolar epithelium, the capillary endothelium, and the spaces between these structures, as well as the perivascular and lymphatic tissues.
- 3. Classification 1. DPLD of Known Cause (drugs or association such as collagen vascular disease) 2. Idiopathic interstitial pneumonias • Idiopathic Pulmonary Fibrosis (UIP pattern) • IIP other than IPF (e.g. NSIP,DIP,AIP, RB-ILD, COP, LIP)
- 4. 3. Granulomatous DPLD (Sarcoidosis) 4. Other forms of DPLD (e.g. LAM, PLCH)
- 5. EPIDEMIOLOGY • Incidence 30 / 100000 per year (USA) • Incidence higher in men
- 6. PATHOGENESIS ILDs are the result of the superimposed processes of inflammation and tissue injury and attempted repair Two major histopathologic patterns: GRANULOMATOUS LUNG DISEASE This process is characterized by an accumulation of T lymphocytes, macrophages, and epithelioid cells organized into discrete structures (granulomas) in the lung parenchyma. The granulomatous lesions can progress to fibrosis.
- 7. INFLAMMATION AND FIBROSIS The initial insult is an injury to the epithelial surface causing inflammation in the air spaces and alveolar walls. If the disease becomes chronic, inflammation spreads to adjacent portions of the interstitium and vasculature and eventually causes interstitial fibrosis.
- 8. CLINICAL PRESENTATION HISTORY Breathlessness (most common): Initially, dyspnea on exertion→ later at rest Nonproductive cough Fatigue Pleuritic chest pain Hemoptysis-- infrequent A family history of ILDs should be sought.
- 9. D/D BASED ON ONSET: ACUTE ONSET: DAYS TO WEEKS Acute interstitial pneumonia Acute pneumonitis from collagen vascular disease(especially SLE) Diffuse alveolar hemorrhage Hypersensitivity pneumonitis CHRONIC: MONTHS TO YEARS Idiopathic pulmonary fibrosis Chronic hypersensitivity pneumonitis Collagen vascular disease–associated ILD
- 10. PHYSICAL EXAMINATION PULMONARY SIGNS With advanced disease, patients may have tachypnea and tachycardia, even at rest. Bilateral, basilar, Velcro-like rales Signs of pulmonary hypertension
- 11. EXTRAPULMONARY SIGNS: Clubbing (e.g. IPF) Skin abnormalities, peripheral lymphadenopathy, hepatosplenomegaly (SARCOIDOSIS) Subcutaneous nodules (RHEUMATOID ARTHRITIS) Muscle tenderness and proximal weakness (POLYMYOSITIS)
- 12. INVESTIGATIONS CHEST RADIOGRAPHY Nodules, linear (reticular) infiltrates, or a combination of the two (reticulonodular infiltrates) Diffuse ground glass pattern– EARLY Cystic areas (honeycomb pattern)-LATE
- 13. HIGH-RESOLUTION CT scan PULMONARY FUNCTION TESTS Reduced lung volumes, reduced diffusing capacity (DLCO ),a normal or supernormal ratio of FEV1 to FVC, Static lung compliance is decreased (decreased lung volume for any given transpulmonary pressure), and maximal transpulmonary pressure is increased (a very high negative pressure must be generated to open the fibrotic alveoli)
- 14. ARTERIAL BLOOD GAS ANALYSIS BRONCHOSCOPIC STUDIES Bronchoalveolar lavage LUNG BIOPSY Transbronchial biopsy Open-lung or thoracoscopic biopsy
- 15. TREATMENT Principal aims: (1) to remove exposure to injurious agents, (2) to suppress inflammation to prevent further destruction of the pulmonary parenchyma, and (3) to palliate the manifestations of these diseases.
- 16. CORTICOSTEROIDS: mainstay of therapy Prednisone, 1 mg/kg for 1 month, followed by 40 mg/day given for 2 months Gradually tapered (5 mg/week) over several months to a maintenance dose of 15 to 20 mg/day Corticosteroids are continued until pulmonary function is stable for 1 year Relapses require returning to high-dose steroids Cytotoxic agents (Cyclophosphamide)or immunosuppressive agents (Azathioprine) may be used in patients who do not improve on steroid therapy or who cannot tolerate corticosteroids
- 17. Thank You