A heterogenous group diffuse inflammatorydisorders that affect the alveoli and septalinterstitium of the lower respiratory tract ofthe lung.
Causes of interstitial lung diseases : Idiopathic pulmonary fibrosis • It is called cryptogenic fibrosing alveolitis or Hamman – rich syndrome • The cause is unknown but the disease represents the inflammatory and immune response of the lung to the tissue damage Collagenic vascular diseases • Rheumatoid arthritis, systemic sclerosis or ankylosing spondylitis • Dermatomyositis, polymyositis or mixed connective tissue diseases
Occupational lung diseases • Inhalation of organic dusts “extrinsic allergic alveolitis” : as Baggosis • Inhalation of inorganic dusts “ Pneumoconiosis” : as Asbestosis Malignancy • Bronchoalveolar carcinoma and lymphangitis carcinomatosis • Leukaemias and lymphomas Infectious diseases• Miliary tuberculosis, viral and atypical pneumonias
Medications• Methotrexate, Azathioprine and bleomycin• Sulphonamides, Aminodarone and insecticidesMiscellaneous• Ulcerative colitis, chronic active hepatitis• Alveolar proteinosis and microlithiasis• Hashimoto’s thyroiditis and Goodpasture’s syndrome
Pathological types• Mural types• Desquamative type• Lymphocytic type
Symptoms : Onset* It usually insidious and gradually progressive* It may be acute with rapidly progressive course“in Hamman rich syndrome”* It may be subacute “in extrinsic allergicalveolitis” Symptoms* Dry cough* Gradual progressive dyspnea appearearly on
Sign : General signs • Clubbing • Cyanosis that appears early on exertion but later at rest Local sign• Crackles• Rhonchi
Radiological investigations : Chest x-ray• Diffuse bilateral reticulonodular pattern through both lung fields• It is more pronounced at the lower lung zone• Honey comb appearance• Homogenous opacity• Multiple shadows of equal size scattered all over lung in milliary TB• Features of complications : Right ventricular enlargement , Pulmonary hypertension
distortion of the lung architecture and traction bronchiectasis
HRCT ( High Resolution CT scan ) Ventilation – Perfusion scanBlood test : leucocyteOther tests : bronchoscopy, lung biopsy, etc.
Specific Treatment : Steroid “Prednisone”Other lines of treatment : Symptomatic treatment as : oxygen inhalation andantitussive • Supportive treatment as : good nutrition and vitamins • Treatment of the cause : as pulmonary infections • Treatment of complications as
Symptomatic treatment as : oxygen inhalation and antitussive• Supportive treatment as : good nutrition and vitamins• Treatment of the cause : as pulmonary infections• Treatment of complications as - Pulmonary hypertension and corpulmonale