Interstitial Lung Diseases

  • A large group of diseases with different causes but with the same or similar clinical and pathological changes.
  • The interstitial lung diseases (ILD) are diseases of lung parenchyma/ alveoli/ alveolar epithelium/ capillary endothelium/ and the spaces between These structures/ perivascular and Imphatic tissues.
  • These are due to chronic, nonmalignant, noninfectious diseases of the lower respiratory tract characterized by inflammation and disruption of the walls of the alveoli.
  • Diffuse parenchymal lung diseases, often collectively referred to as the interstitial lung diseases (ILDs), are a heterogeneous group of disorders that are classified together because of similar clinical, roentgenographic, physiologic, or pathologic manifestations (show table ) .
  • This manifests clinically as a limitation in the ability of the lungs to transfer oxygen from the alveoli to the pulmonary capillary bed.
  • However, the term interstitial is misleading, since most of these disorders are also associated with extensive alteration of alveolar and airway architecture.
  • Patients with these disorders are dyspneic first in connection with exercise and, later, as the disease progresses, even at rest.
  • There is diffuse parenchymal lung involvement, con­nective tissue involvement, and either fibrosis or granuloma formation. The cause may be known or unknown.
  •  The disease may have 2 phases Acute & Chronic phase. The disease is usually recurrent.
  • Interstitiai C1iseases of unknown etiology Sarcoidosis,’Idiopathic pulmonary fibrosis, Wegener’s granulomatosis, SLE, rheumatoid arthritis, tioodpasture’s syndrome.
  • Interstitial diseases of known etiology Asbestos, drugs like amiodarone, antibiotic, gold, hypersensitivit neumonitis.
Interstitial Lung Diseases 2

Interstitial Lung Diseases Clinical Features examination Treatment

Clinical Features of Interstitial Lung Diseases

  • Presentation may be acute, sub-acute or chronic. Age commonly affected is 20 – 40 years.
  • There may be a family history of interstitial lung dis­ease.
  • Some diseases are more common in women but pneu­moconfosis is mOre common in men.
  • ILD is very common in smokers.
  • Symptoms are dyspnoea, wheezing, substernal dis­comfort, chest pain, hemoptysis, fatigue, weight loss .

Interstitial Lung Diseases  Physical examination

  • Tachypnoea, bilateral basal inspiratory crackles, Wheeze, cyanosis, and clubbing.

Lab diagnosis

  • ANA (Antinuclear antibodes), anti immuno globulin antibodies, circulating immune complexes, anti-base­ment anti~6dies=-serum _Rr~ciRitins in hypersensitivity pneumonitis.


  • Bilateral basal reticular pattern.
  • Nodular opacities especially in upper zones. -)Honey-combing.
  • Progressive changes of fibrosis.
Interstitial Lung Diseases 1

Interstitial Lung Diseases Clinical Features examination Treatment


  • CT and High resolution CT for early detection and con­firmation.

Pulmonary function test

  • Spirometry and lung volumes show a restrictive de­fect with reduced total lung capacity, reduced FEV1 and FVC, increased FEV1 j FVC.

Diffusing capacity

  • There is reduction in diffusing capacity for carbon monoxide in ILDs.

Arterial blood gases

  • May be normal, or show hypoxaemia, respiratory al­kalosis, hypocapnia, normocapnia, and rarely hyper­capnia.

Fiberoptic bronchoscopy and bronchoalveolar la­vage

  • Is useful for diagnosis of sarcoidosis, hypersensitiv­ity pneumonitis.

Treatment of Interstitial Lung Diseases

  •   Removal of stimulus
  • Suppression of inflammation
  • Supplemental oxygen
  •  Glucocorticoids-Prednisone 1 mg/kg once daily’ orally for 4-12 wks.
  •   Cyclophosphamide and Azathioprine 0,/ Lung transplantation.


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