Diffuse Interstitial Lung Disease and Pulmonary Fibrosis

Abstract

Diffuse interstitial lung disease (DILD) is a heterogeneous group of lung disorders characterised histologically by diffuse inflammation and fibrosis affecting predominantly, but not exclusively, the pulmonary interstitium. Fundamental points for diagnosis: Previously identified DILD: eliminate pulmonary infection (intracellular and opportunistic pathogens, viruses), pulmonary embolus, pneumothorax, cardiogenic involvement, drug-associated toxicity and carcinomatous lymphangitis before concluding that it is an exacerbation of pulmonary fibrosis. The key examinations are high-definition (HD)-thoracic TDM, bronchoalveolar lavage (BAL), microbiological specimens and echocardiography. In the case of previous severe restrictive respiratory failure, the prognosis is extremely poor.

Previously unknown DILD: look for infectious pneumonia (intracellular pathogens, Pneumocystis, viruses), connective tissue disease, granulomatosis, cancer, drug- or environment-associated toxicity, before concluding an idiopathic cause. The key examinations are extrapulmonary signs, HD-thoracic TDM, BAL, microbiological specimens and immunological investigations. A lung biopsy may be carried out if no diagnosis is made and is contributory in >65 % of cases. Fundamental points for treatment: Non-invasive ventilation is rarely effective, but can help in carrying out BAL. Invasive ventilation should be protective. Antibiotic treatment (consider anti-intracellular pathogens, Pneumocystis) is usually prescribed in view of the high frequency and good prognosis of infectious aetiologies. Corticotherapy has poor efficacy outside connective tissue diseases and granulomatosis, eosinophilic pneumonia, histiocytosis and cryptogenic organising pneumonia. The prognosis is extremely poor in patients with established pulmonary fibrosis. In this situation, palliative care should be discussed.