This is a rare disorder characterized by inflammation and subsequently scarring and fibrosis affecting the interstitium or scaffolding of the lungs. Several different disease processes can result in lung fibrosis. There are known causes like certain drugs, radiation, some occupations, exposure to pigeon droppings, and hence a careful history of occupational and environmental exposures is essential. Usually, no cause is obvious and the ILD is then labeled Idiopathic Interstitial Pneumonia. There are two main types: Idiopathic Pulmonary Fibrosis (IPF) which has a worse prognosis and Non-Specific Interstitial Pneumonia (NSIP) which carries a better prognosis.
A good quality CT scan of the chest (HRCT) is crucial in determining the type of ILD. PFT and TLCO tests give an idea of the extent of fibrosis and the disability it has produced. A six-minute walk test is also a good way of assessing the patient’s functional status and is of prognostic value. A bronchoscopy and trans-bronchial biopsy and, on occasion, an open lungs biopsy may be needed to establish the type of ILD
Currently, treatment involves a low dose of steroids, azathioprine, and N Acetyl Cystine. No drug or combination of drugs can reverse the disease but the aim of treatment is to arrest its progression. Many patients will eventually need oxygen at home and patients should be assessed for this. Pulmonary rehabilitation can also be offered and we are currently assessing the efficacy of rehab. Lung transplantation is a last resort option in selected patients with advanced fibrosis.
Many new drugs are in the pipeline and a new drug called pirfenidone is to be launched shortly in India.