Interstitial lung disease

Definition
Diffuse parenchymal lung disease (DPLD),refers to a group of lung diseases affecting the interstitium (the tissue and space around the air sacs of the lungs).  It concerns alveolarepithelium, pulmonary capillary endothelium,basement membrane, perivascular andperilymphatic tissues.
Aetiology

Inhaled substances	Silicosis; Asbestosis; Berylliosis; Hypersensitivity pneumonitis
Drug induced	Antibiotics; Chemotherapeutic drugs; Antiarrhythmic agents; Statins
Connective tissue disease	Systemic sclerosis; Polymyositis; Dermatomyositis; Systemic lupus erythematosus; Rheumatoid arthritis
Infection	Atypical pneumonia; Pneumocystis pneumonia (PCP); Tuberculosis; Chlamydia trachomatis; Respiratory Syncytial Virus
Idiopathic	Sarcoidosis, Idiopathic pulmonary fibrosis, Hamman-Rich syndrome, Antisynthetase Syndrome
Malignancy	Lymphangitic carcinomatosis

Presentation

• A feeling of breathlessness (dyspnea), especially during or after physical activity
• A dry cough
• Wheezing
• Chest pain
• clubbing

Management
(British Thoracic Society)
In addition to routine respiratory history and examination:

• History of acid reflux, symptoms suggestive of connective tissue disease including Raynaud’s
• phenomenon
• Detailed occupational history
• Exposure to birds and other potential antigens
• Current and previous drugs

Investigations for most (if not all) patients with suspected ILD:

• Full blood count, urea & electrolytes, calcium, lung function tests, ESR, CRP, rheumatoid factor, ANA
• Oxygen saturation at rest
• Urinalysis
• HRCT scan
• Spirometry, lung volumes and gas transfer
• ECG

Additional tests in selected patients:

• Suspected sarcoidosis: serum ACE
• Suspected hypersensitivity pneumonitis: precipitating antibody to suspected antigen
• Suspected vasculitis: ANCA