Interstitial Lung Disease (ILD)

Exam Cram

• Interstitial lung disease is a collection of 100+ lung diseases associated with significant mortality through developing pulmonary hypertension

• Common types: idiopathic (IPF), medication induced, autoimmune and exposure (asbestosis & silicosis)

• Spirometry: restrictive lung disease (reduced FVC and FEV-1)

• Management: endothelin receptor antagonists

Defining ILD

Definitions

• ILD: Interstitial Lung Disease, comprises of around 100 lung diseases.

• Pulmonary Fibrosis: non specific name, often referring to idiopathic but could be related to any cause of pulmonary fibrosis. 

• IPF: idiopathic pulmonary fibrosis, the commonest cause of ILD  and of pulmonary fibrosis. 

5 core types of ILD

1. Exposure/ occupations: asbestosis, silicosis, hypersensitivity pneumonitis

2. Medication related (see below)

3. Autoimmune/ connective tissue disorders: Systemic Lupus Erythematous , Dermato/polymyositis , Rheumatoid Arthritis, Systemic Sclerosis 

4. Sarcoidosis 

5. Idiopathic

Further types

• Histiocytosis X

• Chronic eosinophilic pneumonia

• Goodpasture's Disease 

• GPA 

Cause of drug induced fibrosis (NASSA)

• Nitrofurantoin

• Sulphonamides

• Sulfasalazine

• Amphotericin B

• Chemotherapy- bleomycin

• Radiotherapy

• Tamoxifen

Amiodarone- commonly cited but actually drug induced pneumonitis which usually resolved on cessation of drug without steroids. 

ILD Outline

Assessment

History

• Progressive sob, reduced exercise tolerance

• Dry cough

Examination

• Finger clubbing

• Bi-basal fine inspiratory crackles

Investigations

• Spirometry: restrictive pattern

• TLCO: reduced (marker of disease severity)

• Bronchoscopy +/- lavage or biopsy

Diagnosis

Diagnostic criteria: presentation, HRCT interstitial pattern & hisology from lung biopsy

Differentials: COPD, CHF, 

Classification: 

1. Aetiology- as per subtype

2. Severity markers

Idiopathic Pulmonary Fibrosis

• Management: 

  • Nintedanib

  • Pirfenidone

Med Reg Notes

Upper vs Lower Fibrosis

Upper Lobe Fibrosis

• Ankylosing spondylitis

• Tuberculosis

• Sarcoidosis

• Extrinsic allergic alveolitis

• Silicosis

• ABPA

• Post radiotherapy

Lower Lobe Fibrosis

• Idiopathic

• Rheumatoid Arthritis

• Systemic Sclerosis (Scleroderma)

• SLE

Pulmonary Hypertension 

Refers to increased pressures in the pulmonary arterial tree from the right ventricle. This is comparable to Hypertension which refers to elevated pressures in the systemic arterial system from the left ventricle. 

Pulmonary hypertension is common in lung diseases because the heart has to push harder. Therefore pulmonary HTN is common in ILD, but a distinct disease

Hypersensitivity pneumonitis

• Type of ILD

• Occupation exposure, e.g. farmwork- farmer's lung or bird fancier's lung

• Affects upper lobes

• May not cause finger clubbing

References

1. Types (2017) Stanford Health Care. Available at: https://stanfordhealthcare.org/medical-conditions/chest-lungs-and-airways/interstitial-lung-disease/types.html (Accessed: 07 October 2024).

2. https://www.mayoclinic.org/diseases-conditions/interstitial-lung-disease/diagnosis-treatment/drc-20353113

3. https://www.nhlbi.nih.gov/health/interstitial-lung-diseases/diagnosis

Written in 2024