Interstitial Lung Disease

Dr. Loo Chian Min

Senior Consultant and Head

Department of Respiratory & Critical Care Medicine

Singapore General Hospital

Scope

• Definition

• Classification

• Approach to diagnosis

• Treatment

Definition

• Refers to diseases that affect the lung

parenchyma in a diffuse manner

– Tissue between & includes capillary

endothelium and alveolar epithelium

– Includes septae, peribronchial tissue,

perilymphatic tissue and perivascular tissue

– Diffuse parenchymal lung disease (DPLD)

• Chronic inflammatory diseases

Classification

DPLD

DPLD of known cause

DPLD of unknown

cause

IPF

Non IPF

Granulomatous DPLD

Rare causes of DPLD

ATS AJRCCM 2002

DPLD of known cause

• Collagen vascular disease

• Drug/radiation induced

• Environmental/occupational agents

• Infections

• Vasculitis

DPLD of unknown causes

Idiopathic interstitial pneumonia

• IPF/CPA

• AIP, NSIP, COP, DIP, RBILD, LIP

Granulomatous DPLD

• Sarcoidosis

• Bronchocentric granulomatosis

• Berylliosis

Other DPLD

• LAM

• Langerhan cell histiocytosis /

Histiocytosis X

• Eosionophilic pneumonias

• Alveolar proteinosis

Approach to Diagnosis

• History

• Physical findings

• Investigation

How do patients present?

• Symptoms

– Progressive dyspnea

– Chronic cough

– Pulmonary symptoms related to another

disease (e.g. collagen vascular disease)

• Abnormal investigations

– Chest X-ray

– CT scan

– Lung function abnormalities

History

• Temporal development / natural history

• Risk factors / etiological agents

• Severity of symptoms

Natural History

• Acute (<3 weeks)

– Infection, vasculitis (e.g. Wegener’s, SLE,

Behcet’s) drug induced (e.g. cytoxics), AEP, COP

• Episodic

– HP, eosinophilic pneumonia, vasculitis, Churg-

Strauss, COP

• Chronic

– Organic/inorganic dusts, IPF, NSIP, sarcoidosis,

collagen vascular disease, vasculitis, CEP, post

BMT, IBD, LCH, LAM

Risk Factors /

Etiological Agents

• Rheumatological

symptoms

• Smoking – DIP, RB-

ILD, LCH,

Goodpasture’s

• Drug history

• Occupation / hobbies

/ travel

• Past medical history –

asthma/rash (CSS),

chemo/radiation,

hematuria (vasculitis),

HIV

• GERD

• Family history

Specific Symptoms

• Breathlessness – not specific

• Cough – sarcoid, HP, COP, IPF

• Wheeze – CSS, sarcoid, eosinophilic

pneumonia

• Hemoptysis – Wegener’s,

Goodpasture’s

• Pleurisy – collagen vascular disease

Severity

• Exercise tolerance

– Flat ground

– Incline or climb stairs

• leg edema

– Cor pulmonale

Dempsey. BMJ 2010

BTS. Thorax 1999

Investigations

• Chest radiograph

– Pattern, distribution,

chronicity (comparing

previous films)

– Limited sensitivity and

specificity for specific

diagnosis

HRCT Chest

• Can make correct diagnosis in 61-80%

of cases (Grenier. Radiology 1994)

• Highly sensitive – 94% (Padley. J Thorac Imaging

1993)

• Pattern of disease

• Distribution

• Severity

• Reversibility

• Where to biopsy

HRCT

HRCT in IPF

ATS. AJRCCM 2011

HRCT in other ILDs

Aust Fam Physician 2010 Cordier. ERJ 2006

Pulmonary Function &

Exercise Tests

• Spirometry

– Reversibility or bronchial challenge testing

• Lung volume measurement

– Plethysmography

• Diffusing capacity

• Cardiopulmonary exercise test

• 6 minute walk test

Lung Biopsy

• Bronchoscopy

– Bronchoalveolar lavage

– Transbronchial lung biopsy

• Open lung biopsy

– VATS

– thoracotomy

IPF Diagnosis

Major Criteria

• Exclusion of other known

causes of ILD

• Abnormal PFT

– Restriction

– Impaired gas exchange

• Bibasilar reticular changes

with minimal ground glass

changes

• BAL/TBLB do not support

other diagnoses

Minor Criteria

• Age >50 years

• Insidious onset of

dyspnea on exertion

• Duration >3 months

• Bibasilar fine inspiratory

crackles

ATS AJRCCM 2002

Other Investigations

• FBC

• Renal panel

• Auto-antibodies

• Urine microscopy

• 2D echocardiogram

Treatment • Treat underlying disease

• Treat lung disease

– Remove causative agent

– Immune suppression – prednisolone, azathioprine,

cyclophosphamide, cyclosporin

– Trials in IPF – Pirfenidone, interferon g-1b, bosentan,

sildenafil, etanercept, imatinib

– GERD treatment

– Oxygen, pulmonary rehabilitation, immunization

– Lung transplantation

• Treat complications

– Cor pulmonale, osteoporosis, ulcer & PCP prophylaxis