Interstitial Lung Disease

Question 1

DIFFUSE PARENCHYMAL LUNG DISORDERS (INTERSTITIAL LUNG DISEASE)

Answer 1

• Group of disorders which account for 15% of respiratory clinical practice; Diffuse Lung Injury
and Inflammation that can lead to Lung Fibrosis
• Classified by Granulomatous, Granulomatous with Vasculitis, Autoimmune Rheumatic,
Idiopathic and other forms

Question 2

Granuloma

Answer 2

Mass or Nodule comprising Chronically inflamed tissue formed by
Macrophage response to insoluble/persistent antigen/irritant; If foreign substance is
toxic or reproducing, Macrophages turn over faster forming a Granuloma
o Granulomas characterised by Epithelioid Multinucleate Giant Cell (seen in TB); Also
seen in other infections e.g. Fungal, in Sarcoidosis, Hypersensitivity Pneumonitis etc

Question 3

Sarcoidosis

Answer 3

• Multisystem Granulomatous disorder commonly in
young adults; Bilateral Hilar Lymphadenopathy,
Pulmonary Infiltration, Skin/Eye Lesions
• Unknown Aetiology – Detected on routine CXR;
More common in USA, more severe in African
Americans; 30-40yrs, More common in females;
• Sarcoid Granulomas consist of Focal Accumulations
of Epithelioid cells, Macrophages, and Lymphocytes
(mostly T cells); Overall Lymphopaenia (Depressed
cell-mediated reactivity)
o No evidence of immune defect – No increased vulnerability

Question 4

Presentation of Sarcoidosis

Answer 4

• Respiratory symptoms or asymptomatic with routine CXR, less commonly weight loss,
Peripheral Lymphadenopathy and Fever; CXR may be normal in 20% of non-respiratory cases
• Stage I: BHL, Stage II: BHL + Infiltrate, Stage III: Infiltrate without BHL, Stage IV: Fibrosis
• Bilateral Hilar Lymphadenopathy – Usually
asymptomatic; Associated with dull Chest
Ache, Malaise, Low grade fever; Lung
involvement nearly in all cases seen on CT
o Differential includes Lymphoma
(although rarely Hilar), Tuberculosis
and Bronchial Carcinoma (although
both are rarely symmetrically)
• Pulmonary Infiltration – May be asymptomatic;
Infiltration with normal lung function highly
suggestive of Sarcoidosis; May also present as
Effort Dyspnoea, Cor Pulmonale and death
• CXR shows mottling of mid-zones and generalised fine nodular shadows; Widespread linear
shadows reflecting fibrosis; “Honeycomb” appearance
• Lung Function Tests show typically restrictive defect with reduced gas transfer
• Skin Lesions – Erythema Nodosum (Inflammation of subcutaneous fat) and BHL occur
together only in Sarcoidosis
• Eye Lesions – Anterior Uveitis is common, resulting in misting of vision, pain and red eye;
Posterior Uveitis results in progressive loss of vision
• Calcium Metabolism – Hypercalcaemia due to increased circulating activated vitamin D due to
1α Hydroxylation occurring in Sarcoid Macrophages

Question 5

Management of Sarcoidosis

Answer 5

• CXR, High Res CT, FBC (ACD), ↑ESR, Transbronchial Biopsy (Positive in 90% of cases)
• Serum ACE level – Also raised in Lymphoma, TB, Asbestosis, Silicosis; Useful in accessing
disease activity and response to treatment
o Reduction can occur during Corticosteroid Therapy
• Lung Function Tests – Restrictive Lung Defect; ↓TLC, FEV1, FVC, Gas Transfer; Lung Function
if presenting with Extrapulmonary disease or only have BHL on CXR
• Persistent infiltration should be monitored carefully; Patients with abnormal Lung Function
would benefit from Steroids
• Start Prednisolone 30mg for 6 weeks if disease not spontaneously improved after 6 months;
Step down Prednisolone after
• Eye Involvement/Persistent Hypercalcaemia mandatory indications for Steroid therapy

Question 6

GRANULOMATOUS LUNG DISEASE WITH VASCULITIS

Answer 6

• Either due to respiratory manifestation of systemic disease, or Respiratory disease with
presence of ANCA (Found in acute phases of Vasculitides)
• Wegener’s Granulomatosis, Churg-Strauss Syndrome and Microscopy Polyangiitis; Can also be
due to Goodpasture’s Syndrome

Question 7

Wegener’s Granulomatosis (Granulomatosis with Polyangiitis = GPA)

Answer 7

• Unknown Aetiology; Predominantly affects small arteries; Lesions in Upper Respiratory Tract,
Lungs and Kidneys; Starts with severe Rhinorrhoea, Nasal Mucosal Ulceration, Cough,
Haemoptysis and Pleuritis pain
• Nodular masses or Pneumonic Infiltration with Cavitation on CXR; More visible on Renal
Biopsy; Responds to Cyclophosphamide and Rituximab;
• Midline Granuloma – Affects Nose and Paranasal sinus; Mutilating and poor prognosis

Question 8

Churg-Strauss Syndrome (Eosinophilic Granulomatosis with Polyangiitis = EGPA)

Answer 8

• Classically occur in males 40yrs; Rhinitis, Asthma, Eosinophilia, Systemic Vasculitis especially
of the small arteries and veins, formation of Extravascular Granulomas; ANCA positive
• Involves Lungs, Peripheral Nerves and Skin, sometimes has renal involvement
• Transient Pneumonia-like shadows; Sometimes massive and bilateral
• Skin Lesions – Tender Subcutaneous nodules, Petechial or Purpuric lesions
• Responds well to Corticosteroids; No evidence that antiasthma drugs precipitate disease

Question 9

Microscopic Vasculitis (Microscopic Polyangiitis = MPA)

Answer 9

Kidney and Lung involvement; Recurrent Haemoptysis; ANCA usually positive