Interstitial Lung Disease 2

Question 2

What structure is affected in interstitial lung disease?

Answer 2

Interstitial lung disease (ILD)

aka Diffuse Parenchymal Lung Disease (DPLD)

• a group of diseases affecting the interstitium (tissue and space around the alveolar sacs of the

lung)

Question 3

Pathophysiology of interstitial Lung disease

Answer 3

• injury to the lung —> abnormal healing response —> incorrect repair process —> tissue around #
• the alveoli become scarred and thickened
• scarred and thickened tissue —> more difficult for the oxygen to pass into blood stream

Question 4

Symptoms of Interstitial Lung Disease?

Answer 4

SOB on expiration, non-productive paroxysmal cough, restrictive pulmonary, spirometry, abnormal breath sounds, decreased tolerance to exercise

Question 5

What can be seen on examination of a patient with Interstitial Pulmonary Disease?

Answer 5

O/E: inspiratory crackles, cyanosis and finger clubbing (later stage)

Question 6

Management of Interstitial Pulmonary Disease

Answer 6

• if specific environmental factor is a contributor —> a person should avoid that environment
• if a drug is suspected to be a cause —> discontinuation of a drug
• many cases of an unknown cause or connective tissue disorder —> corticosteroid treatment

(e.g. prednisolone) ; some respond to immunosuppressants

• supportive treatment with oxygen
• Pulmonary rehabilitation
• Lung transplant - if other forms of treatments fail and if there are no other contradictions

Question 7

Examples of substances potentially causing Idiopathic Lung Disease re to occupation

Answer 7

asbestosis, berylliosis, silicosis, cotton worker’s lung

Question 8

Examples of substances potentially causing Idiopathic Lung Disease re to drugs

Answer 8

nitrofurantoin, bleomycin

Question 9

Examples of substances potentially causing Idiopathic Lung Disease re to allergy

Answer 9

extrinsic allergic alveolitis

Question 10

Examples of substances potentially causing Idiopathic Lung Disease re to infections

Answer 10

TB, fungi, viral

Question 11

What other systemic diseases ILD can be associated with?

Answer 11

• Sarcoidosis
• Rheumatoid arthritis
• Systemic sclerosis, connective tissue disease, Sjogren’s syndrome

Question 12

Pathophysiology of Idiopathic Pulmonary Fibrosis

Answer 12

• idiopathic trigger of the process
• Fibrosis occurs usually after tissue damage —> ongoing repair process —> excess collagen/ scar tissue in the interstitial space of the lungs —> chronic process —> progressive loss of lung tissue

Question 13

Risk factors for Idiopathic Pulmonary Fibrosis (3)

Answer 13

old age, being male, tobacco smoking

Question 14

What is the location of Idiopathic Pulmonary Fibrosis and cells involved

Answer 14

Interstitial tissue (contains macrophages and fibroblasts)

Question 15

What happens (pathology) in Idiopathic Pulmonary Fibrosis?

Answer 15

• Damage to epithelium —> type 2 pneumocyte over- proliferate (during the repair process)—> too many myofibroblasts —> too much collagen
• Myofibroblasts do not undergo apoptosis —> more and more collagen is produced —> collagen accumulates —> interstitial layer between alveoli and capillary forms —> problems with ventilation and oxygenation
• Excess collagen (also causes)—> lungs becoming stiff —> hard for air to flow in and out —>

restricted lung expansion (due to fibrosis in interstitium)

Question 16

What results (3) would be seen on spirometry in Idiopathic Pulmonary Fibrosis

Answer 16

A) decrease in TLC (max amount of air lungs
can hold)

B) decrease in FVC (amount of the air exhaled after a deep breath)

C) decrease in FEV1 (air exhaled with max effort in first second)

Question 17

Why in FEV1/|FVC is over 0.7 or above in restrictive disease?

Answer 17

Decreased FVC and FEV1’ but restrictive still is >/= 0.7 of predictive value as it is a ratio o FVC/FEV1 so if both components of the fraction are decreased; overall ratio will not change

Question 18

A characteristic feature of X-ray/ CT in Idiopathic Pulmonary Fibrosis?

Answer 18

Excess collagen —> loss of alveoli —> fluid- filled

spaces = cysts created = ‘HONEYCOMBING’ pattern

Question 20

Symptoms of Idiopathic Pulmonary Fibrosis?

Answer 20

• progressive process —> symptoms will worse over time
• problems with oxygenation and ventilation —> SOB, coughing, cynosis, digital clubbing
• over time —> respiratory failure (as lung loses more and more functional tissue)

Question 21

Diagnosis of Idiopathic Pulmonary Disease?

Answer 21

A) Chest imaging: CT scan - honeycomb appearance and thickening of interstitial walls

B) Spirometry - decrease in: TLC, FVC and FEV1 (characteristics of restrictive lung diseases)

Question 22

Management of Idiopathic Pulmonary FIbrosis

Answer 22

A) Supplemental oxygen

B) Antifibrotic medication - slow the progression but does not stop disease

C) Lung transplant - the only available treatment for severe cases

Question 24

What’s Extrinsic Allergic Alveolitis?

Answer 24

Inflammation of the alveoli within the lung caused by hypersensitivity to inhaled organic dusts

Question 25

Cause of Extrinsic Allergic Alveolitis

Answer 25

Cause: provoking agents

• inhalation of fine particles
• oral drugs

Example:

• Bird fancier’s lung:

antigen: avian (relating to birds) proteins
exposure: feathers or bird droppings

• Farmer’s lung:

Question 26

What are the characteristic features in lung appearance in Extrinsic allergic alveolitis:

A. Acute

B. Subacute

C. Chronic

Answer 26

Acute: lungs are infiltrated with neutrophils and mononuclear cells

Subacute: lungs are infiltrated with lymphocytes

Chronic: Non-caseating epithelioid granulomas develop + progressive lung fibrosis

Question 27

Mechanism of Extrinsic Allergic alveolitis

Answer 27

• Inhalation of antigen —> hypersensitivity reaction (type III and/or type IV) —> exaggerated immune response

*Hypersensitivity type response depends on cause -> can occur in both forms