Fibrotic lung disease (RESP) Flashcards

1
Q

Define interstitial lung disease.

A

Group of disorders characterised by inflammation and progressive scarring (fibrosis) of the lungs

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2
Q

What are some causes of interstitial lung disease? (5)

A
  • idiopathic pulmonary fibrosis (IPF)
  • hypersensitivity pneumonitis (extrinsic allergic alveolitis) - people with chronic exposure to bird droppings
  • pneumoconiosis (asbestosis) - people in coal mining industry
  • substance-induced (amiodarone, nitrofurantoin, methotrexate, bleomycin - chemo drug)
  • secondary to underlying disease e.g. connective tissue disorders, sarcoidosis, vasculitis
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3
Q

Who can hypersensitivity pneumonitis (interstitial lung disease) occur in?

A

People with chronic exposure to bird droppings

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4
Q

What is the pathophysiology of hypersensitivity pneumonitis (interstitial lung disease)?

A

Type 3 hypersensitivity-induced lung damage due to variety of inhaled organic particles

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5
Q

Who does pneumoconiosis AKA asbestosis (interstitial lung disease) happen in?

A

People in the coal mining industry

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6
Q

How does pneumoconiosis (interstitial lung disease) present?

A

Asymptomatic but may lead to progressive massive upper zone fibrosis which is symptomatic

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7
Q

What underlying diseases can cause interstitial lung disease? (3)

A
  • connective tissue disorders
  • sarcoidosis
  • vasculitis
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8
Q

What is the most common type of interstitial lung disease?

A

Idiopathic pulmonary fibrosis - diagnosed when there is no other identifiable cause, rare form of fibrotic lung disease with no known aetiology

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9
Q

Who does idiopathic pulmonary fibrosis tend to affect?

A

Men 50-70 years old

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10
Q

What is idiopathic pulmonary fibrosis characterised by?

A

Scar tissue formation within lungs, dyspnoea, significantly shortened lifespan after diagnosis

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11
Q

List the causes of upper zone fibrosis. (6)

A

CHARTS

  • Coal workers pneumoconiosis
  • Histiocytosis/Hypersensitivity pneumonitis
  • Ankylosing spondylitis
  • Radiation
  • Tuberculosis
  • Sarcoidosis/silicosis
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12
Q

List the causes of lower zone fibrosis. (4)

A

DIAL

  • Drugs - amiodarone, nitrofurantoin, methotrexate, chemo (bleomycin)
  • Idiopathic pulmonary fibrosis
  • Asbestosis
  • Lupus (and other CTDs except ankylosing spondylitis)
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13
Q

Describe the aetiology of interstitial lung disease.

A
  • occurs in genetically predisposed individuals
  • recurrent injury to alveolar epithelial cells –> secretion of cytokines and growth factors by pneumocytes especially TGFb1
  • usually there is interstitial tissue in between alveoli and capillaries containing fibroblasts and macrophages
  • cytokines cause fibroblast activation, recruitment, proliferation, differentiation into myofibroblasts and increased collagen synthesis and deposition –> thickened interstitial layer –> problems with ventilation and oxygenation + stiffer alveoli
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14
Q

Is interstitial lung disease obstructive or restrictive?

A

Restrictive - restricted lung expansion due to fibrosis of interstitium

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15
Q

What is interstitial lung disease characterised by?

A

Honeycombing: loss of alveoli –> fluid-filled cysts surrounded by thick wall

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16
Q

What are the clinical features of interstitial lung disease? (6)

A
  • gradual onset
  • progressive dyspnoea - initially on exertion, then progresses to dyspnoea at rest
  • chronic dry cough
  • bibasal fine end-inspiratory crackles on auscultation
  • weight loss, fatigue, malaise
  • digital clubbing
17
Q

What might you see on examination of interstitial lung disease? (4)

A
  • bibasal fine end-inspiratory crackles
  • clubbing (chronic disease)
  • cyanosis
  • signs of right heart failure (advanced disease)
18
Q

What are the risk factors for interstitial lung disease? (9)

A
  • advanced age
  • male sex
  • family Hx
  • gene mutations and nucleotide polymorphisms
  • cigarette smoking
  • occupational and environmental exposures
  • GORD
  • viral/bacterial infection
  • diabetes
19
Q

What are the first-line investigations for interstitial lung disease? (3)

A
  • CXR
  • high-resolution CT (HRCT) chest
  • pulmonary function tests (spirometry)
20
Q

What do we see on spirometry in interstitial lung disease?

A
  • restrictive lung disease pattern (reduced FEV1, significantly reduced FVC, increased FEV1/FVC ratio >0.7)
  • reduced TLCO (total capacity of the lung for CO)
  • decreased lung volume and compliance
21
Q

What do we see on HRCT in interstitial lung disease?

A
  • honeycombing
  • multiple cystic lesions within lung parenchyma due to fibrosis, ‘ground glass’ appearance
22
Q

What do we see on CXR in interstitial lung disease? (5)

A
  • bilateral lower zone reticulonodular shadowing
  • honeycombing
  • ground-glass appearance
  • signs of cor pulmonale
  • shaggy heart borders
23
Q

What is the gold standard investigation for idiopathic pulmonary fibrosis?

A

High resolution CT

24
Q

What might you see on bloods in interstitial lung disease?

A
  • raised CRP
  • raised Ig
  • ABG - normal in early disease, pO2 decreases with exercise, pCO2 rises in late stage disease
  • ANA and RF (1/3 will be positive)
  • anti-CCP and myositis panel to rule out collagen vascular disease
25
Q

What are some differential diagnoses for interstitial lung disease? (8)

A
  • interstitial pneumonia
  • interstitial lung disease
  • drug-related pulmonary fibrosis
  • asbestosis
  • sarcoidosis
  • Langerhan’s cells histiocytosis (Hx smoking and spontaneous pneumothorax)
  • hypersensitivity pneumonitis (IgG bodies, antigen exposure)
  • lymphangioleiomyomatosis
26
Q

When can idiopathic pulmonary fibrosis be diagnosed?

A

In the absence of findings that suggest an alterative disease process, IPF can be diagnosed on clinical grounds when:

  • an appropriate history of progressive symptoms (dyspnoea and cough)
  • characteristic X-ray findings
  • restrictive physiology on pulmonary function testing
27
Q

What supportive care is offered for interstitial lung disease? (5)

A
  • oxygen therapy
  • pulmonary rehabilitation
  • vaccinations - influenza, pneumococcal
  • PPI if symptomatic reflux
  • palliative care
28
Q

What is the first-line management for an acute exacerbation of idiopathic pulmonary fibrosis? (3)

A
  • admission to hospital + supportive care
  • high-dose prednisolone
  • consider cytotoxic therapy (e.g. cyclophosphamide)
29
Q

What is the first-line management for ongoing idiopathic pulmonary fibrosis? (3)

A
  • antifibrotic therapy - pirfenidone, nintedanib
  • cessation of smoking/drugs associated with pulmonary toxicity
  • pulmonary rehabilitation
30
Q

What is the second-line management for idiopathic pulmonary fibrosis?

A

Lung transplantation - only definitive treatment available, indicated in end-stage ILD

31
Q

What are some complications of interstitial lung disease? (6)

A
  • lung cancer
  • GORD
  • pulmonary hypertension
  • cor pulmonale (right heart failure due to pulmonary hypertension)
  • respiratory failure
  • pulmonary infection
32
Q

Describe the prognosis of interstitial lung disease.

A

Poor, average life expectancy around 3-4 years