Interstitial lung diseases Flashcards

1
Q

What does this chest x-ray show?

A

Interstitial shadowing

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2
Q

What are the features of interstitial shadowing on a chest x-ray?

A
  • Reticular i.e. linear, lace-like pattern
  • “too many lung markings”
  • May be focal or diffuse
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3
Q

What is the interstitium?

A

Refers to supporting structures of the lung

Includes:

  • alveolar endothelium
  • capillary endothelium
  • basement membrane
  • connective tissue
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4
Q

What can thicken the interstitium?

A

In disease it can be thickened by:

  • Fluid
  • Cells

Fibrosis

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5
Q

Where does interstitial lung disease affect?

A
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6
Q

What does the second image show?

A

Thickened septa

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7
Q

What is the extraceullar matrix?

A

3D fibre mesh filled with macromolecules e.g. collagen, elastin

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8
Q

What are the functions of the extracellular matrix?

A
  • Tensile strength/elasticity
  • Low resistance for effective gas exchange
  • Tissue repair/modelling
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9
Q

What does aberrant wound healing cause in fibrosis?

A

In fibrosis, aberrant wound healing leads to excessive deposition in the interstitium

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10
Q

What are the types of interstitial lung disease?

A

ENVIRONMENTAL EXPOSURE

◦Occupational lung disease

  • Silicosis (silica exposure)
  • Coal miners lung (coal dust exposure)
  • Asbestosis (asbestos exposure)

◦Hypersensitivity pneumonitis - mold and bird proteins are common causes

IDIOPATHIC (unknown cause)

Idiopathic pulmonary fibrosis is the prototypical ILD

SYSTEMIC INFLAMMATORY DISEASES

Connective tissue disease-ILD

Sarcoidosis

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11
Q

What is the simplified classification of interstitial lung disease?

A
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12
Q

What does this chest x-ray show?

A

◦Small lungs

◦Increased reticular shadowing

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13
Q

What do these lung function tests indicate?

◦FEV1 56%

◦FVC 50%

◦FEV1/FVC 86%

◦TLCO 50%

A

◦FEV1 56%

◦FVC 50%

◦FEV1/FVC 86%

= restrictive

◦TLCO 50%

= impaired gas transfer

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14
Q

Whats the diagnosis?

◦Older man

◦Chronic history of dyspnoea

◦Radiological evidence of ILD

◦Restrictive lung function with impaired gas transfer

◦No identifiable cause

A

◦Dx = Idiopathic Pulmonary Fibrosis

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15
Q

What are the symptoms of idiopathic pulmonary fibrosis?

A

Symptoms and clinical signs of IPF often appear gradually and include:

◦Slowly progressive exertional dyspnoea

◦Non-productive cough

◦Dry, inspiratory bibasal “Velcro®” crackles

◦+/- Clubbing of fingers

◦Abnormal pulmonary function test results

◦restriction and impaired gas exchange

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16
Q

What is the HRCT pattern?

A

To diagnose idiopathic pulmonary fibrosis on CT -

Basal distribution

Subpleural

Traction bronchiectasis

Honeycombing

If present on CT – no biopsy needed

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17
Q

What disease is this?

A

Idiopathic pulmonary fibrosis

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18
Q

Who is more likley to have idiopathic pulmonary fibrosis?

A

◦is a disease of older age (median age 66yrs)

◦is more common in men (2:1)

◦is more common in smokers (60%)

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19
Q

What are the clinical features of idiopathic pulmonary fibrosis?

A

◦is of unknown cause

◦causes progressive, irreversible fibrosis and is fatal

◦is limited to the lungs (unlike other ILDs eg sarcoidosis)

◦Affects lower and peripheral lung

◦Minimal inflammation – no role for steroids

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20
Q

Is prevelance of IPF in the UK increasing or decreasing?

A

Increasing

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21
Q

What is the prognosis for IPF patients?

A

◦median survival is 3 years from diagnosis

◦BUT 20% still alive at 5 years

◦no reliable way to predict prognosis

◦patients therefore live with considerable uncertainty

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22
Q

How is IPF managaed?

A

oAssess suitability for anti-fibrotic drugs

  • Pirfenidone or Nintedanib
  • Can only be prescribed by specialist centres
  • Aim is to slow rate of disease progression
  • Criteria
  • diagnosis of IPF
  • FVC 50-80% predicted

oAssess suitability for Lung transplant

  • Age <65
  • No significant comorbidities

oOffer best supportive care to all

  • Treat co-morbidities
  • Palliate symptoms
  • Refer to palliative care
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23
Q

Why are anti-fibrotic drugs often poorely tolerated?

A

Often poorly tolerated – weight loss, GI upset, photosensitivity

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24
Q

Whats the diagnosis?

  • 24yo man
  • Rapidly progressive SOB and cough over 3 months, struggling with ADLs
  • No response to antibiotics or inhalers
  • PMHx: depression, on Sertraline
  • Smoker 20/day
  • Unemployed
  • Unable to complete sentences, bilateral crackles, sats 89%
  • No rheumatological symptoms, CTD screening bloods normal
A

Sertraline-induced ILD

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25
Q

Whats the diagnosis?

◦63yo lady

◦Admitted with 10/52 history dry cough and SOB

◦Bilateral crackles all zones, sats 85%

◦No PMHx or regular meds

◦Non smoker

◦No occupational exposures

◦Kept budgies for several years

A

Hypersensitivity Pneumonitispe

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26
Q

What is Hypersensitivity Pneumonitis?

A
  • Diffuse inflammation of parenchyma in response to inhaled antigen
  • Tends to involve upper lobes
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27
Q

What are the antigens that cause Hypersensitivity Pneumonitis?

A
  • Bird-fanciers (bird droppings)
  • Farmers lung (thermophilic fungi)
  • Aspergillus (ubiquitous fungus)
  • Can be anything…
  • Antigen unknown in 50%
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28
Q

How does Hypersensitivity Pneumonitis present acutely?

A
  • SOB, cough, fever, malaise, crackles within 4-6 hours of heavy exposure
  • Often misdiagnosed as infection
29
Q

How does Hypersensitivity Pneumonitis present sub-acute and chronically?

A

Subacute

•Gradual onset of symptoms, weight loss common

Chronic

  • Insidious onset, history of acute episodes may be absent
  • Incomplete resolution with removal of antigen
  • May lead to irreversible fibrosis
30
Q

What is the most common presentation of hypersensitivity pneumonitis?

A

Most cases of hypersensitivity pneumonitis develop only after many years of continuous or intermittent inhalation of the inciting agent

31
Q

How is Hypersensitivity Pneumonitis diagnosed?

A

Serum precipitins (circulating IgG antibody-antigen complexes) to specific antigen may be helpful

  • Infinite number of possible antigens
  • May be positive in asymptomatic individuals

Negative results does not exclude HP

32
Q

What is the management for Hypersensitivity pneumonitis?

A
  • Avoidance of inciting antigen
  • Usually steroid-responsive in early disease
  • May progress to irreversible fibrosis
33
Q

What 3 drugs cause drug-induced ILD?

A

◦Many drugs but most common:

◦Nitrofurantoin

◦Amiodarone

Methotrexate

34
Q

Drug induced ILD may develop months-years after starting the drug.

True or false?

A

True

35
Q

Which conditions cause Connective Tissue Disease-related ILD?

A
  • Rheumatoid Arthritis
  • Sjogrens
  • Scleroderma
  • Polymyositis
36
Q

Which patients are more likely to have Connective Tissue Disease-related ILD?

A

◦Younger patients

◦Female preponderance

37
Q

What should you ask about in a patient’s history when considering Connective Tissue Disease-related ILD?

A

dry eyes/mouth (sicca), Raynaud’s, joint pain/swelling, rashes

38
Q

What tests are done to diagnose Connective Tissue Disease-related ILD?

A

Bloods: Antinuclear antibodies (ANA), rheumatoid factor (RF)

39
Q

What is the management for Connective Tissue Disease-related ILD?

A

Liaise with rheumatology, treat underlying disease (biologics, steroids, immunosuppression)

40
Q

How is ILD diagnosed?

A

Clinical assessment – IS THERE AN IDENTIFIABLE CAUSE? - CTD symptoms, drugs, exposures

Bloods

  • Antinuclear Antibodies (ANA), Rheumatoid factor, Angiotensin-converting enzyme (ACE)

Spirometry/Lung function tests

  • FVC, FEV1/FVC ratio (normal or high), gas transfer NB may have co-existent COPD

CXR

  • Reticular shadowing

HRCT pattern of disease - the cornerstone of diagnosis but, only 60% are diagnostic

•Lung biopsy

  • Enhances diagnosis but risk often outweighs benefit
  • May differentiate IPF from other potentially reversible causes
41
Q

How is ILD treated?

A

MDT for diagnosis:

  • respiratory physician, respiratory radiologist, rheumatologist, +/- specialist histopathologist
  • combination of history, HRCT pattern of disease, auto-immune bloods

Treatment

  • Remove cause - budgie, medication, bagpipes(!) etc…
  • Immunosupression (prednisolone, hydoxychloroquine, Mycophenolate mofetil, methotrexate)
  • Anti-fibrotics for IPF
42
Q

What is sarcoid?

A
  • Multisystem granulomatous disorder
  • non-necrotising granulomas
43
Q

What causes sarcoid?

A
  • Cause unknown
  • 3 x more common in Afro-caribbeans, more severe disease

some familial clusters

44
Q

What age is most likely to get sarcoid?

A
  • Disease of the young
  • 75% of cases aged 30-60 years
45
Q

Sarcoid has a predictable clinical course.

True or false?

A

False

Unpredictable clinical course

46
Q

What disease is this?

A

Sarcoid

47
Q

What disease is this?

A

Sarcoid

48
Q

What are the histological features of sarcoidosis?

A

◦Characterised by granulomatous inflammation

◦Unknown foreign antigen stimulates immune response including:

  • CD4+ T cells,
  • alveolar macrophages
  • multi-nucleate giant cells

◦Organise into granulomas

◦Granulomas occur in TB and fungal infections, but in sarcoidosis they are non-necrotising

49
Q

How is sarcoidosis diagnosed?

A

A biopsy demonstrating granulomas along with clinical picture is needed to confidently diagnose sarcoidosis.

50
Q

Where in the body does sarcoidosis manifest?

A

Can affect any organ - Lung involvement in 90%

51
Q

What are the common presentations for sarcoid?

A
52
Q

What is Lofgren’s Syndrome?

A
  • Excellent prognosis
  • Usually self-limiting
53
Q

What are the symptoms of Lofgren’s Syndrome?

A
  • Erythema Nodosum
  • Bilateral Hilar Lymphadenopathy
  • Arthralgia
54
Q

What are the symptoms of pulmonary sarcoidosis?

A

oMay be asymptomatic (especially with isolated lymphadenopathy)

oCough

oDyspnoea with exertion

oChest tightness

oSystemic symptoms: fatigue, sweats, weight loss, fevers, arthralgia

55
Q

What are the 2 possible clinical outcomes in sarcoidosis?

A
56
Q

What are the 4 stages of pulmonary sarcoidosis?

A
57
Q

Patients may be asymptomatic despite significant CXR abnormalities in sarcoidosis.

True or false?

A

True

58
Q

How is pulmonary sarcoidosis diagnosed?

A

◦No single diagnostic test

◦Combination of clinical picture, exclusion of alternative diagnoses ( esp. lymphoma and TB) and ideally biopsy of affected tissue

◦Baseline tests

  • Renal function, liver function, calcium, serum ACE, CXR, ECG

•Serum Angiotensin-converting enzyme (ACE)

  • Secreted by activated alveolar macrophages in granulomas
  • Low sensitivity (60%), poor specificity
  • Polymorphisms in ACE gene → variation in peripheral blood ACE levels
  • No correlation with CXR stage of disease

◦Biopsy everything!

  • Skin, lymph nodes, blind endobronchial biopsies (44-70% yield)
59
Q

What is the treatment for pulmonary sarcoidsis?

A
  • Less clear-cut for pulmonary disease as often less severe than extra-thoracic disease with spontaneous remission common
  • short-term symptomatic benefit
  • long-term effect on natural history of disease not known
  • Corticosteroids for 6-24 months are mainstay
  • inhaled corticosteroids may provide symptomatic benefit
  • additional immunosuppressants e.g. methotrexate, azathioprine may be necessary
60
Q

What does a obstructive spirometry pattern indicate?

A

◦Indicates the problem is in the airways

◦Useful diagnostically:

  • Reversible airflow obstruction (asthma)
  • Fixed airflow obstruction in a smoker (COPD)

◦Only a few other diseases of the airways (bronchiectasis, obliterative bronchiolitis)

61
Q

What does a restrictive spirometry pattern indicate?

A

◦Indicates there is a problem

◦Not useful diagnostically

◦Useful for monitoring change

  • Acutely e.g. Guillain-Barre
  • Chronically e.g. MND

◦Indicates risk of ventilatory failure

◦Severity indicator for ILD

◦Treatment criteria for IPF

◦Anti-fibrotics only if FVC 50-80% predicted

62
Q

How is restrictive spirometry measured?

A

◦Directly measured by TLC - requires lung function lab

◦FVC reflects the TLC

  • can be done in clinic
  • useful for disease monitoring
63
Q

What causes a restrictive pattern of spirometry?

A

Restriction of lung expansion or loss of lung volume

64
Q

What are the possible causes of restrictive spirometry?

A
65
Q

What are the features of fibrotic lungs on lung function tests?

A
  • Fibrotic lungs are small and stiff
  • Higher elastic recoil than expected for volume
  • FEV1/FVC ratio may be high…but may be normal
  • ↓ TLCO (gas transfer)

•Impaired gas exchange due to disruption of alveolar-capillary interface

66
Q
A
67
Q

Complete the table

A
68
Q

Why is there a decrease in TLCO?

A

↓ TLCO (gas transfer)

•Reduced total surface area for gas exchange

or

•Impaired gas exchange due to disruption of alveolar-capillary interface