Thoracic-respiratory

Question 1

By how much does IPF increase the risk of bronchogenic carcinoma?

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Answer 1

Up to 7-fold

This increased risk is present irrespective of smoking history.

Question 2

What is the histopathological pattern associated with IPF?

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Answer 2

Usual interstitial pneumonia (UIP)

UIP can resemble other conditions like collagen vascular disease and drug toxicity.

Question 3

Where do severe changes occur in UIP?

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Answer 3

Peripheral subpleural parenchyma

Question 4

What does a CXR typically show in IPF patients?

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Answer 4

Basal bilateral asymmetric peripheral reticular and small, rounded opacities

Seen similarly in asbestosis and connective tissue disease, such as rheumatoid arthritis and systemic sclerosis.

Question 5

What does HRCT reveal in IPF?

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Answer 5

• Subpleural bibasal reticular pattern
• Honeycomb destruction
• Mediastinal lymphadenopathy

Traction bronchiectasis may be seen in more severe disease.

Question 6

How does IPF typically progress in the lungs?

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Answer 6

Starts posteriorly at the lung bases and extends cranially and anteriorly

The mid zones are laterally placed, and upper zones lie anteriorly.

Question 7

What is the key finding in IPF pathology?

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Answer 7

Honeycomb destruction

Although less common, this finding can also occur in non-specific interstitial pneumonia (NSIP).

Question 8

What is the mean age of onset for NSIP?

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Answer 8

The mean age of onset is 40-50 years, with no gender preference or association with smoking.

Question 9

What histopathological causes are linked to NSIP?

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Answer 9

NSIP is linked to various non-idiopathic causes, including connective tissue disorders:

• Systemic sclerosis
• Polymyositis
• Dermatomyositis
• Sjögren’s syndrome
• Rheumatoid disease

Question 10

How does the prognosis of NSIP depend on fibrotic extent?

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Answer 10

The prognosis depends on the fibrotic extent, leaning towards IPF.

The more fibrotic the disease, the closer the prognosis tends toward the poor prognosis of IPF.

Question 11

What does CXR show in NSIP cases?

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Answer 11

CXR shows changes in about 90% of cases. The changes range from predominantly interstitial infiltrates to mixed alveolar and interstitial infiltrates, to predominantly alveolar infiltrates, favouring the middle and lower zones.

The spectrum of appearances reflects the cellular to fibrotic spectrum of pathology.

Question 12

What does HRCT reveal in NSIP?

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Answer 12

HRCT consistently shows symmetrical bilateral Ground Glass Opacities (GGO) at the bases due to interstitial thickening from inflammation and fibrosis.

Traction bronchiectasis, reticulation and consolidation probably reflects an associated organising pneumonia.

Question 13

What indicates a predominantly fibrotic process in NSIP?

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Answer 13

Reticulation and/or GGO with architectural distortion/traction bronchiectasis indicates a predominantly fibrotic process (type III NSIP).

Question 14

What favors the cellular type I NSIP?

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Answer 14

GGO without fibrosis favours the cellular type I (type I NSIP).

Question 15

Why is diagnosing NSIP challenging?

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Answer 15

HRCT variability makes a confident diagnosis of NSIP challenging compared to IPF.

Question 16

What challenges exist in differentiating fibrotic type NSIP from IPF?

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Answer 16

Fibrotic type NSIP may include honeycombing and be challenging to differentiate from IPF solely on HRCT.

Question 17

What is respiratory bronchiolitis?

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Answer 17

A common histological finding in heavy smokers that can progress to a more severe form called respiratory RB-ILD, associated with interstitial lung disease.

Question 18

Who are most affected by RB-ILD?

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Answer 18

Most patients are young to middle-aged heavy smokers.

Question 19

What is a common finding on chest radiography for RB-ILD?

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Answer 19

A reticulonodular pattern with patchy ground-glass shadowing, favoring the bases. About 20% have a normal CXR.

Question 20

What are the HRCT findings in RB-ILD?

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Answer 20

• Patchy ground-glass opacities (GGO)
• Poorly-defined centrilobular nodules
• Interstitial thickening (less common)
• Honeycombing (less common)

There is considerable overlap in the HRCT appearances of RB-ILD and DIP reflecting the somewhat arbitrary distinction between the two.

Question 21

What is the primary characteristic of DIP?

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Answer 21

In DIP, macrophages accumulate in distal air spaces, originally thought to be desquamated epithelial cells. Despite histological and etiological similarities to RB-ILD, DIP is considered a separate entity due to a poorer prognosis.

Question 22

Who is primarily affected by DIP?

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Answer 22

DIP primarily affects smokers (90%), with men being more common (mean age 42 years, range 30-54 years).

Question 23

What is the classic radiograph appearance of DIP?

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Answer 23

The ‘classic’ plain radiograph appearance of hazy ground-glass in lower zones extending to costophrenic angles is rare.

Variation exists in radiographic findings, with upper and lower zones predominantly showing ground-glass shadowing and a nodular or granular texture. Reticular patterns, fibrosis, atelectasis, and irregular densities are less common.

Question 24

What does CT scanning reveal in cases of DIP?

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Answer 24

CT scanning identifies GGO in all cases. The distribution is typically:
* Lower zone
* Peripheral
* May be patchy

Minor honeycombing is seen in less than a third of cases.

Question 25

What are the common symptoms of COP? ## Footnote 1b_016

Answer 25

Persistent symptoms: * Short cough history * Dyspnoea * Fever * Weight loss * Chills * Myalgia ## Footnote A rapid and complete response to long-term steroid treatment is usually seen.

Question 26

Which group is more affected by COP, smokers or non-smokers? ## Footnote 1b_016

Answer 26

Non-smokers are more affected than smokers.

Question 27

How is COP characterized on a CXR? ## Footnote 1b_016

Answer 27

COP is characterized by patchy, occasionally subpleural areas of consolidation bilaterally. ## Footnote There are areas of apparent cavitation and small nodular opacities in 10-50% of cases.

Question 28

What patterns can COP present with on HRCT? ## Footnote 1b_016

Answer 28

COP can present with: * Consolidation * Ground-glass opacification * Multiple nodules * Band opacities * Perilobular pattern

Question 29

What is lymphoid interstitial pneumonitis (LIP)? ## Footnote 1b_016

Answer 29

A disease characterized by a widespread interstitial lymphoid infiltrate in the lungs, resembling lymphoma with a chronic interstitial pneumonia course. ## Footnote LIP is distinct from other lung diseases due to its lymphoid infiltrate pattern.

Question 30

In which demographic is LIP more common? ## Footnote 1b_016

Answer 30

More common in women and can affect any age group. ## Footnote The prevalence in women suggests a possible gender-related factor in its development.

Question 31

What underlying conditions are often associated with LIP? ## Footnote 1b_016

Answer 31

* Sjögren’s syndrome - Adult * AIDS - Adult/children ## Footnote LIP without an associated disease is considered rare.

Question 32

What findings can be observed in CT scans of LIP patients? ## Footnote 1b_016

Answer 32

* Bilateral diffuse ground-glass opacities (GGO) * Poorly-defined centrilobular nodules * Patchy distribution is less common. ## Footnote These imaging findings help differentiate LIP from other pulmonary conditions.

Question 33

What abnormality may become predominant in LIP? ## Footnote 1b_016

Answer 33

Cyst formation deep in the lung parenchyma. ## Footnote This differs from the subpleural distribution typically found in IPF.

Question 34

What is acute interstitial pneumonitis? ## Footnote 1b_016

Answer 34

Acute interstitial pneumonitis can be regarded as an idiopathic form of the adult respiratory distress syndrome (ARDS) and is histologically and clinically distinct from other interstitial pneumonias.

Question 35

What are common symptoms preceding acute interstitial pneumonitis? ## Footnote 1b_016

Answer 35

A recent history of a viral type upper respiratory tract infection with constitutional symptoms, such as myalgia, fevers, and malaise, is common.

Question 36

What does a CXR show in acute interstitial pneumonitis? ## Footnote 1b_016

Answer 36

* Bilateral patchy air space opacification * Air bronchograms * Sparing the costophrenic angles (sometimes)

Question 37

What findings does HRCT demonstrate in acute interstitial pneumonitis? ## Footnote 1b_016

Answer 37

* Ground-glass opacification * Air space consolidation * Bronchial dilatation * Architectural distortion

Question 38

What happens to ground-glass attenuation and bronchial dilatation over time in acute interstitial pneumonitis? ## Footnote 1b_016

Answer 38

The extent of ground-glass attenuation and bronchial dilatation increases with disease duration, and follow-up scans in survivors demonstrate clearing of the ground-glass attenuation and consolidation, leaving reticular opacities consistent with residual fibrosis.

Question 39

Describe the x-ray findings and what is the likely diagnosis? ## Footnote 1b_019

Answer 39

Bilateral hilar lymphadenopathy - **Sarcoidosis** ## Footnote * Sarcoidosis a common multi-system disease. * Of all organs, the **lung** is the most commonly involved and accounts for most of the morbidity and mortality. * The exact cause and pathogenesis of sarcoidosis are not known. * More common in** temperate** than in tropical climates and is most common in **black** people (**young black females**).

Question 40

What disease markers have been reported in sarcoidosis? ## Footnote 1b_019

Answer 40

* Circulating immune complexes * Depressed cutaneous delayed type hypersensitivity * Increased CD4 to CD8 ratio * Raised serum ACE levels * Increased uptake radioactive gallium * Abnormal calcium metabolism ## Footnote None of these findings are specific for sarcoidosis!

Question 41

What other diseases can simulate histological or radiological features of sarcoidosis? ## Footnote 1b_019

Answer 41

* Tuberculosis (TB) - often **unilateral hilar lymphadenopathy** * Fungal infection * Hypersensitivity pneumonitis (HSP) * Lymphoma - most often **anterior mediastinal or paratracheal lymphadenopathy** or *unilateral hilar lymphadenopathy* ## Footnote The diagnosis of sarcoidosis is often one of exclusion. A confident diagnosis of sarcoidosis can be made with consistent clinical findings and radiology appearances and with histological evidence of **widespread non-caeseating epithelioid cell granulomas** in more than one organ.

Question 42

Which conditions are associated with **'egg-shell' calcification** of mediastinal/hilar lymph nodes? ## Footnote 1b_019

Answer 42

* Silicosis (5%) * Treated lymphoma (post-radiation Hodgkin disease) * Coal workers' pneumoconiosis (1%) * ** Sarcoidosis (20%)** * Scleroderma * Amyloidosis * Blastomycosis (rare) * Histoplasmosis (rare)

Question 43

What patterns of abnormality are seen in sarcoidosis? ## Footnote 1b_019

Answer 43

* Nodular - Irregular margins in a bronchovascular and subpleural distribution * **Reticulonodular** (most common pattern) - Nodular pattern accompanied with interlobular septal thickening or intralobular linear opacities * Reticular - Interlobular septal thickening, intralobular linear opacities, *traction bronchiectasis, honeycombing (fibrosis)* * Air space consolidation * Ground glass opacification ## Footnote The lung abnormality is typically **bilateral and symmetrical** and involves the **mid and upper zones**. Nodular, reticulonodular, air space and ground glass abnormality may indicate **potentially reversible disease**, whilst reticular shadowing may represent **irreversible fibrosis**.

Question 44

Describe the findings on the HRCT. ## Footnote 1b_019

Answer 44

There is very marked nodular bronchovascular bundle thickening and peripheral subpleural nodules ## Footnote Sarcoidosis

Question 45

Describe the findings on the HRCT. ## Footnote 1b_019

Answer 45

Nodules are clustered around the oblique fissure on each side, with resultant thickening and beading, but nodules are also seen to cluster along the horizontal fissure, causing a curvilinear arc of nodules in the mid right lung. ## Footnote Sarcoidosis