Idiopathic pulmonary fibrosis

Question 1

What is idiopathic pulmonary fibrosis?

Answer 1

Chronic inflammation of the lung resulting in fibrosis of alveoli + interstitium.
= an interstitial lung disease
Fibrosis = excess collagen in connective + interstitial tissue causing thickening

Question 2

What was Idiopathic pulmonary fibrosis previously known as?

Answer 2

cryptogenic fibrosing alveolitis.

Question 3

Describe the aetiology of Idiopathic pulmonary fibrosis

Answer 3

Occurs in genetically predisposed individuals
RESTRICTIVE: fibrosis of the interstitium restricts expansion

Question 4

Describe the pathophysiology of Idiopathic pulmonary fibrosis

Answer 4

Recurrent injury to alveolar epithelial cells results in secretion of cytokines + growth factors
Cytokine release causes activation of fibroblasts between alveoli + capillaries, recruitment, proliferation, differentiation into myofibroblasts + increased collagen synthesis + deposition
This leads to a thickened interstitial layer impairing ventilation + oxygenation.
Alveoli are stiffer + there is loss of alveoli leading to fluid filled cysts surrounded by a thick wall (honeycombing)

Question 5

List 7 risk factors for Idiopathic pulmonary fibrosis

Answer 5

Age 
Male  
Smoking 
FH   
Occupational exposure to metal or wood   
Chronic microaspiration   
Animal + vegetable dusts

Question 6

List 5 symptoms of Idiopathic pulmonary fibrosis

Answer 6

Gradual-onset, progressive dyspnoea on exertion   
Dry irritating cough   
NO wheeze    
Fatigue 
Malaise

Question 7

List 5 signs of Idiopathic pulmonary fibrosis

Answer 7

Clubbing (50%)  
Bibasal fine end inspiratory crackles (like velcro)
Cyanosis  
Weight loss
Signs of RHF in advanced stages

Question 8

What is seen on ABG in Idiopathic pulmonary fibrosis?

Answer 8

Normal in early disease
PO2 decreases with exercise
Normal PCO2, which rises in late stage disease

Question 9

What immunoglobulins may be seen in Idiopathic pulmonary fibrosis?

Answer 9

ANA + Rheumatoid Factor
1/3 of patients are positive

Question 10

Describe pulmonary function tests in Idiopathic pulmonary fibrosis

Answer 10

Restrictive features (reduced FEV1 + FVC, with preserved or increased FEV1/FVC)
Decreased lung volumes
Decreased lung compliance
Decreased total lung capacity

Question 11

What is seen on spirometry in idiopathic pulmonary fibrosis?

Answer 11

FEV1 reduced: vol they can forcibly exhale in 1s reduced

FVC reduced: total vol of air exhaled in 1 breath reduced

FEV1/FVC increased

TLCO reduced: impaired gas exchange as fibrotic areas unable to transfer O2 properly

Question 12

What is the gold standard investigation for diagnosis of Idiopathic pulmonary fibrosis?

Answer 12

Lung Biopsy
Though not always needed

Question 13

What is more sensitive in early disease than CXR?

Answer 13

High resolution CT

Question 14

Describe the epidemiology of Idiopathic pulmonary fibrosis

Answer 14

RARE
6/100,000
M > F

Question 15

What 2 key histories should be ascertained from a patient with suspected idiopathic pulmonary fibrosis?

Answer 15

Full occupational + drug history

Question 16

What may symptoms of idiopathic pulmonary fibrosis be preceded by?

Answer 16

Viral-type illness

Question 17

Name 2 drugs that can produce an illness similar to idiopathic pulmonary fibrosis

Answer 17

Methotrexate
Amiodarone

Question 18

Describe the histological pattern of idiopathic pulmonary fibrosis

Answer 18

Usual Interstitial pneumonia
but not all patients with UIP have IPF