interstitial and occupational lung disease

Question 1

what is an interstitial disease?

Answer 1

• any disease process affecting lung interstitial ie alveoli, terminal bronchi
• it interfered with gas transfer
• restrictive lung pattern
• symptoms: breathlessness, dry cough

Question 2

what are the classifications of interstitial lung disease?

Answer 2

• acute
• episodic
• chronic = part of systemic disease, exposure to agent eg drugs, dust, idiopathic

Question 3

what is sarcoidosis?

Answer 3

• tye 4 hypersensitivity
• multi-system involvement = lungs, lymph nodes, joints, liver, skin, eyes
• non-caseating granuloma of unknown aetiology
• less common in smokers

Question 4

what is acute sarcoidosis?

Answer 4

• erythema nodosum = painful lumps on shins
• bilateral hilar lymphadenopathy
• arthritis
• uveitis, parotitis
• fever
• most common, will go away on its own

Question 5

what is chronic sarcoidosis?

Answer 5

• lung infiltrates (alveolitis)
• skin infiltrations
• peripheral lymphadenopathy
• hypercalcaemia
• other organs = renal, myocardial, neurological, hepatitis, splenomegaly

Question 6

what are the differential diagnosis’s or sarcoidosis?

Answer 6

TB, lymphoma, carcinoma, fungal infection

Question 7

what investigations would you carry out for sarcoidosis?

Answer 7

• chest xray
• pulmonary funciton
• ## blood test

Question 8

what is the treatment for acute sarcoidosis?

Answer 8

• self limiting condition = usually no treatment

- steroids if vital organ affected impaired lung function, heart, eyes, brain, kidneys)

Question 9

what is the treatment for chronic sarcoidosis?

Answer 9

• oral steroids

- immunosuppressions (eg azathioprine, methotrexate, anti-TNF therapy)

Question 10

what is extrinsic allergic alveolitis (hypersensitivity pneumonitis)?

Answer 10

• type 3 hypersensitivity reaction to antigen lymphocytic alveolitis
• aetiology: thermophilic actinomycetes (farmers lung, malt workers, mushroom workers

Question 11

what is acute extrinsic allergic alveolitis 1?

Answer 11

symptoms = cough, breathless, fever, myalgia, pyrexia, crackles, hypoxia, widespread pulmonary infiltrates in CXR
symptoms occur over several hours after acute exposure
treatment = oxygen, steroid, and antigen avoidance

Question 12

what is chronic extrinsic allergic alveolitis II?

Answer 12

• repeated low dose antigen exposure over years
  symptoms: pregressive breathlessness, cough, crackles, pulmonary fibrosis i nCXR - most common in upper zones
• low FEV1 & FVE
  diagnosis = history of exposure, precipitins
  treatment = remove antigen exposure, oral steroids if breathless or low gas transfer

Question 13

what is idiopathic pulmonary fibrosis?

Answer 13

• most common interstitial lung disease
• not an inflammatory disease
• common in smokers
• rheumatoid, SLE, systemic sclerosis, asbestos, amiodarone, busulphan

Question 14

what is the presentation of idiopathic pulmonary fibrosis?

Answer 14

• progressive breathlessness over several years
• dry cough

OE - clubbings, bilateral fine inspiratory crackles

Ix = restrictive defect of PFT
CxR = bilateral infiltrates
CT scan = retriculnodular fibrosis shadowing, worse at lung bases and peripheries
lung biopsy = not necessary if CT scan is diagnostic