Diffuse parenchymal lung disorders / interstitial lung diseases Flashcards
What are interstitial lung diseases?
Group of diseases with bilateral diffuse lung injury and inflammation that can progress to lung fibrosis
Involves interstitial space, alveoli, bronchioles and blood vessels
What is the common presentation?
Dyspnoea
Persistant non productive cough
Abnormal CXR- bilateral diffuse pulmonary infiltrates
Pulmonary symptoms
What is sarcoidosis?
Multi-system granulomatous disorder affecting any organ system, but predominantly the lymph nodes and lung
What genes mutations are associated with sarcoidosis?
HLA-DRB1 and DQB1 alleles
What type of granuloma is present in sarcoidosis?
non-caseating sarcoid granuloma: focal accumulation of epithelial cells, macrophages and lymphocytes.
Describe the pathophysiology of sarcoidosis?
T cells are removed in the lung and trapped in granulomas
–>
Depressed cell mediated reactivity to antigens such as tuberculin and candida albicans + overall lymphopenia with low circulating T cells
Increased number of cells (esp. CD4 helper) in bronchoalveolar lavage
Describe epidemiology of sarcoidosis
age = 20-40
F>M
Afro Caribbean > Caucasian
How does sarcoidosis usually present
Often incidental finding on CXR
Acute sarcoidosis presents with erythema nodosum, and polyarthralgia
What is erythema nodosum?
red lumps caused by inflammation of fat cells
What is polyarthralgia?
Multiple achy joints
What pulmonary features are present in sarcoidosis?
CXR – bilateral hilar lymphadenopathy ± pulmonary infiltrates or fibrosis
Progressive dyspnoea
Dry cough
decreased exercise tolerance
Chest pain
What non pulmonary signs are there?
Literally everything man
But most commonly: Lymphadenopathy, Hepatomegaly, Splenomegaly, Uveitis
What is the differential diagnosis of Bi-hilar lymphadenopathy?
Sarcoidosis
Infection e.g. TB, mycoplasma
Malignancy e.g. lymphoma, carcinoma, mediastinal tumours
Organic dust disease e.g. silicosis, berylliosis
Extrinsic allergic alveolitis (hypersensitivity pneumonitis)
Histocytosis X
What different types of granulomatous disease are there?
Infections Autoimmune Vasculitis Organic dust disease Idiopathic Hypersensitivity pneumonitis Histiocytosis X
What blood test results are typical for a patient with sarcoidosis?
Raised ESR Lymphopenia Raised serum ACE in 60% (non specific) Raised LFTs, Raised calcium Raised IGs
What will urine analysis show for a patient with sarcoidosis?
Raised calcium
Chest Xray is abnormal in 90% what are stages 0-4 for sarcoidosis
0- normal 1- Bi-hilar lymphadenopathy 2- BHL + pulmonary infiltrate 3- pulmonary infiltrate alone 4- Pulmonary fibrosis with honey combing and pleural involvement
What do lung function tests show for patients with sarcoidosis?
generally show restriction and reduced volume
What spirometry results would indicate restrictive lung disease
FVC <0.8 of expected value
FEV1 >0.8 of FVC
A positive tissue biopsy in sarcoidosis is diagnostic. What would a tissue biopsy show?
shows non-caseating granuloma – lung, liver, lymph nodes, skin nodules
What does broncheoalveolar lavage show in patients with sarcoidosis?
Bronchoalveolar lavage (BAL) – shows increased lymphocytes in active disease, increased neutrophils in pulmonary fibrosis
How would you treat BHL associated with sarcoidosis?
BHL alone doesn’t need treatment
For acute sarcoidosis bed rest and NSAIDs are likely to induce a spontaneous recovery.
What are indications that a patient with sarcoidosis needs to be put on oral prednisolone? (corticosteroid)
Parenchymal lung disease
Uveitis
Hypercalcaemia
Neurological/cardiac involvement
If sarcoidosis is not controlled by prednisolone what progressive treatment options are there?
Iv methylprednisolone or immunosuppressants (methotrexate, hydroxychloroquine, ciclosporin, cyclophosphamide)
What are common dose related side effects of methotrexate?
Mucosal damage and bone marrow suppression
What contraindications are there for methotrexate?
Teratogenic so avoid in pregnancy
How does methotrexate act?
Inhibits conversion of folate into active form–> inhibits DNA production and hence cell division
Should prescribe folic acid with it!!
Idiopathic pulmonary fibrosis, what is it?
A type of idiopathic interstitial pneumonia.
Inflammatory cell infiltrate and pulmonary fibrosis of unknown cause.
Idiopathic pulmonary fibrosis symptoms?
Dry cough Exertional dyspnoea Malaise Weight loss Arthralgia
Idiopathic pulmonary fibrosis signs?
Cyanosis
Finger clubbing
Fine end inspiratory crackles
Idiopathic pulmonary fibrosis complications?
Respiratory failure
Increased risk of cancer
Blood test results for patient with idiopathic pulmonary fibrosis
ABG: PaO2 low, if severe then PaCo2 is also high
CRP raised
Ig’s raised
ANA and rheumatoid factors (very unspecific but indicative of disease)
CXR for patients with idiopathic pulmonary fibrosis
Lung volume decreased
Bi-lateral lower zone reticulo-nodular shadows
Honey comb lung
CT shows the same but more sensitive
What would spirometry show for idiopathic pulmonary fibrosis?
Restrictive changes
FVC< 0.8 of expected value
FEV1>0.8 FVC
Lung biopsy may be required for a diagnosis what are the histological changes observed called?
Usual interstitial pneumonia
Treatment for idiopathic pulmonary fibrosis?
O2 Supportive treatment Palliative care Opiates pulmonary rehab Lung transplant is feasible
What is interstitial lung disease?
Characterized by chronic inflammation and/or progressive interstitial fibrosis
Describe the pathology of interstitial lung disease
Fibrosis and remodelling of the interstitium
Chronic inflammation
Hyperplasia of type 2 pneumocytes
Clinical presentation of interstitial lung disease?
Dyspnoea on exertion Non productive paroxysmal (sudden intense recurrence) cough Abnormal breathing sounds Abnormal Xray and CT Spirometry shows restriction, reduced tCO
(everything you would expect tbh)
Name 4 occupational interstitial lung diseases
Asbestosis, berylliosis, silicosis, cotton workers lung
What drugs can cause occupational interstitial lung disease?
Nitrofurantoin (abx for bladder infection) Bleomycin Amiodarone (anti- arrhythmic drug) Sulfasalazine (RA drug) Busulfan (chemo)
What are all the different causes of interstitial lung disease?
Occupational (Asbestosis)
Drugs (amiodarone)
Hypersensitivity (Hypersensitivity pneumonitis)
Infections (e.g. viral)
GORD
Those associated with systemic disorders (e.g. sarcoidosis, SLE)
Idiopathic (idiopathic pulmonary fibrosis)
