Resp Flashcards
1
Q
What is the pathophysiology of pulmonary fibrosis?
A
- Unknown
- Thought to be to do with repetitive injury to alveolar epithelium from environmental stimuli leading to activation of pathways responsible for the repair of damaged tissue
- Wound-healing mechanisms become uncontrolled, leading to overproduction of fibroblasts and deposition of increased extracellular matrix in the interstitium with little fibrosis
- Structural integrity of lung parenchyma is therefore disrupted and there is loss of elasticity and impaired ability to perform gas exchange, leading to progressive respiratory failure
2
Q
What are the risk factors of pulmonary fibrosis?
A
- Cigarette smoking
- Infectious agents (CMV, Hep C, EBV)
- Occupational dust exposure (metals, woods)
- Drugs e.g. methotrexate and some anti-depressants
- Chronic gastro-oesophageal reflux disease (GORD)
- Genetic predisposition
3
Q
What is the presentation of pulmonary fibrosis?
A
- Patchy pattern of disease with the sub-pleural regions of the lower lobes predominantly affected
- Variable interstitial inflammatory infiltrate in the affected areas
- Dry cough ± sputum
- Exertional dyspnoea
- Malaise
- Weight loss
- Arthralgia
- Cyanosis
- Finger clubbing
- Fine bi-basal end-inspiratory crackles
4
Q
What are the differential diagnoses of pulmonary fibrosis?
A
- COPD
- Asthma
- Bronchiectasis
- Congestive heart failure
- Atypical pneumonia
- Lung cancer
- Asbestosis
- Hypersensitivity pneumonitis
5
Q
How is pulmonary fibrosis diagnosed?
A
- Aim is to confirm the presence of pulmonary fibrosis and exclude other causes
- Blood tests: ABG (low PaO2), raised CRP, raised immunoglobulins, check antinuclear antibodies and rheumatoid factor to exclude other conditions
- CXR: small volume lungs with increased reticular shadowing at the bases (may be normal in early disease)
- High resolution CT: abnormalities more pronounced at bases, sub-pleural reticulation, traction bronchiectasis, honeycombing
- Spirometry/ respiratory function tests show a restrictive pattern
- Lung biopsy may be required
6
Q
How is pulmonary fibrosis managed?
A
- Serial lung function testing to monitor disease progression
- Best supportive care: oxygen (e.g. ambulatory oxygen), pulmonary rehabilitation, palliative care (i.e. opiates)
- Treat GORB (contributes to repetitive alveolar epithelial damage)
- Treat cough
- Pirfenidone (antibiotic that slows the rate of FVC decline)
- Lung transplant
- No high dose steroids unless diagnosis is in doubt
7
Q
What is the pathophysiology of sarcoidosis?
A
- Distinct cellular infiltrates and extracellular matrix deposition in lung distal to the terminal bronchioles
- Typical sarcoid granulomas consist of focal accumulations of epithelioid cells, macrophages and lymphocytes (mainly T cells)
- Affects any organ system, but commonly involves the mediastinal lymph nodes and lung
8
Q
What is the presentation of sarcoidosis? (Acute sarcoidosis, constitutional symptoms, respiratory symptoms, and other symptoms)
A
- Typically presents with bilateral hilar lymphadenopathy, pulmonary infiltration and skin/ eye lesions
- 20-40% asymptomatic
- Can affect any organ, but most commonly the lung
- Acute sarcoidosis commonly presents with erythema nodusum (red lumps on shins), ± polyarthritis
Constitutional symptoms:
- Fever
- Weight loss
- Fatigue
Respiratory symptoms:
- 90% have abnormal CXR with bilateral hilar lymphadenopathy ± pulmonary infiltrates
- Dry cough
- Progressive dyspnoea
- Reduced exercise tolerance
- Chest pain
Other symptoms:
- Lymphadenopathy
- Hepatomegaly
- Splenomegaly
- Conjunctivitis
- Glaucoma
- Anterior uveitis
- Hypercalciuria
- Enlargement of lacrimal and parotid gland
- Bell’s palsy (CN7 lesion)
- Facial numbness, dysphagia and visual field defects
- Lupus pernio – blueish-red/purple nodules and plaques over nose, cheek and ears
- Renal stones
- Cardiac arrhythmias
- Heart block
9
Q
What are the differential diagnosis of sarcoidosis?
A
- Rheumatoid arthritis
- Lymphoma
- Metastatic malignancy
- TB
- Lung cancer
- SLE
- Idiopathic pulmonary fibrosis
- Multiple myeloma
10
Q
How is sarcoidosis diagnosed?
A
- Tissue biopsy is DIAGNOSTIC as shows non-caseating granulomata
- CXR used for staging
- Blood tests: raised ESR, LFT, Ca2+ and immunoglobulins, lymphopenia, serum ACE, 24h urinary calcium
- Bronchoscopy
- ECG may show arrhythmias or BBB
- Lung function tests may show reduced lung volumes, impaired gas transfer and a restrictive ventilatory defect (but may also be normal)
- Bronchoalveolar lavage (BAL) shows increased lymphocytes in active disease and increased neutrophils if pulmonary fibrosis present
11
Q
How is sarcoidosis managed?
A
- Patients with bilateral hilar lymphadenopathy don’t need treatment (most will recover spontaneously)
- Don’t treat symptomatic stage 1 or asymptomatic stage 2/3 patients
- Acute sarcoidosis = bed rest and NSAIDs
- Corticosteroids: oral prednisolone then gradually reduce dose (IV methylprednisolone if severe or methotrexate if steroid-resistant)
- Transplantation in severe cases
- Treat extra-organ complications
12
Q
What is the aetiology of bronchiectasis? (Post-infection, congenital, and mechanical bronchial obstruction)
A
- HIV
- Ulcerative colitis
- Hypogammaglobulinaemia
- Rheumatoid arthritis
Post infection:
- Previous pneumonia
- Granulomatous disease e.g. TB
- Measles, whooping cough
- Allergic broncho-pulmonary aspergillosis
- Pertussis
- Bronchiolitis
Congenital:
- Cystic fibrosis
- Deficiency of bronchial wall elements
- Primary ciliary dyskinesia
Mechanical bronchial wall obstruction:
- Foreign body
- Post-TB stenosis
- Lymph node tumour
13
Q
What is the pathophysiology of bronchiectasis?
A
- Failure of mucociliary clearance and impaired immune function contribute to continued insult to bronchial wall through the recruitment of inflammatory cells and uncontrolled neutrophilic inflammation
- Airways dilate due to pulmonary inflammation and scarring as fibrosis contracts
- Secondary inflammation change lead to further destruction of airways
14
Q
What is the presentation of bronchiectasis?
A
- Usually affects the lower lobes
- Chronic cough with production of foul smelling purulent sputum (sometimes flecked with blood)
- Dyspnoea
- Finger clubbing (especially in cystic fibrosis)
- Wheeze
- Infection usually characterised by increased sputum volume and increased purulence
- Chest pain
- Recurrent exacerbations with long recovery time
15
Q
What are the differential diagnoses of bronchiectasis?
A
- COPD
- Asthma
- TB
- Chronic sinusitis
- Cough (from acid reflux)
- Pneumonia
- Pulmonary fibrosis
- Cancer
- Inhalation of foreign body
16
Q
How is bronchiectasis diagnosed? (What would you see on chest x-ray, sputum culture, high resolution CT and spirometry)
A
- CXR – dilated bronchi with thickened walls, multiple cysts containing fluid (show up as cystic shadows)
- Sputum culture – to see bacterial colonisation (major pathogens are Haemophilus influenza, Strep pneumoniae, Staph aureus and Pseudomonas aeruginosa)
- High resolution CT – thickened dilated bronchi with cysts at the end of bronchioles and airways larger than associated blood vessels
- Spirometry shows an obstructive pattern
- Sweat test for patients under 40 if suspected CF
- Bronchoscopy to locate site of haemoptysis
- Immunology
17
Q
How is bronchiectasis managed?
A
- Improved mucus clearance with postural drainage, chest physio and mucolytics
- Antibiotics to treat exacerbations
- Bronchodilators for patients with asthma or COPD
- Anti-inflammatory agents to reduce exacerbations
- Surgery in localised disease or to control severe haemoptysis
18
Q
What are the transudate causes of a plural effusion?
A
- Due to high venous pressure (heart failure, constritcive pericarditis, fluid overload)
- Hypoproteinaemia (cirrhosis, hypoalbuminaemia, nephrotic syndrome)
- Peritoneal dialysis
- Hypothyroidism
