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
19
Q
What are the exudate causes of a pleural effusion?
A
- Pneumonia
- Malignancy
- TB
- Pulmonary infarction
- Lymphoma
- Mesothelioma
- Asbestos exposure
- Myocardial infarction
20
Q
What is a transudate plural effusion?
A
Fluid contains <30g/L of protein since vessels are normal so protein can’t leak out
21
Q
What is an exudate plural effusion?
A
Fluid contains >30g/L of protein because the endothelial cells of vessels are spaced further apart so fluid and protein can both leak out
22
Q
What is the pathophysiology of a pleural effusion? (General, transudate and exudate)
A
- Build-up of fluid results in a pressure increase which puts pressure on the lungs causing breathing difficulties
Transudates:
- Occurs when the balance of hydrostatic forces in the chest favour the accumulation of pleural fluid (i.e. increased pressure due to backing up of blood in left sided congestive heart failure)
Exudates:
- Occurs due to increased permeability and thus leakiness of pleural space and/or capillaries usually from inflammation, infection or malignancy
23
Q
What are the risk factors of a pleural effusion?
A
- Previous lung damage
- Asbestos exposure
24
Q
What is the presentation of pleural effusion?
A
- Can be asymptomatic
- SOB/ SOBOE
- Dyspnoea
- Pleuritic chest pain
- Cough
- Weight loss (malignancy)
- Reduced chest expansion on side of effusion
- Trachea may be deviated away from the effusion if very large
- Stony dull percussion note and diminished breath sounds on affected side
- Loss of vocal resonance
25
How is the pleural effusion diagnosed?
CXR:
- Detectable with >300ml of fluid
- Small effusions reduce costophrenic angles
- Large effusions are seen as water-dense shadows with concave upper borders
- Completely flat horizontal upper border implies that there’s also a pneumothorax
USS:
- Identifies pleural fluid and guides diagnostic therapeutic aspiration
Diagnostic aspiration:
= thoracentesis or pleural tap
- Needle inserted under anaesthesia
- Appearance of pleural fluid is noted (purulent in empyema, turbid in infected effusion, milky in chylothorax)
- Sample is also sent for pH, cytology and microbiology if an infection is suspected
26
How is a pleural effusion managed?
- Depends on underlying cause
- Exudates are usually drained if symptomatic
- Transudates are managed by treatment of underlying cause
- Malignant effusions usually reaccumulate after drainage
- Pleurodesis = an injection that causes the adhesion of the visceral and parietal pleura to help prevent re-accumulation of the effusion
- Surgery if persistent collections and increasing pleural thickness
27
What is the aetiology of cystic fibrosis?
- Autosomal recessive condition
- CF gene is located on the long arm of chromosome 7 coding for the cystic fibrosis transmembrane regulator protein (CFTR)
- Most common mutation is the F508 deletion mutation
28
What is the pathophysiology of cystic fibrosis?
- Mutation on chromosome 7 causes a defective CFTR, leading to a combination of defective Cl- airway secretion and increased Na+ absorption
- Causes increased H2O absorption into cells leading to thickened secretions in a number of organs
- Leads to dehydrated airway surface liquid, mucus stasis, airway inflammation and recurrent infection in the lungs
- Changes in the composition of airway surface liquid predispose the lung to chronic pulmonary infection
- Leads to progressive airway obstruction and bronchiectasis
29
What are the risk factors for cystic fibrosis?
- Family history
| - Caucasian
30
What is the presentation of cystic fibrosis? (In neonates, respiratory symptoms, GI symptoms, and other symptoms)
- Multi system disease, but cause of death is usually respiratory
Neonates:
- Failure to thrive
- Bowel obstruction
- Rectal prolapse
Respiratory:
- Cough
- Thick mucus
- Wheeze
- Recurrent infections
- Bronchiectasis
- Airflow limitation
- Sinusitis
- Nasal polyps
- Spontaneous pneumothorax
- Haemoptysis and breathlessness (late)
Gastrointestinal:
- Thick secretions
- Reduced pancreatic enzymes (mucus blocks pancreatic duct)
- Pancreatic insufficiency
- Distal intestinal obstruction syndrome
- Reduced bicarbonate
- Maldigestion and malabsorption causing poor nutrition
- Cholesterol gallstones and cirrhosis
- Increased incidence of peptic ulcers and malignancy
Other symptoms:
- Male infertility from atrophy of vas deferens and epididymis
- Secondary amenorrhea in females
- Salty sweat
- Clubbing
- Osteoporosis
31
How is cystic fibrosis diagnosed?
- Clinical diagnosis
- Family history of disease
- Genetic screening for CF mutations
- Faecal elastase test
One or more of:
- Sweat test (high sodium and chloride concn)
- Absent vas deference and epididymis
- GI and nutritional disorders
32
How was cystic fibrosis managed?
- Immediate decompression via large bore canula
| - Chest drain if patient is unstable, has secondary pneumothoraces or needle aspiration has failed twice
33
What is the aetiology of the pneumothorax?
- Rupture of a pleural bleb/ sub-pleural bulla thought to be due to congenital defects
- Bronchial asthma
- Carcinoma
- Breakdown of a lung abscess
- Severe pulmonary fibrosis with cyst formation
- TB
- Pneumonia
- Cystic fibrosis
- Trauma (penetrating or rib fracture)
- Iatrogenic e.g. pacemakers or central lines
34
What is the pathophysiology a pneumothorax?
- Negative pressure in the pleural space is lost when there is communication with atmospheric pressure (pleural is breached)
- Elastic recoil in the lung causes it to partially deflate
35
What are the risk factors for pneumothorax?
- Male
- Smoking
- Age (most likely to occur between 20-40y)
- On mechanical ventilation
36
What is the presentation of a pneumothorax?
- May be no symptoms, especially in fit and young patients
- May be a sudden onset of dyspnoea and/or unilateral pleural chest pain
- Patient becomes more breathless and may develop pallor and tachycardia as pneumothorax enlarges
- Mechanically ventilated patients may present with hypoxia
- Reduced expansion, hyper-resonance to percussion and diminished breath sounds of affected lungs
37
What are the differential diagnoses of a pneumothorax?
- Pleural effusion
- Chest pain
- Pulmonary embolism
38
How is a pneumothorax diagnosed?
- CXR – look for area devoid of lung markings, peripheral to the edge of collapsed lung (don’t request in tension pneumothorax)
- ABG
39
How is a pneumothorax managed?
- Chest drain if caused by trauma, haemothorax or mechanical ventilation
- Needle aspiration before chest drain in tension pneumothorax
- Observation
- Oxygen for hypoxia
- Surgery for persistent pneumothorax
- Smoking cessation reduces recurrence
40
What is the aetiology of pulmonary hypertension?
(Pulmonary vascular orders, diseases of lung and parenchyma, MSK, respiratory drive disturbance, cardiac, and other causes)
- Occurs due to an increased in pulmonary vascular resistance or an increase in pulmonary blood flow
Pulmonary vascular disorders:
- Pulmonary embolism
- Primary pulmonary hypertension
- Veno-occlusive disease
Diseases of lung and parenchyma:
- COPD
- Chronic lung disorders
MSK:
- Kyphoscoliosis (abnormal spine curvature)
- Poliomyelitis (polio)
- Myasthenia gravis
Resp drive disturbance:
- Obstructive sleep apnoea
- Morbid obesity
- Cerebrovascular
Cardiac:
- Mitral stenosis
- Left ventricle failure
- Left atrial myxoma
- Congenital heart disease
Other causes:
- Appetite suppression drugs
- Type 1 glycogen storage disease
- Lipid storage disease
- Rheumatic autoimmune disease
- Hepatic mass
- Sickle cell disease
- Familial (genetic)
- Can be idiopathic
41
What is the pathophysiology of pulmonary hypertension?
- Hypoxic vasoconstriction, inflammation and cell proliferation results in narrower vessels and increased right ventricular pressure which causes pulmonary hypertension
- Leads to the damage of the pulmonary endothelium resulting in the release of vasoconstrictors such as endothelin which in turn increases pulmonary vascular resistance (PVR) meaning the right ventricle must pump harder causing right ventricular hypertrophy
- Increased platelet and leukocyte adhesion, elevated serotonin as well as other factor cause further vasoconstriction and remodelling further increasing PVR
- Patients with progressive pulmonary hypertension develop right ventricular hypertrophy, dilatation and eventually failure resulting in death
42
What is the presentation of pulmonary hypertension?
- Exertional dyspnoea, lethargy and fatigue
- Ankle swelling
- Chest pain
- Syncope
- Oedema and abdominal pain from hepatic congestion as RV failure develops
- Features of right heart failure (cor pulmonale) in advanced disease: elevated JVP, hepatomegaly, peripheral oedema, ascites, pleural effusion
43
What are the differential diagnoses of pulmonary hypertension?
- Cor pulmonale
- Cardiomyopathies
- Primary right ventricular heart failure
- Congestive cardiac failure
- Portal hypertension
44
How is pulmonary hypertension diagnosed?
- CXR – enlarged proximal pulmonary arteries, enlarged heart
- ECG – right ventricular hypertrophy with tall and peaked P wave
- ECHO – right ventricular dilatation and/or hypertrophy
- LFTs – to detect portal hypertension
- Autoimmune screening
45
How is pulmonary hypertension diagnosed?
- Treat underlying cause
- Oxygen
- Warfarin
- Diuretics for oedema
- Oral CCBs
- Oral endothelin receptor antagonist
- Phosphodiesterase-5 inhibitors
- Prostanoid analogues
- Consider heart-lung transplant in young patients
2a mid tier
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