Respiratory Flashcards
What is asbestosis?
Diffuse interstitial fibrosis of the lung as a consequence of exposure to asbestos fibres
What are the risk factors of asbestosis?
Cumulative dose of asbestos Cigarette smoking (weak)
What is the aetiology of asbestosis?
When asbestos fibres are inhaled, they deposit at alveolar duct bifurcations and cause an alveolar macrophage alveolitis.
These activated macrophages release cytokines, such as tumour necrosis factor and interleukin-1beta and oxidant species, which initiate a process of fibrosis.
Initial interstitial fibrosis typically occurs in the lower lobes and may progress to extensive fibrosis and honeycombing.
Peri-bronchial fibrosis with a cellular infiltrate may narrow the airway and cause reduced air flow
What is the epidemiology of asbestosis?
There is a latency period of around 20 years from time of first exposure to asbestos to development of radiographical changes, so the diagnosis is typically seen in individuals who began working with asbestos prior to the 1980s and are now usually more than 50 years of age
More likely to be male, workers in the shipyard, construction, and building maintenance industries
What are the presenting symptoms of asbestosis?
Dyspnoea on exertion
Dry, non-productive cough (frequency increases with progression- can be absent in patients with early asbestosis)
Chest tightness from SOB
What are the signs of asbestosis?
Clubbing- only found in advanced asbestosis
Crackles, initially heard at bases and increases with progression of disease.
Ask about occupational exposure, smoking Hx
What are the appropriate investigations for asbestosis?
1st line: CXR (PA and lateral): -lower zone linear interstitial fibrosis -progressively involves the entire lung -pleural thickening Pulmonary function tests: -restrictive changes -may have may have obstructive picture (especially if history of asbestos exposure and smoking) Others: High resolution CT chest Lung biopsy - interstitial fibrosis Bronchial lavage- presence of asbestos bodies in lavage fluid
What is mesothelioma?
An aggressive epithelial neoplasm arising from the lining of the lung, abdomen, pericardium, or tunica vaginalis (pouch of serous membrane that covers the testes)
Asbestos is the chief causative agent
What are the risk factors for mesothelioma?
Asbestos exposure Age 60-85 Weaker risk factors: -male -radiation exposure -genetic predisposition
What is the epidemiology of mesothelioma?
More common in men and white people, and typically occurs in older adults
What are the presenting symptoms of mesothelioma?
Chest pain
Cough
Shortness of breath
Non-specific symptoms: fatigue, fever, sweats and weight loss
What are the signs of mesothelioma?
Diminished breath sounds
Dullness to percussion
What are the appropriate investigations for mesothelioma?
1st line:
- Chest x-ray: unilateral pleural effusion, irregular pleural thickening, reduced lung volumes, and/or parenchymal changes related to asbestos exposure
- CT scan of chest and abdomen with intravenous contrast: pleural thickening, pleural plaques, pleural effusion, enlarged lymph nodes
What is Aspergillus lung disease?
Lung disease associated with Aspergillus fungal infection
What is the aetiology of Aspergillus lung disease?
Inhalation of the ubiquitous Aspergillus (usually Aspergillus fumigates) spores can produce three different clinical pictures
- Aspergilloma:Growth of an A.fumigatus mycetoma ball in a pre-existing lung cavity (e.g. post TB, abscess)
- Allergic bronchopulmonary aspergillosis (ABPA): Aspergillus colonization of the airways (usually in asthmatics) causes mediated immune responses
- Invasive aspergillosis: Invasion of Aspergillus into lung tissue and fungal dissemination (secondary to immunosuppression)
What is the epidemiology of Aspergillus lung disease?
Uncommon
Most common in elderly and immunocompromised
What are the presenting symptoms of Aspergilloma?
Asymptomatic
Haemoptysis, which may be massive
What are the presenting symptoms of Allergic bronchopulmonary aspergillosis (ABPA)?
Difficult to control asthma
Recurrent episodes of pneumonia with wheeze, cough,
fever and malaise
What are the presenting symptoms of Invasive aspergillosis?
Dyspnoea
Rapid deterioration
Septic picture (high temp, PR, RR, low BP)
What are the signs of Aspergilloma on physical examination?
Tracheal deviation in large aspergillomas
What are the signs of Allergic bronchopulmonary aspergillosis (ABPA) on physical examination?
Dullness in affected lung
Reduced breath sounds
Wheeze
What are the signs of Invasive aspergillosis on physical examination?
Cyanosis may develop Septic picture (high temp, PR, RR, low BP)
What are the appropriate investigations for Invasive aspergillosis?
CXR: nodules, consolidation, non-specific infiltrates, pleural-based lesions and cavities
Sputum culture: Aspergillus
CT scan: nodules surrounded by a ground-glass appearance (halo sign) in invasive pulmonary aspergillosis (haemorrhage into the tissue surrounding the area of fungal invasion)
What are the appropriate investigations for ABPA?
Immediate skin test reactivity to Aspergillus antigens
Bloods:
-Eosinophilia
-Raised serum IgE antibodies
CXR: Transient patchy shadows, collapse, distended mucus-filled bronchi producing tubular
shadows (‘gloved fingers’ appearance)
Signs of complications: Fibrosis in upper lobes
(similar to tuberculosis), parallel-line shadows and rings (bronchiectasis)
CT: Lung infiltrates, central bronchiectasis.
Lung function tests: Reversible airflow limitation, reduced lung volumes/gas transfer in progressive cases
What are the appropriate investigations for Aspergilloma?
CXR: Round opacity may be seen with a crescent of air around it (usually in the upper lobes)
[CT or MR imaging if CXR does not clearly delineate a cavity]
Cultures of the sputum may be negative if there is no communication between the cavity and the bronchial tree
What is acute respiratory distress syndrome?
A syndrome of acute and persistent lung inflammation with increased vascular permeability
What are the causes of acute respiratory distress syndrome?
(TOAST) Transfusion Overdose of drugs Aspiration Sepsis Transplantation (PIP) Pneumonia Injury/burns Pancreatitis
What is ARDS characterised by?
A - Absence of raised capillary wedge pressure
R - Reduced blood oxygen (hypoxaemia)
D - Double-sided infiltrates (bilateral infiltrates)
S - sudden onset (acute- within 1 week)
What is the aetiology of acute respiratory distress syndrome?
Severe insult to lungs
Inflammatory mediators released
Capillary permeability increases
Results in pulmonary oedema, reduced gas exchange and reduced lung compliance
(Injury, inflammation, increased permeability)
What is the epidemiology of acute respiratory distress syndrome?
Annual UK incidence 1 in 6000
What are the pathological stages of ARDS?
Exudative
Proliferative
Fibrotic
What are the presenting symptoms of ARDS?
Rapid deterioration of respiratory function
Dyspnoea
Cough
Symptoms of cause
What are the signs of ARDS on physical examination?
Think SMURF: fast, blue, noisy: Cyanosis Tachypnoea Tachycardia Widespread crepitations Hypoxia refractory to oxygen treatment (Usually bilateral but may be asymmetrical in early stages)
What are the appropriate investigations for ARDS? Interpret the results
1st line:
CXR- bilateral infiltrates
ABG- low partial oxygen pressure
Sputum/ blood/ urine cultures- positive if underlying infection
Amylase- elevated in cases of acute pancreatitis
Others:
BNP- <100 nanograms/L make HF less likely, so ARDS more likely
Pulmonary artery catheterisation- Pulmonary artery occlusion pressure (PAOP) ≤18 mmHg suggests ARDS
What is asthma?
Chronic inflammatory airway disease characterized by variable reversible airway obstruction, airway hyper-responsiveness and bronchial inflammation
What are the risk factors of asthma?
Genetic factors:
Family Hx
Atopy (tendency of T lymphocyte (Th2) cells to drive production of IgE on exposure to allergens)- eczema, atopic dermatitis, allergic rhinitis is strongly associated
Environmental factors: House dust mite Pollen, Pets (e.g. urinary proteins, furs) Cigarette smoke Viral respiratory tract infection Aspergillus fumigatus spores
What is the pathogenesis of asthma?
Early phase (up to 1 h): Exposure to inhaled allergens results in cross-linking of IgE antibodies on the mast cell surface and release of histamine, prostaglandin D2, leukotrienes and TNF-a. These mediators induce smooth muscle contraction (bronchoconstriction), mucous hypersecretion, oedema and airway obstruction.
Late phase (after 6–12h): Recruitment of eosinophils, basophils, neutrophil and Th2 lymphocytes and their products results in perpetuation of the inflammation and bronchial hyper-responsiveness.
Airway remodelling: the inflammation and altered function and proliferation of smooth muscle cells and fibroblasts from cytokines and proliferative growth factors
What is the epidemiology of asthma?
Affects 10% of children and 5% of adults
Acute asthma is a very common medical emergency and still responsible for 1000–2000 deaths/year in the UK
What are the presenting symptoms of asthma?
Episodes of wheeze Breathlessness Cough Worse in the morning and at night Interfering with exercise, sleeping, school/ work
What are the exacerbating factors of asthma?
Cold Viral infections Drugs (b-blockers, NSAIDs) Exercise Emotions
What are the signs of asthma on physical examination?
Tachypnoea Use of accessory muscles Prolonged expiratory phase Polyphonic wheeze* on expiration Hyper inflated chest
What are the signs of a severe asthma attack?
PEFR < 50% predicted
HR > 110/min (tachycardia)
RR > 25/min
Inability to complete sentences
What are the signs of a life threatening asthma attack?
PEFR<33% Silent chest Bradycardia Hypotension Confusion Coma Cyanosis
What are the appropriate investigations for asthma? Interpret the results
1st line:
- FEV1/FVC: <70% of predicted
- Peak flow
- CXR: hyper inflated lungs
- FBC: Eosinophilia
What is the acute management of asthma?
O SHIT ME
Oxygen (high flow)
Salbutamol- 2.5-5mg NEB
Hydrocortisone- 100mg IV (or prednisolone 40mg PO)
Ipratropium- 500mcg NEB
Theophylline*: aminophylline infusion- 1g in 1L saline 0.5ml/kg/h
Magnesium sulphate- 2g IV over 20mins Escalate care (intubation and ventilation)
*smooth muscle relaxation (bronchodilation) and suppression of the response of the airways to stimuli
What is the chronic management for asthma? (Stepwise)
Step 1: Inhaled short acting B2 agonist as needed (if used >1 / day move to 2)
Step 2: Step 1 + regular inhaled lose dose steroids (400mcg/day)
Step 3: Step 2 + long acting B2 agonist (if inadequate control increase steroid dose to 800mcg/day)
Step 4: Step 3 + increase inhaled steroid dose to 2000mcg/day and add 4th drug (leukotriene receptor antagonist or B2 agonist tablet)
Step 5: Step 4 + addition of regular oral steroids (maintain high dose inhaled steroids) and refer to specialist
review every 3-6 months
What are the complications of asthma?
Growth retardation
Pectus carinatum (pigeon chest)
Recurrent infections
Pneumothorax
What is the prognosis for patients with asthma?
Children: many improve as they grow
Adults: adult onset is usually chronic
What is Bronchiectasis?
The permanent (chronic) dilation of bronchi due to the destruction of the elastic and muscular components of the bronchial wall with impaired mucuociliary clearance and frequent bacterial infections
What is the aetiology of Bronchiectasis?
Severe inflammation in the lung causes fibrosis and dilation of the bronchi.
This is followed by pooling of mucus, predisposing to further cycles of infection, damage and fibrosis to bronchial walls
Causes:
-Idiopathic is around 50%
-Post infections e.g. TB
-Obstruction of bronchi: Foreign body, enlarged lymph nodes
-Gastric reflux disease.
-Inflammatory disorders: e.g. rheumatoid arthritis
What are the risk factors for Bronchiectasis?
Cystic fibrosis
Host immunodeficiency (increased risk of infection)
Previous infections
Congenital disorders of bronchial airways
Alpha-1 anti-trypsin deficiency
What is the epidemiology of Bronchiectasis?
Most often arises initially in childhood
Incidence has decreased with use of antibiotics, approximately 1 in 1000 per year
What are the presenting symptoms of Bronchiectasis?
Productive cough with purulent sputum or haemoptysis
Breathlessness
Chest pain
Malaise, fever, weight loss
Symptoms usually begin after an acute respiratory illness
What are the signs of Bronchiectasis on physical examination?
Finger clubbing
Coarse creptitations (usually at the bases) which shift with coughing
Wheeze.
What are the appropriate investigations for Bronchiectasis?
Sputum: Culture and sensitivity
*High-resolution CT: Dilated bronchi with thickened walls. Best diagnostic method.
CXR: Dilated bronchi may be seen as parallel lines radiating from hilum to the diaphragm (‘tramline shadows’)- may also show fibrosis, atelectasis, pneumonic consolidations, or it may be normal
PFTs: Reduced FEV₁, elevated residual volume (RV)/total lung capacity (TLC)
Bloods: raised WCC
Test for cause: rheumatoid factor, Alpha-1 anti-trypsin phenotype
What is the management for Bronchiectasis?
Maintenance therapy and treatment of acute exacerbations:
- Inhaled corticosteroids (e.g. fluticasone) have been shown to reduce inflammation and volume of sputum, although it does not affect the frequency of exacerbations or lung function
- Bronchodilators may be considered in patients with responsive disease
- Maintain hydration with adequate oral fluid intake
- Diet and exercise
- Pulmonary rehabilitation
*prophylactic courses of antibiotics (oral or aerosolized) for those with frequent (3/year) exacerbations
What are the common pathogens in Bronchiectasis?
Pseudomonas aeruginosa Haemophilus influenzae Staphylococcus aureus Streptococcus pneumoniae Klebsiella, Moraxella catarrhalis, Mycobacteria
What are the complications of Bronchiectasis?
Life-threatening haemoptysis
Persistent infections
Empyema (collection of pus in the pleural cavity)
Respiratory failure
Cor pulmonale (abnormal enlargement of the right side of the heart)
Multi-organ abscesses
What is the prognosis of Bronchiectasis?
Most patients continue to have the symptoms after 10 years
What is Chronic obstructive pulmonary disease (COPD)?
A preventable and treatable disease state characterised by airflow limitation that is not fully reversible.
It encompasses both emphysema and chronic bronchitis
What is the aetiology of COPD?
Bronchial and alveolar damage as a result of environmental toxins (e.g. cigarette smoke). Overlaps and may co-exist with asthma
What is Chronic bronchitis?
Chronic cough and sputum production on most days for at least 3 months per year over 2 consecutive years
What is emphysema?
Pathological diagnosis of permanent destructive enlargement of air spaces distal to the terminal bronchioles
What is the aetiology of Chronic bronchitis?
Narrowing of the airways resulting from bronchiole inflammation (bronchiolitis) and bronchi with mucosal oedema, mucous hypersecretion and squamous metaplasia
What is the aetiology of emphysema?
Destruction and enlargement of the alveoli
This results in loss of the elastic traction that keeps small airways open in expiration
Progressively larger spaces develop, termed bullae (diameter is >1 cm)
What is the epidemiology of COPD?
Very common (prevalence up to 8%) Presents in middle age or later (65 years and older) More common in males, but likely to change with increased no. female smokers
What are the presenting symptoms of COPD?
Chronic cough and sputum production Breathlessness Wheeze Reduced exercise tolerance (may present with recurrent lung infections)
What are the signs of COPD on physical examination?
Inspection: -May have respiratory distress -use of accessory muscles -barrel-shaped overinflated chest -decreased cricosternal distance -peripheral/central cyanosis Percussion: -Hyper-resonant chest -loss of liver and cardiac dullness. Auscultation: -Quiet breath sounds -prolonged expiration -wheeze -rhonchi (continuous low pitched, rattling lung sounds- sounds like snoring) -crepitations sometimes present. Signs of CO2 retention: Bounding pulse, warm peripheries, flapping tremor of the hands (asterixis). In late stages, signs of right heart failure (e.g. right ventricular heave, raised JVP, ankle oedema)
What are the appropriate investigations for COPD?
*Spirometry and pulmonary function tests:
Obstructive picture as reflected by reduced PEFR, reduced FEV1: FVC ratio
Pulse oximetry: low oxygen saturation
CXR: May appear normal or show hyperinflation (>6 ribs visible anteriorly, flat hemi- diaphragms), reduced peripheral lung markings, elongated cardiac silhouette
Bloods: FBC ( increasedHb and PCV as a result of secondary polycythemia)
ABG: May show hypoxia (low PaO2), normal or high PaCO2
ECG and echocardiogram: For cor pulmonale
Sputum and blood cultures: In acute exacerbations for treatment
What could be another cause of COPD?
Alpha 1-antitrypsin deficiency (<1%) but should be considered in young patients or in those who have never smoked
What can the FEV1: FVC ratio tell us about the stage of COPD?
Mild 60–80%
Moderate 40–60%
Severe <40%
What is the management for COPD?
Stop smoking.
Bronchodilators: Short-acting b2-agonists (e.g. salbutamol) and anticholinergics (e.g. ipratropium), delivered by inhalers or nebulisers. Long-acting bronchodilators should be used if >2 exacerbations per year
Steroids: Inhaled beclometasone should be considered for all with FEV1 <50% predicted or
those with >2 exacerbations per year.
Regular oral steroids should be avoided but may be necessary for maintenance.
-Chest physiotherapy: for airway clearance
-Pulmonary rehabilitation
-Diet and exercise, patient education (flu vaccination)
-Long-term home oxygen therapy for non-smokers (improves mortality)
