Respiratory Flashcards
What is acute bronchitis?
a self-limiting lower respiratory tract infection
What is the difference between bronchitis and pneumonia?
Bronchitis refers to infections causing inflammation in bronchial airways, whereas pneumonia denotes infection in the lung parenchyma resulting in consolidation of the affected segment or lobe.
What criteria is used for diagnosing acute bronchitis?
Criteria by MacFarlane for acute bronchitis:
(a) An acute illness of <21 days
(b) Cough as the predominant symptom
(c) At least 1 other lower respiratory tract symptom:
a. Sputum production
b. Wheezing
c. Chest pain
(d) No alternative explanation for symptoms
What are the main causes of bronchitis?
o Viral (90%) Influenza type A & B Parainfluenza Adenovirus RSV Rhinovirus Coronavirus o Bacterial o Environmental
Presentation of bronchitis
- Cough +/- sputum production that resolves in 2-3 weeks
- Symptoms of preceding or simultaneous URTI
- Malaise
- Chest pain
- Mild dyspnoea
- Auscultation – may be clear / rhonchi, wheezing
Ix for acute bronchitis
Clinical diagnosis but may use pulmonary function tests / CXR / CRP to rule out asthma / pneumonia.
Tx for acute bronchitis
No treatment necessary usually, may need antipyretic & SABA
What is asbestosis?
diffuse interstitial fibrosis of the lung because of exposure to asbestos fibres.
Name types of pneumoconiosis
Asbestosis
Siderosis (iron)
Silicosis (silica)
Farmer’s lung (hay dust)
what is the pathophysiology of asbestosis?
o Inhalation of airborne asbestos fibres into alveoli, causes inflammation and fibrosis of pleural parenchyma which has carcinogenic effects
o Disease progress is more rapid in smokers due to impaired mucociliary clearance
• There is a long latency period from exposure to asbestos.
• Fibrotic changes in the lungs.
What are the pleural abnormalities seen in asbestosis?
o Plaques +/- calcification
o Diffuse pleural thickening
o Benign pleural effusions
o Rounded atelectasis (atelectasis = a complete or partial collapse of the entire lung or lobe of the lung)
What occupations can lead to asbestos exposure?
- Shipping
- Plumbing
- Roofing
- Insulation
- Heat resistant clothing
- Brake lining
What is the presentation of asbestosis?
- Long latency period
- Exertional dyspnoea
- Dry cough»_space;> productive cough
- Digital clubbing
- Bilateral fine, basal end-inspiratory crepitations
Ix for abestosis
CXR
CT chest
Pulmonary function tests = restrictive pattern of disease
Bronchoalveolar lavage = microscopic asbestos bodies
CXR changes with asbestosis
a. Lower zone linear interstitial fibrosis
b. Diffuse bilateral infiltrates predominantly in the lower lobes
c. Progressively involves the entire lung
d. Pleural thickening
e. Rounded atelectasis
f. Pleural effusions
Mx of asbestosis
No curative treatment
o Oxygen therapy / pulmonary rehabilitation
o No smoking
o Immunisation against influenza and pneumococcal pneumonia
o Antimicrobial treatment of respiratory infections
o Pleural decortication / lung transplant
o Palliative care in advanced disease
Complications of asbestosis
- Mesothelioma = malignant tumour that develops from mesothelial cells
- Bronchogenic carcinoma
- Laryngeal cancer
- Pulmonary HTN
- Cor pulmonale
- R sided HF
- Progressive respiratory failure
- Caplan syndrome = RA + pneumoconiosis
What is asthma?
chronic inflammatory airway disease characterised by bronchial hyper-responsiveness, episodic acute asthma exacerbations and reversible airflow obstruction.
What are the 3 characteristic features of asthma?
o Bronchoconstriction = smooth muscles of the bronchi contract causing a reduction in the diameter of the airways
o Reversible airway obstruction = usually responds to bronchodilators e.g., salbutamol
o Hypersensitivity = can triggered by environmental factors
What is the pathology of asthma?
Acute (30 min)
o Mast cell degranulation = histamine release
o Bronchoconstriction, mucus plugs and mucosal swelling
Chronic (12 hours)
o T helper cells release IL-3,4,5 causing mast cell, eosinophil, and B cell recruitment
o Airway remodelling
what are the different types of asthma?
ALLERGIC ASTHMA (extrinsic asthma) – most common type of asthma, begins with intermittent symptoms in childhood and is usually associated with atopy.
NON-ALLERGIC ASTHMA (intrinsic asthma) – uncommon type of asthma that’s not related to atopy and is typically associated with a poor response to standard treatment.
Subtypes / variants:
o Exercise induced asthma
o Adult onset asthma – poor response to standard treatment
o Cough variant asthma – predominant symptom is chronic dry cough
Triggers for asthma
o Allergic asthma:
Atopy
Environmental allergens – pollen, dust mites, domestic animals, mould spores, flour dust
o Non-allergic asthma: Viral RTI Cold air Physical exertion / laughter GORD Chronic sinusitis / rhinitis Aspirin/NSAIDs/b-blockers Stress Irritant induced asthma
Risk factors for asthma
o Family history o Atopic history o History of allergies o Low socioeconomic status o Childhood second hand exposure to smoke
Presentation of asthma
- Episodic symptoms
- Diurnal variability – typically worse at night
- Dry cough with wheeze and SOB
- Chest tightness
- Bilateral widespread polyphonic end expiratory wheeze heard by a healthcare professional
- Prolonged expiratory phase on auscultation
- Hyperresonance to lung percussion
- History of atopic conditions
How is asthma diagnosed?
Diagnosis made based on a combination of the following:
o Presence of more than one variable symptom of wheeze, cough, breathlessness and chest tightness
o Personal/family history of other atopic conditions
o The results of fractional exhaled nitric oxide testing (in over 17s, >40 parts per billion is a positive result, used to confirm eosinophilic airway inflammation)
o Results of objective tests to detect airway obstruction, when the person is symptomatic:
Spirometry
• FEV1/FVC ratio <70%, reduced
• FVC normal
• FEV1 significantly reduced
Bronchodilator reversibility
• Improvement of FEV1 of >12% + increase in volume of >200ml following SABA or corticosteroids = positive result
• In children, just FEV1 >12% = positive result
Variable peak expiratory flow (PEF)
• >20% variability after monitoring twice daily for 2-4 weeks = positive result
o Direct bronchial challenge test with histamine or methacholine (specialist centres)
How are children under 5 diagnosed with asthma?
use clinical judgement as child can’t perform objective tests
What do the British thoracic society SIGN guidelines say for initiating asthma tx?
o High probability of asthma = try treatment
o Intermediate probability of asthma = perform spirometry with reversibility testing
o Low probability of asthma = consider referral and investigation for other causes
What is FVC?
forced vital capacity = measures the amount of gas expelled when a person takes a deep breath and then forcefully exhales maximally and as rapidly as possible
What is FEV?
forced expiratory volume = amount of air expelled during specific time intervals of the FVC test
What is FEV1?
the volume exhaled in the first second. Healthy individuals can exhale 80% of the FVC in one second.
What do you see on spirometry for obstructive disease?
decrease in both FEV1 and FEV1/FVC ratio
what do you see on spirometry for restrictive disease?
normal FEV1/FVC ratio
Red flag symptoms that suggest another diagnosis than asthma
o Prominent systemic features e.g., myalgia, fever, weight loss
o Unexpected clinical findings e.g., crackles, finger clubbing, cyanosis, cardiac disease, monophonic wheeze, stridor
o Persistent non-variable breathlessness
o Chronic sputum production
o Unexplained restrictive spirometry
o CXR shadowing
o Marked blood eosinophilia
Asthma differentials
o Bronchiectasis o COPD o Ciliary dyskinesia o CF o Foreign body aspiration o GORD o HF o Interstitial ling disease e.g., asbestosis o Lung Ca o Pertussis o PE o TB
NICE guidelines for asthma management
- SABA PRN for infrequent wheezy episodes
- regular low dose inhaled corticosteroid
- oral montelukast (oral leukotriene receptor antagonist)
- LABA and continue only if the patient has a good response
- Consider changing to a maintenance and reliever therapy (MART) regime
- Increased inhaled corticosteroid to moderate dose
- Consider increasing the inhaled corticosteroid to high dose or oral theophylline or an inhaled LAMA (tiotropium)
- Refer to specialist
Try draw out NICE ladder for asthma
See notes
Additional management for asthma patients
- Everyone should have an individual asthma self-management programme
- Yearly flu jab
- Yearly asthma review
- Advise exercise and avoid smoking
What is a SABA? Give an example, how it works, when its used and the side effects
Short acting beta 2 adrenergic receptor agonist (SABA)
Salbutamol
Reliver or rescue medication used PRN for acute exacerbations
Dilation of bronchial smooth muscles
Tremor Arrhythmias Tachycardia Hyperglycaemia Hypokalaemia
What is an ICS? Give an example, how it works, when its used and the side effects
Inhaled corticosteroid (ICS)
Beclometasone
Fluticasone
Mometasone
Maintenance or preventer used regularly
Don’t take full effects until they’ve been used for 1 week
Oral thrush Hoarse/croaky voice Cough Nosebleeds Stunted growth in children
What is a LABA? Give an example, how it works, when its used and the side effects
Long acting beta 2 adrenergic receptor agonist (LABA)
Salmeterol
Longer action than SABA, for long term maintenance therapy (taken every day regardless of symptoms)
Dilation of bronchial smooth muscles
Tremor Arrhythmias Tachycardia Hyperglycaemia Hypokalaemia
What is a LAMA? Give an example, how it works, when its used and the side effects
Long acting muscarinic antagonist (LAMA)
Tioptropium
Blocks parasympathetic nervous system to cause bronchodilation
Dry mouth
Constipation
Urinary retention
Give an example leukotriene receptor antagonist, how it works, when its used and the side effects
Leukotriene receptor antagonist
Montelukast
Prevents leukotrienes binding to receptors and causing bronchoconstriction/ inflammation
Oral URTI
Pharyngitis
Headache
Fever
What monitoring is required for theophylline?
Need to monitor plasma theophylline as it has a narrow therapeutic window, checked 5 days after starting and 3 days after dose changes
What is MART?
Maintenance and reliever therapy (MART)
Low dose ICS and LABA combined
Single inhaler for preventer and reliever
Give example oral corticosteroids, when they are used in asthma and the side effects
Methylprednisolone
Prednisolone
For severe persistent asthma
Cushings Osteoporosis Reduced growth Thin skin Immunosuppression Cataracts Oedema Suppressed HPA axis Teratogenic Emotional disturbance Rise in BP Obesity Increased hair growth Diabetes Striae
What is an acute exacerbation of asthma?
rapid deterioration of symptoms, could be triggered by any of the typical asthma triggers such as infection, exercise, or cold weather.
Presentation of acute asthma
- Progressively worsening SOB
- Use of accessory muscles
- Tachypnoea
- Symmetrical expiratory wheeze on auscultation
- Chest sounds tight on auscultation, with reduced air entry
How is acute asthma graded
Moderate
Severe
Life threatening
What is moderate acute asthma
o PEFR 50-75% predicted
What is severe acute asthma?
o PEFR 33-50% predicted
o Respiratory rate >25
o Heart rate >110
o Unable to complete sentences
What is life threatening acute asthma
o PEFR <33% o Sats <92% o Becoming tired o No wheeze, this occurs when the airways are so tight that there is no air entry at all. ‘Silent chest’ o Haemodynamic instability – shock
What are the ABG results seen In acute asthma?
respiratory alkalosis due to tachypnoea causing CO2 drop.
A normal pCO2 or hypoxia is concerning as it means the person is tiring = life threatening asthma.
Respiratory acidosis due to high CO2 = very bad sign
How is the patient monitored during an acute asthma attack?
o RR o Respiratory effort o Peak flow o O2 saturations o Chest auscultation