Respiratory Flashcards
What characterises the presentation of asthma?
Cough (worse at night)
Shortness of breath
Wheeze
What 3 factors contribute to airway narrowing in asthma?
- Bronchial muscle contraction
- Mucosal swelling/inflammation due to mast cell and basophil degranulation
- Increased mucous production
What kind of reaction is atopic asthma?
Asthma is a type 1 hypersensitivity reaction - IgE mediated release of histamine
Name some risk factors for developing asthma
- Atopy/family history of atopy
- Pollution i.e. living in an inner-city environment
- Prematurity and low birth weight
- Viral infections in childhood e.g. bronchiolitis
What often precipitates asthma?
- Cold air - drying of airways causes cell shrinkage which triggers an inflammatory response
- Exercise
- Emotion
- Allergens
- Smoking
- Infection
- Pollution
- NSAIDs
- Beta blockers
How can asthma present?
- Dyspnoea
- Wheeze + chest tightness
- Nocturnal cough
- Acid reflux (40-60%)
- Atopic disease
- Diurnal variation in symptoms - marked morning dipping of the peak flow
What signs would you see on examination of asthma?
- Tachypnoea
- Bilateral widespread polyphonic wheeze
- Reduced air entry
- Hyperinflated chest -> hyper-resonant percussion
- Accessory muscle use
What characterises a severe asthma attack?
PEFR = 33-50% predicted
Unable to complete full sentences
Pulse > 110 bpm
RR > 25/min
What characterises a life-threatening asthma attack? How do you differentiate between this and near-fatal asthma attack?
Life-threatening = PEFR < 33% predicted
- Silent chest
- Confusion
- Exhaustion
- Cyanosis (sats < 92%)
- Bradycardia
- PaO2 < 8kPa
- Normal CO2 (would expect it to be low in asthma attack due to hyperventilation so if it is normal it indicates failing respiratory effort)
Near-fatal = raised CO2
What would you see on spirometry in asthma?
Reduced FEV1/FVC ratio < 0.7 suggesting obstructive patter
Increased residual volume
15% improvement after beta2 agonists/steroids
What is cardiac asthma?
Pulmonary oedema (due to heart failure)
What diseases are associated with asthma?
- Atopic diseases
- GORD
- Churg-Strauss aka eosinophilic granulomatosis - first presents with asthma
- Allergic bronchopulmonary aspergillosis
What is the acute management of asthma?
O SHIT ME
Oxygen 15L/min via NRBM Salbutamol 5mg neb back to back Hydrocortisone 100mg IV or prednisolone 40mg PO for 5 days Ipratropium bromide 5mcg neb Theophylline Magnesium 1.2-2g IV over 20 min Escalate
Step 1 of asthma management in adults
Step 1: mild intermittent asthma - 100% PEFR
- Inhaled SABA PRN
- If used more than 3 times a week go to step 2
Step 2 of asthma management in adults
Step 2: daily symptoms - <80% PEFR
- SABA + inhaled corticosteroid e.g. beclometasone (max 2 puffs twice a day)
Step 3 of asthma management in adults
Step 3
- SABA + ICS + LABA
Step 4 of asthma management in adults
Step 4
- Increase ICS to medium dose
- If LABA helped, keep it, if not bin it and replace with LTRA
What is the biggest cause of COPD?
Smoking - 10-20% of heavy smokers
What else can cause COPD?
Alpha-1-antitrypsin deficiency - alpha-1-antitrypsin inhibits the destruction of the alveolar wall
Pollution
Recurrent infections
Comorbidities
- CVD
- Lung cancer
- Osteoporosis
- Muscle weakness
What is COPD?
A progressive disorder characterised by irreversible obstruction of the airways
Chronic bronchitis = productive cough most days of 3 months per year for 2 years
AND
Emphysema = enlarged air spaces with destruction of alveolar walls
Distinguish between pink puffers and blue bloaters
Pink puffers = emphysema
- increased ventilation to compensate for lack of surface area for gas exchange (decreased perfusion)
- breathless but not cyanosed
Blue bloaters = chronic bronchitis
- obstruction leads to increased residual lung volume
- so there is decreased ventilation but normal perfusion
- retain carbon dioxide so they rely on hypoxic drive to breathe = type 2 respiratory failure
- cyanosed but not breathless
What signs would you see on examination of COPD?
- Tachypnoea
- Flapping tremor
- Sitting in tripod position
- Pursed lip breathing for prolonged expiration
- Use of accessory muscles
- Hyperinflated barrel chest - decreased cricosternal distance
- Decreased lung expansion
- Hyper-resonant percussion
- Cyanosis
- Quiet breath sounds over bullae
- Signs of right heart failure e.g. ankle oedema
What are some complications of COPD?
- Acute infective exacerbations
- Cor pulmonale
- Hypertension
- Polycythaemia
What would an X-ray look like in COPD?
- Hyperinflated chest = more than 6 anterior ribs seen
- Flat hemidiaphragms
- Narrow heart
- Large pulmonary arteries
- Reduced vascular markings