OBSTRUCTIVE AIRWAY DISEASE
Asthma & COPD
Rachel Ventre FY1
SPIROMETRY/ PFT
Obstructive – FEV1/FVC ratio Asthma COPD Bronchiectasis CF
Restrictive – FVC & FEV1. Normal or ratio. Kyphosis/Scoliosis ILD Connective tissue diseases Infection - pneumonia
ASTHMA
DEFINITIONS
Asthma Common, chronic inflammatory airway disease,
characterised by variable (diurnal) reversible airflow obstruction, airway hyper-responsiveness, bronchial inflammation and bronchospasm.
AETIOLOGY
Environment maternal smoking during pregnancy low air quality (pollution) sterile environment (Hygiene hypothesis) occupational allergens (isocyanates, epoxy
resins) Genetic
FHx of atopy. +ve twin studies.
Asthma Triggers?
PATHOPHYSIOLOGY3 main features:
Airway narrowing – bronchiole constriction Irritation – inflammation of mucosal lining Blockage – excess mucous production forming plugs
EPIDEMIOLOGY
Increasing prevalence in UK FHx of atopy B>G 3:2 in children
but equal in adults Onset – any age
Atopy? Type I hypersensitivity to allergens Increased tendency for T lymphocyte’s to drive IgE
production on allergen exposure Associated with Asthma, Eczema and Allergic Rhinitis
(Hayfever). Runs in families.
Symptoms Signs
PRESENTATION
Symptoms Signs• Cough• Wheeze• Chest tightness• Occasional sputum production• Dyspnoea (mild – severe)• Pattern worse at night,
exacerbated by exercise, cold, allergens and physiological stress. Drugs (NSAIDs and βblockers)
• Common allergens animal dander, cats, dust mites, flour, paints, varnishes and detergents
• Tachypnoea• Accessory muscle use• Audible wheeze polyphonic• Hyperinflated chest• Hyperesonant percussion• Reduced air entry• Prolonged expiratory phase
INVESTIGATIONSInitial Dx & assess severityBedside:
PEFR – with diary showing diurnal variation (>20%), morning dip Pulse oximetry
Blood: ABG – acidotic? Eosinophil levels, Aspergillus antibody FBC (WCC), CRP, U&E Blood and sputum cultures
Radiology: CXR – hyperinflation, pneumothorax, pneumonia?
Special tests: Pulmonary function tests
FEV1/FVC < 80% Spirometry – Flow volume loop showing obstructive picture 15% improvement post – salbutamol
Skin prick tests – allergen identification
BTS uses a ‘response to therapy’ approach to asthma Dx.
Chronic monitoring: PEFR – best comparison
MANAGEMENT
Conservative: Smoking cessation Check inhaler technique Patient education – avoid allergens/precipitants Emergency plan – acute exacerbations Vaccinations – pneumococcal and influenza
Medical: BTS guidelines Start at appropriate level for severity. Move up if
necessary and step down if good control for 3 months. Rescue steroids if required in exacerbations.
STEPWISE RX
ACUTE ASTHMA Acute exacerbations are common Medical emergency Responsible for 1000-2000 deaths/yr
?
?
MANAGEMENT
Resuscitate ABCDE Monitor O2 sats, ABG and PEFR High flow 100% Oxygen (15L via non-rebreathable mask) aim sats 94-
98% Nebulisers
SABA (Salbutamol 5mg continuously then 2-4hourly) + Ipatropium Bromide 0.5mg QDS
Systemic corticosteroids hydrocortisone 100-200mg IV then Prednisalone 40mg PO for 5/7
Magnesium sulphate 2g over 20mins IV Bronchodilators IV (ITU only, need cardiac monitoring)
Aminophylline or Salbutamol
Assess severity (ventilation) Consider ITU or intubation if worsening hypoxia and PEFR despite Rx Hypercapnia, resp acidosis, coma, resp drepression/arrest. Also if patient is
tiring! Consider patient performance status (poor poor ITU prognosis)
Rx underlying cause – infection (ABx) or pneumothorax.
COPDCHRONIC OBSTRUCTIVE PULMONARY DISEASE
DEFINITIONS
COPD Chronic progressive lung disorder, characterised
by (mostly) irreversible airflow obstruction, FEV1 <80% predicted and FEV1/FVC ratio <70%. Chronic bronchitis = clinical
Cough & sputum, most days, 3/12 over 2years Chronic inflam of bronchi (medium)
Emphysema = histopathological, CXR/CT changes Permanent destructive enlargement of airspaces Distal to terminal bronchioles (alveolar) = bullae
AETIOLOGY Bronchial and alveolar damage caused by
environmental toxins Cigarette smoking
Process not fully understood. Processes causing lung damage include:
Genetic Alpha 1 antitrypsin deficiency (<1%) Emphysema
Persistent airway inflammation Cytokine release due to inflammation, body responds to irritant particles
Oxidant/antioxidant capacity imbalance
Oxidative stress produced by high free radical concentration in tobacco smoke
Protease/antiprotease imbalance in lungs
Smoke and free radicals impair activity of antiprotease enzymes (e.g. Alpha 1 antitrypsin). Proteases damage lung.
EPIDEMIOLOGY
Very common, many undiagnosed More common in lower socioeconomic status
(relates to smoking prevalence) Presents in middle age or later M>F due to smoking tendencies in past
PRESENTATION Symptoms
Chronic productive cough Following colds and in winter months Increase severity and frequency over time Sputum – can be blood stained in advanced disease
Recurrent respiratory infections Exertional dyspnoea & reduced exercise tolerance Regular morning cough Wheeze
PRESENTATION Signs:
Inspection Percussion
• Wheeze on forced expiration• Tracheal tug
• Tracheal descent in inspiration, reduced cricosternal distance
• Accessory muscle use• sternocleidomastoid and
scalenes• Suprasternal and supraclavical
fossae excavation (prominent)• Indrawn costal margins and
intercostal spaces• Pursed lip breathing• hyperinflation/barrel chest
• Increased AP diameter• Weight loss• Central cyanosis• CO2 flapping tremor and bounding
pulse (hypercapnia)
• Hyper-resonant percussion• Loss of liver and cardiac
dullness
Auscultation
• Quiet breath sounds• Prolonged expiration• Wheeze• Crepitations if infected
INVESTIGATIONS Bedside:
PEFR – reduced Blood:
Secondary polycythaemia ABG - Hypoxia, normal or raised CO2
Radiology: CXR Chest CT – bullae and lung volumes
Special tests: Pulmonary function tests
Spirometry – reduced FEV1 <80% FEV1/FVC ratio – reduced <70% (see below) Increased lung volumes CO gas transfer coefficient decreased when significant alveolar
destruction ECG/Echo – cor pulmonale? Sputum/blood culture
CXR
• Hypertranslucent lung fields
• Low flat diaphragm
• Bullae
• Hyperinflation
• >6ribs ant
• peripheral lung markings
• Elongated cardiac shadow
DIAGNOSIS/SEVERITY
4 classifications of severity of COPD:
MANAGEMENT Conservative:
Avoid bronchial irritation Smoking cessation limits FEV1 decline Occupational allergens
Exercise Pulmonary rehabilitation Weight loss – correct obesity, nutritional improvement Rx depression/social isolation – often associated
MANAGEMENT - MEDICAL
MANAGEMENT
Surgery: Lung transplant in lung patients with alpha 1
antitrypsin deficiency Bullaectomy lung volume reduction surgery (Lobectomy – now
close off the lobe using a filter)
ACUTE COPD MX
Rescusitation – ABCDE 24% O2, 2L via nasal cannula or non-variable flow venture
mask. If Type II resp failure target 88-92% Nebulisers - bronchodilators Corticosteroids (oral/IV) Fluids Theophylline IV Empirical ABx IV if infection (+/- pseudomonal cover? Tazocin,
Meropenum, Gentamycin)
Consider ventilation Consider NIV, intubation or ITU in severe cases. Indication for NIV persistent hypercapnia type II RF,
deterioration despite 1hr best medical Rx and patient tiring.
VIDEO BY ASTHMA UK PEFR
http://www.youtube.com/watch?v=DxBDfqPmaZU
VIDEO ASTHMA UKINHALER TECHNIQUE
MDI http://www.youtube.com/watch?v=FqztOZLqFhE
All other inhalers http://www.asthma.org.uk/knowledge-bank-treat
ment-and-medicines-using-your-inhalers
LTOT Indications:
Chronic hypoxaemia e.g COPD, ILD, Lung Ca PaO2 <7.3kPa on air when clinically stable PaO2 7.3-8kPa if 2* polycythaemia or pulmonary
hypertension (clinical/echo) Nocturnal hypoventilation
e.g obesity, OSA, chest wall disease Specialist referral. Usually with CPAP or NIV.
Palliative care For Rx of dyspnoea in terminal illness.
Assessed by respiratory physiologists requires ABG on and off O2.
ANY QUESTIONS
REFERENCES
BTS guidelines asthma - http://www.brit-thoracic.org.uk/Portals/0/Guidelines/AsthmaGuidelines/qrg101%202011.pdf
BTS guideline COPD - http://www.nice.org.uk/nicemedia/live/13029/49399/49399.pdf
BTS guidlein LTOT - http://www.brit-thoracic.org.uk/Portals/0/Clinical%20Information/Home%20Oxygen%20Service/clinical%20adultoxygenjan06.pdf
Spirometry guideline - http://www.brit-thoracic.org.uk/Portals/0/Clinical%20Information/COPD/COPD%20Consortium/spirometry_in_practice051.pdf
Asthma UK Patient.co.uk – professional Acutemed.co.uk http://www.eguidelines.co.uk/eguidelinesmain/gip/vol_13/au
g_10/jones_copd_aug10.php#.UlqCeBDZIa8
Good books for finals: Clinical cases uncovered