Obstructive Airway Disease

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

MANAGEMENTConservative:

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

?

?

MANAGEMENTResuscitate 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/SEVERITY4 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-treatment-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/aug_

10/jones_copd_aug10.php#.UlqCeBDZIa8

Good books for finals: Clinical cases uncovered