Respiratory Lecture 6 Dr Azeem Alam, MBBS BSc (Hons) Surgical AFP Guy’s and St. Thomas’ Hospital Email: admin@bitemedicine.com Website: www.bitemedicine.com Facebook: https://www.facebook.com/biteemedicine Content reviewed on 11/04/2020. Instagram: @bitemedicine 1
Learning objectives • 2 respiratory topics: COPD and Pneumonia • Case-based discussion(s) to identify the top differentials and why • Theory to cover pathophysiology, diagnostic criteria, investigations and management • Quiz (Mentimeter and multi-step SBAs) 2 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Our commitment to you We have listened to your feedback and we have… Added differentials for every topic More diagrams More Multistep-SBA questions 3 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
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Case 1 History A 57-year-old male presents with a 4-month history of a productive cough and shortness of breath at rest. He has a 20-pack-year smoking history. The diameter of the chest is increased on examination, with some wheezing on auscultation. Observations HR 94, BP 128/84, RR 20, SpO 2 93%, Temp 37.6°C. 5 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Pathophysiology Definition: progressive airflow limitation that is irreversible. Characterised by emphysema and chronic bronchitis . Inflammation Inhaled stimuli causes the activation of macrophages and neutrophils • Risk factors Smoking • Alpha-1 antitrypsin deficiency • Air pollution • 6 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Pathophysiology 8 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Pathophysiology Physiological outcome Remodelling and narrowing of airways • Increased airway resistance • Enlargement of mucus-secreting glands • Hypoxia and vascular bed changes result in pulmonary hypertension (cor pulmonale) • 1 9 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Clinical features Symptoms Signs Shortness of breath: initially exercise- Tar staining induced, eventually at rest Productive cough Tachypnoea Fatigue Barrel chest Hyperresonance on percussion Wheeze and quiet breath sounds Exacerbation • Coarse crepitations • Pyrexia • Asterixis 10 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Differentials COPD Asthma Bronchiectasis Smoking Allergen Associated with cystic • • • Alpha-1 antitrypsin Pollution fibrosis • • deficiency Exercise Recurrent infections • • Later in life Early in life Bronchial dilation • • • Irreversible Atopy Significant purulent • • • Family history sputum • Diurnal variation • Reversible • 11 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Suspected cases NICE recommend investigating for suspected COPD in people over 35 years old , with a risk factor (currently smoking or ex-smoker) and 1 or more of the following: • Exertional breathlessness • Chronic cough • Regular sputum production • Winter ‘bronchitis’ • Wheeze 12 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Investigations Bedside • ECG: right sided heart failure (e.g. right axis deviation and RBBB) • Sputum: culture if evidence of exacerbation Bloods • Inflammatory markers: if evidence of exacerbation • Arterial blood gas : possible type 2 respiratory failure Imaging • CXR: flattened diaphragm and hyperinflation Special tests • Spirometry: FEV1/FVC <0.70 and lack of reversibility post-bronchodilator • TLCO : perform if symptoms are disproportionate to spirometry results 14 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Investigations 2 15 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Management The GOLD classification is widely used, more so than NICE, in guiding the management of COPD [2]. GOLD classify airway obstruction as follows: Severity of airflow obstruction Post-bronchodilator FEV1/FVC FEV1% predicted Stage 1: Mild <0.70 ≥80% Stage 2: Moderate <0.70 50-79% Stage 3: Severe <0.70 30-49% Stage 4: Very severe <0.70 <30% 16 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Management • Smoking cessation advice should be offered to all • Vaccinations: one-off pneumococcal and annual influenza • Inhaler therapy: all patients will be started on a short-acting bronchodilator PRN and may have additional long-acting agents 17 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Management: initial therapy Exacerbations Symptoms Inhaler between exacerbations GOLD A ≤ 1 per year not Mild Any bronchodilator requiring admission (short or long acting) GOLD B Severe LABA or LAMA GOLD C ≥ 2 per year or 1 Mild LAMA requiring GOLD D Severe LAMA or • admission LAMA + LABA or • ICS + LABA • Mild symptoms Severe symptoms (MRC ≤ 1 OR CAT <10) (MRC ≥ 2 OR CAT ≥ 10) 18 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Long-term oxygen therapy • Long term oxygen therapy (LTOT): supplemental O2 for at least 15 hours per day. ABG measured on 2 separate occasions • Indicated if a non-smoker and : • PaO2 <7.3 kPa or • PaO2 ≥7.3 and <8 kPa and 1 of the following: • Secondary polycythaemia • Peripheral oedema • Pulmonary hypertension 20 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Management: exacerbation Management is guided by observations, ABG, inflammatory markers, and CXR. • Controlled oxygen: aim SpO2 88-92% if hypercapnic on ABG, otherwise aim for 94-98% • Nebulised bronchodilators: salbutamol and ipratropium bromide • Corticosteroids : usually a 5-day course • Antibiotics : empirical antibiotics such as amoxicillin and doxycycline • Theophylline : consider if there is an inadequate response to nebulisers • Ventilation: if evidence of worsening respiratory acidosis • Non-invasive ventilation: BiPAP • Mechanical ventilation if BiPAP fails 21 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Summary: COPD • COPD is a progressive, irreversible airflow obstruction due to chronic bronchitis and emphysema • Risk factors include smoking , occupational exposure (dust, chemicals, gases, coal), and genetic causes (alpha-1-antitrypsin deficiency) • COPD can be distinguished from asthma with a lack of reversibility post bronchodilator • GOLD criteria for management is dependent on frequency and severity of the exacerbations • One-off pneumococcal vaccine and an annual influenza vaccine 22 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Distinction question 23 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
A1AT genotypes Disease Genotype Normal PiMM Moderate deficiency PiSS Severe deficiency PiZZ 25 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Case 2 History A 64-year-old female presents to the emergency department with shortness of breath and a productive cough. She has a history of hypertension, for which she takes amlodipine. Observations HR 100, BP 120/80, RR 20, SpO 2 94%, Temp 38.2 °C. 26 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Pathophysiology 3
Aetiology Categorised into: Community-acquired pneumonia (CAP) • Hospital-acquired pneumonia (HAP) • Atypical pneumonia • Aspiration pneumonia • 28 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
Aetiology Category Organism Clinical feature Community-acquired Streptococcus pneumoniae The most common cause • pneumonia of pneumonia Haemophilus influenzae Associated with COPD • Staphylococcus aureus Post viral URTI • (commonly) Abscess and empyema • Hospital-acquired pneumonia Gram-negative bacteria and • May require broad- • Occurs ≥ 48 hours after staphylococcus aureus spectrum antibiotics admission to hospital 30 www.bitemedicine.com Instagram: @bitemedicine Facebook: /biteemedicine
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