Respiratory Flashcards

Question

Non-Invasive Ventilation

Answer 1

Non-invasive ventilation (NIV) involves using a full face mask, hood (covering the entire head) or a tight-fitting nasal mask to blow air forcefully into the lungs and ventilate them. It is not pleasant for the patient but is much less invasive than intubation and ventilation. It is a valuable middle point between basic oxygen therapy and mechanical ventilation. BiPAP is a specific machine that provides NIV. BiPAP stands for Bilevel Positive Airway Pressure. Generally, the term NIV is used instead of BiPAP, as BiPAP refers to a specific machine rather than the therapy. NIV involves a cycle of high and low pressure to correspond to the patient’s inspiration and expiration: IPAP (inspiratory positive airway pressure) is the pressure during inspiration – where air is forced into the lungs EPAP (expiratory positive airway pressure) is the pressure during expiration – stopping the airways from collapsing

Answer 2

Mechanical ventilation is used where other forms of respiratory support (e.g., oxygen and NIV) are inadequate or contraindicated. A ventilator machine is used to move air into and out of the lungs. Patients generally require sedation whilst on a ventilator, as it can be uncomfortable and distressing. Mechanical ventilation has several adverse effects and is only used for the shortest time necessary. An endotracheal tube (ETT) or tracheostomy is required to connect the ventilator to the lungs. There should be no leaks in the circuit. The ventilator should be able to deliver controlled pressures and volumes into the lungs.

Answer 3

Obstructive lung disease is diagnosed when the FEV1 is less than 70% of the FVC, meaning a FEV1:FVC ratio of less than 70%. This suggests that obstruction is slowing the air passage out of the lungs. The person may have a relatively good lung volume, but air can only move slowly in and out of the lungs due to obstruction. In asthma, the obstruction is a narrowed airway due to bronchoconstriction. In COPD, there is chronic airway and lung damage, causing obstruction. You can test the reversibility of this obstruction by giving a bronchodilator (e.g., salbutamol). The obstructive picture is typically reversible in asthma but less so in COPD.

Answer 4

In restrictive lung disease: FEV1 and FVC are equally reduced FEV1:FVC ratio greater than 70% Restrictive lung disease limits the ability of the lungs to expand and fill with air. The lungs are restricted from effectively expanding. This is different from obstructive lung disease, where there is obstructed airflow. Restriction of lung expansion leads to inadequate ventilation of the alveoli and insufficient blood oxygenation. The FEV1:FVC ratio is normal or raised in restrictive lung disease without obstructive pathology affecting airflow through the airways. The FVC is reduced due to the restriction of lung expansion and capacity. Restrictive lung disease includes conditions that limit how well the chest wall and lungs can expand, for example: Interstitial lung disease, such as idiopathic pulmonary fibrosis Sarcoidosis Obesity Motor neurone disease Scoliosis TOM TIP: It is worth remembering that a low FVC indicates restrictive lung disease, and a low FEV1:FVC ratio (under 70%) indicates obstructive lung disease. A low FVC and a low FEV1:FVC ratio indicate a combination of obstructive and restrictive lung disease. This is a common data interpretation question in exams.

Answer 5

Asthma is a chronic inflammatory airway disease leading to variable airway obstruction. The smooth muscle in the airways is hypersensitive and responds to stimuli by constricting and causing airflow obstruction. This bronchoconstriction is reversible with bronchodilators, such as inhaled salbutamol. Asthma is one of several atopic conditions, including eczema, hay fever and food allergies. Patients with one of these conditions are more likely to have others. These conditions characteristically run in families. Asthma typically presents in childhood. However, it can present at any age. Adult-onset asthma refers to asthma presenting in adulthood. Occupational asthma refers to asthma caused by environmental triggers in the workplace. The severity of symptoms of asthma varies enormously between individuals. Acute asthma exacerbations involve rapidly worsening symptoms and can quickly become life-threatening.

Answer 6

Symptoms are episodic, meaning there are periods where the symptoms are worse and better. There is diurnal variability, meaning the symptoms fluctuate at different times of the day, typically worse at night. Typical symptoms are: Shortness of breath Chest tightness Dry cough Wheeze Symptoms should improve with bronchodilators. No response to bronchodilators reduces the likelihood of asthma. Patients may have a history of other atopic conditions, such as eczema, hayfever and food allergies. They often have a family history of asthma or atopy. Examination is generally normal when the patient is well. A key finding with asthma is a widespread “polyphonic” expiratory wheeze. TOM TIP: A localised monophonic wheeze is not asthma. The top differentials of a localised wheeze are an inhaled foreign body, tumour or a thick sticky mucus plug obstructing an airway. A chest x-ray is the next step.

Answer 7

Certain environmental triggers can exacerbate the symptoms of asthma. These vary between individuals: Infection Nighttime or early morning Exercise Animals Cold, damp or dusty air Strong emotions TOM TIP: Beta-blockers, particularly non-selective beta-blockers (e.g., propranolol), and non-steroidal anti-inflammatory drugs (e.g., ibuprofen or naproxen), can worsen asthma. These are worth remembering.

Answer 8

Spirometry is the test used to establish objective measures of lung function. It involves different breathing exercises into a machine that measures volumes of air and flow rates and produces a report. A FEV1:FVC ratio of less than 70% suggests obstructive pathology (e.g., asthma or COPD). Reversibility testing involves giving a bronchodilator (e.g., salbutamol) before repeating the spirometry to see if this impacts the results. NICE says a greater than 12% increase in FEV1 on reversibility testing supports a diagnosis of asthma. Fractional exhaled nitric oxide (FeNO) measures the concentration of nitric oxide exhaled by the patient. Nitric oxide is a marker of airway inflammation. The test involves a steady exhale for around 10 seconds into a device that measures FeNO. NICE say a level above 40 ppb is a positive test result, supporting a diagnosis. Smoking can lower the FeNO, making the results unreliable. Peak flow variability is measured by keeping a peak flow diary with readings at least twice daily over 2 to 4 weeks. NICE says a peak flow variability of more than 20% is a positive test result, supporting a diagnosis. Direct bronchial challenge testing is the opposite of reversibility testing. Inhaled histamine or methacholine is used to stimulate bronchoconstriction, reducing the FEV1 in patients with asthma. NICE say a PC20 (provocation concentration of methacholine causing a 20% reduction in FEV1) of 8 mg/ml or less is a positive test result.

Answer 9

The NICE guidelines (2020) recommend initial investigations in patients with suspected asthma: Fractional exhaled nitric oxide (FeNO) Spirometry with bronchodilator reversibility Where there is diagnostic uncertainty after initial investigations, the next step is testing the peak flow variability. Where there is still uncertainty, the next step is a direct bronchial challenge test with histamine or methacholine. The BTS/SIGN guidelines (revised 2019) are similar to the NICE guidelines. They recommend categorising patients into a high, intermediate or low probability of asthma based on clinical features and investigation results, then assessing the response to treatment before making a diagnosis if there is a good response. The Global Initiative for Asthma (GINA) guidelines (2022) are relatively similar on diagnosis, other than suggesting that FeNO testing is not useful in making or excluding a diagnosis of asthma.

Answer 10

Beta-2 adrenergic receptor agonists are bronchodilators (they open the airways). Adrenalin acts on the smooth muscle of the airways to cause relaxation. Stimulating the adrenalin receptors dilates the bronchioles and reverses the bronchoconstriction present in asthma. Short-acting beta-2 agonists (SABA), such as salbutamol, work quickly, but the effects last only a few hours. They are used as reliever or rescue medication during acute worsening of asthma symptoms. Long-acting beta-2 agonists (LABA), such as salmeterol, are slower to act but last longer. Inhaled corticosteroids (ICS), such as beclometasone, reduce the inflammation and reactivity of the airways. These are used as maintenance or preventer medications to control symptoms long-term and are taken regularly, even when well. Long-acting muscarinic antagonists (LAMA), such as tiotropium, work by blocking acetylcholine receptors. Acetylcholine receptors are stimulated by the parasympathetic nervous system and cause contraction of the bronchial smooth muscles. Blocking these receptors dilates the bronchioles and reverses the bronchoconstriction present in asthma. Leukotriene receptor antagonists, such as montelukast, work by blocking the effects of leukotrienes. Leukotrienes are produced by the immune system and cause inflammation, bronchoconstriction and mucus secretion in the airways. Theophylline works by relaxing the bronchial smooth muscle and reducing inflammation. Unfortunately, it has a narrow therapeutic window and can be toxic in excess, so monitoring plasma theophylline levels is required. Maintenance and reliever therapy (MART) involves a combination inhaler containing an inhaled corticosteroid and a fast and long-acting beta-agonist (e.g., formoterol). This replaces all other inhalers, and the patient uses this single inhaler both regularly as a preventer and also as a reliever when they have symptoms.

Answer 11

The principles of using the stepwise ladder are to: Start at the most appropriate step for the severity of the symptoms Review at regular intervals based on severity (e.g., 4-8 weeks after adjusting treatment) Add additional treatments as required to control symptoms completely Aim to achieve no symptoms or exacerbations on the lowest dose and number of treatments Always check inhaler technique and adherence when reviewing medications The BTS/SIGN guidelines on asthma (2019) suggest the following steps (adding drugs at each stage): Short-acting beta-2 agonist inhaler (e.g. salbutamol) as required Inhaled corticosteroid (low dose) taken regularly Long-acting beta-2 agonists (e.g., salmeterol) or maintenance and reliever therapy (MART) Increase the inhaled corticosteroid or add a leukotriene receptor antagonist (e.g., montelukast) Specialist management (e.g., oral corticosteroids) The NICE guidelines on asthma (2017) suggest the following steps (adding drugs at each stage): Short-acting beta-2 agonist inhaler (e.g. salbutamol) as required Inhaled corticosteroid (low dose) taken regularly Leukotriene receptor antagonist (e.g., montelukast) taken regularly Long-acting beta-2 agonists (e.g., salmeterol) taken regularly Consider changing to a maintenance and reliever therapy (MART) regime Increase the inhaled corticosteroid to a moderate dose Consider high-dose inhaled corticosteroid or additional drugs (e.g., LAMA or theophylline) Specialist management (e.g., oral corticosteroids) The Global Initiative for Asthma (GINA) guidelines (2022) recommend that all patients should be on an inhaled corticosteroid and should not be managed with a SABA (e.g., salbutamol) alone. The first step of their ladder is a combination inhaler containing a low-dose inhaled corticosteroid plus formoterol as required. The second step is maintenance and reliever therapy (MART) with the same inhaler. The NICE and BTS/SIGN guidelines predate the GINA guidelines and may change. Additional management includes: Individual written asthma self-management plan Yearly flu jab Yearly asthma review when stable Regular exercise Avoid smoking (including passive smoke) Avoiding triggers where appropriate

Answer 12

An acute exacerbation of asthma involves a rapid deterioration in symptoms. Any typical asthma triggers, such as infection, exercise or cold weather, could set off an acute exacerbation. Presenting features of an acute exacerbation are: Progressively shortness of breath Use of accessory muscles Raised respiratory rate (tachypnoea) Symmetrical expiratory wheeze on auscultation The chest can sound “tight” on auscultation, with reduced air entry throughout On arterial blood gas analysis, patients initially have respiratory alkalosis, as a raised respiratory rate (tachypnoea) causes a drop in CO2. A normal pCO2 or low pO2 (hypoxia) is a concerning sign, as it means they are getting tired, indicating life-threatening asthma. Respiratory acidosis due to high pCO2 is a very bad sign.

Answer 13

Moderate exacerbation features: Peak flow 50 – 75% best or predicted Severe exacerbation features: Peak flow 33-50% best or predicted Respiratory rate above 25 Heart rate above 110 Unable to complete sentences Life-threatening exacerbation features: Peak flow less than 33% Oxygen saturations less than 92% PaO2 less than 8 kPa Becoming tired Confusion or agitation No wheeze or silent chest Haemodynamic instability (shock) The wheeze disappears when the airways are so tight that there is no air entry. This is ominously described as a silent chest and is a sign of life-threatening asthma.

Answer 14

Patients with an acute exacerbation of asthma can deteriorate quickly. Acute asthma is potentially life-threatening. Treatment should be aggressive and they should be escalated early to seniors and intensive care. Treatment decisions, particularly intravenous aminophylline, salbutamol and magnesium, should involve experienced seniors. Mild exacerbations may be treated with: Inhaled beta-2 agonists (e.g., salbutamol) via a spacer Quadrupled dose of their inhaled corticosteroid (for up to 2 weeks) Oral steroids (prednisolone) if the higher ICS is inadequate Antibiotics only if there is convincing evidence of bacterial infection Follow-up within 48 hours Moderate exacerbations may additionally be treated with: Consider hospital admission Nebulised beta-2 agonists (e.g., salbutamol) Steroids (e.g., oral prednisolone or IV hydrocortisone) Severe exacerbations may additionally be treated with: Hospital admission Oxygen to maintain sats 94-98% Nebulised ipratropium bromide IV magnesium sulphate IV salbutamol IV aminophylline Life-threatening exacerbations may additionally be treated with: Admission to HDU or ICU Intubation and ventilation The decision to intubate a patient with life-threatening asthma is generally made early as it is very difficult to intubate with severe bronchoconstriction. Serum potassium needs monitoring with salbutamol treatment, which causes potassium to be absorbed from the blood into the cells, resulting in hypokalaemia (low potassium). Salbutamol also causes tachycardia (fast heart rate) and can cause lactic acidosis. After an acute attack, management involves: Optimising long-term asthma management Individual written asthma self-management plan Considering a rescue pack of oral steroids to start early in an exacerbation NICE suggest referral to a specialist after 2 attacks in 12 month

Answer 15

Chronic obstructive pulmonary disease (COPD) involves a long-term, progressive condition involving airway obstruction, chronic bronchitis and emphysema. It is almost always the result of smoking and is largely preventable. While it is not reversible, it is treatable. Damage to the lung tissues obstructs the flow of air through the airways. Chronic bronchitis refers to long-term symptoms of a cough and sputum production due to inflammation in the bronchi. Emphysema involves damage and dilatation of the alveolar sacs and alveoli, decreasing the surface area for gas exchange. Unlike asthma, airway obstruction is minimally reversible with bronchodilators, such as salbutamol. Patients are susceptible to exacerbations, during which their lung function worsens. Exacerbations triggered by infection are called infective exacerbations of COPD.

Answer 16

A typical presentation of COPD is a long-term smoker with persistent symptoms of: Shortness of breath Cough Sputum production Wheeze Recurrent respiratory infections, particularly in winter TOM TIP: COPD does NOT cause clubbing, haemoptysis (coughing up blood) or chest pain. These symptoms should be investigated for a different cause, such as lung cancer, pulmonary fibrosis or heart failure.

Answer 17

The MRC (Medical Research Council) Dyspnoea Scale is a 5-point scale for assessing breathlessness: Grade 1: Breathless on strenuous exercise Grade 2: Breathless on walking uphill Grade 3: Breathlessness that slows walking on the flat Grade 4: Breathlessness stops them from walking more than 100 meters on the flat Grade 5: Unable to leave the house due to breathlessness

Answer 18

Diagnosis is based on the clinical presentation and spirometry results. Spirometry will show an obstructive picture with a FEV1:FVC ratio of less than 70%. There is little or no response to reversibility testing with beta-2 agonists (e.g., salbutamol). Reversible obstruction is more suggestive of asthma.

Answer 19

The severity can be graded using the forced expiratory volume in 1 second (FEV1): Stage 1 (mild): FEV1 more than 80% of predicted Stage 2 (moderate): FEV1 50-79% of predicted Stage 3 (severe): FEV1 30-49% of predicted Stage 4 (very severe): FEV1 less than 30% of predicted

Answer 20

Body mass index at baseline (weight loss occurs in severe disease) Chest x-ray to exclude other pathology, such as lung cancer Full blood count for polycythaemia (raised haemoglobin due to chronic hypoxia), anaemia and infection Sputum culture to assess for chronic infections, such as pseudomonas ECG and echocardiogram to assess for heart failure and cor pulmonale CT thorax for alternative diagnoses such as fibrosis, cancer or bronchiectasis Serum alpha-1 antitrypsin to look for alpha-1 antitrypsin deficiency Transfer factor for carbon monoxide (TLCO) tests the diffusion of inhaled gas into the blood (reduced in COPD)

Answer 21

Continuing smoking will progressively worsen lung function and prognosis. Smoking cessation services are available. Patients should have the pneumococcal and annual flu vaccine. Pulmonary rehabilitation involves a multidisciplinary approach to help improve function and quality of life, including physical training and education. Initial medical treatment recommended by the NICE guidelines (updated 2019) involves: Short-acting beta-2 agonists (e.g., salbutamol) Short-acting muscarinic antagonists (e.g., ipratropium bromide) The second step, when symptoms or exacerbations are still a problem, is determined by whether there are asthmatic or steroid-responsive features, measured by: Previous diagnosis of asthma or atopy Variation in FEV1 of more than 400mls Diurnal variability in peak flow of more than 20% Raised blood eosinophil count Where there are no asthmatic or steroid-responsive features, treatment is a combination of: Long-acting beta agonist (LABA) Long-acting muscarinic antagonist (LAMA) Anoro Ellipta, Ultibro Breezhaler and DuaKlir Genuair are examples of LABA and LAMA combination inhalers. Where there are asthmatic or steroid-responsive features, treatment is a combination of: Long-acting beta agonist (LABA) Inhaled corticosteroid (ICS) Fostair, Symbicort and Seretide are examples of LABA and ICS combination inhalers. The final inhaler step is a combination of a LABA, LAMA and ICS. Trimbow, Trelegy Ellipta and Trixeo Aerosphere are examples of LABA, LAMA and ICS combination inhalers. In more severe cases, additional options (guided by a specialist) are: Nebulisers (e.g., salbutamol or ipratropium) Oral theophylline Oral mucolytic therapy to break down sputum (e.g., carbocisteine) Prophylactic antibiotics (e.g., azithromycin) Oral corticosteroids (e.g., prednisolone) Oral phosphodiesterase-4 inhibitors (e.g., roflumilast) Long-term oxygen therapy at home Lung volume reduction surgery (removing damaged lung tissue to improve the function of healthier tissue) Palliative care (opiates and other drugs may be used to help breathlessness) Patients taking azithromycin need ECG and liver function monitoring before and during treatment. Long-term oxygen therapy (LTOT) is used for severe COPD with chronic hypoxia (sats < 92%), polycythaemia, cyanosis or cor pulmonale. Smoking is a contraindication due to the fire risk.

Answer 22

Cor pulmonale refers to right-sided heart failure caused by respiratory disease. The increased pressure and resistance in the pulmonary arteries (pulmonary hypertension) limits the right ventricle pumping blood into the pulmonary arteries. This causes back-pressure into the right atrium, vena cava and systemic venous system.

Answer 23

COPD (the most common cause) Pulmonary embolism Interstitial lung disease Cystic fibrosis Primary pulmonary hypertension

Answer 24

Often patients with early cor pulmonale are asymptomatic. Symptoms of cor pulmonale include: Shortness of breath Peripheral oedema Breathlessness of exertion Syncope (dizziness and fainting) Chest pain

Answer 25

Hypoxia Cyanosis Raised JVP (due to a back-log of blood in the jugular veins) Peripheral oedema Parasternal heave Loud second heart sound Murmurs (e.g., pan-systolic in tricuspid regurgitation) Hepatomegaly due to back pressure in the hepatic vein (pulsatile in tricuspid regurgitation)

Answer 26

Management of cor pulmonale involves treating the symptoms (e.g., diuretics for oedema) and the underlying cause. Long-term oxygen therapy is often used. The prognosis is poor unless there is a reversible underlying cause.

Answer 27

An acute COPD exacerbation presents rapidly worsening symptoms, such as cough, shortness of breath, sputum production and wheezing. Viral or bacterial infection often triggers it. Arterial Blood Gas An acute exacerbation of COPD typically causes a respiratory acidosis involving: Low pH indicates acidosis Low pO2 indicates hypoxia and respiratory failure Raised pCO2 indicates CO2 retention (hypercapnia) Raised bicarbonate indicates chronic retention of CO2 Carbon dioxide (CO2) makes blood acidotic by becoming carbonic acid (H2CO3). Low pH with a raised pCO2 suggests they are acutely retaining CO2, making their blood acidotic, indicating respiratory acidosis. Raised bicarbonate indicates they chronically retain CO2. Their kidneys have responded by producing more bicarbonate to balance the acidic CO2 and maintain a normal pH. During an acute exacerbation, the kidneys cannot keep up with the rising level of CO2, so the blood becomes acidotic despite a raised bicarbonate.

Answer 28

Chest x-ray to look for pneumonia or other pathology ECG to look for arrhythmias or evidence of heart strain Full blood count to look for infection (raised white blood cells) U&E to check electrolytes, which can be affected by infections and medications Sputum culture Blood cultures in patients with signs of sepsis (e.g., fever)

Answer 29

Many patients with COPD retain CO2 when treated with oxygen, referred to as oxygen-induced hypercapnia. The mechanism for this is complex and likely involves ventilation-perfusion mismatch and haemoglobin binding less well to CO2 when also bound to oxygen. Target oxygen saturations of 88-92% are used for patients with COPD at risk of retaining CO2. These may be adjusted to 94-98% when confident they do not retain CO2. Venturi masks are designed to deliver a specific percentage concentration of oxygen. They allow some of the oxygen to leak out the side of the mask and normal air to be inhaled along with oxygen. Environmental air contains 21% oxygen. Venturi masks deliver 24% (blue), 28% (white), 31% (orange), 35% (yellow), 40% (red) or 60% (green) oxygen.

Answer 30

First-line medical treatment of an acute exacerbation of COPD involves: Regular inhalers or nebulisers (e.g., salbutamol and ipratropium) Steroids (e.g., prednisolone 30 mg once daily for 5 days) Antibiotics if there is evidence of infection Respiratory physiotherapy can be used to help clear sputum. Additional options in severe cases include: IV aminophylline Non-invasive ventilation (NIV) Intubation and ventilation with admission to intensive care Doxapram may be used as a respiratory stimulant where NIV or intubation is not appropriate.

Answer 31

Non-invasive ventilation (NIV) involves using a full face mask, hood (covering the entire head) or a tight-fitting nasal mask to blow air forcefully into the lungs and ventilate them. It is not pleasant for the patient but is much less invasive than intubation and ventilation. It is a valuable middle point between basic oxygen therapy and mechanical ventilation. NIV involves a cycle of high and low pressure to correspond to the patient’s inspiration and expiration: IPAP (inspiratory positive airway pressure) is the pressure during inspiration – where air is forced into the lungs EPAP (expiratory positive airway pressure) is the pressure during expiration – stopping the airways from collapsing NIV is considered when the following inclusion criteria are met: Persistent respiratory acidosis (pH < 7.35 and PaCO2 > 6) despite maximal medical treatment Potential to recover Acceptable to the patient The decision to initiate it would be made by a registrar or above. The main contraindications are an untreated pneumothorax or any structural abnormality or pathology affecting the face, airway or gastrointestinal tract. Patients should have a chest x-ray before NIV to exclude pneumothorax. A plan should be in place if the NIV fails so that everyone agrees on whether the patient should proceed to intubation, ventilation, and ICU or whether palliative care is more appropriate. The initial pressures are estimated based on the patient’s body mass. Pressures are measured in cm of water. Potential pressures for an average patient might be: IPAP 16-20cm H2O (usually starting at 12 and increasing every 2-5 minutes until the target pressure is reached) EPAP 4-6cm H2O ABGs are monitored closely whilst on NIV (e.g., 1 hour after every change, then 4 hourly until stable). The IPAP is increased by 2-5 cm increments until the acidosis resolves.

Answer 32

Interstitial lung disease includes many conditions that cause inflammation and fibrosis of the lung parenchyma (lung tissue). Fibrosis involves the replacement of elastic and functional lung tissue with non-functional scar tissue. The conditions we will cover here are:: Idiopathic pulmonary fibrosis (the most important to remember) Secondary pulmonary fibrosis Hypersensitivity pneumonitis Cryptogenic organising pneumonia Asbestosis

Answer 33

The key presenting features are: Shortness of breath on exertion Dry cough Fatigue Patients with idiopathic pulmonary fibrosis have typical findings on examination: Bibasal fine end-inspiratory crackles Finger clubbing TOM TIP: Remember clubbing and bibasal fine inspiratory crackles in idiopathic pulmonary fibrosis. These patients are ideal for OSCEs as they are stable and have good signs.

Answer 34

Diagnosis of interstitial lung disease involves: Clinical features High-resolution CT scan (HRCT) of the thorax (showing a typical “ground glass” appearance) Spirometry Spirometry may be normal or show a restrictive pattern: FEV1 and FVC are equally reduced FEV1:FVC ratio greater than 70% Other investigations where there is doubt about the diagnosis include: Lung biopsy Bronchoalveolar lavage

Answer 35

Generally, there is a poor prognosis and limited management options in interstitial lung disease, and treatment is primarily supportive. Options include: Remove or treat the underlying cause Home oxygen where there is hypoxia Stop smoking Physiotherapy and pulmonary rehabilitation Pneumococcal and flu vaccine Advanced care planning and palliative care where appropriate Lung transplant is an option, but the risks and benefits need careful consideration

Answer 36

Idiopathic pulmonary fibrosis features progressive pulmonary fibrosis with no apparent cause. It presents with an insidious onset of shortness of breath and dry cough over more than 3 months. It usually affects adults over 50 years old. The prognosis is poor, with a 2-5 years life expectancy from diagnosis. Two medications are licensed that can slow the progression of the disease: Pirfenidone reduces fibrosis and inflammation through various mechanisms Nintedanib reduces fibrosis and inflammation by inhibiting tyrosine kinase

Answer 37

Several drugs can cause pulmonary fibrosis: Amiodarone (also causes grey/blue skin) Cyclophosphamide Methotrexate Nitrofurantoin Pulmonary fibrosis can occur secondary to other conditions: Alpha-1 antitrypsin deficiency Rheumatoid arthritis Systemic lupus erythematosus (SLE) Systemic sclerosis Sarcoidosis

Answer 38

Hypersensitivity pneumonitis, also called extrinsic allergic alveolitis, involves type III and type IV hypersensitivity reaction to an environmental allergen. Inhalation of allergens in patients sensitised to that allergen causes an immune response, leading to inflammation and damage to the lung tissue. Bronchoalveolar lavage is performed during a bronchoscopy procedure. The airways are washed with sterile saline to gather cells, after which the fluid is collected and analysed. Raised lymphocytes (lymphocytosis) are suggestive of hypersensitivity pneumonitis. Management involves removing the allergen, oxygen where necessary and steroids. Examples of specific causes: Bird-fancier’s lung is a reaction to bird droppings Farmer’s lung is a reaction to mouldy spores in hay Mushroom worker’s lung is a reaction to specific mushroom antigens Malt worker’s lung is a reaction to mould on barley

Answer 39

Cryptogenic organising pneumonia was previously known as bronchiolitis obliterans organising pneumonia. It involves a focal area of inflammation of the lung tissue. It can be idiopathic or triggered by infection, inflammatory disorders, medications, radiation, environmental toxins, or allergens. Presentation is similar to infectious pneumonia, with shortness of breath, cough, fever and lethargy. Inspiratory crackles may be heard on auscultation. Chest x-ray findings are also similar to pneumonia, with a focal consolidation. A lung biopsy is the definitive investigation. Diagnosis is often delayed due to the similarities to infectious pneumonia. Treatment is with systemic corticosteroids.

Answer 40

Asbestosis refers to lung fibrosis related to asbestos exposure. Asbestos is fibrogenic, meaning it causes lung fibrosis. It is also oncogenic, meaning it causes cancer. The effects of asbestos usually take several decades to develop. Asbestos inhalation causes several problems: Lung fibrosis Pleural thickening and pleural plaques Adenocarcinoma Mesothelioma Patients may be eligible for compensation if they develop asbestos-related health conditions. All deceased patients with occupational asbestos exposure must be referred to the coroner.

Answer 41

A pleural effusion is a collection of fluid in the pleural space. Pleural effusions can be broadly categorised into: Exudative – a high protein content (more than 30g/L) Transudative – a lower protein content (less than 30g/L) Light’s criteria are used for establishing an exudative effusion using protein or lactate dehydrogenase (LDH): Pleural fluid protein / serum protein greater than 0.5 Pleural fluid LDH / serum LDH greater than 0.6 Pleural fluid LDH greater than 2/3 of the normal upper limit of the serum LDH

Answer 42

Exudative causes are related to inflammation. The inflammation results in protein leaking out of the tissues into the pleural space (ex- meaning moving out of). The top causes are: Cancer (e.g., lung cancer or mesothelioma) Infection (e.g., pneumonia or tuberculosis) Rheumatoid arthritis Transudative causes relate to fluid moving across or shifting into the pleural space (trans- meaning moving across): Congestive cardiac failure Hypoalbuminaemia Hypothyroidism Meigs syndrome TOM TIP: Meigs syndrome involves a triad of a benign ovarian tumour (usually a fibroma), pleural effusion and ascites. This often appears in exams. The pleural effusion and ascites resolve with the removal of the tumour.

Answer 43

The typical presenting symptom is shortness of breath. Examination findings are: Dullness to percussion over the effusion Reduced breath sounds Tracheal deviation away from the effusion in very large effusions

Answer 44

Chest x-ray findings are: Blunting of the costophrenic angle Fluid in the lung fissures Larger effusions will have a meniscus (a curving upwards where it meets the chest wall and mediastinum) Tracheal and mediastinal deviation away from the effusion in very large effusions Ultrasound and CT can detect smaller effusions than a chest x-ray, estimate the volume and identify potential causes. Pleural fluid analysis requires a sample taken by aspiration or chest drain. This helps establish the underlying cause by measuring the protein content, LDH, cell count, pH, glucose and microbiology testing.

Answer 45

Diagnosing and treating the underlying cause is the mainstay of management. Conservative management may be appropriate as small effusions will resolve with treatment of the underlying cause. More significant effusions often need aspiration or drainage. Pleural aspiration involves sticking a needle through the chest wall into the effusion and aspirating the fluid. Aspiration can temporarily relieve the pressure, but the effusion may recur, and further drainage may be required. Chest drain can be used to drain the effusion and prevent it from recurring.

Answer 46

Empyema refers to an infected pleural effusion. Suspect an empyema in a patient with improving pneumonia but a new or ongoing fever. Pleural aspiration shows pus, low pH, low glucose and high LDH. Empyema is treated with a chest drain and antibiotics.

Answer 47

Pneumothorax occurs when air enters the pleural space, separating the lung from the chest wall. It can occur spontaneously or secondary to trauma, medical interventions (“iatrogenic”) or lung pathology. The typical patient in exams is a tall, thin young man presenting with sudden breathlessness and pleuritic chest pain, possibly whilst playing sports.

Answer 48

Spontaneous Trauma Iatrogenic, for example, due to lung biopsy, mechanical ventilation or central line insertion Lung pathologies such as infection, asthma or COPD

Answer 49

An erect chest x-ray is the investigation of choice for diagnosing a simple pneumothorax. It shows an area between the lung tissue and the chest wall with no lung markings. There will be a line demarcating the edge of the lung where the lung markings end and the pneumothorax begins. Measuring the size of the pneumothorax on a chest x-ray can be done according to the BTS guidelines (2010). This involves measuring horizontally from the lung edge to the inside of the chest wall at the level of the hilum. CT thorax can detect a pneumothorax that is too small to be seen on a chest x-ray. It can also be used to assess the size of the pneumothorax accurately.

Answer 50

The acute management here is based on the 2010 guidelines from the British Thoracic Society. Always check the latest local and national guidelines, and consult with seniors when managing patients. No shortness of breath and less than a 2cm rim of air on the chest x-ray: No treatment is required as it will spontaneously resolve Follow-up in 2 – 4 weeks is recommended Shortness of breath or more than a 2cm rim of air on the chest x-ray: Aspiration followed by reassessment When aspiration fails twice, a chest drain is required Unstable patients, bilateral or secondary pneumothoraces, generally require a chest drain.

Answer 51

Chest drains are inserted in the “triangle of safety”. This triangle is formed by the: 5th intercostal space (or the inferior nipple line) Midaxillary line (or the lateral edge of the latissimus dorsi) Anterior axillary line (or the lateral edge of the pectoralis major) The needle is inserted just above the rib to avoid the neurovascular bundle that runs just below the rib. Once the chest drain is inserted, obtain a chest x-ray to check the positioning. The external end of the drain is placed underwater, creating a seal to prevent air from flowing back through the drain into the chest. Air can exit the chest cavity and bubble through the water, but the water prevents air from re-entering the drain and chest. During normal respiration, the water in the drain will rise and fall due to changes in pressure in the chest (described as “swinging”). When the chest drain successfully treats the pneumothorax, air will bubble through the fluid in the drain bottle. There will be swinging of the water with respiration. On a repeat chest x-ray, there will be re-inflation of the lung. If these things do not occur, there may be a problem with the drain, such as: Blocked or kinked tube Incorrect position in the chest Not correctly connected to the bottle Once the pneumothorax resolves, there should be no further bubbling in the drain bottle. The swinging of the water with respiration will also reduce. Two key complications of chest drains are: Air leaks around the drain site (indicated by persistent bubbling of fluid, particularly on coughing) Surgical emphysema (also known as subcutaneous emphysema) is when air collects in the subcutaneous tissue

Answer 52

Patients may require surgical interventions when: A chest drain fails to correct the pneumothorax There is a persistent air leak in the drain The pneumothorax reoccurs (recurrent pneumothorax) Video-assisted thoracoscopic surgery (VATS) can be used to correct a pneumothorax. The surgical options are: Abrasive pleurodesis (using direct physical irritation of the pleura) Chemical pleurodesis (using chemicals, such as talc powder, to irritate the pleura) Pleurectomy (removal of the pleura) Pleurodesis involves creating an inflammatory reaction in the pleural lining so the pleura sticks together and the pleural space becomes sealed. This prevents further pneumothoraces from developing.

Answer 53

Tension pneumothorax is caused by trauma to the chest wall that creates a one-way valve that lets air in but not out of the pleural space. The one-way valve means that air is drawn into the pleural space during inspiration, and during expiration, the air is trapped in the pleural space. Therefore, with each breath, more air is drawn into the pleural space and cannot escape. This is dangerous as it creates pressure inside the thorax to push the mediastinum across, kink the big vessels in the mediastinum and cause cardiorespiratory arrest.

Answer 54

Tracheal deviation away from the side of the pneumothorax Reduced air entry on the affected side Increased resonance to percussion on the affected side Tachycardia Hypotension

Answer 55

The management sentence you need to learn and recite in your exams is: “Insert a large bore cannula into the second intercostal space in the midclavicular line.” However, the Advanced Traumatic Life Support (ATLS) recommendations from 2018 recommend using the “fourth or fifth intercostal space, anterior to the midaxillary line” for adults. The reason for choosing this is this site is that the chest wall thickness may be smaller than in the second intercostal space. If a tension pneumothorax is suspected, do not wait for any investigations. A chest drain is required for definitive management once the pressure is relieved with a cannula.

Answer 56

Pulmonary embolism (PE) describes a blood clot (thrombus) in the pulmonary arteries. An embolus is a thrombus that has travelled in the blood, often from a deep vein thrombosis (DVT) in a leg. The thrombus will block the blood flow to the lung tissue and strain the right side of the heart. DVTs and PEs are collectively known as venous thromboembolism (VTE).

Answer 57

Several factors can put patients at higher risk of developing a DVT or PE. In many of these situations (e.g., surgery), prophylactic treatment is used to reduce the risk of VTE. Immobility Recent surgery Long-haul travel Pregnancy Hormone therapy with oestrogen (e.g., combined oral contraceptive pill or hormone replacement therapy) Malignancy Polycythaemia (raised haemoglobin) Systemic lupus erythematosus Thrombophilia TOM TIP: In your exams, when a patient presents with possible features of a DVT or PE, ask about risk factors such as periods of immobility, surgery and long-haul flights to score extra points.

Answer 58

Every patient admitted to hospital is assessed for their risk of venous thromboembolism (VTE). Higher-risk patients receive prophylaxis with low molecular weight heparin (e.g., enoxaparin) unless contraindicated. Contraindications include active bleeding or existing anticoagulation with warfarin or a DOAC. Anti-embolic compression stockings are also used unless contraindicated (e.g., peripheral arterial disease).

Answer 59

Pulmonary embolism can be asymptomatic (discovered incidentally), present with subtle signs and symptoms, or even cause sudden death. A low threshold for suspecting a PE is required. Presenting features include: Shortness of breath Cough Haemoptysis (coughing up blood) Pleuritic chest pain (sharp pain on inspiration) Hypoxia Tachycardia Raised respiratory rate Low-grade fever Haemodynamic instability causing hypotension There may also be signs and symptoms of a deep vein thrombosis, such as unilateral leg swelling and tenderness.

Answer 60

A chest x-ray is usually normal in a pulmonary embolism but is required to rule out other pathology. The Wells score is used when considering pulmonary embolism. The outcome decides the next step: Likely: perform a CT pulmonary angiogram (CTPA) or alternative imaging (see below) Unlikely: perform a d-dimer, and if positive, perform a CTPA D-dimer is a sensitive (95%) but not a specific blood test for VTE. It helps exclude VTE where there is a low suspicion. It is almost always raised if there is a DVT. However, other conditions can cause a raised d-dimer: Pneumonia Malignancy Heart failure Surgery Pregnancy There are three imaging options for establishing a diagnosis of a pulmonary embolism: CT pulmonary angiogram (the usual first-line) Ventilation-perfusion single photon emission computed tomography (V/Q SPECT) scan Planar ventilation–perfusion (VQ) scan CT pulmonary angiogram (CTPA) is a chest CT scan with an intravenous contrast that highlights the pulmonary arteries to demonstrate any blood clots. This is the first-line imaging for pulmonary embolism, as it is readily available, provides a more definitive assessment and gives information about alternative diagnoses, such as pneumonia or malignancy. Ventilation-perfusion (VQ) scan involves using radioactive isotopes and a gamma camera to compare ventilation with the perfusion of the lungs. They are used in patients with renal impairment, contrast allergy or at risk from radiation, where a CTPA is unsuitable. First, the isotopes are inhaled to fill the lungs, and a picture is taken to demonstrate ventilation. Next, a contrast containing isotopes is injected, and a picture is taken to illustrate perfusion. The two images are compared. With a pulmonary embolism, there will be a deficit in perfusion as the thrombus blocks blood flow to the lung tissue. The lung tissue will be ventilated but not perfused. Planar V/Q scans produce 2D images. V/Q SPECT scans produce 3D images, making them more accurate. TOM TIP: Patients with a pulmonary embolism often have respiratory alkalosis on an ABG. Hypoxia causes a raised respiratory rate. Breathing fast means they “blow off” extra CO2. A low CO2 means the blood becomes alkalotic. The other main cause of respiratory alkalosis is hyperventilation syndrome. Patients with PE will have a low pO2, whereas patients with hyperventilation syndrome will have a high pO2.

Answer 61

Supportive management depends on the severity of symptoms and the clinical presentation, including: Admission to hospital if required Oxygen as required Analgesia if required Monitoring for any deterioration Anticoagulation is the mainstay of management. In most patients, NICE (2020) recommend treatment-dose apixaban or rivaroxaban as first-line. Low molecular weight heparin (LMWH) is the main alternative. This should be started immediately in patients where PE is suspected and there is a delay in getting a scan to confirm the diagnosis. Massive PE with haemodynamic compromise is treated with a continuous infusion of unfractionated heparin and considering thrombolysis. Thrombolysis involves injecting a fibrinolytic (breaks down fibrin) medication that rapidly dissolves clots. There is a significant risk of bleeding with thrombolysis, making it dangerous. It is only used in patients with a massive PE where the benefits outweigh the risks. Some examples of thrombolytic agents are streptokinase, alteplase and tenecteplase. There are two ways thrombolysis can be performed: Intravenously using a peripheral cannula Catheter-directed thrombolysis (directly into the pulmonary arteries using a central catheter)

Answer 62

Pulmonary hypertension refers to increased resistance and pressure in the pulmonary arteries. It causes strain on the right side of the heart as it tries to pump blood through the lungs. There is back pressure through the right side of the heart and into the systemic venous system. Pulmonary hypertension is defined as a mean pulmonary arterial pressure of more than 20 mmHg.

Answer 63

The causes of pulmonary hypertension can be classified into five groups: Group 1 – Idiopathic pulmonary hypertension or connective tissue disease (e.g., systemic lupus erythematous) Group 2 – Left heart failure, usually due to myocardial infarction or systemic hypertension Group 3 – Chronic lung disease (e.g., COPD or pulmonary fibrosis) Group 4 – Pulmonary vascular disease (e.g., pulmonary embolism) Group 5 – Miscellaneous causes such as sarcoidosis, glycogen storage disease and haematological disorders

Answer 64

Shortness of breath is the main presenting symptom. Other signs and symptoms include: Syncope (loss of consciousness) Tachycardia Raised jugular venous pressure (JVP) Hepatomegaly Peripheral oedema

Answer 65

ECG changes indicate right-sided heart strain: P pulmonale (peaked P waves) Right ventricular hypertrophy (tall R waves in V1 and V2 and deep S waves in V5 and V6) Right axis deviation Right bundle branch block Chest x-ray changes include: Dilated pulmonary arteries Right ventricular hypertrophy Other investigations include: Raised NT‑proBNP blood test result indicates right ventricular failure Echocardiogram can be used to estimate the pulmonary artery pressure

Answer 66

The prognosis of idiopathic pulmonary hypertension is poor, with a mean survival of 2-3 years after the diagnosis if untreated. Idiopathic pulmonary hypertension may be treated with: Calcium channel blockers Intravenous prostaglandins (e.g., epoprostenol) Endothelin receptor antagonists (e.g., macitentan) Phosphodiesterase-5 inhibitors (e.g., sildenafil) Secondary pulmonary hypertension is managed by treating the underlying cause, such as pulmonary embolism, COPD or systemic lupus erythematosus. Supportive treatments (e.g., oxygen and diuretics) are used for complications such as respiratory failure, oedema and arrhythmias.

Answer 67

Sarcoidosis is a chronic granulomatous disorder. Granulomas are inflammatory nodules full of macrophages. The cause of these granulomas is unknown. It is usually associated with respiratory symptoms but has many extra-pulmonary manifestations, such as erythema nodosum and lymphadenopathy. Symptoms can vary dramatically from asymptomatic to severe or life-threatening.

Answer 68

Sarcoidosis can affect anyone. It seems to be slightly more common in: Aged 20-39 or around 60 Women Black ethnic origin TOM TIP: The typical MCQ exam patient is a 20-40 year old black female presenting with a dry cough and shortness of breath. They may have nodules on their shins, suggesting erythema nodosum.

Answer 69

Less than half of patients with sarcoidosis have skin involvement. However, these findings are worth remembering for exams. Erythema nodosum is characterised by nodules of inflamed subcutaneous fat on the shins. Inflammation of fat is called panniculitis. Erythema nodosum presents as raised, red, tender, painful, subcutaneous nodules across both shins. Over time the nodules settle and appear as bruises. There are many causes of erythema nodosum. Lupus pernio is specific to sarcoidosis and presents with raised purple skin lesions, often on the cheeks and nose. Organs Affected Sarcoidosis can affect almost any organ in the body. The lungs are most commonly affected (in over 90% of patients), so respiratory physicians usually manage sarcoidosis. Lungs: Mediastinal lymphadenopathy Pulmonary fibrosis Pulmonary nodules Systemic Symptoms: Fever Fatigue Weight loss Liver: Liver nodules Cirrhosis Cholestasis Eyes: Uveitis Conjunctivitis Optic neuritis Heart: Bundle branch block Heart block Myocardial muscle involvement Kidneys: Kidney stones (due to hypercalcaemia) Nephrocalcinosis Interstitial nephritis Central nervous system: Nodules Pituitary involvement (diabetes insipidus) Encephalopathy Peripheral Nervous System: Facial nerve palsy Mononeuritis multiplex Bones: Arthralgia Arthritis Myopathy

Answer 70

Lofgren’s syndrome refers to a specific presentation of sarcoidosis with a classic triad of symptoms: Erythema nodosum Bilateral hilar lymphadenopathy Polyarthralgia (joint pain in multiple joints)

Answer 71

The top differentials for the varied presenting features of sarcoidosis are: Tuberculosis Lymphoma Hypersensitivity pneumonitis HIV Toxoplasmosis Histoplasmosis

Answer 72

Blood Tests The blood test findings to remember are: Raised angiotensin-converting enzyme (ACE) (often used as a screening test) Raised calcium (hypercalcaemia) Imaging Various imaging investigations may be performed: Chest x-ray may show hilar lymphadenopathy High-resolution CT scanning may show hilar lymphadenopathy and pulmonary nodules MRI can show central nervous system involvement PET scan can show active inflammation in affected areas Histology Histology helps establish the diagnosis, often by bronchoscopy with an ultrasound-guided biopsy of mediastinal lymph nodes. Histology characteristically shows non-caseating granulomas with epithelioid cells. Other Tests Other tests may be used to determine which organs are affected: U&Es for kidney involvement Urine albumin-creatinine ratio to look for proteinuria LFTs for liver involvement Ophthalmology assessment for eye involvement ECG and echocardiogram for heart involvement Ultrasound for liver and kidney involvement

Answer 73

Conservative management is considered in patients with no or mild symptoms. Oral steroids (for 6-24 months) are usually first-line where treatment is required. Bisphosphonates protect against osteoporosis whilst on long-term steroids. Methotrexate is a second-line option. Lung transplant is rarely required in severe pulmonary disease. Sarcoidosis spontaneously resolves in around half of patients, usually within two years. In some patients, it progresses to pulmonary fibrosis and pulmonary hypertension. Overall mortality is less than 10%.

Answer 74

Obstructive sleep apnoea is caused by collapse of the pharyngeal airway. Apnoeas are episodes where the person stops breathing for up to a few minutes. Partners may report the episodes, while patients are often unaware of them.

Answer 75

Middle age Male Obesity Alcohol Smoking

Answer 76

The presenting features of obstructive sleep apnoea are: Episodes of apnoea during sleep (reported by a partner) Snoring Morning headache Waking up unrefreshed from sleep Daytime sleepiness Concentration problems Reduced oxygen saturation during sleep Severe cases can cause hypertension and heart failure and increase the risk of myocardial infarction and stroke. TOM TIP: When suspecting obstructive sleep apnoea during a history, ask about daytime sleepiness and occupation. Daytime sleepiness should make you suspect obstructive sleep apnoea. Patients that need to be fully alert for work, such as heavy goods vehicle operators, require an urgent referral and may need amended work duties while awaiting assessment and treatment.

Answer 77

The Epworth Sleepiness Scale is used to assess symptoms of sleepiness associated with obstructive sleep apnoea. Sleep Studies Sleep studies are used to confirm the diagnosis, performed by an ENT or sleep specialist service. A simple sleep study involves wearing an oxygen saturation monitor overnight at home. Respiratory polygraphy involves wearing a more elaborate machine that monitors respiratory rate, flow rate (via a nasal sensor), saturations and heart rate, and can usually be done at home. A complex sleep study involves an overnight stay in a sleep centre with polysomnography. It may include monitoring brain activity (EEG), muscle activity (EMG) and heart activity (ECG).

Answer 78

Reversible risk factors should be addressed, with reduced alcohol, smoking cessation and weight loss. Continuous positive airway pressure (CPAP) machines provide constant pressure to maintain airway patency. Surgery is an option but involves significant surgical reconstruction of the soft palate and jaw. The most common procedure is called uvulopalatopharyngoplasty (UPPP).

Answer 79

Dx: <5y clinical, ≥5y spirometry (rev ≥12%) ± FeNO ± PEF (var >20%) Tx: <5y - #1 SABA, #2 mod-dose ICS 8w trial, #3 LTRA, #4 specialist ≥5y - #1 SABA, #2 low-dose ICS, #3 LTRA, #4 LABA Acute: Severity (PEF) – mild/mod >50%, severe 33-50%, life-threatening <33% Tx – O2, salbutamol 5mg, ipratropium 500mcg, hydrocortisone 100mg, magnesium sulphate 1.2-2mg, aminophylline, prednisolone 40-50mg PO once daily 5d

Answer 80

Dx: spirometry with BDR (rev <12%) + CXR + bloods Tx: #1 SAMA or SABA, #2 LABA + ICS (asthma/steroid responsive) or LABA + LAMA*, #3 LAMA* *If on SAMA need to switch to SABA LTOT – PaO2 <7.3 or PaO2 <8 with pulmonary hypertension, polycythemia, nocturnal hypoxaemia or peripheral oedema Acute: Severity (FEV1) – mild >80%, mod 50-79%, severe 30-49%, very severe <30% Tx: O2, salbutamol 5mg, ipratropium 500mcg, aminophylline, ventilation (pH 7.25-7.35 NIV, pH <7.25 IV), prednisolone 30mg PO once daily 7-14d