Respiratory Flashcards
What is Acute Bronchitis?
Acute bronchitis refers to infection and inflammation in the bronchi and bronchioles. Both pneumonia and acute bronchitis are classed as lower respiratory tract infections.
What is the most common cause of acute bronchitis?
Viruses
Managment of acute bronchitis
Acute bronchitis is usually caused by a viral infection and goes away on its own in a few weeks. Most people don’t need treatment for acute bronchitis.
Risk Factors for acute bronchitis
Anyone can get bronchitis, but you’re at higher risk if you:
Smoke or are around someone who does.
Have asthma, COPD or other breathing conditions.
Have GERD (chronic acid reflux).
Have an autoimmune disorder or other illness that causes inflammation.
Are around air pollutants (like smoke or chemicals).
Symptoms of acute bronchitis
A persistent cough that lasts one to three weeks is the main symptom of bronchitis. You usually bring up mucus when you cough with bronchitis, but you might get a dry cough instead. You might also hear a whistling or rattling sound when you breathe (wheezing).
Other symptoms, include:
Shortness of breath (dyspnea).
Fever.
Runny nose.
Tiredness (fatigue).
Viral causes of acute bronchitis
influenza (the flu), respiratory syncytial virus (RSV), adenovirus, rhinovirus (the common cold) and coronavirus.
Bacterial causes of acute bronchitis
Bordetella pertussis, Mycoplasma pneumonia and Chlamydia pneumonia.
What are some other causes (not bacterial or viral) that can cause acute bronchitis?
Pollution.
Smoking cigarettes or marijuana (cannabis).
Dx of acute bronchitis
Clinical dx
Ix for acute bronchitis
Nasal swab, CXR, Blood tests, Sputum test, Pulmonary Function tests
What is asthma?
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.
Different onsets and presentation conditions of asthma
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.
Pathophysiology of asthma
Asthma is characterised by chronic inflammation of the airways. There are several mechanisms which lead to airway inflammation, including:3
Inflammatory cell infiltration of airways
Smooth muscle hypertrophy
Thickening and disruption of the airway membrane
What type of hypersensitivity is asthma?
Type 1
Non-Modifiable Risk Factors for asthma
Non-modifiable risk factors include:
Personal or family history of atopy
Male sex (asthma development) or female sex (persistence to adulthood)
Prematurity and low birth weight
Modifiable Risk factors for asthma
Modifiable risk factors include:
Exposure to tobacco smoke, inhaled particulates and occupational dust
Obesity
Social deprivation
Infections in infancy
Presentation of asthma
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
Patients who have asthma, may have a history of other conditions; like what?
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 findings for an asthamatic patient
Examination is generally normal when the patient is well. A key finding with asthma is a widespread “polyphonic” expiratory wheeze.
Differentials for a localised wheeze
inhaled foreign body, tumour or a thick sticky mucus plug obstructing an airway. [A chest x-ray is the next step.]
Differential Dx for asthma
Respiratory: bronchiectasis, COPD, fibrosis, pulmonary embolism, infection (pertussis and tuberculosis), lung cancer
Gastrointestinal: gastro-oesophageal reflux
Cardiac: heart failure
Other: chronic sinusitis, allergic rhinitis, foreign body inhalation, vocal cord dysfunction
Typical triggers of asthma
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
Which medications can worsen asthma?
Beta-blockers, particularly non-selective beta-blockers (e.g., propranolol), and non-steroidal anti-inflammatory drugs (e.g., ibuprofen or naproxen), can worsen asthma.
Name the Ix for asthma
Spirometry, Reversibility Testing, FeNO, Peak flow variability, Direct broncial challenge test
Asthma Ix; Spirometry
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).
Asthma Ix; Reversibility Testing
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.
Asthma Ix; FeNO
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.
Asthma Ix; Peak flow variability
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.
Asthma Ix; Direct bronchial challenge testing
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.
What are the initial Ix for patients with suspected asthma?
The NICE guidelines (2020) recommend initial investigations in patients with suspected asthma:
Fractional exhaled nitric oxide (FeNO)
Spirometry with bronchodilator reversibility
If there is diagnostic uncertainty,after the initial Ix for asthma which tests can be used?
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.
Name some medications types that can be used to treat long term asthma
Beta-2 adrenergic receptor agonists
Inhaled corticosteroids (ICS)
Long-acting muscarinic antagonists (LAMA)
Leukotriene receptor antagonists
Theophylline
Maintenance and reliever therapy (MART)
What are Beta-2 adrenergic receptor agonists and how do they work?
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.
What is the purpose of a SABA like Salbutamol for 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
What is the purpose of a LABA like Salmeterol in asthma management?
Long-acting beta-2 agonists (LABA), such as salmeterol, are slower to act but last longer.
What are Inhaled corticosteroids, how do they work + what are they used for ?
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.
What are LAMA’s and how do they work?
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.
What are Leukotriene receptor antagonists and how do they work?
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.
How does Theophylline work for asthma management?
Theophylline works by relaxing the bronchial smooth muscle and reducing inflammation.
Why do you have to monitor plasma theophylline levels for asthmatic patients using it?
Theophylline has a narrow therapeutic window and can be toxic in excess, so monitoring plasma theophylline levels is required.
What is MART ?
Maintenance and reliever therapy (MART) involves a combination inhaler containing an inhaled corticosteroid and a fast and long-acting beta-agonist (e.g., formoterol).
How does the addition of MART change the asthma management of that patient?
MART 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.
What are the principles of long-term asthma management?
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
What are the 8 stages of asthma management as suggested by the NICE guidelines?
- Short-acting beta-2 agonist inhaler (e.g. salbutamol) as required
2..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)
What are acute asthma exacerbations?
Acute asthma exacerbations involve rapidly worsening symptoms and can quickly become life-threatening. Any typical asthma triggers, such as infection, exercise or cold weather, could set off an acute exacerbation.
What are the presenting features of an acute exacerbation ?
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
What would an ABG show for someone having an acute asthma exacerbation?
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.
What are the 3 categories when grading acute asthma?
Moderate
Severe
Life-threatening
Moderate Acute Asthma Exacerbation
PEFR 50-75% best or predicted
Speech normal
RR < 25 / min
Pulse < 110 bpm
Severe Acute Asthma Exacerbation
Peak flow 33-50% best or predicted
Respiratory rate > 25/min
Heart rate/Pulse > 110bpm
Unable to complete sentences
Life-threatening Acute Asthma Exacerbation
Peak flow < 33% best or predicted
Oxygen saturations < 92%
PaO2 less than 8 kPa
Becoming tired
Confusion or agitation
No wheeze or silent chest
Haemodynamic instability (shock)
If the patient has normal pCO2 in an acute asthma attack - what does that mean?
indicates exhaustion and should, therefore, be classified as life-threatening.
Explain “silent chest” as a feature of life-threatening asthma
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.
Management of Mild asthma exacerbations
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
Management of Moderate asthma exacerbations
Consider hospital admission
Nebulised beta-2 agonists (e.g., salbutamol)
Steroids (e.g., oral prednisolone or IV hydrocortisone)
Management of Severe asthma exacerbations
Hospital admission
Oxygen to maintain sats 94-98%
Nebulised ipratropium bromide
IV magnesium sulphate
IV salbutamol
IV aminophylline
Management of Life-Threatening asthma exacerbations
Admission to HDU or ICU
Intubation and ventilation
Criteria for discharge post acute asthma exacerbation
been stable on their discharge medication (i.e. no nebulisers or oxygen) for 12-24 hours
inhaler technique checked and recorded
PEF >75% of best or predicted
OSHITME neumonic for acute asthma exacerbation
O xygen
S albutamol ; 2.5-5mg NEB
H ydrocortisone ; 100mg IV (or prednisolone 40mg PO)
I pratropium ; 500mcg NEB
T heophylline/Aminophylline infusion
M agnesium Sulphate ; 2g IV over 20 mins
E scalate care (intubation + ventilation)
3 SE of salbutomol
Hypokalemia, Tachycardia, Lactic Acidosis
Why does [K+] need to be checked with salbutamol treatment?
Serum potassium needs monitoring with salbutamol treatment, which causes potassium to be absorbed from the blood into the cells, resulting in hypokalaemia (low potassium).
Complications of asthma
pneumonia, pneumothorax, respiratory failure, status asthmaticus, impaired quality of life, steroid side effects, and death.
What is COPD?
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.
Pathophysiology of COPD?
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.
What is Emphysema?
Emphysema involves damage and dilatation of the alveolar sacs and alveoli, decreasing the surface area for gas exchange.
Presentation of COPD
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
COPD does NOT cause ______, ________, or _________. These symptoms should be investigated for a different cause, such as lung cancer, pulmonary fibrosis or heart failure.
clubbing, haemoptysis (coughing up blood) or chest pain.
What is the MRC Dyspneoa Scale ?
The MRC (Medical Research Council) Dyspnoea Scale is a 5-point scale for assessing breathlessness:
MRC Dyspnoea Scale : Grade 1
Breathless on strenuous exercise
MRC Dyspnoea Scale : Grade 2
Breathless on walking uphill
MRC Dyspnoea Scale : Grade 3
Breathlessness that slows walking on the flat
MRC Dyspnoea Scale : Grade 4
Breathlessness stops them from walking more than 100 meters on the flat
MRC Dyspnoea Scale : Grade 5
Unable to leave the house due to breathlessness
Dx of COPD
Diagnosis is based on the clinical presentation and spirometry results.
What are the spirometry results for COPD?
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.
Severity of COPD is graded using_____
forced expiratory volume in 1 second (FEV1):
What are the 4 stages of severity for COPD
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
Ix for COPD
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)
Long-term management of COPD
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.
Medicinal Management of COPD
- SABA + SAMA
- No asthmatic or steroid-responsive features : LABA + LAMA
- asthmatic or steroid-responsive features: LABA + ICS
- LABA + LAMA + ICS
Initial medical treatment of COPD
Short-acting beta-2 agonists (e.g., salbutamol)
Short-acting muscarinic antagonists (e.g., ipratropium bromide)
Where there are no asthmatic or steroid-responsive features, treatment is a combination of:
Long-acting beta agonist (LABA)
Long-acting muscarinic antagonist (LAMA)
examples of LABA and LAMA combination inhalers.
Anoro Ellipta, Ultibro Breezhaler and DuaKlir Genuair
Where there are asthmatic or steroid-responsive features, treatment is a combination of:
Long-acting beta agonist (LABA)
Inhaled corticosteroid (ICS)
examples of LABA and ICS combination inhalers.
Fostair, Symbicort and Seretide
The final inhaler step is a combination of _____
a LABA, LAMA and ICS.
examples of LABA, LAMA and ICS combination inhalers.
Trimbow, Trelegy Ellipta and Trixeo Aerosphere
In more severe cases of COPD, 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 ___ and ____ monitoring before and during treatment.
ECG and liver function
What is used for severe COPD with chronic hypoxia (sats < 92%), polycythaemia, cyanosis or cor pulmonale?
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.
What is Cor Pulmonale?
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.
Causes of Cor Pulmonale?
COPD (the most common cause)
Pulmonary embolism
Interstitial lung disease
Cystic fibrosis
Primary pulmonary hypertension
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
Signs of cor pulmonale on examination include:
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)
Managment of Cor Pulmonale
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.
What is an acute COPD exacerbation?
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.
What does an ABG show for acute exacerbation of COPD
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.
Ix for acute exacerbation of COPD
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)
Oxygen Therapy for COPD
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.
First line medical tx for an acute exacerbation of COPD
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.
Non-Invasive ventilation
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
Complications of COPD
hypercapnic respiratory failure, secondary polycythaemia, cor pulmonale, bronchiectasis, anxiety, depression, osteoporosis, sleep disturbance.
