Respiratory Flashcards
What is asthma?
a chronic inflammatory airway disease characterised by reversible, intermittent airway obstruction and hyper-reactivity
What makes up the atopic triad?
Asthma
Hayfever
Eczema
What is occupational asthma?
asthma caused by environmental triggers in the workplace
What is the aetiology of asthma and when does it typically present?
gentic predispostion + environmental trigger
typically presents in childhood but can be adult onset
What are the main features of asthma?
Episodic + diurnal variability: symptoms fluctuate at different times of the day, typically worse at night
SOB
Chest tightness
Dry cough
Wheeze
should improve with bronchodilators
may have family hx or hx of eczema, hay fever, food allergies
What are some potential triggers for asthma?
- Infection
- Nighttime or early morning
- Exercise
- Animals
- Cold, damp or dusty air
- Strong emotions
- Beta-blockers, NSAIDs
What are the risk factors for asthma?
family hx
allergens/irritants
atopic disease hx
cigarette smoking/ vaping
respiratory viral infection early in life
nasal polyposis
low socioeconomic status
What is the pathophysiology of an asthma exacerbation?
Early phase
- Excess of T helper 2 cells (type 2 inflammation)
- TH2 cells produce IL4, IL13 and IL5
- IL4+13 cause plasma cells to release IgE which activate mast cell degranulation
- Histamine, leukotriene and prostaglandins (T1 hypersensitivity reaction)
- Bronchospasm, increased mucus production and oedema Late phase
- More inflammatory cells recruited from blood (chemotaxis)
- Second phase of exacerbation
What are some of the long term consequences of asthma?
subepithelial fibrosis
basement membrane thickening
hypertrophy of smooth muscle cells
larger volume of mucus
increased vascularity
What is the forced expiratory volume in 1 second (FEV1) spirometry test and what does it measure?
the air a person can forcefully exhale in 1 second.
This measures how easily air can flow out of the lungs.
It is reduced with airflow obstruction
What is reversibility testing?
involves giving a bronchodilator (e.g., salbutamol) before repeating the spirometry to see if this impacts the results
What is the FEV1/FVC ratio for obstructive lung disease?
FEV1:FVC ratio of less than 70%.
person may have a relatively good lung volume, but air can only move slowly in and out of the lungs due to obstruction
What are FEV1 and FVC like in restrictive airway disease?
FEV1 and FVC are equally reduced
FEV1:FVC ratio greater than 70%
What is restrictive lung disease?
limits the ability of the lungs to expand and fill with air.
The lungs are restricted from effectively expanding
Difference in spirometry for restrictive and obstructive?
a low FVC indicates restrictive lung disease
a low FEV1:FVC ratio (under 70%) indicates obstructive lung disease
What does peak flow measure?
measures the “peak”, or fastest point, of the expiratory flow of air
a simple way of demonstrating how much obstruction to airflow is present in the lungs
and how well a condition such as asthma is controlled
What is PaO2?
partial pressure of oxygen, the amount of oxygen dissolved in the blood.
A low PaO2 indicates hypoxia.
What is FiO2?
fraction of inhaled oxygen.
Room air has an FiO2 of 21%, meaning the oxygen conc in room air is 21%
What investigations should be done for a patient presenting with suspected asthma?
Spirometry: FEV1/FVC ratio <70%
BDR test (reversibility): improvement in FEV₁ of 12% or more in response to beta agonists
peak expiratory flow rate (PEFR)
FeNO
CXR
FBC with differential
What are some differentials for asthma?
COPD
Chronic rhinosinusitis
CHF
Bronchiectasis
CF
What is the first-line management of asthma?
Short-acting beta agonist: salbutamol inhaled: (100 micrograms/dose inhaler) 100-200 micrograms inhaled up to four times daily – as needed, reliever
What can be used in the management of asthma if a SABA isn’t effective alone?
- Inhaled corticosteroid (ICS) beclometasone
- Long-acting beta 2 agonist (formoterol) inhaled + ICS
- Leukotriene receptor antagonists (montelukast)
- Long acting muscarinic antagonists, e.g. tiotropium
How do beta-2 adrenergic receptor agonists work?
bronchodilators
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
SABAs work for a few hours, e.g. salbutamol
How do inhaled corticosteroids work?
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 the presenting features of an acute asthma 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
initial resp alkalosis
What is a moderate acute asthma exacerbation defined as?
Peak flow 50 – 75% best or predicted
What is a severe acute asthma exacerbation defined as?
Peak flow 33-50% best or predicted
Respiratory rate above 25
Heart rate above 110
Unable to complete sentences
What is a life-threatening acute asthma exacerbation defined as?
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)
What is silent chest?
wheeze disappears when the airways are so tight that there is no air entry
What can be used to manage an acute asthma exacerbation?
- O2 therapy
- Nebulised salbutamol or ipratropium bromide
- Systemic corticosteroids: prednisolone
- IV magnesium sulfate
How can asthma attacks be prevented?
Daily inhaled corticosteroids
Avoidance of known triggers
What are the possible complications of asthma?
COPD from airway remodelling
Acute exacerbations
Oral/ oesophageal candidiasis secondary to use of ICS
dysphonia secondary to use of ICS
What are the main features of a life threatening acute asthma attack?
A CHEST
Arrhythmia/ Altered conscious level
Cyanosis, PaCO2 normal
Hypotension, Hypoxia (PaO2<8kPa, SpO2 <92%)
Exhaustion
Silent chest
Threatening PEF < 33% best or predicted (in those >5yrs old)
How is a life threatening asthma attack managed?
O SHIT MI pneumonic
Oxygen
Salbutamol
Hydrocortisone (Prednisolone)
Ipratropium bromide
Theophylline
Magnesium sulphate
Intubation and ventilation
What is bronchiectasis?
Permanent, abnormal dilation of bronchi due to the destruction of the elastic and muscular components of the bronchial wall
What can cause bronchiectasis?
Post infectious: childhood, mycobacteria, pneumonia, COVID
COPD
Asthma
Connective tissue disorders (RA, Sjogrens)
Allergic bronchopulmonary aspergillosis
Genetic: CF
Immunodeficiency
Yellow nail syndrome
What is the pathophysiology of bronchiectasis?
dilation and thickening of the bronchi due to chronic inflammation in response to micro-organisms colonising the airways.
Persistent airway inflammation leads to bronchial wall oedema and increased mucus production
Inflammation leads to progressive destruction of airways, which serves as a nidus for subsequent airway colonisation
Vicious cycle of progressive damage and recurrent infections
What can be heard on auscultation for bronchiectasis?
Crackles
High-pitched inspiratory squeaks
Rhonchi
Wheezing
What investigations and imaging can be done for bronchiectasis?
CXR: Tram-track opacities, ring shadows
FBC
Sputum culture and sensitivity
High-resolution chest CT: thickened, dilated airways, varicose constrictions, cysts and/or tree-bud pattern
What are the symptoms of bronchiectasis?
Recurrent pulmonary infections
Chronic daily productive cough with mucopurulent sputum production
SOB
Weight loss
Fever
Fatigue
Rhinosinusitis
How does an acute exacerbation of bronchiectasis present?
worsening of cough
change in sputum colour
increase in sputum volume
fever
fatigue
What is the general management for bronchiectasis?
- Exercise and nutrition
- Vaccines (e.g., pneumococcal and influenza)
- Respiratory physiotherapy to help clear sputum
- Pulmonary rehabilitation
- Long-term abx for frequent exacerbations (e.g., 3 or more per year)
- Inhaled colistin for Pseudomonas aeruginosa colonisation
- Long-acting bronchodilators for breathlessness
- Long-term oxygen therapy in reduced oxygen saturation
- Surgical lung resection may be considered for specific areas of disease
- Lung transplant is an option for end-stage disease
What is the abx of choice for exacerbations caused by Pseudomonas aeruginosa?
Ciprofloxacin
What are some signs of bronchiectasis?
Finger clubbing
Signs of cor pulmonale (e.g., raised JVP and peripheral oedema)
Scattered crackles throughout the chest that change or clear with coughing
Scattered wheezes and squeaks
What is COPD?
Persistent, irreversible limitation of airflow through the lungs
In COPD, what is chronic bronchitis?
long-term symptoms of a cough and sputum production due to inflammation in the bronchi
In COPD what is emphysema?
damage and dilatation of the alveolar sacs and alveoli, decreasing the surface area for gas exchange
What is the epidemiology of COPD?
more common in older people, especially aged 65 years+
COPD prevalence is highest in the WHO region of the Americas and lowest in the South-East Asia and Western Pacific regions.
The pooled global prevalence is 15.7% in men and 9.93% in women
What causes COPD?
Exposure to inhaled toxins, i.e. smoking (up to 70% of cases), air pollution, occupational exposure
Genetic: alpha 1 antitrypsin deficiency
What is the pathophysiology causing loss of elastic recoil in COPD?
Inflammation due to exposure from inhaled toxins, e.g. cigarettes
Neutrophils and macrophages recruited and secrete proteases
Excess protease activity causing destruction of lung tissue
Loss of support for alveolar leading to reduced elastic recoil and emphysema
Reduced structural support causes collapse of smaller airways and trapped air, hyperinflation
What is the pathophysiology causing narrowing of the airways in COPD?
Inflammation increases oxygen free radicals, causing mucosal oedema, mucous hypersecretion and bronchoconstriction
Airways are narrower and have increased resistance to airflow
Fibrosis and irreversible
In COPD, what does the loss of elastic recoil and airway narrowing lead to?
impaired mucocilliary clearance and increase in the work of breathing
Reduced alveolar ventilation, hypoxia, hypercapnia
What are the grades 1-5 of the MRC dyspnoea scale?
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
What might be present on physical exam of a COPD patient?
tachypnoea
respiratory distress
use of accessory muscles
intercostal retraction
Barrel chest
hyper-resonance on percussion
distant breath sounds and poor air movement
What symptoms may be present in COPD?
Dyspnoea- persistent and worsening, initially worse with exercise
Cough (commonly producing sputum)
Tachypnoea and use of accessory muscles
frequent bronchitis and recurrent infections
wheeze
waking at night with breathlessness
cyanosis
cor pulmonale
fatigue
What are the risk factors for COPD?
cigarette smoking
advanced age
genetic factors
lung growth and development
What are GOLD stages 1-4 of severity using post-bronchodilator FEV1 in 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
What physiological abnormalities are seen in COPD?
mucous hypersecretion
ciliary dysfunction
airflow obstruction
hyperinflation
gas exchange abnormalities
pulmonary HTN
What are the 3 groups (a,b,e) in the management of COPD?
Group A: low symptom burden and 0-1 exacerbations per year
Group B: increased symptom burden but still 0-1 exacerbations per year
Group E: 2 or more exacerbations per year
What is the initial pharmacological treatment for group A COPD?
0-1 exac, CAT less than 10
SABA or LABA (salbutamol or formoterol), SAMA or LAMA (ipratropium or tiotropium) – long acting more commonly used
a bronchodilator
What is the pharmacological treatment for group B COPD?
0-1 exac, CAT over 10
LABA/LAMA
glycopyrronium/formoterol
What is the pharmacological treatment for group E COPD?
2 or more exac or 1 hospital exac
1st line: LABA/LAMA
2nd line: LABA/LAMA + ICS
glycopyrronium and budesonide/formoterol inhaled
Apart from BA and MA, what other pharmacological treatments are available for COPD?
- Mucolytics: carbocisteine
- Systemic prednisolone in acute exacerbations
- Roflumilast (diarrhoea side effects)
- Azithromycin (abx 3x a week to reduce inflammation)
What are non-pharmacological treatment options for COPD?
Smoking cessation
Pulmonary rehabilitation
Vaccination
What are the differentials for COPD?
Asthma
Congestive heart failure
Bronchiectasis
Tuberculosis
Bronchiolitis
Upper airway dysfunction
What investigations can be done for COPD?
Post-bronchodilator spirometry: FEV1:FVC ratio of less than 70%
CXR: flattened diaphragm, hyperinflation
Pulse oximetry: low
FBC checking for: polycythaemia (haematocrit >55%), anaemia, and leucocytosis
What are the treatment options for an acute exacerbation of COPD?
- SABA, e.g. salbutamol inhaled or nebulised
- Short-acting muscarinic antagonist, e.g. ipratropium bromide
- Target O2 sats of 88-92% (excess oxygen may suppress drive for ventilation and precipitate hypercapnia and type 2 resp failure)
- Corticosteroid: pred or hydrocortisone
- Non-invasive ventilation
What investigations are done for an acute exacerbation of COPD?
ABG
CXR
ECG
FBC
Inflammatory markers
Sputum culture
What are the target oxygen sats for patients with COPD at risk of retaining CO2?
88-92%
What is the risk of oxygen therapy in COPD?
Many patients with COPD retain CO2 when treated with oxygen, (oxygen-induced hypercapnia).
likely involves ventilation-perfusion mismatch and haemoglobin binding less well to CO2 when also bound to oxygen
hypoxic drive theory may not be right
What are some of the complications of COPD?
Exacerbations
Pulmonary HTN
Ptx
cor pulmonale
lung cancer
recurrent pneumonia
depression
respiratory failure
Anaemia
polycythaemia
What are the most common causes of acute dyspnoea in ED?
Asthma
COPD
Heart failure
Pneumonia
What the 5 aetiological categories causing dyspnoea?
Pulmonary disease
Cardiovascular disease
Respiratory muscle dysfunction
Psychogenic dyspnoea
Deconditioning/obesity.
What are the key physiological consequences of CF?
Thick pancreatic and biliary secretions that cause blockage of the ducts, resulting in a lack of digestive enzymes such as pancreatic lipase in the digestive tract
Low volume thick airway secretions that reduce airway clearance, resulting in bacterial colonisation and susceptibility to airway infections
Congenital bilateral absence of the vas deferens in males
How does CFTR mutation affect cells?
CFTR gene on chromosome 7 mutation.
Decreased secretion of chloride out of cells, increased resorption of sodium, more water in cell
Sticky, thick mucus
What is cystic fibrosis?
an autosomal recessive genetic condition affecting mucus glands resulting from mutations in CFTR channel
What causes CF?
Autosomal recessive
Mutations in the CFTR gene on chromosome 7
most common is the delta-F508 mutation
What are the risk factors for CF?
family hx of CF
known carrier status of both parents
white ethnicity
What are the symptoms of CF?
Chronic cough
Thick sputum production
Recurrent respiratory tract infections
Loose, greasy stools (steatorrhoea) due to a lack of fat digesting lipase enzymes
Abdo pain and bloating
Failure to thrive
Meconium ileus in newborns
What investigations should be done for CF?
screened for at birth with the newborn bloodspot test
genetic testing
sweat test
How does the sweat test work in CF?
Pilocarpine and electrodes attached to skin
Small current passed over causing skin to sweat
sweat collected on gauze
sweat chloride ≥60 mmol/L
What are the main colonisers in CF? And how are they treated?
staph aureus and pseudomonas aeruginosa
pseudomonas: long term nebulised abx, e.g. tobramycin or oral ciprofloxacin
s.aureus prevention: long term prophylactic flucloxacillin
How is CF managed?
Chest physiotherapy several times a day is essential to clear mucus and reduce the risk of infection and colonisation
Exercise improves respiratory function and reserve, and helps clear sputum
High calorie diet
CREON tablets to digest fats in patients with pancreatic insufficiency
Treat chest infections when they occur
Bronchodilators can help treat bronchoconstriction
Nebulised DNase (Mucolytic)
Nebulised hypertonic saline
Vaccinations including pneumococcal, influenza and varicella
What should CF patients be screened for?
diabetes, osteoporosis, vitamin D deficiency and liver failure
What are the 2 types of pleural effusion?
Exudative – a high protein content (more than 30g/L)
Transudative – a lower protein content (less than 30g/L)
What is a pleural effusion?
a collection of fluid in the pleural space between parietal and visceral pleura in the thorax
What can cause an exudative pleural effusion?
malignancy
pleural infection
PE
autoimmune pleuritis
as a result of inflammation
What can cause a transudative pleural effusion?
Congestive cardiac failure
Hypoalbuminaemia
Cirrhosis
Meigs syndrome
fluid moving across or shifting into the pleural space
What are the risk factors for a pleural effusion?
CHF
Pneumonia
Malignancy
Recent CABG
What is present on a physical exam for a pleural effusion?
Dullness to percussion over the effusion
Reduced breath sounds
Tracheal deviation away from the effusion in very large effusions
What is seen on a CXR for a pleural effusion?
Blunting of the costophrenic angle
Fluid in the lung fissures
Larger effusions will have a meniscus
Tracheal and mediastinal deviation away from the effusion in very large effusions
What investigations should be done for a pleural effusion?
CT and ultrasound
Pleural fluid analysis
CXR
How might a pleural effusion present?
dullness to percussion
dyspnoea
cough
pleuritic chest pain
What is empyema?
infected pleural effusion