The respiratory system - Breathlessness airflow Flashcards
List the different causes of asthma
Atopic asthma
Hygiene hypothesis
Aspirin-induces asthma
Occupation asthma
Excercise-induced asthma
a) What is atopy?
b) What are the 3 conditions that atopic individuals are predisposed to?
a) Atopy is a genetic predisposition to IgE-mediated allergen sensitivity
b)
- Allergic asthma
- Atopic dermatitis
- Allergic rhinitis
Patients with aspirin-induced exhibit Samter’s triad.
What is involved in Samter’s triad
- Asthma
- Aspirin sensitivity
- Nasal polyps
Summarise the pathophysiology of asthma
The pathophysiology of asthma includes airway narrowing due to bronchial muscle contraction (bronchoconstction), inflammation caused by mast cell degranulation and increased mucus production
describe the histology seen in asthma
Curschmann spirals, which are where shed epithelium becomes whorled mucous plugs
List 5 pathological changes in asthma
- Thinking of basement membrane
- Hypertrophy of smooth muscle
- Vasodilation
- Oedema of mucosa and submucosa infiltration with eosinophils and neutrophils
- Mucous plug
- Desquamation of epithelium
- Mucous gland hyperplasia
- Thickening of basement membrane
Clinical features of asthma
a) Symptoms
b) Signs
a)
- Cough (may be worse at night)
- Dyspnoea
- Chest tightness
- Poor sleep
b)
- Polyphonic expiratory wheeze
- Prolonged expiratory phase
- Tachypnoea
- Hyperinflated chest
- Hyperresonant on percussion
- Harrison’s sulcus: a groove at the inferior border of the rib cage that may be seen in children with chronic sever asthma
Describe the symptoms, vitals, saturations and PEFR for the following severity of asthma attacks
a) Moderate
b) Severe
c) Life-threatening
d) Near-fatal
a)
Symptoms - increasing symptoms of asthma
Vitals - RR < 25 and pulse < 110 bpm
Saturations - ≥ 92%
PEFR - ≥ 50-70%
b)
Symptoms - can’t complete sentences
Vitals - HR ≥ 110, RR ≥ 25
Saturations - ≥ 92%
PEFR - ≥ 33-50%
c)
Symptoms - silent chest, cyanosis, exhaustion, confusion, poor respiratory effort
Vitals - PaO2 < 8kPa
Saturations - < 92%
PEFR - < 33%
d) Raised PaCO2 or requires mechanical ventilation with raised inflation pressures
Name the 1st and 2nd line diagnostic tests involved in asthma
1st line - Lung function testing: Spirometry and bronchodilator reversibility
2nd line -
- Peak expiratory flow rate (PEFR)
- Eosinophilic inflammation E.g., Fractional exhaled nitric oxide (FeNO) testing, blood eosinophilia, skin-prick testing
Describe the diagnostic changes seen in spirometry in asthma
FEV1: Reduced
FVC: may be normal but often reduced (due to air trapping)
FEV1/FVC: < 70%
How can asthma and COPD be differentiated in diagnostic testing?
Bronchodilator reversibility is demonstrated in asthma, but not COPD
What level of bronchodilator reversibility is diagnostic in asthma?
Increased in FEV1 OF 12% (15% in exercise-induced asthma)
What is the role of peak expiratory flow rate?
To monitor asthma
What PEFR variability is diagnostic in asthma?
> 20% is diagnostic
What level of FeNO is diagnostic of asthma?
FeNO > 40 parts per billion (ppt)
List the criterial for specialist asthma referral
- Diagnosis is unclear
- Suspected occupational asthma
- Poor response to treatment
- Severe/life-threatening attack
Name the urgent investigations required in an acute asthma attack and their purpose
ABG - type II respiratory failure is a sign of life-threatening attack
Routine blood tests - to look for precipitating causes of an asthma attack e.g., infection
Chest x-ray - to exclude differentials
Describe the 1st line, 2nd line, 3rd line and follow up discharge management of an acute asthma attack
1st line
- Ipatriopium bromide nebuliser 500mcg: given 4-6 hourly
- Salbutamol nebuliser 2.5mg
- Oxygen if sats < 94%
- Steroids: prednisolone PO 40-50mg or hydrcoritsone. Continued for at least 5 days
2nd line
- IV magnesium sulphate
- Beta 2 agonist infusion
- IV aminophylline
3rd line
- Intensive care admission which may involve invasive ventilation
Follow up discharge
- for a patient to be discharged from hospital follow an asthma attack they must be stable on their regular asthma regime for 24 hours
- Review Inhaler technique before discharge
What are the indications for. patient to be discharged following an asthma attack?
Patient must be stable on their regular asthma regime for 24 hours
Describe the non-pharmacological management of chronic asthma
- Smoking cessation
- Avoidance of precipitating factors (e.g., known allergens)
- Review inhaler technique
Describe the pharmacological management of adult chronic asthma
- SABA as PRN therapy (salbutamol) Low-dose ICS
- LABA: Salmaterol, formeterol
- Increase ICS or LTRA (leukotriene receptor antagonist)
- Specialist referral
Describe the pharmacological management in paediatric chronic asthma
- SABA as PRN therapy + very low dose ICS
- If ≥ 5 yo LABA, if <5 you add LTRA
- Increase ICS to low dose or if ≥ 5 yo add LABA/LTRA. If no response to LABA consider stoping it
- Specialist referral
Name 3 ways to measure asthma disease control
- RCP 3 questions
- Asthma control questionnaire (ACQ)
- Asthma control test
- Mini-asthma quality of life questionnaire
Name 3 asthma mimics and describe their symptoms
Acid reflux - dry cough, wheeze, SOB, hoarse voice, dental erosions, chest pain
Churg-Strauss syndrome - asthma, peripheral neuropathy, glomerulonephritis
Allergic bronchopulmonary aspergillosis (ABP) - wheeze, cough, dyspnoea, sputum production, reduced exercise intolerance
What is COPD?
A clinical syndrome characterised by:
- Chronic bronchitis
- Emphysema
- Obstructive bronchiolitis
Describe the epidemiology of COPD
- Predominately affects adults > 40 years old
Name two causes of COPD
- Smoking
- Alpha-1 antitrypsin deficiency
How is alpha-1 antitrypsin deficiency inherited?
It is an autosomal recessive disorder with co-dominant expression
Describes how alpha-1 antitrypsin deficiency causes COPD
Alpha-1 antitrypsin is a protease inhibitor that is synthesised by the liver. It acts in the lung parenchyma to oppose the action of elastase
Elastase is a protease that causes the breakdown of elastin, a protein important to the structural integrity of the alveoli. This causes emphysema
Smoking increases the risk of these patients’ developing symptoms
Describe the pathophysiology of COPD
Chronic bronchitis - leads to goblet hyperplasia, mucus hyper secretion, chronic inflammation, fibrosis and narrowing of small airways
Emphysema - alveolar wall destruction
Obstructive bronchiolitis
Risk factors of COPD
a) Host factors
b) Exposure
a)
- Genetic (alpha-1 antitrypsin deficiency)
- Lung growth, low BW, age
b)
- Tobacco smoke
- Biomass fuels, open fires
- Occupational dusts and exposures
-Chronic uncontrolled asthma
- Lower socioeconomic status
Clinical features of COPD
a)
- Chronic cough: usually productive
- Sputum production
- Breathlessness: usually on exertion in early stages
- Frequent episodes of ‘bronchitis’: usually in winter
- Wheeze
b)
- Dyspnoea
- Pursed lip breathing
- Wheeze
- Coarse crackles
- Loss of cardiac dullness (due to hyper expansion of lungs from emphysema)
- Downward displacement of liver (due to hyper expansion of lungs from emphysema)
- Signs of CO2 retention: drowsy, asterixis, confusion
- Signs of cor pulmonale: peripheral oedema, raised JVP, hepatomegaly (causes left parasternal heave)
Describe the features of an acute exacerbation of COPD
Temperature
- Pyrexia > 38 degrees Celsius (if infective)
Respiratory distress
- Accessory muscle use
- Pursed lip breathing
- SOB
Productive cough
- Sputum
CO2 retention
- Flapping tremor
- Confusion
Auscultation
- Crackles
- Wheeze
What scale is used to grade the severity of breathlessness
mMRC dyspnoea scale
Describe the diagnostic changes seen in spirometry in COPD
FVC: May be normal but often reduced
FEV1: Reduced
FEV1/FVC: <70%
Describe the factors that cause spirometry variation
Height - tall people have larger lungs
Age - respiratory function declines with age
Sex - lung volumes smaller in females
Race - studies show blacks and asians have smaller lung volumes
Posture - little difference between sitting and standing; reduced in supine position
What features are supportive of COPD (vs asthma)?
- Smoker or ex-smoker
- Symptoms in older adults (> 35 years old)
- Chronic productive cough
- Persistent/progressive breathlessness
- Nigh-time waking with symptoms uncommon
- Variability uncommon (diurnal or day-to-day)
Describe the following stages of COPD according to severity, FEV1/FVC, FEV1% predicted
a) Stage 1
b) Stage 2
c) Stage 3
e) Stage 4
a)
Severity: mild
FVE1/FVC: < 0.7
FEV1% predicted: ≥ 80
b)
Severity: moderate
FVE1/FVC: < 0.7
FEV1% predicted: 50-79
c)
Severity: severe
FVE1/FVC: < 0.7
FEV1% predicted: 30-49
d)
Severity: very severe
FVE1/FVC: < 0.7
FEV1% predicted: < 30
Describe the investigations involved in COPD and their indications
Bedside
- Observations: pulse oximetry
- BMI
- Sputum culture: signs of infection
- ABG: if hypoxia or hypercapnia is suspected
- ECG: if cor pulmonate suspected
Bloods
- FBC: assess for anaemia and polycythaemia. Signs of infection
- Alpha-1 antitrypsin levels
Imaging
- CXR
- CT scan: if lunger cancer suspected, alternative diagnosis suspected
- Echocardiogram: if cor pulmonate suspected
Describe the CXR changes in COPD
Hyperexpanded lungs
Flattened hemidiaphragms
Increased number of anterior ribs
Saber-sheath trachea diffuse coronal narrowing of the intrathoracic portion of the trachea with the concomitant widening of the sagittal diameter)
What 3 parameters are used to diagnosis
Symptoms
Risk factors
Spirometr
Describe the non-pharamocologcial management of COPD
- Education
- Smoking cessation
- Vaccination: influenza, pneumococcal
- Pulmonary rehabilitation
- Self-management plans: rescuer pack with antibiotics and steroids
- Management of co-morbidities
- Nutrition including vitamin D supplementation
- Review inhaler technique and adherence
Describe the pharmacological management of stable COPD
- SABA or SAMA
- LABA + LAMA or LABA + ICS is evidence of steroid responsiveness or asthmatic features)
- LABA + LAMA + ICS (If on LABA + LAMA then 3 month trial of triple therapy and if on LABA + ICS then triple therapy straight away)
Name the oral therapies apart from inhalers that can be used in COPD and their indications
Corticosteroids - acute exacerbations
Theophylline - bronchodilator actions
Mucolytics - used in patients with a chronic productive cough to reduce frequency of cough and sputum productions
Antibiotics - for infective acute exacerbations
Describe the management of an acute exacerbation of COPD
Oxygen - in acute setting use non-rebreather mask but once confirmed they are a CO2 retainer use a Venturi mask with target rate of 88-92%
Bronchodilator - salbutamol 2.5mg nebulised, ipatroprium 500mcg nebulised
Corticosteroids - prednisolone 30mg once daily given for at least 5 days
Antibiotics - to treat exacerbations of COPD with signs of infection (e.g., more purulent sputum). Can use doxycycline or co-amoxiclav
Why must you be cautious when using oxygen therapy in COPD users and how is the prevented
Patients who have COPD may be CO2 retainers, therefore high oxygen may cause CO2 to increase. Therefore at increased risk of developing T2RF
This is prevented by using a venturi mask with a saturation target of 88-92%
Describe the indications for Bilevel Positive Airway Pressure (BiPAP) in COPD
- Acute or acute or chronic hypercapnia respiratory failure
- Cardiogenic pulmonary oedema
- Type 1 respiratory failure and clinically tiring
- Weaning from mechanical ventilation
a) Describe the indications of long-term oxygen therapy (LTOT)
b) How long should patients be on LTOT per day and how much oxygen should they be on in order to see a benefit?
c) What must you advise patients before LTOT?
a)
- Pao2 < 7.3 kPa OR
- PaO2 < 8 kPa with any of: pulmonary hypertension (pulmonary artery pressure > 25mmHg)
- Increases respiratory rare optimisation of oxygen therapy
b) LTOT is required for at least 15 hours a day/at 2-4 litres/min
c) Must stop smoking 3 months before
Name 5 complications of COPD
- Cor pulmonale
- Respiratory failure
- Pneumonia: often recurrent
- Pneumothorax: rupture of bulls disease
- Polycythaemia or anaemia
- Depression
Other causes of a chronic cough
a) Intrathoracic
b) Extrathoracid
a)
- Asthma
- Lung cancer
- Tuberculosis
- Left heart failure
- Interisital lung disease
- Cystic fibrosis
- Idiopathic cough
b)
- Chronic allergic rhinitis
- Post nasal drip syndrome
- Upper airway cough syndrome
- Gastroesophageal reflux
- Medications (e.g., ACEi)
Other causes of a chronic cough
a) Intrathoracic
b) Extrathoracid
a)
- Asthma
- Lung cancer
- Tuberculosis
- Left heart failure
- Interisital lung disease
- Cystic fibrosis
- Idiopathic cough
b)
- Chronic allergic rhinitis
- Post nasal drip syndrome
- Upper airway cough syndrome
- Gastroesophageal reflux
- Medications (e.g., ACEi)
What are indications to step up the management of asthma/COPD
- Ongoing symptoms
- PRN (If > 3 doses/week)
