Respiratory Conditions Flashcards
What is asthma
A chronic inflammatory airway disease characterised by episodic exacerbations of bronchoconstriction causing an obstruction to airflow going in and out of the lungs
This is a reversible airway obstruction which typically responds to bronchodilators scubas a salbutamol.
What is bronchoconstriction
Where the smooth muscles of the airways (the bronchi) contract, causing a reduction in the diameter in the airways
What causes bronchoconstriction in asthma
Airway hypersensitivity and can be triggered by environmental factors
What are the typical triggers of asthma
Infection Night time or early morning Exercise Animals Cold, damp or dusty air Strong emotions
How does asthma present
Episodic symptoms
Diurnal variability, typically worse at night
Dry cough with wheeze and SOB
A history of other atopic conditions
Family history
Bilateral widespread polyphonic wheeze heard on auscultation
How is suspected asthma investigated
First line:
- Fractional exhaled nitric oxide
- Spirometry with bronchodilator reversibility
Follow up if uncertainty over diagnosis:
- Peak flow variability (diary of several measurements a day for 2-4 weeks)
- Direct bronchial challenge test with histamine or methacholine
How is asthma managed long term
Key treatments are:
- Short acting beta 2 adrenergic receptor agonists (eg. salbutamol)
- Inhaled corticosteroids (eg. beclometasone)
- Long acting beta 2 agonists (eg. salmeterol)
- Long acting muscarinic antagonists (eg. tiotropium)
- Leukotriene receptor antagonists (eg. montelukast)
- Theophylline
- Maintenance and reliever therapy
How do short acting beta 2 adrenergic receptor agonists work in asthmatic patients
Work quickly but effect only lasts for an hour or two
Adrenalin acts on the smooth muscles of the airways to cause relaxation
This results in dilation of the bronchioles and improves the bronchoconstriction present in asthma
Used as reliever or rescue medication during acute exacerbations of asthma
How do inhaled corticosteroids work in asthmatic patients
Reduce the inflammation and reactivity of the airways
Used as maintenance or preventer medications and are taken regularly, even when well
How do long acting beta 2 agonists work in asthmatic patients
Adrenalin acts on the smooth muscles of the airways to cause relaxation
This results in dilation of the bronchioles and improves the bronchoconstriction present in asthma (same as short acting but have a much longer action)
How do long acting muscarinic antagonists work in asthmatic patients
Block acetylcholine receptors which are stimulated by the parasympathetic system and cause contracting of bronchial smooth muscles.
Blocking these receptors leads to bronchodilation
How do leukotriene receptor antagonists work in asthmatic patients
Leukotrienes are produced by the immune system and cause inflammation, bronchoconstriction and mucus secretion in the airways.
These work by blocking the effects of leukotrienes
How does theophylline work in asthmatic patients
Relaxes the bronchial smooth muscle and reduces inflammation
Has a narrow therapeutic window and can be toxic in excess so monitoring plasma theophylline levels in the blood is required
Done 5 days after start of treatment and 3 days after each dose change
How does maintenance and reliever therapy work in asthmatic patients
A combination inhaler containing a low does inhaled corticosteroid and a fast acting LABA
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 is the stepwise ladder for asthma treatment according to NICE guidelines
- SABA as required for infrequent wheezy episodes
- Add a regular low dose inhaled corticosteroid
- Add an oral leukotriene receptor antagonist
- Add a LABA inhaler (continue only if good response)
- Consider changing to combined MART
- Increase inhaled corticosteroid to a moderate dose
- Consider increasing the inhaled corticosteroid to a high dose or oral theophylline or an inhaled LAMA
- Refer to specialist
What additional management should be provided for asthmatics
Self-management programme
Yearly flu jab
Yearly asthma review
Advise exercise and avoid smoking
What is acute asthma
An acute exacerbation asthma is characterised by a rapid deterioration in asthmatic symptoms which can be triggered by the typical asthma triggers
How does acute asthma present
Progressively worsening SOB
Use of accessory muscles
Fast respiratory rate (tachypnoea)
Symmetrical expiratory wheeze on auscultation
Chest can sound tight on auscultation with reduced air entry
How is acute asthma categorised
Moderate:
-PEFR 50-75% predicted
Severe:
- PEFR 33-50% predicted
- Resp rate >25
- Heart rate >110
- Unable to complete sentences
Life-threatening:
- PEFR <33%
- O2 sats <92%
- Becoming tired
- No wheeze (airways so tight no air entry at all, AKA a ‘silent chest’)
- Haemodynamic instability (ie. shock)
How is moderate acute asthma treated
Nebulised beta-2 agonist (salbutamol 5mg as often as necessary)
Nebulised ipratropium bromide
Oral prednisolone or IV hydrocortisone, continued for 5 days
Antibiotics if evidence of bacterial infection
How is severe acute asthma treated
O2 as required to maintain sats 94-98%
Aminophylline infusion
Consider IV salbutamol
How is life-threatening acute asthma treated
IV magnesium sulphate infusion
Admission to ICU or HDU
Intubation (decision to intubate should be made early as it is very difficult to intubate in sever bronchoconstriction
What will ABGs show in acute asthma
Initially, respiratory alkalosis as tachypnoea causes a drop in CO2
A normal pCO2 or hypoxia is concerning as it means patient is tiring and indicated life-threatening asthma
A respiratory acidosis due to high CO2 is a very bad sign
How are patients with acute asthma monitored for response to treatment
Respiratory rate Respiratory effort Peak flow O2 sats Chest auscultation
Also monitor serum potassium when on salbutamol as it causes potassium to be absorbed from blood into the cells and can also cause tachycardia
What is COPD
Chronic Obstructive Pulmonary Disease
A non-reversible, long term deterioration in air flow through the lungs, caused by damage to lung tissue due to smoking. The damage to the lung tissue causes an obstruction to the flow of air through the airways, making it more difficult to ventilate the lungs and making them more prone to infection
How does COPD present
Common: Cough Shortness of breath Sputum production Exposure to risk factors Recurrent respiratory infections, especially in winter Barrel chest Hyper-resonance on percussion Distant breath sounds on auscultation Poor air movement on auscultation Wheezing on auscultation Coarse crackles
Uncommon: Tachypnoea Asterixis Distended neck veins Lower-extremity swelling Fatigue Weight loss Muscle loss Headache Pursed lip breathing Cyanosis Loud P2 Hepatojugular reflux Hepatosplenomegaly Clubbing
What are the risk factors for COPD
Strong:
Cigarette smoking
Advanced age
Genetic factors
Weak: White ancestry Exposure to air pollution Exposure to burning solid or biomass fuel Occupational exposure to dusts, chemicals, vapors, fumes, or gases Developmentally abnormal lung Male sex Low socio-economic status Rheumatoid arthritis
What is the MRC (Medical Research council) dyspnoea scale
5 point scale for assessing the impact of patient’s breathlessness
Grades:
- Breathless on strenuous exercise
- Breathless on walking up hill
- Breathlessness that causes patient to slow when walking on flat
- Stop to catch breath after walking 100 meters on the flat
- Unable to leave the house due to breathlessness
How is a diagnosis of COPD made
Based on clinical presentation and spirometry
What will show on a COPD patient’s spirometry
An obstructive picture
Overall lung capacity (FVC) is not as bad as ability to quickly exhale air out of lungs (FEV1)
This is due to damage to airways causing airway obstruction
FEV1/FVC ratio <0.7
Also no dramatic response to reversibility testing with beta-2 agonists during spirometry test (if responsive then consider asthma as differential)
What does FVC stand for
Forced vital capacity
What does FEV1 stand for
Forced expiratory volume in 1 second
How is the severity of COPD graded
Using FEV1
- > 80% of predicted
- 50-79% of predicted
- 30-49% of predicted
- <30% of predicted
What investigations can be done in a case of suspected COPD
Spirometry Chest x ray FBC BMI Sputum culture ECG Echocardiogram CT thorax Serum Alph-1 antitrypsin Transfer factor for carbon monoxide
What is the long term management of COPD
Smoking cessation is essential
Pneumococcal and anual flu vaccines
- short acting bronchodilators (beta 2 agonists) or short acting antimuscarinics
2.If not asthmatic or steroid responsive then have a combined LABA and a LAMA
If they are asthmatic or steroid responsive then have a LABA plus an ICS, if not enough then step up to LABA, LAMA and ICS combination inhaler
- In more severe cases options are:
- Nebulisers
- Oral theophylline
- Oral mucolytic therapy to break down sputum
- Long term prophylactic antibiotics
- Long term oxygen therapy at home
When is long term oxygen therapy used in COPD
Severe COPD that is resulting in chronic hypoxia, polycythaemia, cyanosis, or heart failure secondary to pulmonary hypertension (cor pulmonale)
Cannot be used if they smoke as significant fire hazard
What is an exacerbation of COPD
An acute worsening of symptoms, such as a cough, SOB, sputum production, and wheeze, which is usually caused by a viral or bacterial infection
What are Venturi masks
Oxygen masks that are designed to deliver a specific concentration of oxygen by allowing some of the oxygen to escape out the side of the mask and normal air to be inhaled along with oxygen Blue: 24% O2 White: 28% O2 Orange: 31% O2 Yellow: 35% O2 Red: 40% O2 Green: 60% O2
