Breathlessness- core conditions Flashcards
Asthma
A chronic inflammatory condition of the airways which is characterised by recurrent symptoms and airflow obstruction which is usually variable and reversible
Pathophysiology of asthma
Inhaled allergens stimulate the development of T helper cells which produce a variety of cytokines which stimulate the production of IgE, eosinophils and mast cells. IgE then binds to mast cells and is cross linked by antigens lead to cell degeneration and the release of mediators such as histamine, prostaglandin and leukotrienes. This causes bronchoconstriction and the early athematic response. The late asthmatic response is associated with increased airway inflammation and is driven mainly by Eosinophils.
When to consider asthma
• Symptoms of SOB, cough, wheeze and chest tightness
• Recurrent/variable nature of symptoms
• Diurnal variation in symptoms- morning increase in symptoms and overnight
• Personal and family history of atopy
• Identifiable triggers i.e. exercise, infection, pollen, dust, animal dander, NSAID’s etc
Asthma- common investigations
• Peak expiratory flow (PEF)- measures maximum speed of expiration, usually monitored over 2-4 weeks. Variability of 20% or more is significant
• Spirometry: main investigation for identifying obstruction, measures how much air is breathed out and how quickly. An FEV1/FVC ratio of less than 70% means there is an obstruction
• Reversibility: for patients with obstructive spirometry, patient is given dose of bronchodilator and spirometry is re-performed. Increase in FEV1 of both 12% and 200mL in volume is positive
• Fractional exhaled Nitric oxide (FeNo): a positive FeNo (>40ppb) suggests eosinophilic inflammation
• These investigations have a high rate of false negatives
Stepwise management for asthma
Different therapies are added in till the asthma is controlled. You move up and down the treatment ladder as needed in order to maintain the lowest controlling therapy.
• Step 1 (suspected asthma)- Short acting Beta-2 agonist (Salbutamol): use when required. Consider a low dose inhaled corticosteroid (ICS) i.e. beclomethasone
• Step 2- add inhaled long acting beta agonist (LABA) i.e. Salmeterol to low dose ICS
• Step 3- consider increasing ICS to medium dose or adding Leukotriene receptor antagonist (LTRA) i.e. Montelukast. If there is no improvement with the LABA this can be stopped.
• Step 4- refer patients for specialist care
Aims of treatment
• No daytime symptoms
• No night time awakening due to asthma
• No need for rescue medication
• No exacerbation
• No limitations on activity including exercise
• Normal lung function (FEV1 and or PEF >80% predicted or best)
• Minimal side effects
Moderate acute asthma exacerbation
• Increasing symptoms
• PEF >50-75% best or predicted
• No features of acute severe asthma
Severe acute asthma exacerbations
Any one of:
• PEF 33-50% best or predicted
• Respiratory rate >25/min
• Heart rate >110/min
• Inability to complete sentences in a breath
• Altered consciousness
• Exhaustion
• Arrhythmias
• Hypotension
• Cyanosis
• Silent chest
• Poor respiratory effort
Near fatal acute asthma exacerbation
Raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressure
Investigations for acute asthma
• Peak expiratory flow (PEF)- this is expressed as a % of the patients previous best value, in the absence of this % of predicted is a rough guide
• Pulse oximetry/arterial blood gas- the aim of oxygen therapy is to maintain SpO2 94-98%. Patients with an SpO2 of <92% or features of life threatening asthma require ABG
Investigations for acute asthma: Chest x-ray
Chest x-ray is not routinely recommended in patients except for:
• Suspected pneumomediastinum or pneumothorax
• Suspected consolidation
• Life threatening asthma
• Failure to respond to treatment satisfactorily
• Requirement for ventilation
Management of acute asthma
• A to E structure
• Controlled oxygen therapy (94-98%)
• Salbutamol nebulisers, can be given back to back if there is a poor response to the initial dose
• Hydrocortisone (IV) or Prednisolone (PO)
• Ipratropium nebulisers- in severe or life threatening cases or where there is an inadequate response to initial treatment
• Magnesium sulphate (IV) or Theophylline (as aminophylline infusion IV) can be considered under specialist guidelines
• Incubation and ventilation may also be required
COPD
Airway obstruction which is chronic and progressive, includes chronic bronchitis and emphysema
Chronic bronchitis- a productive cough that lasts at least three months of two consecutive years
Emphysema- the abnormal, permanent enlargement of the air spaces due to the breakdown of alveoli.
Consider COPD when they present with:
• Are over 35 with a risk factor i.e. smoking
• Exertional breathlessness
• Chronic cough
• Regular sputum production
• Wheeze
• Frequent winter ‘bronchitis’
Clinical signs and risk factors for COPD
Clinical signs include: Barrel chest, Cyanosis, Flapping tremor, Pursed lip breathing, Use of accessory muscles, wheeze
Risk factors: smoking, pollution and exposure to dust, Alpha 1 antitrypsin deficiency
Investigations into COPD
chest x-ray
• Useful to exclude other causes like malignancy
• In COPD you will see Hyperextended lungs, Flattened Hemidiaphragm, Bullae
Spirometry
• FEV1/FVC ratio <70% (below)
• Scalloping of flow/volume curve
Management of COPD- non medical
• Smoking cessation
• Pneumococcal vaccination and annual influenza vaccine
• Pulmonary rehab- combines physical therapy with disease education and nutritional, psychological and behavioural intervention. Programme is done in groups and lasts 6-8 weeks
COPD- medication: short acting and combination therapy
• Short acting bronchodilator i.e. salbutamol. They will initially be offered either a SABA or a Short Acting Muscarinic antagonist
• Combination therapy: Long acting beta agonist (LABA) and Long Acting Muscarinic Antagonist (LAMA) or
a Long Acting Beta Agonist and Inhaled Corticosteroid (ICS). The second option is normally for patients with asthmatic features
Medications: triple therapy and extra
• Triple therapy- for patients who still have day to day symptoms which affect the quality of their life or they have one severe or two moderate exacerbations within a year. LABA + LAMA + ICS
• May need long term oxygen therapy, home nebulisers, prophylactic antibiotics and mucolytics. Some patients may need lung volume reduction surgery
You go from short acting to combination therapy to triple therapy if symptoms are not controlled
Acute exacerbations of asthma
Sustained worsening of the patients symptoms from their usual stable state which is beyond normal day to day variations and is acute in onset
Management of acute exacerbations of COPD
• A to E assessment
• Controlled oxygen therapy- should be monitored with ABG’s to ensure they are not hypercapnic
• Steroids (PO)
• Salbutamol nebulisers (bronchodilator)
• Ipratropium nebulisers (bronchodilator)
• Consider antibiotics- if symptoms are severe or there are changes to the sputum
• Non invasive ventilation- if there is hypercapnia and acidaemia
• Intubation and ventilation can be considered in patients with severe exacerbations who don’t respond to treatment
Investigations for acute exacerbations of COPD
• Blood tests- including FBC, urea and electrolytes, C reactive protein
• Cultures- blood cultures, sputum cultures. Will show if there is a source of infection
• Arterial blood gas- is there evidence of hypercapnia, acidosis. Is oxygen appropriate
• Chest x-ray: to exclude pneumonia/ other pathology
