Lecture 8.1: COPD Flashcards
What is the long form of COPD?
Chronic Obstructive Pulmonary Disease
What is COPD?
- The name for a group of lung
conditions that cause breathing
difficulties - It includes: emphysema (damage to
the air sacs in the lungs), chronic
bronchitis (long-term inflammation of
the airways)
What is COPD predominantly caused by?
Smoking
What is COPD characterised by (NICE)?
- COPD is characterised by airflow
obstruction - The airflow obstruction is usually
progressive - Not fully reversible
- Does not change markedly over
several months
How many people in the UK are living with COPD?
1.2 million
Risk Factors for COPD (7)
- Smoking
- Coal Mining/Mining of any kind really
- Asbestos Exposure
- People with Asthma
- Exposure to fumes from burning fuel
- Occupational exposure to dusts and
chemicals - Genetics
Causes of COPD (4)
- Vast majority in HICs due to smoking
- Alpha-1 anti-trypsin deficiency
- Occupational exposure (e.g. coal dust)
- Pollution (including indoor smoke
pollution)
What percentage of Smokers get COPD?
15%
What is Emphysema?
- A pathological process in which there is
destruction of the terminal bronchioles
and distal airspaces - Leads to loss of alveolar surface area
- Spaces get bigger to form bullae
Why do small airways collapse in Emphysema?
- Spaces get bigger to form bullae
- Destruction of tissues removes
‘scaffolding’ support of small airways,
which tend to collapse - Leads to airflow obstruction
What is Pulmonary Compliance?
A measure of the lung expandability
What is the Equation of Pulmonary Compliance?
Compliance = Δvolume/Δpleural pressure
What is the effect of loss of tissue in Emphysema?
- Loss of tissue increases compliance
- Lung recoil reduced so lungs have
higher resting expiratory level - Hyperinflation
Centrilobular/Centriacinar Emphysema
- Primarily the upper lobes
- Occurs with loss of the respiratory
bronchioles in the proximal portion of
the acinus - With sparing of distal alveoli
Panlobular/Panacinar Emphysema
- Involves all lung fields
- Particularly the bases
What is Chronic Bronchitis?
A daily productive cough that lasts for 3 months of the year and for at least 2 years in a row
Pathophysiology of Chronic Bronchitis
- Chronic mucus hypersecretion
- Mucus hyper secretion caused by
inflammation in larger airways - Leads to chronic productive cough and
frequent infections - Get re-modelling and narrowing of
airways
Symptoms of COPD (5)
- Cough
- Sputum Production
- Progressive Breathlessness
- Dyspnoea
- Increasingly frequent exacerbations
MRC Dyspnoea Score (5 Grades)
- Grade 1: not troubled except in hard
exercise - Grade 2: short of breath when hurrying
or walking up slight hill - Grade 3: walks slower than
contemporaries on level ground
because of breathlessness - Grade 4: stops for breath after walking
100m or so - Grade 5: too breathless to leave the
house, or breathless on dressing and
undressing
Signs of COPD (10)
- ‘Purse Lip’ Breathing
- Increases pressure within airways to
delay closure - Tachypnoea
- Use of accessory muscles
- Hyperinflation (harder to breath)
- May have wheeze or quiet breath sounds
- Cyanosis
- Carbon dioxide retention
- Right heart failure (cor pulmonale)
Investigations for COPD
- Spirometry
- Chest X-Ray
- High Resolution CT
- ABGs (to assess respiratory failure)
- Alpha-1 anti trypsin assay for younger patients
How is Airflow Obstruction Staged?
- Mild airflow obstruction: FEV1.0 50-80%
predicted - Moderate airflow obstruction: FEV1.0 30-49%
predicted - Severe airflow obstruction: FEV1.0 <30%
predicted
Pathophysiology of Emyphsema
- Parenchymal destruction
- Matched V/Q defect
- Mild hypoxia
- Cachexia
Pathophysiology of Chronic Bronchitis
- Airway inflammation
- V/Q mismatch
- Severe hypoxia and hypercapnia
- Pulmonary hypertension and cor pulmonale
Cor Pulmonale
What is abnormal enlargement of the right side of the heart as a result of disease of the lungs or the pulmonary blood vessels
2 Types of Management of COPD
- Stable disease management
- Management of exacerbations
Stable COPD Management (10)
- Smoking cessation support
- Pulmonary rehabilitation
- Bronchodilators
- Anti-muscarinics
- Steroids
- Mucolytics
- Diet
- Influenza vaccination
- Long term oxygen therapy in advanced disease
- Lung volume reduction if appropriate
Drug Therapy for COPD: Bronchodilators
- A type of medication that make breathing easier
by relaxing the muscles in the lungs and
widening the airways (bronchi) - Beta-2 agonists (eg salbutamol)
- May help with emphysema even if there is no
improvement in FEV1
Adverse Effects of Beta-2 Agonists (5)
- Tachycardia
- Tremor
- Anxiety
- Palpitations
- Hypokalaemia
Drug Therapy for COPD: Steroids
- Steroids help reduce inflammation
Drug Therapy for COPD: Mucolytics
- Mucolytics help clear mucus
- Carbocysteine
Drug Therapy for COPD: Anti-Muscarinics
- Also known as anticholinergic agents
- Are effective bronchodilators used in the
treatment of chronic obstructive pulmonary
disease (COPD) - Used to alleviate dyspnea and improve
exercise tolerance
Adverse Effects of Anti-Muscarinics
- Dry Mouth
- Upper Respiratory Tract Infection
- Nausea
- Pharyngitis
- Supraventricular Tachycardia
- Atrial Fibrillation
- Urinary Difficulty/Retetention
- Constipation
What is the Effect of Anti-Muscarinics on the Urinary System
- Decreasing the motility of smooth muscle cells
in the urinary tract and increasing the tone of
the sphincters controlling urination - They do this by inhibiting parasympathetic.
stimulation of the myenteric and submucosal
neural plexuses - Anticholinergic agent that blocks the activity of
the muscarinic acetylcholine receptor
Adverse Effects of Corticosteroids (10)
- Thin Skin
- Bruising
- Cataracts
- Adrenal Insufficiency
- Osteoporosis
- Diabetes
- Increased Weight
- Mental Disturbance
- GI Symptoms
- Proximal Myopath
Managing Acute Exacerbations (6)
- Aim for oxygen saturation 88-92% with.
controlled oxygen therapy - Use nebulised bronchodilators
- Oral/sometimes IV steroids
- Antibiotics if suspect infection
- Consider IV Aminophylline
- If ABGs do not improve consider ventilator
Long Term Oxygen Therapy
- Help to stop long term hypoxia leading to
renal and cardiac damage - Continuous oxygen for at least 16 hours each
day - Offered if arterial pO2 consistently below
7.3kPa - Patients must be non-smokers
- Patients must not be retaining high levels of
carbon dioxide - Balance with loss of independence
Endobronchial Valves
- A small one-way valve, which may be
implanted in an airway feeding the lung or
part of lung - The valve allows air to be breathed out of the
section of lung supplied - Prevents air from being breathed in
- This leaves the rest of the lung to expand
more normally and avoid air-trapping
Pulmonary Rehabilitation Encourages…?
6-12 week supervised MDT programme of:
* Exercise supervised and unsupervised at home
* Diet
* Disease education
Why can’t we give too much oxygen to COPD patients?
- Normal oxygen threshold is reduced in COPD patients
- Giving them O2 increases saturation in lungs enough
that their body breaths less - This means less CO2 is blown off
- This could leads to hypercapnia which can be very
dangerous
