Session 8: COPD Flashcards
What is COPD?
Airflow disease (obstructive) caused by two conditions. Usually progressive and associated with an abnormal inflammatory response to noxious particles and gases.
COPD is an umbrella term for two conditions, which?
Chronic bronchitis Emphysema
Aetiology of COPD
90% due to tobacco smoking. <10% due to alpha1-antitrypsin deficiency.
When does COPD most commonly present?
In older patients which have smoked more or less their entire lives.
Explain how alpha1-antitrypsin deficiency leads to COPD.
Alpha1-antitrypsin is an antiprotease. In this condition there is an imbalance between proteases and antiproteases in the lung. This leads to destruction of the alveolar walls and elastin leading to emphysema.
When does alpha1-antitrypsin-associated COPD most commonly occur?
In young ages as it is inherited.
Broad pathophysiology of COPD.
Exposure to tobacco smoking and other noxious particles leads to a chronic inflammatory response. This leads to oxidative injury which damages the parenchyma of the lungs, the peripheral airways, the vasculature as well as the alveoli.
Two broad pathological changes occur in COPD, which?
Increased production of mucus and reduced clearance of mucus and associated pathogens. Respiratory defects + vasculature.
Explain the cause of disrupted clearance of mucus and pathogens in COPD.
Enlargement of the mucus-secreting glands in the airways. Metaplasia of ciliated respiratory epithelium to normal columnar with increased expression of goblet cells. This also leads to ciliary destruction and dysfunction.
Explain the respiratory defects and vasculature changes of COPD.
Breakdown of elastin leads to reduced elastic recoil. Also causes narrowing of bronchioles due to loss of radial traction. Also causes alveoli to collapse and form larger alveoli (formation of bullae). This leads to reduced surface area and reduced exchange. The vascular bed changes causes hypoxia, vasoconstriction and pulmonary hypertension.
What is emphysema caused by?
Breakdown of elastin.
Consequences of chronic bronchitis.
Increased mucus production and reduced clearance.
Is COPD reversible?
No
COPD leads to airway resistance. What causes it (think 3 changes)?
1 - Luminal obstruction because of increased mucus secretions and reduced clearance. 2 - narrowing of small bronchioles as radial traction is lost (outward pull) by elastin of surrounding alveoli. 3 - Elastin loss leads to reduced elastic recoil -> reduced expiratory force.
What is the consequence of reduced expiratory force?
Hyperinflation
State a cardiac consequence of COPD
Right heart failure (cor pulmonale)
Explain how cor pulmonale can occur in COPD.
Hypoxia due to the obstructive nature of the disease. This leads to vasoconstriction of the pulmonary vessels. This vasoconstriction leads to pulmonary hypertension. This can lead to RV hypertrophy and subsequent R heart failure.
What is the common history of a patient with COPD?
Older with a long history of smoking.
What is the most common initial symptom of COPD?
Coughing
Describe the initial cough associated with COPD.
Usually a morning cough that becomes more constant as the disease progresses. It is usually a productive cough meaning it produces sputum.
The sputum of the cough in COPD may change. Due to what?
Exarcerbations or superimposed infections related to COPD.
Give an example of another common initial symptoms of COPD.
Shortness of breath that may get worse upon exertion. This can progress to shortness of breath even on rest as the disease gets worse.
Upon physical examination of a patient with COPD, what might you find? (Early to middle stages)
Tachypnoea Use of accessory muscles to aid the patients breathing Barrel chest Hyper-resonance upon percussion. Reduced intensity breath sounds Reduced air entry Wheezing (not as common)
Cause of barrel chest.
Hyperinflation and air trapping secondary to incomplete expiration
Cause of hyper-resonance upon percussion.
Hyper inflation and air trapping
Late features upon physical examination in COPD.
Central cyanosis Flapping tremors Signs of right-sided heart failure.
Cause of flapping tremors in late stage COPD.
Hypercapnia
What are the signs of right-side heart failure in COPD?
Ankle oedema Distended neck veins (JVP) Hepatomegaly
Investigations of COPD.
Spirometry DLCO (Decreased diffusing capacity of the lung for carbon monoxide) CXR Sputum sample
In the case of acutely unwell COPD patients, what other investigation might you do?
Pulse oximetry and ABG levels
In the case of a young person with COPD, what other investigation might you do?
Alpha-1 antitrypsin levels.
How would spirometry show up on a patient with COPD?
FEV1/FEV ratio <70% Obstructive pattern with scooped curve Pattern doesn’t reverse upon use of bronchodilators.
What might the CXR show on COPD?
Flattened diaphragm Hyperlucent lungs Increased diameter of the antero-postero chest.
What else might the CXR show? (Not as common)
Complications of the COPD such as pneumonia or a pneumothorax
Upon doing all the investigations for COPD. How will the results differ between COPD and asthma?
The spirometry patterns would reverse upon the use of bronchodilators. There would also be no decreased DLCO. Sputum sample in asthma might show eosinophils and can also be found in blood.
Preventive and non-medical treatment of COPD.
Smoking cessation Patient education Pneumococcal vaccination to prevent pneumonia Pulmonary rehabilitation
Medical treatment of COPD.
Bronchodilators (SABA, LABA, SAMA, LAMA) Inhaled corticosteroids Long term oxygen therapy Surgical intervention
Explain why pulmonary rehabilitation is important.
As COPD gets worse the patient will get increased SOB upon exertion. This makes a lot of patients discouraged to exercise. This causes atrophy of respiratory muscles and leads to a vicious cycle of worsening symptoms. Can also lead to social isolation and depression.
Why is long term oxygen therapy important?
Because extended periods of hypoxia causes pulmonary hypertension. This can lead to cor pulmonale.
Explain how long term oxygen therapy is carried out.
Continuous low doses of oxygen at home or at least 16 hours in a day.
Give examples of surgical interventions done in severe COPD.
Removal of large bull. Lung volume reduction. Lung transplant
Definition of acute exacerbation of COPD.
Event characterised by change in the patient’s baseline (not general baseline) of dyspnoea, cough and sputum production and is acute onset.
Give an example of why acute exacerbation of COPD might occur.
Infection
What is the usual presentation of acute infectious exacerbation of COPD?
Severe SOB Fever Chest pain
Management of acute exacerbation of COPD.
Pulse oximetry and ABG levels. Close monitoring of O2 sat Appropriate antibiotics Nebulised bronchodilators Oral steroids 24% or 28% O2 therapy with close monitoring of CO2 levels Non-invasive ventilation to not cause type 2 respiratory failure.
Appropriate antibiotics are usually used to cover what pathogens?
Haemophilus influenzae Streptococcus pneumoniae
What is the antibiotics usually used for these pathogens?
Amoxicillin
Complications of COPD
Recurrent pneumonia Pneumothorax Respiratory failure Cor pulmonale
