COPD Flashcards
What is meant by ‘blue bloaters’ and ‘pink puffers’?
- pink puffers (emphysematous): have inc alveolar ventilation, near normal PaO2 but normal/decreased PaCO2 –> breathless but not cyanosed (-> may prog to type I resp failure)
- blue bloaters (bronchial): have reduced alveolar ventilation, low PaO2 and a high PaCO2 –> cyanosed but not beathless -> may develop cor pulmonale
Pink puffers have severe emphysema, and characteristically are thin and free of signs of right heart failure. Blue bloaters, on the other hand, have frequent episodes of right heart failure, and produce copious sputum resulting in coughing and respiratory infections. Blue bloaters presents more of a chronic bronchitis picture although they too may exhibit emphysematous changes.
What are the symptoms of COPD?
- dyspnoea
- cough productive w/ sputum
- bilateral expiratory wheeze
What are the signs of COPD?
- tachypnoea + use of accessory muscles
- hyperinflated lungs
- reduced cricosternal distance (<3cm)
- barrel chest
- breathing through pursed lips
- prolonged expiration on PE
- cyanosis
- reduced chest expansion bilaterally
- normal percussion / hyper-resonance
- normal/decreased tactile fremitus
- decreased breath sounds
- wheeze, rhonchi (rattling due to secretions)
What are differential diagnoses for breathlessness?
It can be helpful to classify the differentials based upon associated symptoms, eg:
- wheeze - asthma, COPD, HF, anaphylaxis
- stridor - foreign body, tumour, epiglottitis, anaphylaxis, trauma
- crackles - HF, pneumonia, bronchiectasis, fibrosis
- clear chest - PE, hyperventilation, metabolic acidosis, anaemia, drugs, shock, CNS disease
- other - pneumothorax, pleural effusion
What are the differential diagnoses for cough?
- infection -> URTI, pneumonia, TB
- trauma -> vocal trauma, burns, foreign body
- autoimmune -> Wegener’s
- iatrogenic -> ACEi
- immune -> allergies (eg. asthma, atopy, rhinits, ABPA)
- neoplasm -> laryngeal
- GORD -> often associated w/ nocturnal cough
COPD is characterised by chronic inflammation that affects central and peripheral airways, lung parenchyma and alveoli, and the pulmonary vasculature.
What are the main components of these changes?
- narrowing + remodelling of the airway -> decreased recoil, luminal secretions, fibrosis
- increased numbers of goblet cells
- enlargement of mucus glands
- vascular bed changes (leading to pulmonary hypertension) -> hypoxia leads to pulmonary vessel constriction
In contrast to asthma (eosinophils), it is the macrophages, neutrophils and leukocytes that are responsible for generating the inflammatory process
What are the causes of COPD?
- tobacco smoking
- occupational exposure
- air pollution
- genetic susceptibility (eg. a1-antitrypsin deficiency)
How do you quantify smoking in “pack years”?
- defines a person’s life time smoking load
- cig/day per pack of 20 x no yrs smoked
- eg. 20 cigs per day for 52 years = 52 pack years
- 30 cigs per day for 40 years = 60 pack years
usually need 20 pack year to cause COPD
What investigations are important for COPD?
- spirometry -> ratio <0.7
- pulse oximetry -> low
- ABG -> hypercapnic, hypoxic
- CXR
- FBC -> raised haematocrit, poss inc WBC
- ECG -> RVH, arrhythmia, ischaemia
What does this CXR show for COPD?
- this CXR shows hyperinflation, flattened diaphragm and increased intercostal spaces
- it is often normal even when the disease is advanced but classic features include:
- bullae
- hyperinflation
- flat hemidiaphragm
- consolidation
- collapse
- retrosternal air space on lateral film
Describe the role of spirometry in diagnosing and determining the severity of COPD
- FEV1: vol of air forcibly exhaled in 1 sec
- FVC: vol of air totally exhaled
- should be 80-120% of predicted
- 70% of total should be inhaled in first sec
- ie FEV1/FVC should be ~70%
- <0.7 indicates obstructive disease
- bronchodilator showing >15% improvement indicates significant reversibility
Which organisms are likely to produce acute infective exacerbations of COPD, that can be found in sputum culture?
- haemophilus influenzae
- steptococcus pneumoniae
- ocassionally moraxella catarrhalis
What might an ECG show in advanced cor pulmonale?
- P wave is taller (P pulmonale)
- right bundle branch block (RSR’ complex)
- changes of right ventricular hypertrophy
What would an ABG show in COPD?
Pink puffers (normal PaCO2, PaO2 > 8 kPa) have emphysematous lung tissue destruction. Diffusing capacity is decreased by destroyed pulmonary capillaries. ABGs are near normal due to compensatory hyperventilation. The only subtle changes typically are a PaO2 slightly depressed (often in the mid 9s, resulting in mild pulmonary vasoconstriction), and a low-normal PaCO2.
Blue bloaters (PaCO2 > 6kPa, PaO2 < 8 kPa) suffer from pulmonary hypoxic vasoconstriction from the marked hypoxia and respiratory acidosis. This in turn leads to right ventricular hypertrophy and cor pulmonale. The right heart failure then leads to systemic venous congestion, peripheral edema, hepatic congestion, and ascites. Secondary erythrocytosis may occur, spurred by the hypoxia. Changes on ABG’s are much more pronounced.
What are the 7 products free on prescription for nicotine replacement therapy?
- patch
- gum
- inhalator
- microtabs
- losenge
- nasal spray
- mouth spray
Practitioners advocate cutting down combined with NRT, some evidence to show that this aids abstinence. Combinging products appear to be safe and more effective.
What are the NICE guidelines for medical management of COPD?
- NICE only recommends oral theophylline after trials of short + long-acting bronchodilators or to ppl who cannot used inhaled therapy
- mucolytics - consider in pts w/ chronic productive cough and continue if symptoms improve
