Flashcards in Resp Session 6 Deck (66):
What two conditions is COPD a combination of?
Emphysema and chronic bronchitis
What is the pathogenesis of chronic bronchitis?
Inflammation in large always causes:
Remodelling and narrowing of airways
Hyper secretion of mucus and proliferation of goblet cells
Chronic productive cough and frequent infections
What is the pathogenesis of emphysema?
Terminal bronchioles and distal airspaces destroyed causing:
Loss of elastic tissue --> hyperinflation
Small airways collapsing on expiration
Bullae due to large redundant air spaces
What causes COPD?
Alpha-1 antitrypsin deficiency (esp
What are the S/S if COPD?
Cough with sputum
Purse lip breathing
Use of accessory muscles in breathing
Wheeze --> quiet breath sounds --> silent chest
What are the S/S of more advanced cases of COPD?
Peripheral +/- central cyanosis
CO2 retention flap
What are the 5 stages of the MRC dyspnoea score used to assess COPD?
1. SoB on strenuous exercise only
2. SoB on hurrying/walking up slight hill
3. Walks slower due to SoB
4. Stops for breath after walking ~100m on level ground
5. Too SoB to leave house/SoB on dressing
What investigations can be used in COPD?
Alpha-1-antitrypsin blood test
Why is HRCT used in investigation of COPD?
Gives detailed assessment of macroscopic alveolar destruction in emphysema, useful if considering surgery
Why is CXR mandatory in COPD investigation?
To exclude other diagnoses
What do NICE guidelines state are mild, moderate and severe levels of airflow obstruction detectable by spirometry?
Mild: FEV1 = 50-80%
Moderate: FEV1 = 30-49%
How is COPD diagnosed?
Hx: smoker, >40 y.o. with onset of symptoms later in life, chronic productive cough, persistent and progressive SoB
obstructive pattern on spirometry
How is stable COPD managed?
Long term O2 and surgery if appropriate
What is the cycle of reconditioning seen in stable COPD pts?
Feel SoB --> avoid activities that worsen SoB --> do less --> muscles weaken --> worsened SoB --> feel depressed --> avoid activities etc.
What are some of the S/E associated with treatment of stable COPD?
Beta-2 agonist: tachycardia, anxiety, hypokalaemia, tremor
Antimuscarinics: urinary difficulty, dry mouth, URT, glaucoma
How is an acute COPD exacerbation managed?
Aim for sats of 88-92% with titrated O2 therapy
Abx if blood tests indicate infection
Consider IV bronchodilator
Repeat ABG to assess need for ventilation
How can COPD generally be distinguished from asthma by using clinical features?
Pts tend to be smokers
S/S >65 y.o.
Chronic productive cough
Persistent and progressive SoB
Night time waking with cough/wheeze uncommon
Diurnal pattern/day-to-day variability uncommon
What characterises COPD?
Airflow obstruction which is usually progressive, not fully reversible and does not change markedly over several months
What are common microbial flora of the URT?
What are URTIs most commonly caused by?
Self limiting viruses
Why can viral URTI lead to secondary bacterial infection?
Due to viral action on cilia
Give some examples of common URTIs.
What deferences does the respiratory tract have against infection?
Ciliated columnar epithelium
Lymphoid follicles of pharynx and tonsils
Secretory IgA and IgG
Give some examples of LRTIs.
How does a poor swallow lead to aspiratory pneumonia?
Allows secretory pool in pharynx which can enter LRT
What is acute bronchitis?
Inflammation of medium sized airways often seen in smokers
What are the S/Sof acute bronchitis?
Increased sputum production
Sob due to exudation
Pulmonary oedema and cellular infiltration
How does a CXR appear in acute bronchitis?
Normal as terminal bronchioles and air sacs are not affected
What can cause acute bronchitis?
What is the treatment for acute bronchitis?
Abx if absolutely necessary
What is penumonitis?
Non-infective inflammatory disease
What is chronic bronchitis?
Recurrent bouts of SoB associated with but not caused by infection (not primarily infective)
What is pneumonia?
Inflammation of the lung alveoli, terminal bronchioles and lung parenchyma
What are the S/S if pneumonia?
Pleuritic chest pain
Opacities on CXR
How is pneumonia classified?
Presentation (acute->bacterial/viral, chronic->TB)
Lung pathology - lobar, broncho (patchy), interstitial
What is the pathogenesis of pneumonia?
Acute inflammatory response --> exudation of fibrin rich fluid, neutrophil and macrophage infiltration --> fluid filled air sacs --> heavy, stiff lung --> red hepatisation --> grey hepatisation
What factors may help identify the causative agent in pneumonia?
Pre-existing lung disease
How long does grey hepatisation take to develop following red hepatisation in pneumonia?
What are the typical causative agents of CAP?
What are atypical causes of CAP?
Coxiella bunetti (livestock)
Chlamydia psittaci (birds)
What are the S/S of CAP?
Cough +/- sputum (yellow, rusty, recurrent jelly)
Pleuritic chest pain
What causative agent does recurrent jelly sputum suggest?
What is detected O/E in CAP?
Dullness to percussion
Tactile vocal fremitus
What investigations are used to support diagnosis and assess severity of CAP?
What methods can be used to collect samples for sputum and blood culture to identify the causative agent in CAP?
Broncho alveolar lovage fluid
Nose and throat swabs
Urine antigen tests
Serum antibody test
When are urine antigen tests or serum antibody tests used to investigate CAP?
Atypical causes due to difficulty in culture
What are the criteria included in the CURB-65 score used to assess severity of CAP?
Urea > 7 mmol per litre
RR > 30
What does a CURB-65 indicate?
Severe pneumonia, consider admittance to hospital
What is the empiric Tx for CAP?
Mild-moderate: amoxicillin (doxycycline or erythromycin for penicillin allergic pts)
Moderate-severe: co-amoxiclav (clarithromycin/doxycycline for penicillin allergic pts and to cover atypical penicillin resistant causes)
How can CAP lead to chronic lung disease?
Resolution of infection with fibrous scarring
What complications can arise following CAP?
Lung abscess --> empyema
Bronchiectasis --> recurrent infections
What is atypical pneumonia?
Pneumonia caused by organisms without a cell wall
What additional features are seen in atypical pneumonia?
Extra-pulmonary features e.g. hepatitis, hyponatraemia
What is the Tx for atypical pneumonia?
Agents that work on protein synthesis: macrolides and tetracyclines
What is the pathogenesis of viral pneumonia?
Immune cells and virus cause damage to epithelial cells --> necrosis/haemorrhage into lung parenchyma --> acute hypoxia --> ARDS
How is viral pneumonia identified on CXR?
Patchy/diffuse ground glass opacity on CXR
What causes viral pneumonia?
Respiratory syncytial virus
What is the definition of hospital acquired pneumonia?
Onset within 48hrs of being in hospital
What causative agents are associated with hospital acquired pneumonia?
What is the Tx for HAP?
1st line: co-amoxiclav
2nd line: pipperacillin/Tazobactam/meropenem
What method is used to distinguish causative agent of HAP form UR flora?
Bronchial lava he
What is aspiration pneumonia?
Exogenous material/endogenous secretions --> resp tract seen in dysphagia, epilepsy, alcoholics, drowning
What is the causative agent for aspiration pneumonia?
Mixed infection as you can't selectively aspirate certain organisms, commonly viridans streptococci and anaerobes
What is the treatment for aspiration pneumonia?
What causative agents are seen in immunosuppression associated LRTI?
HIV: PCP, TB, atypical mycobacteria
BM transplant: CMV
Splenectomy: encapsulated organisms e.g. S.pneumoniae, H.influenzae, malaria