Respiratory: Acute Bronchitis, Pneumonia & Pneumothorax Flashcards
What is acute bronchitis?
LRTI which is usually self-limiting in nature.
It is a result of inflammation of the trachea and major bronchi.
Clinical features of acute bronchitis?
- cough (may or may not be productive)
- sore throat
- rhinorrhoea
- wheeze
may have:
- low grade fever
- wheeze
How is acute bronchitis usually diagnosed?
Clinical diagnosis
What test can be done to guide whether antibiotic therapy is indicated in acute bronchitis?
CRP testing
How can acute bronchitis be differentiated from pneumonia?
- Sputum, wheeze, breathlessness –> may be absent in acute bronchitis whereas at least one tends to be present in pneumonia.
- Focal chest signs (e.g. dullness to percussion, crepitations, bronchial breathing) –> typically absent in acute bronchitis, present in pneumonia.
- Systemic symptoms (e.g. malaise, myalgia, and fever) –> may be absent in acute bronchitis, whereas they tend to be present in pneumonia.
Management of acute bronchitis?
Mainly supportive:
- analgesia
- good fluid intake
When should Abx therapy be considered in acute bronchitis?
- systemically very unwell
- have pre-existing co-morbidities
- have a CRP of 20-100mg/L (offer delayed prescription) or a CRP >100mg/L (offer antibiotics immediately)
What Abx is 1st line in acute bronchitis?
Doxycycline
Prognosis of acute bronchitis?
The disease course usually resolves before 3 weeks, however, 25% of patients will still have a cough beyond this time.
What age children are at risk of pneumonia?
<5
What are the 5 ‘typical’ causes of bacterial pneumonia?
1) Strep. pneumoniae
2) H. influenzae
3) Staph. aureus
4) Klebsiella pneumoniae
5) Pseudomonas aeruginosa
Which organism typically causes pneumonia in COPD patients?
H. influenzae
Which organism typically causes pneumonia post-influenza?
Staph. aureus
Which organism typically causes pneumonia in alcoholics & those with impaired swallowing?
Klebsiella pneumoniae
Which organism typically causes pneumonia in patients with CF or immunocompromised states?
Pseudomonas aeruginosa:
What are the 4 ‘atypical’ pneumonia?
1) Mycoplasma pneumoniae
2) Chlamydophila psittaci
3) Legionella pneumophila
4) Coxiella burnetii (causes Q fever)
Which pneumonia is seen following exposure to birds?
Chlamydophila pneumoniae
Which pneumonia is seen in IVDU?
Staph. aureus
Which pneumonia is associated with contaminated water sources?
Legionella pneumophila
What is the most common viral cause of pneumonia?
Influenza virus
Define ventilator-associated pneumonia (VAP)
pneumonia that develops ≥48 hours after endotracheal intubation
How is CURB-65 score used to determine hospital admission?
Home-based care for patients with a CRB65 score of 0 or 1
Consider hospital-based care for patients with a CURB65 score of 2 or more
What investigation is recommended in pneumonia to help guide Abx use?
CRP test:
- CRP < 20 mg/L - do not routinely offer antibiotic therapy
- CRP 20 - 100 mg/L - consider a delayed antibiotic prescription
- CRP > 100 mg/L - offer antibiotic therapy
Investigations in pneumonia?
1) CXR
2) blood and sputum cultures, pneumococcal and legionella urinary antigen tests (in intermediate or high-risk patient)
3) CRP monitoring
What 2 atypical pneumonia are tested for using urine antigen tests?
1) pneumococcal
2) legionella
What Abx is 1st line for low-severity community acquired pneumonia?
Amoxicillin (5 day course)
If penicillin allergic –> a macrolide or tetracycline
1st line Abx for moderate and high-severity CAP?
Dual antibiotic therapy –> amoxicillin and a macrolide (7-10 day course).
Pneumothorax can be classified into spontaneous, traumatic or iatrogenic.
What can spontaneous be further categorised into?
1ary –> no underlying pulmonary disease
2ary –> underlying disease e.g. COPD, CF
What investigation is diagnostic for a pneumothorax?
CXR –> visceral pleural lines or absence of lung markings peripherally.
What type of patients do 1ary spontaneous pneumothoraces typically occur in?
Tall, lean males.
What are 1ary spontaneous pneumothoraces typically linked to?
Subpleural bleb rupture (this is an anatomical lung defect).
What are some pre-existing lung diseases that can predispose to pneumothorax? (5)
1) COPD
2) Asthma
3) CF
4) Lung cancer
5) PCP
What are 2 connective tissue diseases that can predispose to pneumothorax?
1) Marfan’s
2) RA
Give some risk factors for pneumothorax
1) tall, lean males
2) pre-existing lung disease
3) connective tissue disease
4) ventilation, including non-invasive ventilation
What is catamenial pneumothorax?
Recurrent spontaneous pneumothorax occurrig within 72 hours before or after onset of menstruation.
It is thought to be caused by endometriosis within the thorax.
What is a tension pneumothorax?
If the entry point of air becomes a one-way valve (air enters but does not exit the pleural space).
The accumulating air compresses the mediastinum, impairing venous return to the heart, leading to a decreased cardiac output and potential circulatory collapse.
Pathophysiology of a pneumothorax?
Normally the pleural space has a slightly negative pressure relative to atmospheric pressure –> ensures the lungs remain inflated against the chest wall.
1) Breach in integrity of lung or chest wall –> air enters pleural space –> disrupts the normal pressure gradient
2) Air accumulates –> intrapleural pressure becomes progressively more positive relative to the lung’s intrinsic pressure.
3) Affected lung starts to collapse due to its natural elastic recoil –> reduction in the lung volume on the affected side.
What is a key mechanism of injury in a traumatic pneumothorax?
Penetrating or blunt chest trauma.
What are some causes of iatrogenic pneumothorax?
Complication of medical procedures e.g:
- thoracentesis
- central venous catheter placement
- ventilation (including non-invasive ventilation)
- lung biopsy
Clinical features of a pneumothorax?
1) Sudden onset pleuritic chest pain
2) SOB
3) Exam findings:
- diminished breath sounds
- hyper resonance on percussion
- decreased chest wall movement on affected side
4) Severe –> hypoxia, tachypnea, tachycardia, and hypotension.
Clinical features of a tension pneumothorax?
1) severe respiratory distress
2) tracheal deviation
3) jugular venous distension
4) haemodynamic instability
In cases of pneumothorax where the diagnosis is uncertain or the CXR is inconclusive, what investigation can be done?
CT scan of chest
What does mx of a 1ary pneumothorax depend on?
Size
Mx options of a 1ary pneumothorax?
1) If rim of air is <2cm AND patient is not short of breath –> consider discharge
2) Otherwise –> attempt aspiration
3) If this fails (> 2cm or still short of breath) –> chest drain
Mx of 2ary pneumothorax if rim of air is >2cm?
If patient is >50 y/o and rim of air is >2cm and/or patient is short of breath –> chest drain
Mx of 2ary pneumothorax if rim of air is 1-2cm?
1) Aspiration should be attempted.
2) If aspiration fails (ie. pneumothorax is still >1cm) –> chest drain
All patients should be admitted for 24 hours.
Mx of 2ary pneumothorax is <1cm?
Give O2 and admit for 24 hours
If a patient has a persistent air leak or insufficient lung re-expansion despite chest drain insertion, what can be considered?
Video-assisted thoracoscopic surgery (VATS) –> to allow for mechanical/chemical pleurodesis +/- bullectomy.
If a patient has recurrent pneumothoraces, what can be considered?
VATS –> to allow for mechanical/chemical pleurodesis +/- bullectomy.
Smoking advice regarding pneumothorax?
Patients should be advised to avoid smoking to reduce the risk of further episodes.
Fitness to fly following a pneumothorax?
Absolute contraindication.
Patients may travel 2 weeks after successful drainage if there is no residual air.
Can travel by air 1 week post check x-ray.
Scuba diving following a pneumothorax?
Diving should be permanently avoided unless the patient has undergone bilateral surgical pleurectomy and has normal lung function and chest CT scan postoperatively.
