Pneumonia Flashcards
Definition of pneumonia.
Inflammation of the substance of the lung.
Classifications of pneumonia.
CAP
HAP
Aspiration pneumonia
Pneumonia in the immunocompromised host
Ventilator-acquired pneumonia
Risk factors of CAP.
<16 yo and >65 yo
Co-morbidities such as HIV, DM, CKD, Malnutrition and recent viral resp infection
CF, Bronchiectasis, COPD, obstructing lesion
Smoking, alcohol, IV drug use
Immunosuppressant therapy
What is lobar pneumonia?
When the whole of one or more lobes is affected.
What is diffuse pneumonia?
When the lobules of the lung are mainly affected
What is bronchopneumonia?
When the infection is centred on the bronchi and bronchioles.
Clinical features of CAP.
Dry or productive cough, sometimes haemoptysis
Dyspnoea
Fever
Chest pain (usually pleuritic)
Extrapulmonary features
Non-specific such as recurrent falls.
CXR features of pneumonia.
Airspace opacification
Filling of the alveoli with infectious material and pus
Initially patchy
Becomes confluent as infection develops
Examination findings of pneumonia.
Dullness on percussion
Decreased breath sounds
Bronchial breath sounds
Rhonchi
Crackles, Rales
Increased vocal fremitus
Causative organisms of CAP.
S. pneumoniae
H. influenzae
Moraxella catarrhalis
Atypicals such as…
Mycoplasma pneumoniae
S. aureus
Legionella pneumophila
Chlamydophila psittaci
What are extrapulmonary features of CAP?
Myalgia, arthralgia and malaise
Myocarditis and pericarditis
Headache
Abdo pain, diarrhoea and vomiting
Hepatitis
Labial herpes simplex reactivation
Erythema multiforme
Erythema nodosum
Stevens-Johnson syndrome
In which particular causative organisms are extrapulmonary features more common?
Legionella pneumophila
Mycoplasma pneumoniae
What causative organisms is associated with the following;
Myalgia, arthralgia and malaise
Myocarditis and pericarditis
Erythema nodosum and multiforme.
Mycoplasma pneumoniae
What causative organisms is associated with the following;
Myalgia, arthralgia and malaise
Headache
Meningoencephalitis
Hepatitis
Legionella pneumophila
Which organism is associated with labial herpes simplex reactivation?
Pneumococcal pneumonia
What is the initial assessment of CAP?
Assessing the severity of the pneumonia.
Chest examination
How is the severity of pneumonia assessed?
CURB-65
Explain CURB-65
Confusion (< 8/10 score)
Urea level (> 7 mmol/l)
Resp rate (> 30 b/min)
Blood pressure (systolic < 90 mmHg, diastolic < 60 mmHg)
Age > 65
What is a mild pneumonia infection?
CURB-65 of 0-1
How should a mild pneumonia be treated?
Send back home
No need for microbiological diagnostic tests or further investigations.
Give oral amoxicillin 500mg TD
or
ora clarithromycin 500mg BD
or doxycycline 100 mg OD
for 5 days
When should a patient with pneumonia be referred to hospital?
If scoring above 1.
At the score of 1 it can still be a clinical judgment, especially if urea levels are normal.
Usually urea levels are only measured if referral to hospital.
This means that a CURB65 score of 1 might be 2.
What other markers can assess the severity of pneumonia?
CXR (more than one lobe involved)
PaO2 ( < 8kPa)
Low albumin ( < 35 g/L)
WCC ( < 4 x 10^9/L or > 20 x 10^9/L)
Positive blood culture
Co-morbidities
Absence of fever in elderly
What investigations should be done on patients requiring hospital admission?
CXR
Blood tests
Microbiological tests.
A CXR might come back normal, why should it be repeated after 2-3 days?
Because the radiological abnormalities might lag behind the clinical signs.
Should the CXR be repeated again after this?
Why/Why not?
After 6 weeks it should be repeated to rule out underlying bronchial malignancy.
What blood tests should be done in CAP?
FBC
Serum creatinine
Electrolytes
Biochemistry
CRP
Abnormal bloods in S. pneumoniae.
WCC > 15 x 5^9/L
Inflammatory markers significantly elevated;
ESR > 100 mm/h
CRP > 100mg/L
Abnormal bloods in mycoplasma.
WCC usually normal
If there is anaemia haemolysis needs to be ruled out via Coombs test and measurement of cold agglutinins.
Blood tests of Legionella.
Lymphopenia without marked leucocytosis.
Hyponatraemia
Hypoalbuminaemia
High serum levels of liver aminotransferases (hepatitis)
What other tests might be done in CAP?
Sputum culture and blood cultures
ABGs if sats less than 94%
HIV test
When should sputum cultures and blood cultures be done in CAP?
In moderate to severe CAP
Management of pneumonia CURB65 1.
(Patient has been referred to hospital due to CRB-65 score of 1)
Maybe suitable for short stay or ambulatory care.
No microbiological diagnostic testing necessary if not suspecting Mycoplasma epidemic.
Give:
Oral amoxicillin 500 mg TD
or
Oral clarithromycin 500 mg BD
or
Doxycycline 100 mg OD
Management of CAP CURB-65 = 2.
Blood cultures done
Sputum
Pneumococcal antigen if suspected clinically.
Serology or PCR if there is an epidemic.
Amoxicillin 500-1000 mg TD and clarithromycin 500 mg BD orally.
or
Doxycycline 100 mg OD
or
Levofloxacin 500 mg BD
or
Moxifloxacin 400 mg OD
Management of CRB-65 scoring 3-4 outside of hospital.
Urgent referral to hospital for assessment and admission.
Management of CURB-65 = 3-5.
Antibiotics as soon as possible.
Co-amoxiclav 1.2g TD IV and clarithromycin BD IV.
Give fluoroquinolone if legionnaire’s.
Alternatively
IV cephalosporin like ceftriaxone 2g OD and clarithromycin 500 mg BD.
IV benzylpenicillin 1.2g QD and fluoroquinolone.
ALSO
Do blood cultures, sputum, pneumococcal antigen, legionelly antigen serology and viral PCR.
Tailor treatment to results later on.
What other managements might be used in CAP?
Oxygen if desaturated
IV fluids if hypotensive
Thrombophylaxis
Physiotherapy (only if sputum retention)
Nutritional supplementation
Analgesia
When is thrombophylaxis done in CAP?
If admitted > 12h
LMW heparin and thromboembolus stockings.
Why does analgesia help a lot in CAP?
If there is pleuritic pain the patient might avoid coughing up sputum.
This can lead to sputum retention, atelectasis or secondary infection.
Prevention of pneumonia.
Stop smoking
Vaccination against influenza for risk-groups.
Over 65 and admitted with CAP should have pneumococcal vaccine before discharge from hospital.
Complications of pneumonia.
Resp failure
Sepsis
Pleural effusion
Empyema
Lung abscess
Organising pneumonia
How common is pleural effusion in CAP?
Around one-third to one-half of cases.
The majority of them are simple exudative effusions.
What is empyema?
Purulent fluid in the pleural space.
A fate worse than pleural effusion.
What are early indications of empyema?
Ongoing fever and rising or persistently elevated inflammatory markers despite antibiotics.
Investigations in pleural effusion.
Pleural aspiration under ultrasound guidance to make a diagnosis and fluid sent for gram stain, culture, fluid protein, glucose and LDH.
What can be used in order to differentiate between transudate and exudate?
Light’s criteria.
What specific criteria suggests an empyema?
Exudative effusion with pleural fluid of < 7.2 pH.
Management of empyema.
Fluid should be urgently drained to prevent further complications.
Complications of empyema.
Development of a thick pleural rind or prolonged hospital admission.
Increased mortality risk.
Increased duration of abx treatment.
What might have to be done in severe cases of empyema?
Thoracic surgical intervention.
How can a lung abscess be detected?
Severe localised suppuration with cavity formation visible on CXR or CT.
Clinical features of lung abscess.
Production of large quantities of sputum which is often foul-smelling owing the growth of anaerobic bacteria.
Swinging fever, malaise and weight loss.
Usually few clinical signs, clubbing might be present if chronic.
Markers of lung abscess.
Normocytic anaemia and raised ESR/CRP.
Investigation and treatment of lung abscess.
CT
Bronchoscopy to obtain samples or remove foreign bodies.
Tx guided by culture results or clinical judgment.
Surgical drainage might be necessary.
Causes of lung abscess.
Aspiration pneumonia
TB
S. aureus and K. pneumoniae
Septic emboli
Inadequately treated CAP
Spread from amoebic liver abscess.
Foreign body
Definition of HAP.
New onset of cough with purulent sputum along with a compatible CXR demonstrating consolidation, in patients who are beyond 2 days of their initial admission or who have been in a healthcare setting within the last 3 months.
Causative organisms of HAP.
G- bacteria such as Pseudomonas, Escherichia spp, Klebsiella spp.
Anaerobic bacteria like Enterobacter spp.
S. aureus and MRSA
Acinetobacter spp.
Treatment of legionella pneumophila pneumonia.
Fluoroquinolone with clarithromycin or rifampicin if severe.
Treatment of Chlamydophila species.
Tetracycline
Treatment of HAP pneumonia such as g- bacilli, pseudomonas and anaerobes.
Aminoglycoside IV + antipseudomonal penicillin IV or 3rd generation cephalosporin IV.
Causative organisms of ventilator-associated pneumonia.
Multidrug resistant gram negative organisms such as Acinetobacter baumanii.
Explain why aspiration pneumonia might occur.
Any motor neuron disease or if swallowing is impaired (CN IX and particularly CN X).
Increases the risk of food getting down into the airways instead of oesophagus.
GORD can also cause aspiration of acid droplets, as can vomiting.
Why is vomiting very noxious in aspiration pneumonia?
It can be very severe and even fatal as there is intense destructiveness of the lung parenchyma due to gastric acid.
This can especially complicate anaesthesia.
What is Mendelson’s syndrome?
Acute chemical pneumonitis caused by aspiration of stomach contents especially in pregnancy.
What are the most common places where aspirated objects get lodged?
Right middle lobe
The apical or posterior segments of the right lower lobe.
What is persistent pneumonia commonly due to?
Anaerobes leading to lung abscess or even bronchiectasis.
Treatment of aspiration pneumonia.
Should be guided by positive cultures.
If not then co-amoxiclav.
Treatment of aspiration pneumonia in case of S. pneumoniae or anaerobe positive.
Cephalosporin and metronidazole IV.
Causative organisms of pneumonia in the immunocompromised patient.
S. pneumoniae
H. influenzae
S. aureus
M. catarrhalis
M. pneumoniae
G- bacilli
Pneumocystis jirovecii
Fungi
Viruses like CMV and HSV
Give examples of which patients might be susceptible to Pneumocystis jirovecii.
Long term corticosteroids
Monoclonal antibodies
Methotrexate
Anti-rejection medication
HIV (particular at CD4 < 200/mm3
Where is Pneumocystis jirovecii found?
In the air.
Clinical features of Pneumocystis jirovecii pneumonia.
High fever
Dypsnoea
Dry cough
Rapid desaturation on exercise and exertion
CXR features of Pneumocystis jirovecii.
Diffuse bilateral alveolar and interstitial shadowing beginning at the perihilar regions and then making its way out spreading like a butterfly.
Localised infiltration
Nodules
Caviation
Pneumothorax
Treatment of Pneumocystis jirovecii pneumonia.
Empirical treatment only if very severe in high-risk patients.
However diagnosis should be done first by indirect immunofluorescence on induced sputum or bronchoalveolar lavage fluid.
High-dose co-trimoxazole
Special features of Klebsiella pneumonia.
Causes a cavitating pneumonia particularly of the upper lobes.
Cavitating pneumonias.
S. pneumoniae can cause cavitation in children.
Mycoplasma tuberculosis
Aspergillus
S. aureus
Legionella
