Pneumonia Flashcards
What is pneumonia? What are the 4 types?
Acute lower respiratory tract infection causing inflammation of lung alveoli .
- CAP - primary or secondary to underlying disease
- HAP - hospital acquired pneumonia - >48hr after admission
- Aspiration - happens to people with stroke, myasthenia, bulbar palsies, reduced consciousness, oesophageal disease, or poor dental hygiene.
- Immunocompromised patient
Histologically there is bronchopneumonia and lobar pneumonia.
How do you confirm and diagose a pneumonia?
X Ray - must have consolidation
List the typical and atypical organisms causing community acquired pneumonia.
Typical (85%): streptococcus pneumoniae, haemophilus influenzae
Atypical(15%): legionella, mycoplasma, coxiella, chlamydia.
Viruses account for up to 15%. Flu may be complicated by community-acquired MRSA pneumonia.
What are the causes of hospital acquired pneumonia?
Most commonly gram -ve enterobacteria or staph. aureus. Also pseudomonas, klebsiella, bacteroides, and clostridia.
Which microbes most commonly cause pneumonia in immunocompromised patients?
- Strep. pneumoniae
- H. influenzae
- Staph. aureus
- M. catarrhalis
- M. pneumoniae
- Gram -ve bacilli and pneumocystis jirovecii (formerly named P carinii)
- Other fungi, viruses (CMV, HSV) and mycobacteria
What are the symptoms of pneumonia?
- Fever
- Rigors (sudden cold feeling)
- Malaise
- Anorexia
- Dyspnoea
- Cough
- Purulent sputum
- Heamoptysis
- Pleuritic pain
What are the signs associated with pneumonia?
- Pyrexia
- Cyanosis
- Confusion (can be the only sign in the elderly, may be hypothermic)
- Tachyponea
- Tachycardia
- Hypotension
- Signs of consolidation (reduced expansion, dull percussion, increased tactile vocal fremitus, bronchial breathing)
- Pleural rub
What tests would you do if you suspect pneumonia?
- Assess oxygenation: oxygen saturation, ABGs, and BP.
- Blood tests: FBC, U&E, LFT, CRP (GPs should consider a point of care CRP to guide antibiotic prescription where LRTI is suspected, NICE 2014)
- CXR: lobar or muultilobar infiltrates, cavitation, or pleural effusion
- Sputum: for microscopy and culture
- Urine: check for legionella and pneumococcal urinary antigens
- Pleural fluid: aspirate for culture
- Bronchoscopy and bronchoalveolar lavage: if the patient is immunocompromised or on ITU
How do you assess the severity of pneumonia?
- BUT this system may underscore the young so use clinical judgement. Other factors increasing risk of death: comorbidity, bilateral/multilobar. PaO2 <8kPa*
- In GP setting urea not used and a score of 2-3 definitely needs consideration of admission.*
How do you manage pneumonia?
- Antibiotics - broad spectrum initially then according to culture results
- Oxygen to keep PaO2>8kPa and/or saturation >94%
- IV fluids (anorexia, dehydration, shock)
- VTE prophylaxis
- Analgesia if pleurisy
- Follow up at 6 weeks for a CXR
What are the complications of pneumonia?
- Pleural effusion
- Empyema
- Lung abscess
- Respiratory failure
- Septicaemia
- Others: Brain abscess, pericarditis, myocarditis, cholestatic jaundice, repeat CRP and CXR in patients not improving to look for progression/complications.
Which antibiotics would you give for mild-mod CAP?
Consult the local guidelines
Amoxicillin 0.5-1g PO TDS 5 days
[penicillin allergic: clarithromycin 500mg PO BD 5 days]
Which antibiotics would you give for severe CAP?
- Co-amoxiclav 1.2g IV TDS AND
- clarithromycin 500mg PO/IV BD
Switch to oral when afebrile for 48hrs and continue for 5 days
[levofloxacin 500mg PO/IV BD 5 days]
Which antibiotics for non-severe vs severe HAP?
Non-severe:
- Doxycycline 200mg PO stat then 100mg BD 5 days
- [co-trimoxazole 1.44g PO/IV BD if allergy]
Severe:
- Co-trimoxazole 1.44g PO/IV BD 5 days OR (co-amox 1.2g IV TDS + gentamicin IV)
Which antibiotics to treat aspiration pneumonia?
Co-trimoxazole 1.44g PO/IV BD
AND metronidazole IV 500mg or 400mg PO TDS
for 7 days
Which at-risk groups should get the pneumococcal vaccine?
- All adults over 65
- Chronic heart/liver/kidney/lung conditions
- Diabetes mellitus or not well controlled diabetes
- Immunosuppressed e.g. low spleen function/AIDs/on chemotherapy or prednisolone >20mg/d
CI - pregnant/lactating/anaphylaxis to previous vaccine
Describe the type of respiratory failure you can get in pneumonia.
Type 1 - PaO2 <8kPa
Treat with high flow oxygen (60%) and transfer to ITU if it does not improve.
If rising PaCO2/worsening acidosis then consider elective ventilation
Aim to keep saturations at 94-98% and PaO2 at >8kPa
What are the causes of lung abscess ?
- Inadequately treated pneumonia
- Aspiration (e.g. alcoholism, oesophageal obstruction, bulbar pasly)
- Bronchial obstruction (tumour, foreign body)
- Pulmonary infarction
- Septic emboli (septicaeamia, right heart endocarditis, IV drug use)
- Subphrenic or hepatic abscess
What clinical features are associated with lung abscesses?
- Swinging fever
- Cough
- Purulent, foul smelling sputum
- Pleuritic chest pain
- Haemoptysis
- Malaise
- Weight loss
Look for finger clubbing, anaemia, crepitations, empyema (can develop in 20-30%)
What are the tests and treatments for lung abscesses?
BLOODS (FBC, ESR, CRP, blood cultures)
SPUTUM microscopy, culture, cytology
CXR: walled cavity, often with fluid level.
Consider bronchoscopy.
Treatment: ANTIBIOTICS (until healed at about 4-6wks), POSTURAL DRAINAGE, repeated ASPIRATION, ANTIBIOTIC instillation, SURGICAL excision.
Name some common viral pneumonias.
- Influenza
- Swine flu (H1N1)
- CMV
- Varicella zoster
- Measles
Which bacteria associated with pneumonia colonises water tanks kept t <60oC?
Legionella pneumophilia - e.g. in hotel air conditioning and hot water systems so causes outbreaks
Flu-like symptoms precede a dry cough and dyspnoea.
CXR will show BI-basal consolidation
What is the commonest chalmydial infection?
- Chlamydophilia pneumoniae causing pneumonia
- Person to person spread and BIPHASIC illness
Symptoms: pharyngitis, hoarseness, otitis, then pneumonia.
Which type of pneumonia can be acquired from parrots?
Chlamydophilia psittaci which causes psittacosis, headache, fever, dry cough, lethargy, arthralgia, anorexia, and D&V.
CXR will show patchy consolidation.
Which pneumonial bacteria occurs in epidemics about every 4 years?
Mycoplasma pneumoniae
Which pnemonial bacteria is a common causes of pneumonia in those after surgery or with CF?
Pseudomonas - common in bronchiectasis and CF, also causes HAP, particularly in ITU or after surgery.
Which rare bacteria causes a cavitating pneumonia particularly in the upper lobes and is drug resistant?
Klebsiella pneumonia
Occurs in elderly, diabetics and alcoholics.
Name two strains of avian influenza.
H5N1
H7N9
Responsible for most of human illnesses worldwide
What is the microbiological difference between typical and atypical?
Typical - have a cell wall –> treated with BETA LACTAMS (affect the cell wall PBP penicillin binding protein)
Atypical - no cell wall –> treated with MACROLIDE (affect the ribosomal RNA P site)
What is the difference between bronchopneumonia and lobar pneumonia?
Broncho - low virulence organisms in elderly, patchy consolidation
Lobar - mostly strep pneumo, affects the whole lobe
What are the stages of lobar pneumonia?
- Congestion
- Red hepatisation
- Grey hepatisation
- Resolution
Treatment for PCP?
Co-trimoxazole 960BD
2nd line: clindamycin + primiquine, IV methylpred
What is the most likely pneumonia cause in a 18yo female presenting with fever and low sats?
Streptococcus pneumoniae
What is shown?
- CXR - double heart border (‘Sail’ sign)
- Collapsed lower lobe
What % of CAP is caused by S pneumoniae?
30-50%
What are some signs of Streptococcus pneumoniae?
-
Acute onset
- Severe pneumonia
- Fever and rigors
- Lobar consolidation
- Rusty coloured sputum is characteristic of S. pnuemoniae
Why is no identification of CAP organisms usually made?
- Difficulty obtaining a good sample
- Early treatment with antibiotics is commenced
What are the causes of CAP at different ages?
- 0-1 months –> E. coli, GBS, Listeria monocytogenes
- 1-6 months –>Chlamydia trachomatis, Staphylococcus aureus, RSV
- 6 months - 5 years –> Mycoplasma pneumoniae, Influenza
- 16-30 years –> Mycoplasma pneumoniae, Streptococcus pneumoniae
What % of CAP is caused by H. influenzae?
15-35% of CAP
What organisms are responsible for cavitation?
- Staph aureus
- Klebsiella
- Haemophilus
- TB
NB: squamous cell carcinomas of the lung commonly cavitate.
What is the most likely cause of cavitation on CXR in a man with LLL pneumonia and haemoptysis?
Haemophilus influenzae is most likely
When is haemophilus influenzae pneumonia more common?
In pre-existing lung disease
What are the clinical features of legionella pneumophilia?
- Confusion
- Abdo pain
- Diarrhoea
- Lymphopaenia
- Hyponatraemia
What are the main causes of HAP?
- Enterobacteriaciae (e.g. E. coli, K. pneumoniae) – 31%
- Staphylococcus aureus – 19%
- Pseudomonas spp – 17%
- Haemophilus influenzae – 5%
- Acinetobacter baumanii – 4%
- Fungi (Candida spp) – 7%
What XR appearance does PCP cause?
Bilateral ground glass shadowing in a bat wing appearance
22yr old man on chemo for leukaemia with prolonged neutropenia and has tried several antibiotics without luck. What is the diagnosis?
Aspergillus fumigatus
