Pneumonia - Features + Treatment Flashcards
Who does pneumonia primarily affect?
Young children, elderly and immunocompromised
What is the most common (bacterial cause) of pneumonia?
Streptococcus pneumoniae (30%)
What are the leading respiratory virus causes of pneumonia?
RSV, rhinovirus, influenza (30%)
What are 4 other bacterial causes of pneumonia?
- Haemophilius influenzae
- Staphylococcus aureus
- Klebsiella pneumoniae
- Pneumocystis jirovecii
Describe the aetiology (spread) of pneumonia?
- Nasopharyngeal aspiration → normal ecological niche = nasopharynx
- Droplet spread
- Inhalation of airborne microorganisms → spore format e.g. aspergillus
- Haematogenous spread
Describe the action of cells in the respiratory immune system
1) Mucociliary clearance → entrapment in mucus, ciliary escalator
2) Alveolar macrophages → phagocytosis, inflammation
3) Neutrophils → phagocytosis (but can reach phagocytosis capacity)
4) Complement and antibodies → opsonisation, agglutination
5) Lymphocytes → inflammation, activation of other immune cells
What is the pathophysiology of pneumonia?
1) Alveoli fill with pus (can see on x ray or CT)
2) Impaired gas exchange → by pathogen and infiltrates from blood
3) SIRS → systemic inflammatory response, sepsis
4) Bacteraemia
What causes congestion?
Vascular engorgement, intra-alveolar fluid
What is red hepatisation?
When there is exudation of red cells, neutrophils and fibrin in the alveoli (precedes grey hepatisation)
What is grey hepatisation?
Disintegration of RBCs, persisting inflammatory cells leaving a fibrinosuppurative exudate in the alveoli
Do lungs normally scar due to pneumonia?
No
What are the (non-specific) symptoms of the infection?
- Dyspnoea
- Cough
- Sputum ± purulence (inflammatory infiltrate)
- Fever (cytokines)
Why is there not much pain in pneumonia?
Bc there is not much nerve supply to the lung itself
What are the signs of infection?
- Tachypnoea
- Tachycardia
- Hypotension
- Pyrexia (fever)
- Crackles
- Whispering pectoriloquy
- Increased tactile fremitus
- Increased vocal resonance
- Central cyanosis
- Altered mental status
What investigations would you do to determine pneumonia?
- ABG (if hypoxic bc checking for type 2 respiratory failure)
- CXR
- FBC
- U&E, CRP, LFT
- Blood and sputum cultures
- Viral PCR
- Atypical serology
- Urine Ag for legionella and S. Pneumoniae (useful if positive)
What is whispering pectoriloquy?
When as the consolidated lung has better sound transfer, what sounds like upper respiratory sounds might be at the bottom
What is atypical serology useful for?
Tells us what has caused the pneumonia (more useful for epidemiology than acutely)
What are the urine Ag for legionella and S. Pneumoniae useful for?
To find out the bacteria to be able to narrow down the spectrum of antibody (initially given broad spectrum)
What does consolidation of the (right) middle lobe normally obscure?
The heart
What does consolidation of the (right) lower lobe usually obscure?
The diaphragm
Where is right upper lobe consolidation located?
Above the horizontal fissure
What does left lingula consolidation obscure?
The left heart border
Which consolidation can be difficult to see with a CXR and why? (But can see with CT)
(Left) lower lobe as it is behind the diaphragm
Why might you want to follow up after consolidation CXR?
To check it’s not lung cancer
What is patchy consolidation called?
Diffuse bronchocentric consolidation
What is the scoring system used for CAP?
CURB65
What does CURB65 tell us?
It predicts mortality and tells us which patients need to be in hospital/ICU/GP/home
What are the 5 parts of the CURB65 score?
1) Confusion → AMTS ≤ 8
2) Serum urea > 7mmol/L
3) RR ≥ 30
4) Systolic BP < 90 or diastolic BP ≤ 60mmHg (evidence of sepsis?)
5) Age ≥ 65
How does the CURB65 scoring system work?
1 point for each feature
What would you do with a CURB65 score of 0?
Oral antibiotics at home → however, if patient has hypoxia and low sats, don’t send home (just a guideline)
What would you do with a CURB65 score of 1?
Consider hospital admission
What would you do with a CURB65 score of 2?
Consider IV antibiotics
What would you do with a CURB65 score of 3?
Consider ICU admission
How do you manage pneumonia (ABCDE)?
A - ensure patent airway
B - oxygen to maintain desired saturation (94-98%) or mechanical ventilation (in patient with COPD or other factors)
C - IV fluids if required → inotropes, haemofiltration (kidney support - ICU)
D - GCS (confusion)
E - analgesia, antipyretics
ANTIBIOTICS
Describe antibiotic treatment in pneumonia
- Within 4 hours
- Empirical (and broad spectrum in pt unwell) at initiation, then narrow if specific organism cultured
- OP → penicillin derivative bc cover strep pneumo and others
- IP moderate severity → penicillin derivative + macrolide (some are resistant)
- IP severe → IV beta-lactamase resistant antibiotics (co-amoxiclav or cephalosporin) + macrolide
How would you diagnose viral pneumonia?
- Cytology → intranuclear or cytoplasmic inclusion bodies
- Viral cultures
- PCR → for nasopharyngeal aspirates
- Rapid Ag detection
- Serology
How do you management viral pneumonia?
Largely supportive, not v much evidence for anti-virals but give them for some viruses
What medications are used to treat viral pneumonia linked to influenza?
- Amantadine → slightly reduces URT symptoms and myalgia
- Oseltamivir → to prevent spread of flu rather than to treat patient
- Zanamivir
What medications are used to treat viral pneumonia linked to RSV?
Ribavarin
What medications are used to treat viral pneumonia linked to HSV or VSV?
Aciclovir (v effective)
What are 5 examples of immunosuppressed patients?
1) Malignancy
2) Steroids
3) Asplenia
4) Diabetes
5) CKD
What are 4 differential diagnoses for pneumonia?
1) Malignancy
2) Vasculitides
3) Infarcted lung, PE
4) Pulmonary oedema
What are the complications of pneumonia (can appear even if treat if treatment is late) and describe them/their treatment?
1) Septic shock → hypotension, fever
2) Adult respiratory distress syndrome → supportive care, low pressure ventilation, ECMO
3) Parapneumonic effusion and empyema → pus or fluid pH < 7.2, intercostal drain, VATS
4) Cavitation and abscess → prolonged antibiotics (4-6 weeks response), resection
5) MI → double the rate of MI after pneumonia
What is adult respiratory distress syndrome?
Lung inflammation syndrome after systemic infection, most common = pneumonia
When should you drain fluid?
If lots of fluid, pus or acidic
What does ARDS look like on CXR?
Large white space covering almost all of one lung
What does empyema look like on a CXR?
Loculated abscess → white blob
How do you treat an abscess?
Co-amoxiclav
Describe the follow-up after pneumonia
1) Clinical review at 6 weeks (might still feel tired) → mainly want to check that CXR is better (not cancer)
2) CXR if smoker, <50, still symptomatic
How do you prevent pneumonia?
1) Vaccination
2) Prophylactic antibiotics
Describe vaccination to prevent pneumonia
1) Pneumovax → against strep pneumo, >65s are vaccinated
2) Prevenar → has an adjuvant. esp. for children <2, responsible for reduction in pneumococcal states and probably general reduction
3) Influenza vaccine
When are prophylactic antibiotics given and which ones?
1) Splenectomy → should be on penicillin life-long
2) After transplant → septrin, aciclovir and penicillin
When would you not want to identify the species causing the pneumonia?
If patient has CURB65 score of 0 → no benefit if patient will get better on their own anyway
Which antibiotic is usually used for gram negative bacteria?
Gentamicin
Which antibiotic gives a risk of C.difficile?
Ciprofloxacin
What is prodrome?
Early symptoms indicating the onset of a disease or illness
What does a prodrome in pneumonia indicate?
More likely to be flu and strep pneumo
