Bacterial Pneumonia Flashcards
CAP and requirements of diagnosis
Community Acquired Pneumonia
Evidence of lower respiratory tract infection (LRTI), e.g.
- Cough
- Sputum
- Breathlessness
- Chest pain
AND
CXR evidence of pneumonia
What is the likely diagnosis of this patient
Pneumonia
Risk factors of CSP
Males
Elderly
Alcoholics
Chronic Disease
Aetiology of CAP
Conventional bacteria [most common]
‘Atypical’ bacteria
Viruses
Conventional vs Non-conventional bacteria
Conventional bacteria have cell walls and thus can be treated with antibacterials that target cell walls; non-conventional bacteria do not have cell walls
Examples of bacteria that cause pneumonia
Streptococcus pneumococcus
H. influenzae
Mycoplasma pneumoniae (atypical bacteria)
Streptococcus pneumococcus
Most common cause of CAP in those without COPD
Capsular polysaccharide is the major virulence factor
Relative resistence to penicillin is becoming common
Haemophilus influenzae
The capsulated bacteria is primary cause of CAP in children who have not received Haemophilus vaccination
Non-capsulated H. influenza is an important cause of disease in COPD
Mycoplasma pneumoniae
Second most cause of CAP
Causes >30% of CAP in 17-44 year olds; seasonal
Can cause occasional epidemics
Has characteristic extra-pulmonary features (e.g. skin)
Legionella pneumophila
Cause of both sporadic and outbreak CAP
Can cause severe disease, especially in immunocompromised patients and smokers
Requires specific high dose fluoroquinolone or macrolide antibiotic treatment
Which serogroup of Legionella pneumophila causes almost all human infection with the disease
Serogroup 1
Investigation of CAP (Clue, 4 steps)
Confirm diagnosis (CXR)
Assess severity of disease
Define aetiological agent (respiratory sample, blood sample)
Identify complications
Microbiological Investigations of pneumonia
Sputum analysis and culture
Immunofluorescence on sputum samples
Blood Cultures
Urinary pneumococcal and legionella antigen
Antimicrobial Chemotherapy
Based on:
Assessment of likely pathogen
Severity of illness
Likelihood of drug resistance (local and national); tell the lab about how infection was acquired
CURB65 Score
Score for pneumonia severity
Confusion (MMT score 8 or less) Urea (new elevation >7 mmol/L) Respiratory rate > 30bpm BP (Systolic <90, DS <60) 65 or more years old
Low severity CAP
CURB 65 0 or 1
Oral antibiotics amoxicillin 500mgs qds for 5 days
OR
Doxycycline 200mgs loading then 100mg od
Only IV if unable to take oral therapy
If severe allergy to penicillin, ciproflaxacin (quinolone) 400mgs bd + (glycopeptide) vancomycin
These patients should be manageable in community unless frail
JESUS CHRIST DO NOT MEMORISE THIS!!! JUST BE VAGUELY AWARE
Where is the pneumonia in this patient
Right upper lobe
Moderate severity CAP
CURB 65 2
Amoxicillin 500mgs qds 7 days + clarithromycin 500mgs bd for 7 days
OR
Doxycycline 200mgs loading then 100mg od
IV only if unable to take oral treatement
Normally managed in a hospital environment
JESUS CHRIST DO NOT MEMORISE THIS!!! JUST BE VAGUELY AWARE
Severe CAP
CURB 65 3
Co-amoxiclav 1.2g tds + amoxacillin 1g tds + clarithromycin 500mgs bd iv for 10 days
If severe allergy to penicillins or MRSA
Levofloxacin 500mgs bd + vancomycin 1g bd
Severe CAP (Score >3)
Continue treatment of score = 3,
Add levofloxacin 500mgs bd for 14 days
Ensure legionella antigen in urine requested and culture sputum if possible (alert lab)
