Pneumonia Flashcards
define pneumonia?
(+ clinical definition?)
inflammation of lung parenchyma distal to the terminal bronchioles, which includes the respiratory bronchioles, alveolar ducts, and alveoli
LRTI Sx
+ focal Sx (crackles), systemic Sx (fever) OR {unexplained CXR shadowing}
what is a chest infection?
- non-specific term for LRTIs
- tends to be used for milder presentations – i.e. acute bronchitis – rather than pneumonia
- acute bronchitis +/- productive cough and fever, but no focal chest signs and CXR is clear
- unlike pneumonia, Abx not routinely indicated
common causes CAP?
ordered from most to least likely
• BACTERIA
- Strep. pneumoniae (50)
- H. influenzae (7)
- Staph. aureus (2)
- Moraxella catarrhalis (2)
• ‘ATYPICALS’:
- Chlamydophila pneumoniae (10)
- Mycoplasma pneumoniae (5-15)
- Legionella pneumophila (3)
• VIRAL:
- COVID :(
- influenza A+B
- RSV
• IMMUNO↓:
- Pneumocystis jirovecii (Pneumocystis pneumonia, PCP)
- CMV
definition and causes of HAP?
• develops >48h post-admission
• pathogens similar to CAP in the first 4 days
• later
- Gram -ve enterobacteria (Klebsiella, E. coli)
- Staph. aureus (inc. MRSA)
- Legionella
- Pseudomonas
causes aspiration pneumonia? bugs?
- NM (stroke, myasthenia gravis)
- ↓consciousness (anaesthesia, alcohol intoxication)
• similar to HAP
- Klebsiella in alcoholism
- anaerobes like Peptostreptococcus, Fusobacterium, and Prevotella
Commonly affects right lower lobe**
causes and clinical picture of atypical pneumonia?
- either bugs that aren’t common, or bugs that can’t be gram stained (Mycoplasma, Chlamydophila)
- generally “walking well” (mild clinical picture, but mostly in M+C)
- also caused by Legionella from stagnant water, and that can be nasty
Sx + Ex to expect in pneumonia?
- SOB
- cough with purulent sputum +/- possibly blood
- pleuritic pain
- fever, malaise
- cyanosis, confusion
- ↑RR, ↑HR, AF
- consolidation leads to dull percussion
- ↑vocal resonance (VR)
- bronchial breathing (i.e. ↑breath sounds, BS)
- **both pneumonia and effusion cause dull percussion, but pneumonia is noisy (↑VR, ↑BS) while effusion goes shhh (↓VR, ↓BS).
what may cause a lobar pneumonia with rusty sputum, 10 percent have oral herpes?
Strep. pneumo
cause more common in COPD patients?
H. influenzae and Moraxella
cause if it may be bilateral, and can occur post-influenza?
S. aureus
persistent dry cough, mild fever, malaise, headache, and myalgia, but usually self-resolves over weeks?
(peaks in 4-yearly epidemics)
immunological complications include erythema multiforme and haemolytic anaemia
Mycoplasma pneumo (atypical)
gradual onset, initial pharyngitis/URTI symptoms, and headache. Usually self-resolves, but may take months?
Chlamydophila pneumo (atypical)
flu-like prodrome followed by cough (dry then productive or bloody), SOB, + D,V. Bilateral in severe cases?
Legionella
“Pontiac fever” is infection without lung involvement
dry cough, bilateral pneumonia, desaturation on exertion, HIV+?
PCP
“currant jelly sputum”?
Klebsiella
acquired from sheep and other farm animals. Part of Q fever, which includes flu-like symptoms, hepatitis, and endocarditis?
Coxiella burnetii
acquired from birds. Causes fever, dry cough, headache, splenomegaly, and arthritis?
Chlamydophila psittaci
“P”igeon = “P”sittaci
Ix pneumonia?
• CURB-65 to score severity. 1 for each of:
- Confusion: abbreviated mental test ≤8 or disoriented
- Urea >7 (in the community, this is optional, use CRB-65 instead)
- RR ≥30
- BP: SBP <90 or DBP ≤60
- Age ≥65
0-1 is mild
2 may require hospitalisation
≥3 is severe and may require ITU
How to Ix/Tx a mild CAP in the community?
- 70 percent of patients with mild CAP are managed in the community
- they require few, if any, Ix beyond obs
- if the diagnosis is unclear, get a CRP
- **Diagnose pneumonia and give Abx if CRP >100 mg/L. Consider diagnosis if CRP 20-100.
inpatient Ix of pneumonia?
BEDSIDE
• O2 sats. ABG if <92% or severely unwell
• ECG if tachy
• Sputum culture
• Strep. pneumo and Legionella urine antigen tests. 75 percent sensitive
BLOODS • FBC • U+E (Legionella ↑urea and ↑creatinine, ↓Na+ due to SIADH) (Mycoplasma: ↓Na+) • LFT (↑LFTs commoner in Legionella) • CRP (↑↑CRP suggests Strep. pneumo) • blood culture • Mycoplasma - +ve cold agglutinin test
IMAGING
• CXR (also arrange follow up CXR 6 weeks later to check if clear and rule out underlying lung disease)
• High-res CT for PCP may show ground glass opacities
Tx CAP?
• Mild-moderate: amoxicillin PO
- Clarithromycin or doxycycline if allergic
- Clarithromycin if atypical suspected (monotherapy if mild, added to amoxicillin if moderate)
• Severe: co-amoxiclav, cefuroxime, or cefotaxime IV (or levofloxacin if allergic), plus clarithromycin IV
- If hospitalised, start within 4 hours
- Monitor response to treatment with CRP
Tx HAP?
- piperacillin/tazobactam, 3rd generation cephalosporin, meropenem, or levofloxacin IV
- Co-amoxiclav is a PO alternative or stepdown
- Add vancomycin or teicoplanin or linezolid if MRSA suspected
Tx aspiration pneumonia?
• clindamycin, levofloxacin, or piperacillin/tazobactam
Tx PCP?
- co-trimoxazole
* add steroids if moderate or severe: prednisolone PO or hydrocortisone IV
