26 - Lower Respiratory Tract Infections Flashcards
What is pneumonia
Pneunoitis + consolidation + exudation due to infection
Respiratory symptoms of pneumonia
Cough + Pleural pain, dysponea, tachypnoea
Systemic symptoms of pneumonia
Sweating, fevers, rigors, shivers, aches and pains
Types of pneumonia
Hospital/community acquired
Atypical/typical
Hospital acquired pneumonia bacteria
Gram neg - multi drug resistant = Pseudomonas Aeruginosa = Enterobacter = Klebsiella = Moraxella catarrhalis
When do you get HAP
48-72 hours after being admitted
Predesposing factors for HAP
Abnormal conscious state, intubation, ventilation, surgery, immunosuppression
Symptoms of CAP
Sudden onset of chills –> Fever –> Pleuritic chest pain+ productive cough
Chest X-ray in CAP
Lobar consolidation (due to strep pneumonia)
Most likely cause of CAP
S. pneumoniae
ALL GRAM POS
CAP Typical pathogens
Streptococcus pneumoniae – most common Haemophilus influenzae Moraxella catarrhalis (Staphylococcus aureus post influenza) Group A streptococcus (Upper RTI) • streptococcus pyogenes ONLY GET THIS IN CAP NOT HAP
CAP Atypical pathogens
Mycoplasma pneumoniae (15-20%) Chlamydophilia pneumoniae (5%) C.psittaci (2-5%) Legionella pneumophillia (5%) Coxiella burnetii (1%) Pneumocystis carinii/PCP <1%
Mycoplasma pneumoniae
• Droplet transmission
• Epidemics
• Occurs in the young
• CXR shows patchy bilateral bronchopneumonia
o S. AUREUS causes a bilateral CAVITATING bronchopneumonia
Chlamydophila pneumoniae
- Intracellular pathogen
* Implicated as potential pathogen / co-pathogen in coronary artery disease and cerebrovascular disease
C.psittaci
• Zoonosis acquired from birds
Legionella Pneumophilia
- Preferred habitat – WARM WATER
- Large outbreaks associated with cooling towers/spas/air cond.
- History – exposure to cooling towers
Clinical features of Legionella pneumophilia
multi-system disease with confusion, muscle aches, pneumonia, renal failure, liver involvement + diarrhoea
Lab features of legionella pneumophilia
o CXR - Patchy interstitial involvement or consolidation
o Hyponatraemia often present
o Urea frequently raised
o Liver function tests abnormal
Coxiella burnetii
- Causes Q FEVER
* Transmitted via infected animals through milk, excreta
Pneumocystis carinii/PCP
- Important cause of pneumonia in the severely immunocompromised ie HIV
- Presents with non productive cough
- Treat with co trimoxazole or pentamidine by slow iv for 2-3 weeks
What is atypical pneumonia
Pneumonia not due to sprep pneumoniae
Doesn’t respond to conventional b-lactam therapy
More insidious
Difficult to culture
= Non-productive cough, fever, headache, chest x-ray more abnormal than suggested by clinical examination
inflammation restricted to alveolar septa and interstitial tissues - essentially interstitial pneumonitis
bilateral - patchy CXR
typical- unilateral
Complications of pneumonia
Pleural effusion Empyema thoracis Lung abcess = Single - psudomonas = Multiple - staphylococcus aureus
Diagnosing pneumonia
Hx + clinical
Chest examination
Sputum
Serodiagnosis
How to determine severity of pneumonia
CURB 65 score
What does CURB 65 stand for
C - confusion U - urea >7mmol R - resp rate >30 B - BP <90mmhg 65 - age >65
Treatment of mild, moderate, severe pneumonia
o Mild – amoxicillin
o Moderate – add clarithromycin
o Severe – as above + co-amoxiclav
Treatment of HAP
Tazocin
Treatment of pneumonia due to Legionella
fluoroquinolone
Tx pneumonia due to chlamydophila
tetracycline
Tx of pneumonia due to PCP
High dose co-trimoxazole
