RHS17 - Respiratory Tract Infections 6 Flashcards
List the major types of pneumonia, where those types are likely acquired, and whether they’re usually caused by bacteria or viruses
- Lobar Pneumonia - community acquired - bacteria
- Bronchial Pneumonia - nosocomial - virus
- Interstitial pneumonia - ventilator associated - causes vary
List the common bacterial and viral causes of pneumonia. Say which ones are often drug resistant or likely to be nosocomial. Say which ones cause “atypical” pneumonia
- Viral Causes - any virus that can cause a LRTI
- Bacteria
- Streptococcus pneumoniae (can be nosocomial)
- Klebsiella pneumoniae (often nosocomial)
- Psudomonas aeruginosa (often nosocomial and drug resistant)
- Mycoplasma pneumoniae (atypical)
- Legionella pneumophilia (atypical)
- Chlamydophila pneumoniae (atypical)
- Mycobacterium tuberculosis
- Haemophilus influenzae
C
What are the clinical features of “typical” community acquired pneumonia (CAP)
- Usually only inolves one lobe (lobar) with signs of consolidation over that lobe - dullness, increased fremitus/egophony/whispered pectoriloquy, bronchial breath sounds
- Acute onset fever
- Acute onset pleuritic chest pain
- Acut onset productive cough
What is streptococcus pneumoniae AKA? Give its identifying lab information.
AKA - Pneumococcus (pneumococcal pneumonia) or Diplococcus
- Gram positive diplococci
- Alpha hemolysis
- Sensitive to optochin (taxos P disk)
What clinical features would suggest a pneumonia is caused by stretococcus pneumoniae?
- Winter & Early Spring incidence
- Lobar consolidation
- Sinusitis
- Otitis media
- Rusty sputum (S. pneumoniae produces H2O2 which oxidizes iron)
Commonest cause of CAP
What are S. pneumoniae’s virulence factors?
- Capsule
- IgA protease
- Pneumolysin & Autolysin
- Inhibitis ciliated epithelium cell activity
- Binds to cholesterol in alveolar and endothelial cells and punches holes in the membrane
- Transformation - can turn normal flora S. pneumoniae into a pathogenic strain
What are the vaccines available for pneumococcal pnuemonia and when are they usually given?
- Pneumococcal Polysaccharide Vaccine (PPSV23)
- Adults >65yo
- 2-64yo for people with certain medical condition (splenectomy)
- 19-64yo smokers
- Pneumococcal Conjugate Vaccine
- <2yo
- >65
- 2-64yo for people with certain medical conditions (splenectomy)
What kind of bacteria is klebsiella pneumoniae? What are its virulence factors?
- Gram negative bacillus
- Large polysaccharide capsule (CPS/K) antigen
- LPS (O antigen)
- Impedes complement system
- Necrotization of lung tissue
- Pili (fimbriae)
- Epithelial attachment
What are the clinical features that would suggest a pneumonia was caused by Klebsiella pneumoniae?
- Thick, reddish, tenacious sputum (red currant jelly sputum)
- Foul smelling sputum/breath
- It is a bronchopneumonia
- There are lung abscesses seen on CXR
- Person is an alchoholic, has diabetes, and/or has COPD
- Person has recently been on a ventilator or has had some time of venous/arterial catheter in.
How is klebsiella transmitted
Via contact with a fomite (not through air)
What Abxs are Klebsiella pneumoniae resistant to and how?
Carbapenem
They produce carbapenemase
What kind of bacterium is pseudomonas aeruginosa? How is typically transmitted?
- Gram negative bacilli
- Obligate aerobes
- These bacteria are usually found in still fresh water sources so are usually contracted from water
What clinical features would suggest a pneumonia was caused by pseudomonas aeruginosa?
- Recent still fresh water exposure (like from scuba equipment)
- Yellow-Green mucus that may smell like grapes
- Started as Swimmer’s Ear (otitis externa not media)
- Patient has a structural defect in acquired immunity
- Burn victims
- Cystic fibrosis
- Recent ventilator use
How does atypical CAP usually present?
With milder symptoms than a typical pneumonia which appear in a more gradual way over several days to weeks
E
