Lecture 7: Pneumonia Flashcards
Routes to lower respiratory tract (3)
Inhalation, aspiration, bloodstream
Host defenses in lungs include…(4)
Removal of inhaled material, antimicrobial peptides, phagocytic and inflammatory cells, adaptive immune responses (humoral and cellular)
Removal of inhaled material by these three mechanism
Progressively branching airways, cough, mucociliary tract
First cellular line of defense
Pulmonary alveolar macrophages
Can viruses/bacteria affect our natural defenses?
Yes: some pathogens can damage our ciliary system, inhibit phagocytosis, damage IgA
Why would we be exposed to a large inocolum of pathogen?
Large volume due to laryngeal/gastric dysfunction or large concentration of pathogen due to gum/sinus disease, low stomach acid, prolonged illness, or being on a ventilator
Most common pneumonia bug
Streptococcus pneumoniae (50% of cases); gram positive diplococci
Virulence factor of Streptococcus pneumoniae
Polysaccharide capsule protects from phagocytosis
Another gram positive, seen in clusters. Associated with what settings?
Staphylcoccus aureus –> secondary complication of resp tract infections due to influenza and hospitalized patients
What’s a small coccbacillary gram-neg organism that can cause pneumonia. Associated with what patients?
Hemophilus influenzae; patients with COPD
Klebsiella pneumoniae associated with what two things?
Currant jelly sputum, often seen in alcoholics
Pseudomonas aeruginosa is primarily seen in patients who are…
Hospitalized, previously treated with antibiotics
Pseudomonas aeruginosa and Klebsiella pneumoniae are both (type of bacteria)
Gram-negative bacillus
Where do we find Legionella pneumophila. Can this affect healthy people? What kind of bacteria?
Cooling towers; yes; poorly staining gram-negative
What kind of bacteria is Chlamydophila pneumoniae
Obligate intracellular parasite
What is special about Mycoplasma pneumoniae and what does it cause?
Smallest living free organism; “walking pneumonia” (chest looks worse than clinical presentation)
How would we get an anerobic organism infection?
Aspiration of secretions due to impaired consciousness or difficulty swallowing
Association between viruses and pneumonia
Do not cause pneumonia very often, but influenza can cause it
Definition of pneumonia
Infection and inflammation of pulmonary parenchyma
Define bronchopneumonia
Distal airway inflammation prominent + alveolar disease with patchy distribution (S. aureus and gram negatives)