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)
Define lobal pneumonia
Infectious process throughout entire lobe with dense consolidation; infection spreads from alveolus –> alveolus
Define interstitial pneumonia
Inflammatory process w/in interstitial walls rather than alveolar spaces; diffuse and bilateral markings; mycoplasma and viruses
Lung pathophysiology in pneumonia
Inflammation and infection –> decreased ventilation (V/Q mismatch) which can become shunt if bad enough –> hypoxemia
When might a patient have CO2 retention?
If they already have an extremely limited reserve (healthy patients hyperventilate to get rid of excess CO2)
Symptoms of pneumonia (4)
Fever, cough (productive if bacterial but dry if viral/mycoplasm in interstitium), SOB, pleuritic chest pain
Lung exam of pneumonia
Rales and consolidation (high pitched bronchial breath sounds, tactile fremitus, egophony, whispered pectorliquoy, dullness to percussion)
Typical pneumonia description
Acute, productive cough, consolidation, increased WBC, X-ray demonstrates lobar consildation
Typical pneumonia bugs
Strep pneumoniae, hemophilus influenza, klebsiella pneumoniae, staph aureus, anaerobes
Atypical pneumonia description
Gradual presentation, non-productive cough, normal WBC, more systemic complaints
Atypical pneumonia bugs
Mycoplasma, chlamidophyla, legionella, viruses
Fungus that can cause pneumonia
Histoplasmosis, coccidiomycosis, blastomycosis, cryptococcosis, aspergillus, pneumocystis jiroveci
Histoplasmosis
Ohio River valley, dimorphic (yeast in body), can lead to granulomas, should be self-limited in healthy people
If someone has chronic lung disease, what an they get with Histoplasmosis?
Chronic pulminary histoplasmosis, which looks like tuberculosis
Coccidiomycosis
San Joaquin Valley, can cause granulomas, self-limited in healthy but disseminated in immunocompromised, can look like TB if someone has chronic pulmonary disease
Blastomycosis
Soil-dwelling, midwestern US, primary response is neutrophilic + granulomas
Acute infection of Blastomycosis?
Looks like typical pneumonia, generally self-limited unless immunocompromised
Cryptococcosis
Soil contaminated with bird droppings, cleared in healthy but pneumonia or dissemination in immunocompromised
Scary complication of cryptococcosis
Meningoencephalitis
Aspergillus
Acute angle branching, it’s everywhere so only immunocompromised patients get it
What are the complications of aspergillus
Allergic bronchopulmonary aspergillosis, aspergilloma, invasive aspergillosis, chronic necrotizing pulmonary aspergillosis
Allergic bronchopulmonary aspergillosis (ABPA)
Happens to asthmatis, organism acts as antigen causing inflammation (doesn’t invade)
Aspergilloma
Happens to people with pre-existing cavity in lungs which is colonized (ball of fungus), little tissue invasion, may be asymptomatic or with hemoptysis if it bursts
Invasive aspergillosis
Happens to people who are immunocompromised (neutropenic), invades into lung tissue
Chronic necrotizing pulmonary aspergillosis
Happens to people with underlying lung disease/mild immuncompromised, necrosis often leads to cavity formation
Pneumocystis jiroveci
Seen in immunocompromised, alveolar filling leads to hypoxemia
Compliations of pneumonia
Lung abscess (generally by bugs that cause necrosis), empyema (pneumonia extends to pleural surface causing pus in pleural space)
Why do we drain empyema?
Without you can get scarring (fibrothorax) cause antibiotics won’t go to this poorly perfused space
If community-acquired pneumonia…
Common bugs, treatment should cover these bugs: macrolide or doxycyclne OR fluroquinolone OR beta-lactam plus macrolide
If hospital-acquired pneumonia…
Could be gram-negatives or MRSA
If health-care associated pneumonia…
Could be resistant strains
What’s a type of pneumonia related to a medical device?
Ventilated-associated pneumonia
