Flashcards in Lec 7 Pneumonia Deck (78):
What is definition of pneumonia?
infection of pulmonary parenchyma
What 3 general routes to lower respiratory tract?
- inhalation of particles
- blood stream [less common]
What virulence factor for chlamydophila pneumonia?
What virulence factor for mycoplasma pneumoniae?
shear off cilia
What virulence factor for influenza virus?
reduces tracheal mucus velocity
What virulence factor for strep pneumoniae?
- produces proteases that split secretory IgA
- has capsule that inhibits phagocytosis
Which 2 types of bugs are resistance to microbicidal activity of phagocytes?
What things might cause increase volume of inoculum?
- laryngeal dysfunction
- gastric dysfunction = stomach really full + you vomit
What things can increase concentration of pathogen?
- gingival or sinus disease = source of bacteria in you
- achlorhydria [less acid in stomach that kills bacteria]
- prolonged critical illness
- breathing tube
What is morphology of strep pneumoniae?
gram positive cocci in pairs or diplococci
has polysaccharide capsule
Where does strep pneumo come from?
normally inhabits oropharynx in adults
What kind of pneumonia do you get with S. pneumonia?
- mostly lobar
- also bronchopneumonia
What is morphology of staph aureus?
gram positive cocci in clusters
What settings do you usually get staph aureus pneumonia?
- secondary complication of resp tract infection with influenza
- hospitalized immune compromised pt
- widespread dissemination through blood stream
What kind of pneumonia do you get from staph aureus?
What is morphology of hemophilus influenzae?
small coccobacillary gram negative organism
What kind of setting do you usally get H influenza pneumonia?
often colonizes nasopharynx of normal people and lower airway of pts with COPD
What is morphology of klebsiella pneumoniae?
large gram-negative bacillus
What is setting of klebsiella pneumonaie pneumonia?
often in alcoholics
found in GI tract
What bug should you think if you hear "thick blood mucoid sputum" = currant jelly sputum?
What is morphology of pseudomona aeruginosa?
gram negative bacillus
What is setting of pseudomonas aeruginosa pneumonia?
- found in environmental sources
- big problem in pts who are debilitated, hospitalized and previously treated with antibiotics
What is setting of legionella pneumophila infection?
- affects previously healthy and those with prior resp impairments
What is morphology of legionella pneumophila?
gram negative bacillus
stains very poorly so can't use conventional stani methods
What are some signs of legionella pneumophila pneumonia?
may have lots of nonrespiratory manifestations
-- GI, CNS, hepatic, renal
What is morphology of chlamydophila pneumoniae?
obligate intracellular parasite
note readily cultured
What is morphology of mycoplasma pneumoniae?
- intermediate between virus and bacteria
- no rigid cell walls
- do not need host cell to replicate
Who gets mycoplasma pneumoniae? how does it present?
happens in young adults
get walking pneumonia = chest radiograph looks much worse than clinical presentation
What is most common predisposing factor for anaerobic pneumonia?
aspiration of secretions by:
-- impaire consciousness --> coma, alcohol, seizure
-- difficulty swallowing [neuromuscular disease]
also at higher risk if poor dentition or gum disease = larger burden of organisms
Who mostly gets viral pneumonia?
What is pathology of pneumonia?
infection and inflammation of distal pulmonary parenchyma
have influx neutrophils, edema, erythrocytes,etc
What is bronchopneumonia?
distal airway inflammation and alveolar disease
spread of infection/inflammation occurs through airways
involves > 1 lobe
What are 4 major causes of bronchopneumonia?
- staph aureus [+ cluster]
- strep pneumo [+ diploccoci]
- Klebsiella [- large rod, currant]
- H influenza [- small coccobacilli]
What is lobar pneumonia?
infectious process through entire lobe of lung
appears as dense consolidation
spread from alveolus to alveolus through interalveolar pores of Kohn
What are 3 major causes of lobar pneumonia?
s. pneumoniae = most frequent [+ diplococci]
legionella [- rod poor stain]
klebsiella [- large rod, currant]
What is interstitial pneumonia?
- inflammatory process within interstitial walls rather than alveolar spaces
- diffuse patchy inflammation
- distribution > 1 lobe
What major causes for interstitial pneumonia?
- viruses [influenza, RSV, adenovirus]
What symptoms of pneumonia?
- generalized system response: fever, cough, SOB, high WBC, chest pain, tachycardia, can get hypotension/shock
- affects of lung function: decreased ventilation in affected areas, can lead to V/Q mismatch == shunt --> hypoxemia
What does pneumonia due to CO2?
don't usually have CO2 retention unless you already have limited reserve [bad COPD]
most pts with pneumonia usually have primary respiratory alkalosis = hyperventilate
What does type of cough [productive vs nonproductive] tell you about etiology?
productive = probably viral
non-productive = probably viral or mycoplasma
What info do you see on physical exam?
- tactile fremitus
- dullness to percussion
What findings on lung exam suggest opening/closing of distal air spaces
What findings on lung exam suggest consolidation?
- tactile fremitus
- dullness to percussion
What is typical pneumonia? How does it present?
- acute presentation
- productive cough
- lung exam shows consolidation
- leukocytosis with neutrophils
- lobar consolidation with air bronchograms
What bugs cause typical consolidation?
- strep pneumo
- H. influenza
- stap aureus
What is atypical pneumonia? how does it present?
- gradual presentation
- non-productive cough
- normal WBC
- systemic complaints more prominent than respiratory ones
What bugs cause atypical pneumonia?
- chalmidophyla pneumoniae
What is morphology of histoplasma capsulatum?
- dimorphic fungus = branching hyphae in soil; round or oval yeast in the body
What is setting of histoplasmosis?
- Mississipi and Ohio River valleys
- inhale spores from bird/bat droppings --> organism converts to years --> delayed hypersensitivity and granulomatous inflammation
What happens with histoplamosis in immune competent vs compromised?
competent = self-limited infection
compromised = progressive disseminated histoplasmosis
What is chronic pulmonary histoplasmosis?
chronic lung disease in pt with preexisting structural lung abnormality [ie COPD]
What is setting of coccidiodomyocosis?
"san joaquin valley fever" in california, utah, SW US
granulomatous inflammatory response
causes pneumonia and meningitis; can disseminate to bone + skin
increase rate after earthquakes b/c spores in dust thrown into air
What is morphology of coccidodes immitis?
dimorphic fungus = mycelia in soil; spherules in tissue
How does size of histoplama vs coccidioides compare to RBC
histoplama = smaller than RBC
coccidioides = much larger than RBC
What happens to coccidioidomycosis in immune competent vs compromised?
competent = self limited
compromised = hematogenous spread and disseminated disease
chronic pulm involvement can look like TB
What is setting of blastomycosis infection?
- primarily midewester + SE US and central america
- causes inflammatory lung disease; can disseminate to skin and bone
granulomatous nodules + pyogenic response
combo of macrophages and T lymphocytes and neutrophils
resembles bacterial pneumonia
What is morphology of blastomyces?
broad based budding yeast
What signs/symptoms in blastomycosis?
acute infection resembles bacterial pneumonia --> abrupt onset fever, cihlls, cough, purulent sputum
may be self limited
if impaired cellular immunity --> at risk for more severe disease
What setting of asperigullus infection?
- widespread = no specific geography
pretty much everyone is exposed; it depends on your immune system
What is morphology of aspergillus
always appears as mycelia
What is most pathologic type of aspergillus?
What is allergic bronchopulmonary aspergillosis? who gets it?
associated w/ asthma and cystic fibrosis
organism stays in airways and is an antigen rather than invasive
causes bronchiectasis and eosinophilia
What is aspergilloma? who gets it?
seen in people with preexisting lung cavity from TB or sarcoidosis
orgniasm colonizes cavity wtih little tissue invasion
clinically = hemoptysis or no symptoms
What is invasive aspergillosis? who gets it?
seen in immunocompromised and neutropenic
--> post transplant, radiation, cancer, etc
invades and spreads through lung tissue
What is chronic necrotizing pulmonary aspergillosis? who gets it?
seen in pts with underlying lung disease or mild impairment of pulmonary or systemic host defense mech [DM, corticosteroids]
indolent, localized invasion
necrosis of tissue --> cavity formation
What kind of aspergillus colonization happens in each time of persion:
- normal host
- person with previous TB
- person with chronic lung disease
- normal host --> nothing
- asthmatic or CF --> allergic bronchopulmonary aspergillosis [ABPA]
- person with previous TB --> aspergilloma
- person with chronic lung disease --> chronic necrotizing aspergillosis
- immune compromised --> invasive pulmonary aspergillosis
Who gets pneumocystis jiroveci pneumonia?
immune compromised particular cellullar immune compromised = AIDS (esp CD4 < 200)
in pt with AIDS, cancer, organ transplant, immunosuppression
What happens in pneumocystis pneumonia?
inhale it; get diffuse interstitial pneumonia
present with insidious onset fever, dyspnea
hypoxemia due to alveolar filling
What is morpholgoy of pneumocytsis jiroveci?
disc shaped yeast on methenamine silver stain
What is lung abscess?
- localized collection of pus within parenchyma
- abscess contents = primarily neutrophils
What are some complications of pneumonia?
- lung abcess
What type of bugs cause lung abscess from pneumonia?
- those that cause significant tissue necrosis
== anaerobes, staph aureus, gram negatives
What is an empyema?
pus in pleural space from pneumonia extending to pleural surface
thick/creamy or yellow fluid within plueral space and lots of leukocytes [neutrophils]
What is treatment for empyema?
drain b/c antibiotics can't reach
if dont drain can develop pleural scarring and fibrothorax
You have diagnosed an ill-appearing patient with pneumonia based on history, physical exam and chest radiograph.
A. perform bronchoscopy with biopsy and wait a few days for culture results and antibiotic sensitivity before administering antibiotics
B. empirically administer antibiotics
if you do A this process will continue and pt will get worse
What types of bugs usually hospital acquired pneumonia?
- gram negative organisms [pseudomonas, klebsiella], MRSA
What are most common community acquired causes of pneumonia?
- strep pneumo
- staph aureus
- H influenzae