Pathology of Lung Infections Flashcards
neutrophils are characteristic of what kind of inflammation
- acute inflammation
neutrophils respond to what infection
where are the neutrophils located?
- bacterial
- in alveoli
lymphocytes are characteristic of what kind of inflammation
- chronic inflammation
lymphocytes respond to what infection
where are the lymphocytes located?
- viruses
- in septae
granulomatous inflammation is in response to what
- fungi
- mycobacteria
what is a characteristic cell seen in granulomata in mycobacterial pneumonia
- langhans giant cells
bronchopneumonia pattern
- scattered foci of consolidation in either a single lobe or multiple lobes
in which patients do we normally see bronchopnuemonia
- terminally ill patients
what is lobar pneumonia
- complete consolidation of a lobe
usual etiologic agent of lobar pneumonia
- strep pneumo
pneumococcal pneumonia is caused by
- strep pneumo
composition of strep pneumo
- encapsulated
- gram +
- diplococci
strep pneumo infections are often preceded by
- viral infection that alters bronchial secretions
what pneumococcal pneumonia looks like on days 3-4
- intra-alveolar accumulation of neutrophils and erythrocytes
- red hepatization
which pneumococcal pneumonia looks like on days 5-7
- serum and fibrinous exudates
- macrophages
- gray hepatization
anaerobic bacteria are normal inhabitants of
- oral cavity
how people get anaerobic bacterial infections
- aspiration
result of actinomycetes infection
- abscesses with colonies of organisms
- sulfur granules
result of nocardia infections
- abscesses, often in immunocompromised
how do we distinguish infections from actinomyces and nocardia
- use an AFB stain
common predisposing factor for complications of bacterial pneumonias
- alcoholism
what a pyoxthorax/empyemia
- infection of pleural fluid
in which stage of TB do you see the granulomatous host response and Ghon complex
- primary TB
what is a Gohn complex
- Gohn focus + infected lymph node
what a Gohn focus
- granulomatous inflammation near fissure
what is miliary spread of TB
- TB organisms that disseminate hematogenously
why do we get hemoptysis with TB infection
- inflame response erodes into pulmonary artery
people most at risk for fungal pneumonia
- immunocompromised patients
host response for histoplasma fungal pneumonia
- granulomatous host response
detection of fungal pneumonia in tissue sections
- silver stains
where in the US do we find histoplasma
- Mississippi and Ohio river valleys
- bird droppings
where in the US do we find coccidiodes immitis
- southwestern US
- San Joaquin valley
where in the US do we find cryptococcus infections
- pigeon droppings
where in the US do we find blastomycyes dermatidiis
- mississippi, Ohio, and Missouri River basins
histoplasmosis is indistinguishable from ______ without
- TB
- silver stains or culture
3 diseases caused by aspergilla
- invasive aspergillosis
- aspergilloma (fungus ball)
- allergic bronchopulmonary aspergillosis
what happens in invasive aspergillosis
- organisms invade blood vessels
where does an aspergilloma grow
- within a preexisting cavity
blood test results in a patient with allergic bronchopulmonary aspergillosis
- eosinophils of blood and sputum
- increased serum IgE
what is useful for diagnosis in pneumocystis pneumonia
- broncho-alveolar lavage
what do you see histologically in pneumocystis pneumonia
- frothy exudation within alveolar spaces
what does CMV viral infection look like histologically
- Owl Eye bodies
- large cells with large intranuclear inclusions
3 M’s of herpes virus on histological stain
- multi-nucleation
- margination
- molding
Bacterial pneumonia patterns
(1) bronchopneumonia - patchy (focal) areas of consolidation
- virtually any bacteria capable of producing this pattern
(2) lobar pneumonia - complete consolidation of lobe
- usually s. pneumoniae
Most bacteria are normal inhabitants of the
nasopharynx and oropharynx
Bacteria reach the alveoli by
- aspiration/inhalation
- hematogenous seeding
- direct spread from adjacent site
does s. penumo have a capsule?
yes
encapsulated gram + diplococci
pneumococcal pneumonia often preceded by
viral infection
Pathology of pneumococcal pneumonia
Early (3-4 days) = red hepatization
-neutrophils come in
Later (5-7 days) = gray hepatization
-macrophages come in
anaerobic bacteria often cause
necrosis +/- abscesses
foul-smelling sputum
which bacteria RARELY cause pneumonia
filamentous bacteria
ex: actinomyces israelii & nocardia asteroides
difference between actinomyces and nocardia
actinomyces: AFB stain - (not acid fast)
nocardia: AFB stain + (acid fast)
Major pre-disposing factor for abscesses (complication of bacterial pneumonia)
alcoholism (because they have abundant anaerobic oral bacteria)
Complications of bacterial pneumonia
A = abscesses B = bacteremia P = pyothorax/empyema
Mycoplasma infection can result in
acute pneumonia
tracheo-bronchitis
mycobacterium tuberculosis (TB) radiology
gohn complex, multiple nodules, cavitites
mycobacterium tuberculosis (TB) pathology
small, acid-fast AFB
- slow growing (3-6 weeks to culture)
- AFB stains for detection in tissue sections
Primary Tuberculosis - type of inflammatory response
Granulomatous host response
When does ghon complex form
Primary Tuberculosis
Symptoms of Primary Tuberculosis
90% asymptomatic (granulomas confide the organisms)
Secondary Tuberculosis
New infection in a “previously” sensitized patient, or
“reactivation” of primary tuberculosis (from decreased immune resposne)
Granulomas in Secondary Tuberculosis
in apical/posterior upper lobes
Complications of Tuberculosis
- Miliary TB
- Hemoptysis
- Broncho-plural fistula
- Cavity –> home for future aspergilloma
Fungal pneumonia host response
Granulomatous host response
