Pulmonary Pathology 4 Flashcards
What are 2 ways PNA can be classified?
by clinical setting and by anatomic distribution
what are the different types of PNA based on the classification by anatomic distribution?
bronchopneumonia and lobar pna
what is bronchopneumonia?
PNA where the infection is spreading along the airways
what are the pathologic stages of lobar PNA?
congestion (1-2 days), red hepatization (2-4 days), grey hepatization (4-8 days), and resolution (1-3 weeks)
what are the complications associated with lobar PNA?
abscess, empyema, and bacteremia (sepsis)
what are the 5 organisms that cause typical CAP?
s. pneumoniae, H. influenza, s. aureus, K. pneumoniae, P. aeruginosa
what is streptococcus pneumoniae?
lancet shaped gram positive diplococci (pairs and chains); most common cause of CAP- vaccination recommended for infants, patients> 65, and in respiratory disease/smoking
what is h. influenza?
gram negative, causes virulent PNA in children; recommended vaccination for type B for children 5 or younger
what is staphylococcus aureus?
abscess formation; iv drugs; gram positive
what is klebsiella pneumoniae?
alcoholics, currant jelly sputum, gram negative
what is pseudomonas aeruginosa?
gram negative, cystic fibrosis, diabetics, grapes
what are the major differences between typical and atypical bacterial CAP?
typical is more abrupt onset, respiratory symptoms predominate, consolidation on CXR, older adults or young children; atypical PNA is slower onset, systemic symptoms predominate, patchy infiltrates on CXR and young adults/teens
what are the 4 most likely organisms to cause atypical PNA?
myocoplasma PNA, legionella pneumophilia, chlamydia pneumonia, chlamydia psittaci
why is myocoplasm pneumoniae likely to cause atypical pna?
it is the smallest free living, self-replicating microorganism; no cell wall- it can just travel along the airways unchecked
what is legionalla pneumophila?
gram negative bacillus; grows in warm fresh water; AC units, hot tubs; airborne disease–> outbreaks
what 4 things cause community acquired viral PNA?
influenza (H1N1) 2) SARS 3) COVID-19 4) RSV
what are the 4 radiographic features of viral PNA?
more likely to be multilobar in distribution, follows an airway pattern- bronchocentric
how does the histology of bacterial PNA differ from the histology of viral PNA?
bacterial infiltrates in the alveolar spaces; viral PNA infiltrates in the interstitium
how is the influenza virus classified?
by 2 proteins–> hemagluttanin and neurominidase
difference between an antigenic shift and an antigenic drift?
antigenic drift: causes epidemics, minor changes to proteins; antigenic shift: causes pandemics, genomic alterations with major resulting changes to protein structures
what is normally the source of antigenic shifts?
animal reservoirs
what is the most direct route to viral proteins?
ss RNA (+)
COVID-19 has a tropism for what?
ACE 2 receptors in the respiratory epithelium
entry of sars-cov 2 initiates what?
a response that involves a cytokine storm, which leads to ARDS and DAD
what is happening in the circulation of COVID-19 patients?
there’s coagulation–> megakaryocytes enter the circulation
neonates are at risk of PNA due to what organisms?
1) group B strep 2) gram negative bacilli 3) listeria
children greater than 1 month old are at risk of developing PNA from what viral thing?
respiratory syncytial virus, parainfluenza virus, influenza A and B, adenovirus, rhinovirus
children greater than 1 month old are at risk of developing PNA from what bacterial organisms?
s. pneumoniae, H. influenza, M. catarrhalis, s. aureus
older children/adolescents have additional concern for which bacterial PNAs?
M. pneumoniae and C. pneumoniae
what is respiratory syncytial virus (RSV)?
paramyxovirus; the babies are having an accumulation of mucus in their bronchial airways and as the viral infection progresses it is inflamming their bronchial wall and thickening it
besides RSV, what are 3 other examples of paramyxoviridae?
human metapneumovirus, parainfluenza, measles
bacterial infections are not typically associated with epidemics; what is the exception to this?
legionella and pertussis
how does bacterial pna sound on auscultation?
crackles on lung exam
how does viral pna sound on auscultation?
wheezes
which type of pna typically involves the pleura?
bacterial
what is a complication of PNA specifically staph aureus and klebsiella?
lung abscess
what type of pna is at risk for lung abscess?
aspiration
which bacteria are more likely to cause aspiration pna?
anaerobic bacteria
what is the ghon complex?
the parenchymal area that is caseating granulomatous infectious focus and a hilar lymph node
what do you do if you see a granuloma?
you are going to put an acid fast stain on it–> tb shows tuberculosis
what is the outcome of a primary complex of tb?
it can become a healed infection, it can become a latent lesion, which can then progress to secondary tb, or it can become progressive primary tb which leads to miliary tb
what is chronic PNA?
pneumonia lasting for months in an immunocompetent patient
what are the most common causes of fungal chronic PNA?
histoplasma, blastomycosis, and coccidiomycosis
where is histoplasma endemic to?
midwest and caribbean
how does histoplasma present?
subclinical infection with granulomatous response (calcifications or coin lesions on CXR)
if you do a silver stain on histoplasma, what would it look like?
pumpkin seeds
where is blastomyces endemic to?
central and SE US
what are the histologic features of blastomyces?
broad-based budding
where is coccidiodes endemic to?
endemic in southwestern US
how does coccidiodes present?
infection yields a granulomatous response with eosinophils; often a subclinical self-limited disease; spherials containing the endospores
what is pneumocystis jiroveci and how does it look?
opportunistic fungal infection; aids defining illness; cup-shaped yeast forms
what is cytomegalovirus?
opportunistic viral infection; aids defining illness; big cell virus
what is mycobacterium avium complex?
thin mycobacteria seen as slender red forms on acid-fast staining
what does lung transplant rejection show?
mononuclear infiltrates around vessels
