Lec 9 Pneumonia Pathology Flashcards
Bronchopneumonia: what do you see in image
image: patchy consolidation of lung centered on bronchi
Lobar pneumonia: what distinguishes it?
- affects entire lung lobe
- associated with increased virulence of organism or most host vulnerability [infants, elderly]
What do you see on histology with bacterial pneumonia?
neutrophils in bronchi, bronchioles, and adjacent alveolar spaces
Can you tell which bacteria just from histology image?
Not reallly
staph aureus = really virulent so more likely to cause hemorrhage
pseudomonas = likes to hang out around RBCs + invade blood vessel wall
What puts you at risk for community acquired pneumonia?
usually baceteria or virus
- Extremes of age
- Chronic diseases (congestive heart failure, COPD, and diabetes)
- Congenital or acquired immune deficiencies
- Decreased or absent splenic function (sickle cell disease or post splenectomy
WHat is major cause of community acquired pneumonia?
strep pneumo = 80-90%
Who is at risk for nosocomial pneumonia?
- pt with severe underlying disease
on mechanical ventilater
What bugs cause nosocomial pneumonia?
staph aureus
pseudomonas
other gram neg rods [klebsiella, legionella]
EColi
What bugs cause community acquired pneumonia?
- stre pneumo
- H influenza
- klebsiella, legionella
- staph aureus
What are potential outcomes of bacterial pneumonia?
- resolution
- pleural effusion
- empyema
- fibrosis
- abcess
- bacteremia
What is a lung abscess? what causes it?
localized collection of pus within parenchyma
cause: 2ndary to bacterial or fungal infection; bronchila obstruction; septic emboli; aspiration
What are symptoms of lung abscess
cough, fever, foul-smelling sputum, fever, chest pain, weight loss
What is treatment of lung abscess?
need to resect
What is atypical pneumonia? most common causes?
pneumonia without alveolar exudate
largely confined to alveolar septa and pulmonary interstitium
lymphocytic infiltrate in interstitium rather than neutrophils in air spaces [as in typical]
see patchy inflammatory changes in lungs
most commonly due to mycoplasma, viruses
What is morphology of atypical pneumonia?
- predominant in interstitium
- localized within walls of alveoli
- widened septa filled with inflammatory infiltrate of lymphocytes and occassionally plasma cells
intra-alveolar neutrophils generally absent
What type of viral infections involve lung?
- cytomegalovirus
- herpesvirus
- adenovirus
- influenza
What pts generally get viral pneumonia?
pts who are immune compromised by
- AIDS
- chemo
- transplant
what does CMV infection look like
intranuclear and intracytoplasmic inclusions
big cell [meGALO] with huge dark nucleus from intranuclear inclusion
KNOW THIS
What does herpes infection look like?
ulcerative process involving airways
multi-nucleated big cells with intranuclear inclusions [not intracellular]
nuclei tend to mold together = pomegranite appearance
KNOW THIS
What does adenovirus infection look like?
single large intranuclear inclusion = “smudge cell”
tend not to form big pneumocytes like the others
no intracytoplasmic inclusions
What does primary TB infection look like?
caseating/necrotizing granuloma
What is ghon complex?
primary pulm granuloma [usually above or below interlobar fissure PLUS involvement of hilar lymph nodes
Where does secondary TB usually involve?
lung apex
How does miliary TB look?
multiple small granulomas in lungs
can spread to other organs due to lymphatic and hematogenous spread
Who gets MAI?
pts with HIV/immune compromised
pts with right/middle lobe syndrome
What happens in MAI with immune compromised
potential findings:
granulomas
big sheets of histiocytes
“mycobacterial pseudotumor”
How does right middle lobe syndrome make you at risk for MAI
happens in pts with bronchiectasis of right middle lobe; have difficulty clearing secretions
What are features of histoplasma capsulatum?
Small spores (2-5 mu) = same size as RBC
Unequal narrow budding = looks like bowling pins
Intra- or extracellular
Best seen by silver impregnation (GMS)
How does histoplasmosis present?
similar to TB
get disseminated in immune compromised
What location should you think for histoplasmosis?
mississipi and ohio river valleys
also caribbean, asia
What do histoplasmosis granulomas look like on H & E?
fibrotic rim
well circumscribed granulomas
What location associated with coccidioides?
arizona, san joaquin valley
What are features of coccidioides on stain?
- similar to histo = coin lesion [large granuloma looks like coin], large fibrotic granuloma with central necrosis
large organisms much bigger than RBC
thick walled spherules with lots of endospores
see on H&E but better with GBS or PAS stain
What location associated wtih blastomycosis?
deep south – louisiana or mississipi
What presentation of blastomycosis?
skin/pulmonary disease
large granulomas with central necrosis containing large numbers of neutrophils in the middle of granulomas
What are features of blastomycosis?
- big organism
- broad base budding
- granuloma with central necrosis containing neutrophils
What are features of aspergillus?
- fungal hyphae, septate, narrow angle branching (40-60 degrees)
- mostly visible with H&E but best with GMS silver stains
What are non-invasive vs invasive aspergillosis?
non-invasive = fungal ball in body cavity
invasive = in immune compromised, goes into blood vessels get hemorrhage, infarction
What are two diseease presentations of cryptococcus?
meningitis
pulmonary
What happens in pulmonary cryptococcus?
- occurs in both immune competent and compromised
see more frequently in immune suppressed, malignancy, DM
most pts are asymptomatic
What are features of cryptococcus?
- big range of sizes; oval to elliptical
- may have discernible halo on H&E
- narrow based budding
capsule hilighted by muccarmine, DPAS, alcian blue
How can cryptococcus look?
- granulomas
- fibroinflammatory mass with histiocytes
- mucoid pneumonia
What do we see in pneumocystis jiroveci?
- pneumocystis filling alveolar spaces with pink foamy material
diagnose by histology slides with GMS silver stain
What is morphology of PCP?
- some crescent shaped, some circles
- about same size of RBC
- dark rim with central dot
- no budding
