Pneumonia (Nichols) Flashcards
Basic pneumonia definition:
inflammation of lung
Almost all acute bacterial pneumonias are _______ before they become pneumonia, and may center around ____ early on
multifocal bronchitis
bronchi
Almost all acute bacterial pneumonias
are due to:
aspiration of saliva containing pathogen
note: term “apiration pneumonia” = gastroesoph contents
Infiltrate = radiologic manifestation of:
pneumonia, edema or hemorrhage –blood, pus or water
Not Specific
Consolidation = radiologic or phys exam manifestation of:
alveoli filled with blood, pus or water
(Not Specific!!)
Most types of pneumonia start with:
acute inflammation (neutrophilic infiltration)
What are characteristic of subacute bacterial pneumonia?
foamy macrophages (subacute = macrophages replacing neutrophils--garbage collectors replacing first responders-- starting about day 3)
ALVEOLAR NON-NECROTIZING
Acute Bacterial Pneumonia
Pneumococcus
Legionella
Mycoplasma
ALVEOLAR NECROTIZING
Acute Bacterial Pneumonia
Staph aureus
Pseudomonas
Klebsiella
INTERSTITIAL NON-NECROTIZING
Acute Bacterial Pneumonia
Mycoplasma
Most commonly identified agent of community-acquired pneumonia:
Who is the typical patient?
Streptococcus pneumoniae (“pneumococcus”)
older adults with smoking, COPD, alcoholism, preceding viral infection, etc.
Pneumococcus stage 1
Gross?
Micro?
day 1:
G–congestion with exudation of serous and frothy, blood-tinged fluid into alveoli
M–engorged septal capillaries, with a few erythrocytes, edema fluid and bacteria in alveoli
Pneumococcus stage 2
Gross?
Micro?
days 2-3:
G–red hepatization with drier, granular, dark red consolidation (~ liver)
M–continuing congestion, extravasation of red cells and numerous neutrophils and abundant fibrin in alveoli, infection spreading through pores of Kohn into adjacent alveoli
Pneumococcus stage 3
Gross?
Micro?
days 4-7:
G–grey hepatization with continuing consolidation, but color change to grey
M–degenerating dead cells (neuts, RBC, sloughed pneumocytes and bacteria) in the alveoli; fibrin nets extending through pores of Kohn; foamy macrophages replace neutrophils
Pneumococcus stage 4
Gross?
day 8 and following: slimy yellowish exudate, resolution without scarring
Pneumococcus symptoms?
fever
cough productive of purulent, blood-tinged (“rusty”) sputum
Pneumococcus signs?
fever, tachypnea, pulmonary rales and tubular breath sounds, dullness to percussion
Pneumococcus CXR
Rare?
Common?
lobar alveolar consolidation with air bronchograms (rare)
segmental or subsegmental alveolar infiltrates without air bronchograms (common)
Pneumococcus diagnostic test results?
G+ sputum with lancet-shaped encapsulated diplococci
Urine antigen test
STAPHYLOCOCCUS AUREUS PNEUMONIA
Gross pathology?
heavy plum-colored lungs
>exude bloody fluid on sectioning
>develop numerous small abscesses
STAPHYLOCOCCUS AUREUS PNEUMONIA
Micro pathology?
- aggregates of bacteria
- acute bronchitis (necrotizing)
- alveolitis and bronchiolitis + abundant degenerating neutrophils, fibrin, edema fluid, hemorrhage and evolving abscesses
(“a b” x3)
STAPHYLOCOCCUS AUREUS PNEUMONIA
CXR?
areas of alveolar consolidation in a bronchopneumonia pattern
more commonly than other acute pn: severe, bilateral, abscesses, pleural effusions
Staph aureus pneumonia is characteristically:
abscessing
When is a lung abscess drained?
it isn’t, unless it becomes an empyema
How do you isolate Staph aureus cultures?
primarily seen in stains of microbiology laboratory cultures
NOT clinical specimens of pus, sputum, etc.
Where would you find legionella?
hide inside amoebae in warm water
water heaters, shower heads, air conditioners…
LEGIONELLA PNEUMONIA
gross?
bulging firm red or tan areas of consolidation
LEGIONELLA PNEUMONIA
micro?
- acute non-necrotizing alveolitis
- early infiltration by numerous macrophages + neutrophils
(once subacute > all macrophages)
LEGIONELLA PNEUMONIA
symptoms?
cough high fever, chills, rigors dyspnea headache diarrhea confusion myalgia CP
LEGIONELLA PNEUMONIA
signs?
pulmonary rales, relative bradycardia
LEGIONELLA PNEUMONIA
CXR?
initially unilateral bronchopneumonic (alveolar) infiltrate
progresses (in 50%) to pleural effusion
LEGIONELLA PNEUMONIA
high yield dx tests?
urine antigen CBC: leukocytosis, thrombocytopenia Urinalysis: hyponatremia, azotemia, liver dysfunction (must culture on special charcoal medium)
What are the 3 legionella tip-off?
diarrhea, confusion, hyponatremia
PSEUDOMONAS AERUGINOSA PNEUMONIA
gross?
firm red areas of hemorrhagic consolidation
+/- yellow areas of consolidation with a rim of hemorrhage (target lesions)
PSEUDOMONAS AERUGINOSA PNEUMONIA
micro?
> acute necrotizing alveolitis
>Pseudomonas vasculitis (bac invading blood vessels from the adventitia) with associated infarction/hemorrhage