9.3 Pulmonary infections Flashcards
pneumonia:
3 main patterns seen on CXR
-which are due more to virus or bacteria
- lobar–entire lobe
- bronchopneumonia–circles
- interstitial–looks like lines
lobar and broncho: bacteria
interstitial (‘atypical’): virus
Legionella
- type of pneumonia
- important associations, populations, etc
- broncho
- community acquired, superimposed on COPD, and immunosuppressed.
klebsiella pneumoniae
- type of pneumonia
- important associations, populations, etc
- lobar
- aspiration of enteric flora, so assoc with debilitated populations: nursing homes, diabetics, alcoholics. Thick ‘currant jelly’ sputum
TB:
what are 4 common organ sites for spread?
- brain (classically meningitis at base of brain)
- cervical lymph nodes
- kidney (sterile pyuria)
- lumbar vertebrae (Pott’s disease)
Ghon complex
formed from primary TB.
-a focal, caseating necrosis in the lower lobe of lung and hilar lymph nodes. becomes fibrosed and calcified.
where in lung does 2ndary TB usu occur, and why
- lung apex, b/c poor lymphatic draining and high O2 tension.
- as opposed to lower lobe Ghon complexes
TB symptoms:
- primary: asymptomatic
- secondary: fevers, night sweats, hemoptysis, weight loss
interstitial pneumonia:
- CXR
- histology
- lines on lungs on xray
- air sacs are empty, but inflammatory cells are in the interstital spaces
Aspiration pneumonia
-3 common organisms
anaerobic bacteria in the oropharynx that are aspirated
- bacteroides
- fusobacterium
- peptococcus
Classic gross phases of lobar pneumonia (4)
- congestion–congested vessels, edema
- red hepatization–from exudate of neutrophils, RBCs into air sacs. lobe becomes solid
- grey hepatization–RBCs turn grey
- resolution–Type II pneumocytes are stem cells for regeneration
mycoplasma pneumoniae
- type of pneumonia
- important associations, populations, etc
- important organism properties
- important complications
- interstitial
- military recruits, college dorm students.
(most common cause of atypical in young adults)
- not visible on gram stain–no cell wall
- -autoimmune hemolytic anemia (IgM against I antigen on RBCs causes cold hemolytic anemia)
- erythema multiforme
bronchopneumonia
-characterized by what on CXR and gross pathology
-patches of consolidation around bronchioles. often multifocal and bilateral
Aspiration pneumonia
-classic presentation
- abscess in lower right lung lobe.
- R side b/c of angle of bronchus
Pulm infections
-dx tests
- CXR
- sputum gram stain, culture
- blood culture
Pulm infections
-what are the lung’s main defenses against microbes
- cough
- mucociliary escalator
CMV
- type of pneumonia
- important associations, populations, etc
- interstitial
- common cause in posttransplant, immunosuppressed.
TB spread to kidney
-how presents?
-presents as sterile pyuria (WBC in urine, but negative culture)
caseating granuloma in lung:
- differential
- how to differentiate
- TB
- fungal
- do AFB stain (acid fast bacillus, for TB)
Elderly, immunocompromised pt with pneumonia:
think what?
influenza virus. (also, watch out for superimposed S Aureus or H influenzae pneumonia)
What 3 organisms typically cause pneumonia superimposed on COPD?
- haemophilus influenzae
- moraxella catarrhalis
- legionella
what are the #1 and #2 most common organisms that cause secondary pneumonia?
what kind of pneumonia do they present with?
- strep pneumo–lobar
- staph aureus-broncho
Haemophilus influenzae
- type of pneumonia
- important associations, populations, etc
- broncho
- common cause of 2ndary pneumonia, and pneumonia superimposed on COPD
TB: primary vs secondary TB
primary: first exposure–focal, caseating necrosis in lower lobe of lung and hilar lymph nodes, undergoes fibrosis and calcification–Ghon complex. Asymtomatic
secondary: reactivation of TB
Pt who just got a kidney transplant, gets pneumonia
think what?
CMV–for immunosuppressed
When is TB typically reactivated?
- Elderly age
- AIDS
How does interstitial pneumonia present differently from lobar or broncho?
It’s ‘atypical,’ usu viruses.
So, it’s mostly upper resp symptoms. (minimal sputum, cough, low fever)
Comatose or alcoholic pts are increased risk of what lung problem?
Aspiration pneumonia
-usu anaerobic bacteria in the oropharynx
empyema
pus in pleural space
TB meningitis
-how usu present?
-usu at base of brain
Pt with cystic fibrosis presents with pneumonia
think what?
Think Pseudomonas
coxiella burnetii
- type of pneumonia
- important associations, populations, etc
- organism details
- interstitial
- farmers, veterinarians.
- Coxiella spores are deposited on cattle by ticks, or present in cattle placenta.
coxiella burnetii
-how is it different from other Rickettsiae organisms (eg Rocky mountain, typhus)? (3 things)
- only one that causes pneumonia
- does not require arthropod vector (uses heat resistant spores that ticks can deposit on cattle)
- does not produce skin rash
Legionella
-how to visualize it
-intracellular organism. visualize with silver stain.
pseudomonas aeruginosa
- type of pneumonia
- important associations, populations, etc
- broncho
- Cystic Fibrosis!
bronchopneumonia
-list common organisms (5)
bacteria:
- staph A
- Haemophilus influenza
- Pseudomonas
- Moraxella catarrhalis
- Legionella
Atypical pneumonia:
- # 1 and #2 most common causes in young adults
- most common cause in infants
- common in post transplant immunosuppressed
- mycoplasma pneumoniae, then chlamydia pneumoniae
- RSV
- CMV
Moraxella catarrhalis
- type of pneumonia
- important associations, populations, etc
- broncho
- community-acquired, also superimposed on COPD
Q fever is caused by what?
what populations
Coxiella burnetii
- farmers, veterinarians
- Coxiella spores are on cattle or cattle placentas
Strep pneumo
- type of pneumonia
- important associations, populations, etc
- lobar
- most common causes of community-acquired pneumonia and 2ndary pneumonia. adults, elderly
Staph aureus
- type of pneumonia
- important associations, populations, etc
- broncho
- 2nd most common cause of 2ndary pneumonia. often has abcess or empyema
Currant jelly sputum (bloody, thick, mucoid)
-think what
klebsiella pneumoniae
Military recruit or dorm student with pneumonia:
think what?
mycoplasma pneumoniae
TB: what to see on biopsy
caseating granulomas
-do AFB stain (acid fast bacillus) b/c caseating granuloma could also be fungus
RSV
- type of pneumonia
- important associations, populations, etc
- interstitial
- most common cause of atypical in infants
Infant with pneumonia
think what?
RSV
TB spread to bone
-how presents?
-lumbar vertebrae (Pott disease)
vertebral collapse.
Influenza
- type of pneumonia
- important populations (3)
- pt has increased risk of what?
- interstitial
- common in elderly, immunocompromised, and those with interstitial lung disease
(increases risk for superimposed S Aureus and H influenza, which is more likely to kill pt)
chlamydiae pneumoniae
- type of pneumonia
- important associations, populations, etc
- interstitial
- 2nd most common cause of atypical in young adults, after mycoplasma
Organisms that cause interstitial pneumonia (6)
- mycoplasma pneumoniae
- chlamydia pneumoniae
- RSV
- CMV
- influenza
- coxiella burnetii
Lobar pneumonia:
most common causes. how are they different in population
- strep pneumoniae (95%)
- most common community-acquired and 2ndary pneumonia (on top of viral). adults and elderly. - klebsiella pneumoniae (5%)
- enteric flora that is aspired, so: debilitated individuals like nursing homes, alcoholics, diabetics. Thick ‘currant jelly’ sputum.
Farmer/veterinarian with pneumonia
think what?
Coxiella burnetii (Q fever)
