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Flashcards in Pulmonary Infections -Patel Deck (39):

What is Community Acquired Pneumonia? What organism commonly causes it?

an infection that begins outside of the hospital or is diagnosed within 48 h of hospital admission in a patient who has not resided in a long-term facility for 14 days or more before the onset of symptoms

Streptococcal pneumonia is the most common


What is hospital acquired pneumonia? What does HCAP (healthcare acquired associated pneumonia) include? Why do we care about these?

HAP=48 hours after admission to the hospital

HCAP=non-hospitalized patients with extensive healthcare contacts like:
-Nursing home resident
-Hemodialysis patients
-Hospitalization for >2 days in last 90 days

both HAP and HCAP may be more resistant organisms--> need more broad based medication


What is the most common organism to cause lobar pneumonia?

Streptococcal pneumonia (gram + diplococci)

then Klebsiella (esp in alcoholics and diabetics)


What are the stages of lobar pneumonia?

-congestion 24 hours --> lots of exudate in alveoli--> hypoxia

-red hepatization (1-3 days)--> RBCs and PMNs inside ==> exudates, neutrophils and hemorrhage

-gray hepatization (4-8 days) --> degradation of RBCs =fibrinosppurative exudate



What is bronchopneumonia? What bugs normally cause this?

Inflammation and exudate starts in bronchioles and extend to alveoli

Patchy distribution involving multiple** lobes

-Staph. aureus-secondary pneumonia after viral infection
-H influenza- pneumonia with COPD
-Pseudomonas- pneumonia is cystic fibrosis pts
-Legionella- source is water like water fountain or water from air conditioner--> pneumonia is immmunocompromised pts


What is the typical cause of interstitial pneumonia? What are the normal symptoms?


mild symptoms --> does not affect the alveoli directly (just parenchyma)--> no hypoxia

no solid consolidation on x-ray


Which bug will present with GI symptoms and pneumonia?



What is required on imaging for a diagnosis of pneumonia? If a pt with suspected pneumonia has a negative chest x-ray, what should you do next?

presence of infiltrate on imaging (chest x-ray) along with clinical finding

negative chest x-ray:
-repeat in 48 hours with empiric antibiotics
-CT chest
-consider other diagnosis


What labs should be ordered for a hospitalized pt with CAP or HAP?

-blood culture
-sputum culture
-urine antigen for lenionella and pneumococcus

optional for outpatient CAP


What determines whether a sputum culture is adequate?

-culture yield 25 neutrophils and <10 squamous epithelial cells on low-power field


What bug should you think of in a child with pneumonia and a middle ear infection?



What is the specific diagnostic test for mycoplasma? Legionella? Streptococcal pneumonia?

Mycoplasma: serology for IgM and IgG, PCR

Legionella and strept pneumoniae=urine antigen test


What bug should be suspected in CAP found in a healthy pt?

strept pneumonia


What bug should be suspected in children < 5yo or adults >65 yo and/or functional asplenia?

H. influenzae


What bug should be suspected in pneumonia after influenza, lung abscess or nosocomial pneumonia?

Staph aureus


What is the outpatient treatment for pneumonia in a previously healthy pt with no risk of drug resistance? What if they have comorbidities or factors

-healthy: macrolide or doxycycline

-comorbidities: Beta-lactam + macrolide or doxycycline

OR flouroquinolones


What is the treatment for pneumonia in a hospital setting (CURB-65=2+)?

Beta lactam + macrolide

or resp FQ (reserve for beta-lactam allergic pts)


What is the treatment for severe pneumonia (CURB-65 >3)?

Potent antipneumococcal beta-lactam (cefotaxime, ceftriazone or ampicillin-sulbactam) + azithromycin or RFQ


When should MRSA pneumonia be suspected?

-Severe, rapidly progressive pneumonia
-During influenza season (superimposed bacterial pneumonia)
-Pneumonia with cavity on CXR (from PVL toxin)
--> Tend to cause necrotization of lung tissue fast.
-Previous history of MRSA infection.


What 3 things should be checked in pts who do not respond to treatment?

wrong organism?

complication? (empyema, lung abscess, occult infection)

wrong diagnosis?


What can aspiration pneumonia lead to? What is a common pathophysiology of this?

chemical pneumonitis (abrupt onset of dyspnea with low grade fever, cyanosis and diffuse crackles)

lung abscess (necrotizing pneumonia)

*often due to compromised consciousness (alcoholism, anesthesia)


What are some signs of an aspiration pneumonia--> lung abscess (necrotizing pneumonia)? What are some causes of this?

-Patient is sick for few days
-Foul smelling sputum
-Chest x-ray shows consolidation with cavity

-Anaerobes (Bacteroides, fusobacterium, peptostreptococcus, provetella)
-Klebsiella (red currant sputum)
-S. aureus (PVL toxin)


If a pt is infected with mouth anaerobes, will the sputum culture be +?

probably not because the bugs need a special culture to grow

mixed flora is common in aspiration pneumonia


Where are lung abscesses likely to form? How long does this take?

Right lower lobe

takes 7-10 days for necrosis


What are the clinical features of aspiration pneumonia? What should it be treated with?

-Indolent course with cough, fever, night sweats for 2 weeks or more

-Sputum culture does not help in making diagnosis.

-Rx : clindamycin or carbapenems should be used to treat.


What 3 bugs are likely to cause HAP? What should be used to treat these?

Multidrug-resistant (MDR) bacterial pathogens:

-pseudomonas (5 days amino glycoside therapy with B-lactam)

-enterobacteriaceae (carbapenem)

-MRSA (linezolid or vancomycin)


What has to be obtained prior to starting HAP pts on antibiotics?

lower reap tract culture

obtained bronchoscopically


What is nosocomial pneumonia? What should be done to prevent nosocomial pneumonia?

all healthcare related pneumonia

-decontaminate oropharynx (chlorhexidine 0.12%)
-prevent aspiration (sit semi-recumbent and subglottic suction)


What are the 2 tests for latent TB?

-PPD --> type IV hypersensitivity reaction

-interferon gamma release assay (IGRA) --> Tcell response to M TB antigen


Can a BCG vaccine convert a PPD test?



What is a considered a + PPD test? (3 different populations)

induration > 5mm for HIV infection, organ transplant, recent contact with active TB or chest ray consistent with old TB

induration > 10 for recent arrival (< 5 yrs) from a high risk country, IV drug user, health care worker, children < 4yo or exposed to adults with high risk for TB

induration > 15 mm for no risk factors


A 32-yr-old man working as full time RN, has PPD results showing 11 mm induration. Is this PPD positive for latent TB?


Induration > 10=+


What are some features of Primary Active TB?

arises after initial exposure

causes focal, caveating necrosis of lower lobes

noncavitary lesion

calcification of ipsilateral hilar lymph nodes

caseating necrosis --> Ghon complex


What are some features of Reactivation TB?

-immune suppression

-Upper lobe cavitation or fibronodular infiltrate

-atypical presentation common in HIV pts


What are some features of Miliary TB?

-hematogenous seeding

-fine, well-demarcated nodules, uniform in size

-nodules enlarge --> fluffy and results in diffuse airway filling defects


What is the diagnostic approach for suspected TB?

-any pt with cough > 2-3 weeks or with at least 1 other symptom (fever, night sweats, weight loss, hemoptysis)
--> chest x-ray

-if suggests TB, admit/isolate and :
-collect 3 sputum cultures for acid-fast bacilli (AFB) smear microscopy and culture (one should be tested using nucleic acid amplification (NAA) test)


If the sputum is positive for AFB stain and culture is pending, will you empirically treat for TB?


start treatment before get culture back --> presumptive diagnosis (epidemiological exposure, x-ray findings, sputum/fluid analysis, histopathology)


What should be done for inpatient infection control in TB?

-airborne isolation

-negative pressure room with N95 mask


What is the treatment for TB?

INH+RIF+ETH+PZA for 2 months --> if sputum negative, go down to 2 drugs (INH and RIF) for total 6-9 months

(INH= isoniazide
RIF = rifampin
ETH= ethambutol
PZA= pyrazinamide)