Flashcards in Tutorial 2: Pneumonia Deck (108)
What is CAP?
community-acquired pneumonia: acute infection of the pulmonary parenchyma acquired outside of the hospital
What are the two categories of nosocomial pneumonia?
hospital-acquired pneumonia (HAP)
ventilator-associated pneumonia (VAP)
What is HAP?
hospital-acquired pneumonia: pneumonia acquired ≥48 hours after hospital admission, and did not appear to be incubating at the time of admission.
What is VAP?
ventilator-associated pneumonia: pneumonia acquired ≥48 hours after endotracheal intubation.
What was HCAP, and how is it treated now?
Health care-associated pneumonia; currently treated as CAP
Referred to pneumonia acquired in health care facilities (eg, nursing homes, hemodialysis centers) or after recent hospitalization
What are the non-modifiable (/less modifiable) risk factors for pneumonia?
- Older age (≥65)
- Chronic comorbidities
- Viral respiratory tract infection
- Impaired airway protection (LOC, dysphagia)
What chronic comorbidities are risk factors for CAP?
COPD (comorbidity with highest risk for hospitalization)
- other chronic lung disease (bronchiectasis, asthma)
- CHF and other chronic heart disease
Once you have one risk factor for CAP, does having more increase your risk?
Yes: risk factors are additive
eg CHF, smoking, COPD
What are the three categories of most common causes of CAP?
What is the single most common bacterial cause of pneumonia?
Streptococcus pneumoniae (pneumococcus)
What pathogens are "typical bacterial" causes of CAP? (7 listed)
•S. pneumoniae (most common bacterial cause)
•Group A streptococci
•Aerobic gram-negative bacteria (eg, Enterobacteriaceae such as Klebsiella spp or Escherichia coli)
•Microaerophilic bacteria and anaerobes (associated with aspiration)
What pathogens are "atypical bacterial" causes of CAP? (5 listed)
What defines "atypical" bacterial causes of CAP?
- resistant to beta-lactams
- can't be visualized on Gram stain or cultured using traditional techniques
What respiratory viruses cause CAP? (8 listed)
•Influenza A and B viruses
•Respiratory syncytial virus
•Coronaviruses (eg, Middle East respiratory syndrome coronavirus)
What features are associated with CAP due to community acquired MRSA?
Necrotizing or cavitary pneumonia
What recent discovery has changed our understanding of pneumonia?
Lung microbiome: lung parenchyma was previously thought to be sterile
e.g. change from pathogen colonization of sterile lung to pathogen competition with microbiome -- and dysbiosis as a risk factor for pneumonia
What are the most common symptoms associated with CAP?
- Cough (with or without sputum production)
- pleuritic chest pain
What are the most common physical exam findings associated with CAP?
- tachypnea (RR > 24: 45-70%; most sensitive sign in older pt)
- increased WOB
- adventitious breath sounds, including rales/crackles (about 1/3 of pt) and rhonchi
- fever (80%, though freq absent in older pt)
Tactile fremitus, egophony, and dullness to percussion also suggest pneumonia.
What is the gold standard for diagnosis of pneumonia?
Infiltrate on CXR, in context of supportive clinical syndrome (eg, fever, dyspnea, cough, and sputum production)
What are the most common lab findings associated with CAP?
- CBC: Leukocytosis (15-30), leftward shift
- leukopenia can occur; generally poor prognosis
- inflammatory markers (CRP< ESR, procalcitonin)
What other features might CAP present with (not most common, but not rare)?
- GI (N/V/D)
- MS changes
What features on CXR are consistent with CAP?
- lobar consolidations
- interstitial infiltrates
What if the CXR is negative, but you still really suspect pneumonia based on clinical picture?
Esp if immunocompromised (less infl response so less infiltrate) or known exposure to pathogen that causes pneumonia (eg legionella)
Name 2 score tools used to calculate mortality and determine site of treatment for CAP
PSI (Pneumonia Severity Index), aka PORT score
When do you treat a pt with CAP as ambulatory?
Normal vital signs aside from fever
No concern for complication
When do you admit a pt with CAP?
SpO2 <92% on RA (sig change from baseline)
Also consider for practical concerns like inability to take oral meds, functional impairment, social issues affecting adherence or followup
What groups are not well represented in CAP scoring, and should be considered for admission even with mild scores?
patients with early signs of sepsis, rapidly progressive illness, or suspected infections with aggressive pathogens
When do you admit a pt to ICU for CAP?
- respiratory failure requiring mechanical ventilation
- sepsis requiring vasopressor support
What criteria support early ICU admission, due to anticipated progression to sepsis? (name 5; 9 listed)
- Hypotension requiring fluids
- T < 36
- RR ≥ 30
- PaO2/FiO2 ratio ≤250
- BUN ≥ 7 mmol/L
- Leukocyte count <4
- Platelet count <100
- Multilobar infiltrates