Pneumonia Flashcards
T/F Pneumonia kills more children than HIV/AIDS, malaria, and measles combined
True
What is the general pathophysiology of pneumonia
- Pathogens enter lower airways, triggering inflammation.
This causes edema, narrowing the airways.
This causes pus, triggering more WBCs, narrowing the airways further.
Ultimately, gas exchange is poor.
Children have higher risk of death because their airways are small to begin with.
Seniors have decreased lung compliance and weaker immune systems.
What are the 5 sources of pathogens for pneumonia
- Microaspiration
- occurs during sleep, nasopharyngeal colonization - Inhalation of infectious particles
- Common in VIRAL pneumonia
- TB, legionalla (via water sources) - Macroaspiration
- contaminated solids or liquids - Hematogenous spread
- septic emboli - Disturbances to normal flora in alveoli
What is the order of factors that increase likelihood of developing infection
- Failure of host defenses
- Size of inoculum - legionalla, poor dental care, macroaspiration
- Virulence
What is legionnaire’s disease?
Sources?
Transmit?
Sources:
- AC units
- cooling towers
- hot tubs,
- Plumbing (cruise ships, hospitals, hotels),
- natural water sources (camping, fishing trip) usually in spring-fall
Legionella forms biofilm inside the piping (to protect itself)
- cannot spread to other people since inoculum via droplets too small
T/F Legionella is an intracellular parasite
True
- Cell wall agents will not work
What is the morphology of strep. pneumoniae?
Gram pos in pairs
or chains (a-hemolytic)
Whats the major virulence factor of strep. pneumoniae
Polysaccharide capsule
- helps the bacteria evade natural defenses
What are some of the respiratory tract defenses (4)
- Cough reflex
- Mucociliary elevator
- Anatomical barriers
- Local immune mediators
What are some anatomical barriers to bacteria (4)
- Epiglottis
- 90 degree turn at nasophraynx
- sharp-angled branching of airways
- Most conchae (traps bacteria)
What are some local immune mediators (4)
- Surfactant
- Secretory IgA and IgG
- alveolar macrophages
- Bronchus-associated lymphoid tissue (BALT)
What are risk factors of pneumonia (9)
- Extremes of age (<5, 65+)
- Immunocompromised
- Underlying lung disease
- PPI therapy (inc bacteria in stomach, travels up)
- Recent influenza virus infection
- Impaired cough reflex
- Impaired epiglottal function (loss of protection)
- Dysfunctional mucociliary action (Could be due to smoking)
- Bronchial obstruction
How does secondary bacterial pneumonia occur after influenza? i.e What does influenza infection lead to? (3)
How long does this susceptibility last?
- Hyporesponsiveness of alveolar macrophages
- Damage to airway epithelium -> inc bacterial adherence
- Impaired mucociliary function -> dec bacterial clearance
Lasts 30 days
T/F Viral pneumonia due to influenza is less common than bacterial and associated with less mortality
False
- Associated with GREATER mortality
What do the following chest x-ray findings mean
Diffuse or patchy infiltrates
Lobar consolidation
Necrotizing
Caseating or cavitary
Diffuse or patchy infiltrates
- fluid through the whole lung
Lobar consolidation
- fluid in a defined area
Necrotizing
- destruction of lung parenchyma
Caseating or cavitary
- cavities in lung parenchyma; tuberculosis
How long does hospital acquired pneumonia present?
48hrs after admission
- more likely to be gram neg and drug resistant
T/F Not all hospital exposure is the same for HAP i.e psych ward vs ICU
True
What do we need to diagnose CAP (2)
- clinical findings (localized (SOB, cough) + systemic inflammation (fever, tachy, inc WBCs)
AND - Diagnostics (Radiographic imaging, microbiology)
What are signs and symptoms of CAP
- Fever: ACUTE onset
- Cough: could be dry or productive (with/without sputum)
Breathing (6)
- Dyspnea (SOB)
- Increased work of breathing: you can tell pt is using more muscles to breathe, nose flaring, grunting - diaphragm isn’t doing enough
- Hypoxemia: low O2 in blood
- Pleuritic chest pain: sharp pain on deep inhalation
- Breathing SOUNDS: Crackles/Rales + Ronchi (gurgling/bubbling sounds on breathing)
- Tachypnea: increased RR, number depend on age
- Leukocytosis (high WBCs) (low WBCs = bad prognosis)
- Tachycardia (fever, hypoxia)
- Mental status change (due to hypoxia, less common)
- GI changes (less common)
What is the sensitivity of chest-xray ?
False positive reasons?
Sensitivity: 32-78%
- ability to rule OUT non-pneumonia cases
False positives:
- MANY non-infectious things can cause abnormal CXR such as fluid present
- Atelectasis, Pulmonary Embolism, chemical pneumonitis, HF with pulmonary edema
What is the specificity of chest-xray ?
False negative reasons?
Specificity: 59-94%
- ability to confirm true pneumonia cases
False negatives:
- Will not visualize the fluids in immunocompromised patients, dehydration
- fluid present can be due to other causes
If a patient presents with respiratory crackles are you able to diagnose pnemonia and prescribe antibiotics
No
What does the CURB-65 score not consider when predicting severity of pneumonia
Co-morbidities
Which severity test predictor is more accurate, PSI or curb-65
PSI
Interpret the CURB-65 scores for
Low risk for death
Moderate risk for death (consider admit)
High risk for death (consider death)
Curb
Low risk = 1
Moderate risk (5-10% death) = 2
High risk (15-40% death) = 3+
Define confusion in CURB-65 score
Mini Mental State Exam (MMSE) <9
OR
new disorientation to person, place or time
“oriented to 3”: pt knows WHO they are, WHERE they are, and the DATE
When would we admit kids to the hospital for pneumonia
Vomiting
Tachypnea
Hypotension
Chest retraction (can see intercoastal muscles retracting when breathing)
Cannot take anything orally
O2 sats <92%
Concerning social situation
Most common pathogen for pneumonia
Strep. Pneumo
T/F Bacterial pneumonia is more common than viral
False
What bugs can be present in pneumonia (9)
Gram +
- Strep pneumo
- Staph aureus
- GAS
Gram -
- H. influ
- M. Catt
- Pseudomonas
Atypicals
- Legionella
- Mycoplasma pneu
- Chlamydiophila
Differentiate between viral vs bacterial CAP
Onset
Recent symptoms
Pain
Community factors
Lung involvement
Viral
Onset
- slow (insidious)
Recent symptoms
- muscle aches, fever, dry cough
Pain
- SOB without pleuritic pain
Community factors
- viral exposure in community
Lung involvement
- possibly both lungs
Bacterial
Onset
- acute
Recent symptoms
- no recent viral symptoms
Pain
- pleuritic pain (chest)
Community factors
- none
Lung involvement
- More likely unilateral
- Diffuse infiltrate
What are risk factors for H. influ? (2) When to cover it? (outpatient, inpatient, ICU)
Comorbidities
- COPD
- structural long disease
Only cover in inpatient or ICU
- need to cover Beta-lactamase strains as well
- Use Amoxi-clav or Pip-taz
When do we cover atypicals? Where is it more common?
When to cover? (outpatient, inpatient, ICU)
Typically self-limitting
More common in outpatients
No need to cover
What are the risk factors for legionalla? Sx?
Risk of legionalla on CAP
When to cover for it? (outpatient, inpatient, ICU)
Sources:
- AC units
- cooling towers
- hot tubs,
- Plumbing (cruise ships, hospitals, hotels),
- natural water sources (camping, fishing trip) usually in spring-fall
Sx: Diarrhea, hyponatremia
Causes hospitalization (more severe)
- most common causes of ICU
Outpatients:
- only if no improvement in 3-5 days
Inpatients:
- only if risk factors present
ICU
- cover for all
What are risk factors of pseudomonas (4)
When to cover it? (outpatient, inpatient, ICU)
Only colonizes unhealthy lungs (opportunistic pathogen)
- Bronchiectasis (widening of bronchi)
- Previous culture (sputum)
- Recent hospitilization (esp w broad spectrum use)
- COPD with risk factors for colonization
(FEV <30%, chronic steroid, BS abx in the last 3 months)
Only in inpatient, ICU
Risk factors for staph aureus
When to cover it? (outpatient, inpatient, ICU)
Risk factors
- necrotizing or post-influenza (twice sickening)
- Risk for MRSA (USA, crowded, recent hospital)
- Surveillance swabs
Only in inpatient, ICU
Describe the pos/neg predictive value of surveillance swabs for staph aureus
Negative predictive value
- good for ruling out
Poor positive predictive value
Less effective in older patients
What are risk factors for penicillin-resistant strep pneumo (10)
When to cover it?
- 65+
- Alcohol misuse
- Antibiotics 3-6 months (esp ML or FQ)
- Cancer
- Chronic - heart, lung, liver, kidney disease
- Diabetes
- Daycare
- Hospitalization in the last 3 months
- Immunosuppresion
- Smoking
outpatient, inpatient, all ICU patients (despite risk factors)
If PRSP suspected, INCREASE the dose of the penicillin
- If recent FQ or ML, switch the class
What bugs do you cover if inpatient pneumonia (2)
Which drug to use
Cover S. pneumo
B-L producing H. influ
Use amoxi-clav
Cover legionalla, pseudomonas, staph aureus if risk factors
What bugs to cover for ICU pneumonia patients (3)
Strep pneumo
H. influ
Legionalla
Add pseudomonas, staph aureus if risk factors
What bug to cover if outpatient
Strep pneumo
- consider risk factors for PRSP
- switch class if recent FQ or ML
Could add legionella if no improvement in 3-5 days
When to do sputum cultures?
How to take it?
What do the results indicate?
For who: if hospitalized (NOT for outpatients)
Consider the quality of sputum culture, Must be from DEEP airway (deep cough)
- Epithelial cell presence: from the throat (BAD)
- Pus presence: from the deep airways (GOOD)
if +, can narrow therapy
if -, does not rule out pneumonia
Sputum culture which is higher sensitivity or specificity
Specificity
When is blood culture recommended in pneumonia
In moderate-severe disease
When do we do a urinary antigen test for legionella (4)
- ICU admission
- Direct admission from PHO
- not responding after 48-72 hours outpatients
- Inpatients during peak season (June to October)
What are short comings of the urinary antigen testing for legionella? (3)
- Only tests serogroup 1 (80% of cases, 1/5 chance that patient will test negative if they have other serogroup
- Long turnaround time (2-3 days M-F)
- Antigen can persist up to 1 year after infection (don’t repeat is positive 6 months ago)
