Pneumonia Flashcards by Pierre Wadeie

T/F Pneumonia kills more children than HIV/AIDS, malaria, and measles combined

True

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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.

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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

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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

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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

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T/F Legionella is an intracellular parasite

True
- Cell wall agents will not work

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What is the morphology of strep. pneumoniae?

Gram pos in pairs
or chains (a-hemolytic)

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Whats the major virulence factor of strep. pneumoniae

Polysaccharide capsule
- helps the bacteria evade natural defenses

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What are some of the respiratory tract defenses (4)

Cough reflex
Mucociliary elevator
Anatomical barriers
Local immune mediators

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What are some anatomical barriers to bacteria (4)

Epiglottis
90 degree turn at nasophraynx
sharp-angled branching of airways
Most conchae (traps bacteria)

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What are some local immune mediators (4)

Surfactant
Secretory IgA and IgG
alveolar macrophages
Bronchus-associated lymphoid tissue (BALT)

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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

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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

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T/F Viral pneumonia due to influenza is less common than bacterial and associated with less mortality

False
- Associated with GREATER mortality

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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

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How long does hospital acquired pneumonia present?

48hrs after admission
- more likely to be gram neg and drug resistant

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T/F Not all hospital exposure is the same for HAP i.e psych ward vs ICU

True

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What do we need to diagnose CAP (2)

clinical findings (localized (SOB, cough) + systemic inflammation (fever, tachy, inc WBCs)
AND
Diagnostics (Radiographic imaging, microbiology)

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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

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)