Pneumonia 1.0 Flashcards
Signs of Infection
• Inflammation
• Redness
• Heat
• Pus
• Systemic signs/symptoms:
- Fever, increased HR, increased RR, increased WBC
- specific – e.g., painful red sore, abscess, headache,
seizures, ear ache, shortness of breath, cough, pain,
etc.
- In severely ill - septic shock - hypotension, reduced
renal function, reduced cardiac output, Acute
Respiratory Distress Syndrome (ARDS), obtunded,
unconscious
Fever
• normal body temperature, slight circadian rhythm
- slight elevation in late afternoon
• fever most common & most non-specific feature of infection
- > 37.5 (oral / armpit) (99.5 o F)
- > 38 o C (tympanic / rectal) (100.2 o F)
• very young and elderly may not respond with fever
• heart rate increases 10 -15 bpm for each 1 o increase
in temp
• Other causes of fever
- Drug fevers
- Trans
- Lymphoma
- Post MI
• useful indicator of response to therapy
• treatment controversial - rarely truly required (only if
> 41 o C or 105 o F) or febrile convulsions
• fever results in
- enhanced leukocyte migration
- augmented lymphocyte function
- reduced microbial replication
- improved survival
White Blood Cell Count (WBC)
• normal white count 4.0 - 11.0 x 10 9 /L (4,000 -
11,000/mm 3 )
• WBC increased (leukocytosis) in most bacterial or
fungal infections (may be diminished in very severe
infections or in neonates)
- > 11 x 10 9 /L suspect bacterial or fungal infection
- > 15 -17 x 10 9 /L “very sick”
- Sepsis - may be very high - 50 x 10 9 /L
(50,000/mm3) or very low
• WBC may be low or normal in viral infections with
↑ lymphocytes
Maturation of Granulocytes
see slide 9
Increased bone marrow response to infection, release more mature neutrophils to helpw ith infection
High proportion of bands indcates infection
Blood C&S
• Should be performed in acutely ill febrile patients
• Ideally, when collected from peripheral sites, should be from two different sites at least a few minutes to an hour apart and before administration of antimicrobials
(when possible)
Obe from catherter site and one from peripheral site
Quick growth from one site vs the other might be indicative of line infection
Sputum C&S
• Often performed in lower respiratory tract infections
• Specimen quality can be assessed by considering the
relative proportions of the components seen under the
microscope
- PMNs
- Epithelial cells
• Obtaining specimen via endotracheal suction or
bronchoscopy/BAL less likely to be contaminated by
upper airway organisms
Procalcitonin
What is it?
• A biomarker used to help predict the likelihood of
bacterial infection
• A lot of clinical research of late into the use of
procalcitonin in antibacterial decision-making
- Especially respiratory infections, critical care, and
sepsis
• May be a useful tool for antimicrobial stewardship
• Triggers for synthesis include bacterial toxins and
proinflammatory cytokines
• Suppressors of synthesis released during viral
infection (e.g. interferon gamma) may account for
specificity for bacterial infection
• Optimal cutoff values and monitoring frequencies not
yet established
• Results should be interpreted in the clinical context
Procalcitonin
Procalcitonin cutoff ranges?
Antibacterial prescriptions (procalcitonin-based vs standard guideline)?
Shown to reduce antibacterial use without increasing adverse outcomes (or mortality) in patients with lower RTIs presenting to ED
- Based on randomized trial (ProHOSP trial) (1381
patients)
- Procalcitonin cutoff ranges:
• < 0.1 mcg/L - antibacterials strongly discouraged
• 0.1-0.25 mcg/L - antibacterials discouraged
• 0.25-0.5 mcg/L - antibacterials recommended
• > 0.5 mcg/L - antibacterials strongly recommended - Antibacterial prescriptions (procalcitonin-based vs
standard guideline)
• All patients (75% vs 87.7%; p < 0.05, NNT 9)
• Acute bronchitis (23.2% vs 50%; p < 0.05, NNT 4)
• CAP (90.7% vs 99.1%; p < 0.05, NNT 12)
• Mean duration of antibacterial exposure (5.7 days vs
8.7 days; p < 0.05) - No significant difference in adverse outcome,
mortality, ICU admission, or
disease-specific complications
Procalcitonin (PCT)
Meta-analysis of 14 randomized trials (4211 patients), findings?
• Meta-analysis of 14 randomized trials (4211 patients)
- No increased risk from all-cause mortality or
treatment failure when procalcitonin used to guide
initiation and duration of antibacterial treatment in
patients with acute respiratory infections.
- Consistent reduction in antibacterial usage (mainly
primary care, ED, and ICU patients)
- Patients at low risk for severe bacterial infections
(e.g. primary care), PCT algorithm was used to
determine if antibacterial therapy should be started
at all.
- Patients at higher risk (e.g. ICU or ED), PCT mainly
used to determine when treatment could be
discontinued
• Due to substantial overlap in PCT levels among
patients, testing should only be one of several factors
considered in a decision to withhold antibacterials
Procalcitonin
Another recent randomized trial (1656 patients) comparing PCT-guided antibacterial therapy to usual care in ED for lower RTI,
findings?
Another recent randomized trial (1656 patients) comparing PCT-guided antibacterial therapy to usual care in ED for lower RTI did not result in less exposure to antibacterials.
• Overall:
- 57% vs 61.8% received antibacterials during first 30
days
- Mean antibacterial days 4.2 vs 4.3
• Acute bronchitis: 17.3% vs 32.1% (significant)
• Adherence to PCT guideline was less than optimal
- 72.9% adherence in ED, 64.8% adherence for entire
protocol period
Procalcitonin
2016 IDSA/ATS Guidelines for HAP/VAP
2019 IDSA/ATS Guidelines for CAP
2016 IDSA/ATS Guidelines for HAP/VAP
• Suggest: procalcitonin level plus clinical criteria should
be used to guide discontinuation of antibiotic therapy
in HAP/VAP (weak recommendation, low-quality
evidence)
2019 IDSA/ATS Guidelines for CAP
• Recommend: empiric antibacterial therapy should be
initiated in adults with clinically suspected and
radiographically confirmed CAP regardless of initial
serum procalcitonin level (strong recommendation,
moderate quality of evidence)
Clinical Case
• KL is a 67 year old ♀ who presents to the ED with new onset cough,
fever, and shortness of breath. On examination, her temperature is
38°C, BP 110/80 mmHg, HR 92 bpm, O 2 sat 94% on RA, RR 25/min, with
decreased air entry and crackles on the left side. Her WBC count was
14, SCr 78, BUN 6.2. Chest X-ray showed infiltrates in the left lower
lobe.
• Her past medical history is significant for mild hypertension,
hypothyroidism, and osteoarthritis of the right knee, all of which are
reasonably controlled with candesartan, levothyroxine, and
acetaminophen (+/- naproxen). She has no known allergies.
What is your approach to this patient?
???
Bacterial Pneumonia
• A major cause of death worldwide - 6th leading cause
of death overall
• The major cause of death from infectious diseases in
the US
• Typically in top 5 of most common causes of
hospitalization in Canada
• Those > 65 years of age at greatest risk
- > 50% of cases and 90% of mortality in these patients
• Mortality is < 1% in outpatients but 14% in those
hospitalized
• A viral infection precedes pneumonia in up to 50% of
cases
Community-Acquired Pneumonia (CAP)
Define as ?
CAP defined as:
- An acute infection of the pulmonary parenchyma
- Associated with some symptoms of acute infection
Accompanied by:
- An acute infiltrate on chest radiograph or auscultory
findings consistent with pneumonia
- Altered breath sounds, rales, rhonchi, crackles,
bronchial breath sounds
- Usually 2 of: fever >37.8 o C, hypothermia, rigors,
sweats, new cough ± sputum change in colour of
respiratory secretions in patients with chronic cough,
chest discomfort, onset of dyspnea
- Fatigue, myalgias, abdominal pain, anorexia,
headache
Pneumonia
x-ray of lung with Right Lower Lobe Pneumonia
see slide 21
