Chapter 153 Pneumonia Flashcards
Risk factors for CAP include
alcoholism, asthma, immunosuppression, institutionalization, and an age of ≥70 years.
Risk factors for pneumococcal pneumonia include
Risk factors for pneumococcal pneumonia include dementia, seizure disorders, heart failure, cerebrovascular disease, alcoholism, tobacco smoking, chronic obstructive pulmonary disease, and HIV infection.
is more likely in patients with skin colonization or infection with CA-MRSA.
CA-MRSA pneumonia
tend to infect patients who have recently been hospitalized and/or received antibiotic therapy or who have comorbidities such as alcoholism, heart failure, or renal failure.
Enterobacteriaceae
is a particular problem in patients with severe structural lung disease, such as bronchiectasis, cystic fibrosis, or severe chronic obstructive pulmonary disease.
P. aeruginosa
Risk factors for ____ include diabetes, hematologic malignancy, cancer, severe renal disease, HIV infection, smoking, male gender, and a recent hotel stay or ship cruise.
Legionella infection
Gross hemoptysis is suggestive of
CA-MRSA pneumonia.
the sensitivity and specificity of the findings on physical examination are less than ideal,
averaging 58% and 67%, respectively.
In chest X-ray:
pneumatoceles suggest infection with 1._____
and
an upper-lobe cavitating lesion suggests 2._____
- S. aureus
2. tubercu- losis.
To be adequate for culture, a sputum sample must have
> 25 neutrophils and
<10 squamous epithelial cells per low-power field.
Certain high-risk patients including those with —should have blood cultured.
neutropenia secondary to pneumonia, asplenia, complement deficiencies, chronic liver disease, or severe CAP
Urinary antigen tests
Pneumococcal urine antigen
Legionella urine antigen test
PCR can detect the nucleic acid of
Legionella species,
M. pneumoniae,
C. pneumoniae and mycobacteria.
Biomarkers of severe inflammation. The two currently in use are
C-reactive protein (CRP) and procalcitonin (PCT).
may be of use in the identification of worsening dis- ease or treatment failure
CRP C-reactive protein
____ may play a role in determining the need for antibacterial therapy.
Procalcitonin PCT
For CAP, the main resistance issues currently involve
S. pneumoniae and CA-MRSA.
Risk factors for penicillin-resistant pneumococcal infection include
recent antimicrobial therapy, an age of <2 years or >65 years, attendance at day-care centers, recent hospitalization, and HIV infection.
resistance to macrolides is increasing through several mechanisms:
Target-site modification
Efflux mechanism
___ caused by ribosomal methylation in 23S rRNA encoded by
the ermB gene results in high-level resistance (MICs, ≥64 μg/mL) to macrolides, lincosamides, and streptogramin B–type antibiotics.
Target-site modification
______ encoded by the mef gene (M phenotype) is usually associated with low-level resistance (MICs, 1–32 μg/mL)
efflux mechanism
Changes can occur in one or both target sites (topoisomerases II and IV) from mutations in the gyrA and parC genes, respectively.
Pneumococcal resistance to fluoroquinolones
Methicillin resistance in S. aureus is determined by the ______ gene which encodes for resistance to all β-lactam drugs
mecA gene
If CA-MRSA is suspected, either ______ can be added to the initial empirical regimen;
linezolid or vancomycin
Indication for CTT
If the fluid has
- pH of <7
- glucose level of <2. 2 mmol/L
- lactate dehydrogenase concentration of >1000 U/L or
- if bacteria are seen or cultured
then it should be completely drained
Chest radiographic abnormalities are slowest to resolve
4–12 weeks
Two forms of influenza vaccine are available:
intramuscular inactivated vaccine and intranasal live-attenuated cold-adapted vaccine. The latter is contraindicated in immunocompromised patients.
Three factors are critical in the pathogenesis of VAP:
- colonization of the oropharynx with pathogenic microorganisms, 2. aspiration of these organisms from the oropharynx into the lower respiratory tract
- compromise of the normal host defense mechanism
three common findings in at-risk patients with VAP
(1) tracheal colonization with pathogenic bacteria in patients with endotracheal tubes
(2) multiple alternative causes of radiographic infiltrates in mechanically ventilated patients, and
(3) the high frequency of other sources of fever in critically ill patients.
was developed by weighting of the various clinical criteria usually used for the diagnosis of VAP
Clinical Pulmonary Infection Score (CPIS)
Maximal score of Clinical Pulmonary Infection Score (CPIS)
12
But if
Initially 8-10
The standard recommendation for patients with risk factors for MDR infection is for three antibiotics:
two directed at P. aeruginosa and one at MRSA.
For HCAP:
Patients without Risk Factors for MDR Pathogens
Ceftriaxone (2 g IV q24h) or cefotaxime (2 g IV q6–8 h) or
Moxifloxacin (400 mg IV q24h), ciprofloxacin (400 mg IV q8h), or levofloxacin (750 mg IV q24h) or
Ampicillin/sulbactam (3 g IV q6h) or
Ertapenem (1 g IV q24h)
For HCAP
Patients with Risk Factors for MDR Pathogens
- A β-lactam:
Ceftazidime (2 g IV q8h) or cefepime (2 g IV q8–12h) or
Piperacillin/tazobactam (4. 5 g IV q6h) or
Imipenem (500 mg IV q6h or 1 g IV q8h), or meropenem (1 g IV q8h)
plus - A second agent active against gram-negative bacterial pathogens:
Gentamicin or tobramycin (7 mg/kg IV q24h) or amikacin (20 mg/kg IV q24h) or
Ciprofloxacin (400 mg IV q8h) or levofloxacin (750 mg IV q24h)
plus - An agent active against gram-positive bacterial pathogens:
Linezolid (600 mg IV q12h) or
Vancomycin (15 mg/kg q12h initially with adjusted doses)
If the CPIS decreases over the first 3 days, antibiotics should be stopped after ____.
An 8-day course of therapy is just as effective as a 2-week course and is associated with less frequent emergence of antibiotic-resistant strains.
In addition to the ____% failure rate for MRSA infection treated with vancomycin,
VAP due to Pseudomonas has a ____% failure rate, no matter what the regimen.
40%
50%
The most sensitive component of the CPIS is improvement in
oxygenation
Clinical improvement, if it occurs, is usually evident within _____ of the initiation of antimicrobial treatment.
48–72 h
