CAP-PE Pathology - Truwit Flashcards
Rust-colored sputum is classic for which pathogen?
Streptococcus pneumoniae
E/A changes heard on auscultation of the lungs indicate what?
consolidation
What is the most common etiology of CAP?
Unknown. The responsible pathogen is not identified approximately 50% of the time.
The sputum gram stain and culture are often discordant, or multiple agents (including atypicals) are present
If the pathogen *is* identified, it is most often streptococcus pneumoniae
Why is an atypical pneumonia “atypical”?
The pathogen is atypical
Also: sputum, physical findings of consolidation, WBC elevation, and alveolar exudate may be absent
This is not unique however - Hx, PEx, and CXR usually are unhelpful in differentiating atypical pneumonia from CAP
Name the (4) major atypical bugs of pneumonia
Mycoplasma pneumoniae
Chlamydia pneumoniae
Chylamydia trachomatis (newborns)
Legionella pneumophila
Name some risk factors for presence penicillin-resistant/drug-resistant pneumococci
Age > 65
beta-lactam use in last 3 months
alcoholism
immunosuppression
multiple medical comorbidities
exposure to children at day care centers
Name some risk factors for presence of enteric gram negatives in CAP
Nursing home reisdent
cardiopulmonary disease
multiple medical comorbidities
recent Abx therapy
Name some modifying risk factors for pseudomonas in CAP
brochiectasis (think cystic fibrosis)
steroids >10 mg/day
BSA >7 days in past month
Malnutrition
When organisms are identified in CAP, what organisms are most likely when…
- Outpatient without modifying risk factors or cardiopulmonary disease
- Outpatient with modifying risk factors or cardiopulmonary disease
- S. pneumoniae, M. pneumoniae, C. pneumoniae, H. influenza, viruses (also consider miscellaneous like Legionella, TB, and endemic fungi)
- Same as without modifying risk factors, plus DRSP, mixed (bacteria + atypical), enteric gram negatives, M. catarrhalis, and aspiration
What is the Abx treatment approach for…
- Outpatient without modifying risk factors or cardiopulmonary disease
- Outpatient with modifying risk factors or cardiopulmonary disease
- Advanced generation macrolide or doxycycline
- (Oral beta-lactam plus (macrolide or doxycycline)) OR antipneumococcal fluoroquinolone alone
What criteria system is used to prognosticate CAP mortality risk (and therefore, need to admit to the hospital)?
What are the elements of this rubric?
CURB-65
Confusion
Urea (>19.1 mg/dL)
Respiratory Rate >30 br/min
Blood pressure <90mmHg systolic or <=60mmHg diastolic
Age >=65
CAP mortality is reduced if Abx are administered how quickly after presentation?
< 8 hours
What are (3) complicating factors that often decrease the utility of sputum analysis in CAP?
Why use it then?
30% of patients unable to produce a specimen
30% of patients treated with Abx prior to admission
25% of patients will have organisms that are difficult/slow to culture
CHEAP
Among hospitalized patients, what bugs (when found) are likely in:
- Hospitalized (non-ICU) without modifying risk factors or C-P disease?
- Hospitalized (non-ICU) with modifying risk factors or C-P disease?
- ICU-admitted without risk for pseudomonas?
- ICU-admitted with risk for pseudomonas?
- S. pneumoniae, H. influenza, M. pneumoniae, C. pneumoniae, mixed (bacteria + atypical), viruses, legionella, and miscellaneous (M. Tb, endemic fungi, PCP)
- Same as (1) plus DRSP, enteric gram negatives, aspiration
- S. pneumoniae and DRSP, legionella spp, H. influenza, enteric gram negative bacilli, S. aureus and MRSA, mycoplasma pneumoniae, viruses and miscellaneous (chlamydia, M. tuberculosis, endemic fungi)
- Same as (3) plus P. aeruginosa
What is the Abx treatment approach for:
- Hospitalized (non-ICU) without modifying risk factors or C-P disease?
- Hospitalized (non-ICU) with modifying risk factors or C-P disease?
- ICU-admitted without risk for pseudomonas?
- ICU-admitted with risk for pseudomonas?
- IV macrolide alone (or IV beta lactam plus doxycycline if intolerant) OR antipneumococcal fluoroquinolone alone
- (IV beta-lactam plus (macrolide or doxycycline)) OR antipneumococcal fluoroquinolone alone
- IV beta-lactam (cefoxatime, ceftriaxone) plus IV macrolide OR antipneumococcal fluoroquinolone alone. If MRSA or gram+ cocci in sputum, give vacomycin
- IV beta-lactam with antipseudomonal activity plus antipseudomonal fluoroquinolone OR IV beta-lactam with antipseudomonal activity plus IV aminoglycoside plus IV atypical coverage
In CAP, what is the approximate therapy response time after start of Abx for an uncomplicated, stable patient?
When does the fever typically resolve?
When does the WBC count typically resolve?
PEx findings?
Clearing of opacities on CXR?
up to 72 hours
2-4 days
4 days
>7 days in 20-40% of patients
50% @ 2wks; 67% @ 4wks; 75% @ 6wks
What is the typical course of oral Abx therapy (following transition from IV) in CAP?
What other criteria must be met before transition from IV to PO Abx?
7-14 days
Improvement of fever, cough/RD, leukocytosis, GI absorption
Describe Light’s Criteria for exudative effusions
If any one of the following is true, the fluid is an exudate:
- Pleural fluid LDH > 2/3 * (serum upper normal limit for LDH)
- Pleural fluid LDH / serum fluid LDH > 0.6
- Pleural fluid protein / serum fluid protein > 0.5
Describe the criteria for determining if a parapneumonic effusion should be drained with a chest tube
- Criteria A
- 0 - minimal (<10mm on lat decubitus XR)
- 1 - moderate, free-flowing (>10mm on lateral decubitus and <1/2 hemithorax)
- 2 - large free-flowing effusion (>1/2 hemithorax), loculated or thickened effusion on CT scan
- Criteria B (bacteriology)
- X - unknown
- 0 - negative culture and gram stain
- 1 - positive culture or gram stain
- 2 - overt pus
- Criteria C (pH)
- X - unknown
- 0 - >=7.20
- 1 - <7.20
[A,B,C] = [0,X,X] or [1,0,0] -> no drainage
[A,B,C] = [2,1,1] or [X,2,X] -> yes drainage
What factors, affecting the chest wall, might lead to dyspnea?
Muscle weakness
Skeletal deformities (including trauma, scoliosis, etc)
What factors, affecting the pleural spaces, might cause dyspnea?
The lung parenchyma?
Pleural: Fluid, air, tumor
Parenchyma: Interstitial, alveolar
What is the mnemonic for differential diagnosis of dynspnea due to interstitial disease?
SHITFACED
- Sarcoidosis
- Hypersensitivity pneumonitis
- Idiopathic pulmonary fibrosis
- Tuberculosis and tumor
- Fungi
- Asbestosis
- Collagen vascular diseases
- Eosinophilic granuloma
- Drug-induced lung disease
What conditions are on the differential for dynspnea due to an airway problem?
Pulmonary arteries?
Neural?
Pericardium?
Airway: Bronchitis, emphysema, asthma, BOOP, upper airway obstruction
Arterial: PE, pulmonary HTN, pulmonary vasculitis
Neural: phrenic nerve dysfunction, quadraplegia (trauma -> SCI)
Pericardium: fluid-based or restrictive
What is the mnemonic for differential diagnosis of dyspnea due to alveolar disease?
PeCan PIE
- Pus
- Cells
- Proteins
- Inflammatory processes
- Edema
What conditions affecting the heart might lead to dyspnea?
What about conditions affecting the blood?
Psych?
Heart: Cardiomyopathy, diastolic dysfunction, ischemia, valvular origin, conduction abnormalities
Blood: anemia, altered hemoglobin states (smokers)
Psych: **diagnosis of exclusion** - hyperventilation syndrome or heightened response to stimuli (secondary to anxiety?)
Describe the Wells Clinical Prediction Model for diagnostic likelihood of of pulmonary embolism
Clincal variables and point values:
- Signs and symptoms of DVT - 3.0
- Alternative diagnosis is less likely than PE - 3.0
- HR > 100 bpm - 1.5
- Immobilization or surgery in past 4 weeks - 1.5
- Previous VTE - 1.5
- Hemoptysis - 1.0
- Malignancy (or treatment for malignancy in last 6 months) - 1.0
Scoring:
- low probability: <2 points
- if D-dimer negative, stop
- if D-dimer positive, go to imaging study
- moderate probability: 2 to 6 points
- high probability: >6 points
