CAP Flashcards
CAP
- Community-acquired pneumonia
- Acute infection of pulmonary parenchyma and has been acquired in the community
Pneumonia
- Leading cause of death by infection
- Affects the very young and elderly
- Challenges: diagnoses, wide microbe etiology, resistance
Pathogenesis - Entry
- Inhalation
- Direct spread from upper respiratory tract
- Aspiration
- Hematogenous seeding (less likely)
Pathogenesis - Other
- Impaired defense mechs contribute to risk: smoking, alcohol, stroke
- Altered host function: age, COPD, AIDS, imumunosuppressive agents, malnutrition
- Prior viral infection (flu)
- Site of care varies by microbe infecting patient
Smoking Risks
- Impairs ciliary function
- Contributes to CAP risk
Alcohol/Smoke Risks
- Impairs cough and epiglottic reflex
- Contributes to CAP risk
Risk Factors + Pathogens
- COPD - H. influenzae, M. catarrhalis (B-lactamase producers)
- Alcoholism: S. pneumoniae, aspiration
- Injection drug use: S. aureus
S. Pneumoniae
- Most common pathogen in CAP
- Colonizes upper respiratory tract in ~10% of healthy adults
- Polysaccharide capsules: >90 serotypes, target for vaccines
- Resistance is an issue
S. Pneumoniae Abx Resistance
Resistance to following:
- PCN
- Macrolides
- Fluoroquinolones
- Cephalosporins
Risk for S. Pneumoniae
- Age >= 65 years old
- Comorbidities: asthma, diabetes, COPD, malignancy, chronic heart/lung/liver/kidney disease
- Alcoholism
- Immunosuppression
- Exposure to child in daycare
- Beta-lactam, macrolide, or fluoroquinolone use in last 3 months
H. Influenzae
- Gram “-“ coccobacillus
- Colonizer of URT
- Indistinguishable clinical features from S. pneumoniae
- ~30% produce beta-lactamases
Atypical Bacteria
- M. pneumoniae, C. pneumoniae, Legionella spp
- Symtoms: non-productive cough, absence of leukocytes
- Abnormal X-ray
- Hard to identify/isolate in lab
- Abx options: FQN, azithromycin, doxy
M. Pneumoniae
- Mycoplasma pneumoniae
- Short rod-shaped bacteria w/o cell wall
- Not detectable on gram stain
- Responsible for ~10-20% of cases
- Transmission high in close congregate settings (dorms)
C. pneumoniae
- Chlamydophilia pneumoniae
- Gram “-“ obligate intracellular bacteria
- Responsible for ~5-10% of cases
- Mild symptoms, usually worse in elderly
L. pneumophila
- Legionella pneumophila
- Naturally occurring aquatic bacteria (intracellular)
- Accounts for 1-5% of CAP, rare
- Causes severe disease
- Increased risk: recent travel (2 weeks), contaminated water, elderly, smoking, immunocompromised
- Urine antigen test available
Clinical Symptoms
- Cough
- Sputum production
- Fever
- Chills
- Dyspnea
- Pleuritic chest pain
- N/V
Physical Exam Findings
- Tachycardia
- Tachypnea
- Diminished breath sounds
- Egophony
Diagnosis
- Chest X-ray showing infiltrate is “gold standard” and should always be obtained when pneumonia is suspected
- Additional diagnostic testing is optional in outpatient and recommended in some hospitalized patients
CAP Risk Assessment
- Treat either outpatient, inpatient medical floor, or ICU
- Treatment depends on severity and mortality risks
- Risks are determined from vital signs/stability, physical exam, lab tests, and need for IV therapy
CAP Scoring Systems
- PSI (Pneumonia severity index) is preferred, larger proportion assessed for OP treatment
- Assessess risk for mortality (hospitalization required)
- Not designed to select level of care needed for hospitalized patients
PSI Risk Class I
- Absence of risk factors
- 0.4% 30 day mortality risk
- Recommended Tx Site: Outpatient
PSI Risk Class II
- =<70 points
- 0.7% 30 day mortality risk
- Recommended Tx Site: Outpatient
PSI Risk Class III
- 71-90 points
- 2.8% 30 day mortality risk
- Recommended Tx Site: Outpatient or brief inpatient
PSI Risk Class IV
- 91-130 points
- 8.5% 30 day mortality risk
- Recommended Tx Site: Inpatient
PSI Risk Class V
- > 130 points
- 31.1% 30 day mortality risk
- Recommended Tx Site: Inpatient
CURB-65
- Requires no labratory data
- Doesn’t consider outpatient treatment as much as PSI
Admitting CAP to ICU
- Major criterion: need for vasopressors, need for mechanical ventilation
- At least 3 of the minor criteria for severe CAP
Minor Criteria
- RR >= 30 breaths/min
- Multilobar infiltrates
- Confusion/disorientation
- Uremia
- Leukopenia
- Thrombocytopenia
- Hypothermia
- Hypotension
- PaO2/FiO2 ratio =< 250
Etiology Identification
- Organism identified in only ~30% of CAP cases
- Start empiric abx from procalcitonin diagnostic tests AND additional tests/labs
Additional Tests/Labs for Empiric Treatment
- Pretreatment sputum/bronchoalveolar lavage gram stain and culture
- Pretreatment blood gram stain and culture
- Urine legionella antigen test
- Urine pneumococcal antigen test
Empiric Outpatient Therapy + NO Comorbidities/Risk Factors for Drug-Resistance
-Strong Recommendation: Amoxicillin 1g PO TID
Conditional Recommendations:
-Doxy 100 mg PO BID
Macrolide (If resistance <25%):
-Azith 500 mg PO day 1, then 250 mg PO daily x 4days
-Clarithromycin 1000 mg ER PO QD or 500 mg BID
Don’t use FQN
Empiric Outpatient Therapy + Comorbidities/Risk Factors for Drug-Resistance
B-Lactam + Macrolide
- Augmentin 875/125 or 2000/125 PO BID
- Cefpodoxime 200 mg PO BID
- Cefuroxime 500 mg PO BID
OR Respiratory FQN -Moxifloxacin 400 mg PO QD -Levofloxacin 750 mg PO QD -Gemifloxacin 320 mg PO QD
Empiric Inpatient Therapy + Non-ICU
B-Lactam -Ceftriaxone 2g IV q24h -Cefotaxime 2g IV q8h -Unasyn 3g IV q6h -Ceftaroline 600 mg IV q12h PLUS Macrolide -Azithromycin 500 mg IV/PO QD -Clarithromycin 500 mg PO daily
OR
Respiratory FQN:
-Moxifloxacin 500 mg IV/PO q24h
-Levofloxacin 750 mg IV/PO q24h
DON’T use corticosteroids
MRSA + CAP
- Low prevalence
- Results in severe disease
- Empiric coverage recommended for patients with history of respiratory isolation within year, severe CAP with history of hospitalization or locally validated risk factors
- Treatment: Vanco 15 mg/kg IV q12h OR Linezolid 600 mg IV/PO q12h
- De-escalate treatment if PCR is negative or doesn’t grow in culture
P. aeruginosa + CAP
- Low prevalence
- Risk factors: lung disease, immunosuppression, ventilation
- Empiric coverage recommended for patients with history of respiratory isolation within year, severe CAP with history of hospitalization or locally validated risk factors
- De-escalate treatment if doesn’t grow in cultures
-P. aeruginosa + Treatment Options
- Zosyn: 4.5g IV q6h
- Cefepime 2g IV q8h
- Ceftazidime 2g IV q8h
- Primaxin: 500 mg IV q6h
- Meropenem 1g IV q8h
- Aztreonam 2g IV q8h
Aspiration
- May result in pneumonitis
- Many patients have symptom resolution in 24-48 hours without treatment
- Anaerobic bacteria don’t play a major role
- Anaerobic coverage rarely indicated unless lung abscess or empyema suspected
Empiric Inpatient Treatment + ICU
- B-Lactam PLUS Macrolide or Respiratory FQN
- Can also add empiric coverage for P. aeruginosa and MRSA if necessary
Duration of Therapy
- Continue treatment until patient is stable, minimal 5 days of Tx
- Hemodynamically stable and improving clinically with PE
- Cavitary or extrapulmonary disease may require longer therapy
- Other considerations: narrow therapy if possible, consider switching IV=>PO if able to and normal GI tract
Viral Influenza
- Symptoms: fever, chills, cough, sore throat, runny nose, muscle aches, HA, fatigue, N/V, diarrhea
- Rapid testing recommended during influenza season
Severe Viral Influenza Risks
- <5 y.o. or >= 65 y.o.
- Preggo or postpartum (2 wks post-delivery)
- Patients with certain comorbidities
- American Indian or Alaskan natives
- Long-term aspirin therapy
- Patients in long-term care facilities
Influenza Treatment Indications/Benefits
- Indicated for patients at risk of serious complications and positive PCV/symptoms, hospitalized or severely ill patients with positive PCR/symptoms
- Best benefits when starting within 48 hours
- Shown to decrease severity of symptoms and time of illness by 1-2 days
Influenza Treatment Options
- Oseltamivir (Tamiflu): 75 mg PO BID x5d
- Zanamavir (Relenza): two 5mg inhalations BID x5d
- Peramivir (Rapivab): 600mg IV once
- Baloxavir marboxil (Xofluza): 40 mg PO once
General Prevention
- Vaccine for 6+ mo
- Pneumococcal vaccines for 65+ y.o. and high-risk comorbidities
- Smoking cessation
