Lower Respiratory Tract Infections Flashcards
What are the LRTIs?
Bronchitis, Pneumonia
What are the symptoms of bronchitis?
Acute cough (usually <3 weeks) due to inflamm of trachea and lower airways
Generally starts w viral URTI
When is antibiotics indicated in bronchitis?
Not indicated unless suscpected SECONDARY bacterial infection. Treat based on culture.
Adjunctive abx treats secondary bacterial infection NOT bronchitis
What are the symptoms of pneumonia?
Fever, chills, malaise
Alt mental status (elderly)
Tachycardia, hypotension
Cough
Increased sputum pdtn
SOB
Chest pain
Tachypnoea
Hypoxia
What are the signs of pneumonia?
WBC, CRP, procalcitonin
Urinary antigens
Lung auscultation, lung CT, lung ultrasonography: new infiltrates or dense consolidations, usually unilateral
What is the pathophysiology of pneumonia?
Aspiration or inhalation of bacteria containing respiratory secretions or aerosols.
Hematogenous spreading: Bacteremia extrapulmonary source to the lungs
Proliferation of pathogens in the lower airways and alveoli
What are the risk factors for general pneumonia?
Hx of pneumonia
Smoking
Chronic lung conditions (e.g. asthma, COPD, CF, lung cancer)
Immune suppression
Prone to aspiration
Elderly
What are the risk factors specific for HAP?
Prolonged hospitalisation
Coma, impaired consciousness
Mechanical ventilation
Supine position
Lack of hand hygiene compliance
Contaminated medical devices
Opioid analgesics
Sedatives
Prev abx use
Malnutrition
Define CAP.
Pneumonia onset in community or <48h after hospitalisation
Define HAP.
Pneumonia onset >=48h after hospitalisation
What are the treatment categories for pneumonia?
CAP:
Outpatient, no comorbidities
Outpatient w comorbidities
In patient, non-severe
In patient, severe
HAP,VAP
What bugs must we cover for outpatient, no comorbidities?
S. pneumoniae
What bugs must we cover for outpatient w comorbidities?
S. pneumoniae, H. influenzae, Atypicals
What bugs must we cover for inpatient, non-severe?
S. pneumoniae, H. influenzae, Atypicals
Based on risk factors: P. aeruginosa, MRSA
What bugs must we cover for inpatient, severe?
S. pneumoniae, H. influenzae, Atypicals, S. aureus, Gram -ve (K. pneumoniae), Burkholderia pseudomallei
Based on risk factors: P. aeruginosa, MRSA
If abscess present: anaerobes
What bugs must we cover for HAP, VAP?
P. aeruginosa, S. aureus, Enterobacterales, Gram -ve , Anaerobes
Based on risk factor: MRSA
What is the recommended regimen for outpatient, no comorbidities?
Amoxicillin 1g Q8H
Penicillin allergy: Respi fluoroquinolones
What is the recommended regimen for outpatient w comorbidities?
Amoxicillin-clavulanate or Cefuroxime AND
Azithromycin or clarithromycin or doxycycline
OR
Respi fluoroquinolones
What is the recommended regimen for inpatient, non-severe?
Amoxicillin-clavulanate or cefuroxime or ceftriaxone AND
Azithromycin or clarithromycin or doxycycline
OR
Respi fluoroquinolones
If P. aeruginosa risk factors: modify regimen to include pseudomonal coverage (pip-tazo, ceftazidime, cefepime, meropenem, imipenem, ciprofloxacin, levofloxacin)
If MRSA risk factors: add Vancomycin, linezolid
Start IV, then de-esc to PO (but if well, start PO)
What is the recommended regimen for inpatient, severe?
Amoxicillin-clavulanate or Pen G AND
Ceftazidime
(for Burkholderia pneumonallei, H. influenzae) AND
Azithromycin or clarithromycin
OR
Respi fluoroquinolone AND
Ceftazidime (for Burkholderia pneumonallei, H. influenzae)
If P. aeruginosa risk factor: Modify regimen to cover (pip-tazo, ceftazidime, cefepime, imipenem, meropenem, ciprofloxacin, levofloxacin)
If MRSA risk factor: add vancomycin or linezolid
If anaerobe cover req: PO/IV metronidazole. If metronidazole cannot be used, use PO/IV clindamycin
What is CURB-65?
Confusion: 1
Urea >7.0 mmol/L: 1
RR >=30 bpm: 1
BP < 90/60 mm Hg: 1
>65y: 1
What is the recommended regimen for HAP, VAP?
Antipseudomonal beta lactam: piperacillin-tazobactam, ceftazidime, cefepime, imipenem, meropenem AND
Antipseudomonal fluoroquinolones: Ciprofloxacin (if pt wants to be discharged, dont want to overlap gram +ve coverage) > Levofloxacin AND
Amikacin
If MRSA risk factors: add vancomycin or linezolid
When do we give double anti-pseudomonal therapy for inpatient, severe?
- Risk of AMR (P. aeruginosa isolated in last 1y, IV abx in last 90d, RRT prior to VAP)
- Institution antibiogram shows >10% isolates resistant to agents considered for coverage of P. aeruginosa as monotherapy
- Prevalence but high risk of mortality
Do not use amikacin as monotherapy for pseudomonal coverage
What are the MRSA risk factors?
- Respi isolation of MRSA in last 1y
- IV abx use or hospitalisation in last 90d
- MRSA PCR screen +ve
Whar are the P. aeruginosa risk factors?
- Respi isolation of P. aeruginosa in last 1y
- IV abx use or hospitalisation in last 90d
Describe the process in determining CAP stratification and treatment.
- Determine severity using CURB-65
- Based on IDSA to determine inpatient nonsevere or severe
Define VAP.
Pneumonia onset >=48h after initiation of mechanical ventilation
How do we de-escalate inpatient CAP?
De-escalate when hemodynamically stable (gd BP, RR, vitals), improving clinically, able to ingest oral meds.
If culture +ve: streamline to AST
If culture -ve: remove pseudomonal and MRSA coverage after 48h if not isolated and pt is improving
How do we de-escalate HAP, VAP?
De-escalate when hemodynamically stable (gd BP, RR, vitals), improving clinically, able to ingest oral meds.
If culture +ve: streamline to AST
If culture -ve: remove only MRSA, gram -ve, anaerobe coverage after 48h if not isolated and pt is improving (MUST keep pseudomonal, enterobacterales, MSSA coverage)
What is the treatment duration for CAP?
Min 5d
Provided pt achieved clinical stability: Resoln of vital sign abnormalities (HR, RR, BP, O2 sat, T), Ability to maintain PO intake, Baseline mental status
7d if suspected/proven MRSA or Pseudomonas:
Longer courses for abx therapy for
- CAP complicated with other deep-seated infections (e.g. meningitis, lung abscess) –> 2-3 weeks
- Infection w other , less common pathogens (e.g. Burkholderia pseudomallei, Mycobacterium tuberculosis or endemic fungi) –> 3-6 weeks Burkholderia, 3-6mo Mycobacterium
What is the treatment duration for HAP/VAP?
7d regardless of pathogen
Provided pt achieved clinical stability: Resoln of vital sign abnormalities (HR, RR, BP, O2 sat, T), Baseline mental status
No evi that longer treatment duration reduces recurrence or mortality
Longer courses of abx for pneumonia complicated w other deep seated infections
What is the IDSA criteria for severe CAP?
> = 1 major criteria OR >=3 minor criteria
Major criteria: mechanical ventilation, septic shock, use of vasoactive meds
Minor criteria: CURB, PaO2/FiOx2 <=250, multilobar infiltrates, leukopenia (wbc < 4x10^9), hypothermia (core T < 36 deg C)
