LRTI - Acute Bronchitis and Pneumonia Flashcards
Describe the clinical presentation of acute bronchitis
Acute cough of less than or equals to 3 weeks
- Happens due to inflammation of the lower airways
Is a bacterial culture needed for acute bronchitis?
No. Acute bronchitis is usually self limiting. Only needed if there are complications of bacterial infection suspected
Describe the pathogenesis of pneumonia
Exposure to particles happen due to inhalation, aspiration or hematogenous secretions from bacteremia.
Pathogen then enters susceptible host and virulent pathogen
Proliferation of microbe in lower airway/ alveoli then causes pneumonia
What are the risk factors and how are they associated with pneumonia?
Smoking: suppress neutrophil function and damage the lung epithelium
Chronic lung conditions such as COPD, Asthma and lung cancer. Destroys lung tissue and offer pathogen routes for infection
Immune suppression from HIV, sepsis, glucocorticoid use and chemotherapy
What are the general systemic presentations of pneumonia?
Fever and chills
Malaise
Change in mental status (elderly)
Tachycardia
Hypotension
What are the localised symptoms of those with pneumonia?
Cough
Shortness of breath
Chest pain
Tachypnoea
Hypoxia
Increased sputum production
What are some diagnostic tools to consider to help us confirm the presence of infection?
Radiological findings: Chest xray, lung CT and lung ultrasonography
- Findings include new infiltrates / dense consolidates
Lab findings: general and non-specific
Urinary antigen tests: detect S.pneumoniae and legionella pneumophilla only
Respiratory, gram stain and culture
Which subgroup is suitable for conducting pre-treatment blood and respiratory gram stain and cultures?
Severe CAP
Those with risk factors of drug resistent pathogens
- Being empirically treated for MRSA / P.Aeruginosa
- Previously infected with MRSA / P.Aeruginosa in a year
- Hospitalized / received parenteral antibiotics in last 90 days
Define the three types of pneumonia
Community acquired pneumonia: Onset in community / <48h upon hospital admission
Healthcare associated pneumonia: Onset > 48h after hospital admission
Ventilator associated pneumonia: Onset >48h after mechanical ventilation
What are the types of pathogen in outpatient and inpatient (non severe) cases of community acquired pneumonia?
S.Pneumoniae
H.Influenzae
Atypical organisms: Mycoplasma pneumoniae, chlamydia pneumoniae and legionella pneumoniae
What are the types of pathogen in inpatient (severe) cases of community acquired pneumonia?
S.Pneumoniae
H.Influenzae
Atypical organisms: Mycoplasma pneumoniae, chlamydia pneumoniae and legionella pneumoniae
S.Aureus
Gram negative bacilli: Klebsiella pneumoniae, burkholderia pseudomallei
Why is it important for risk stratification of CAP?
Determines the
- Location of treatment
- Organism
- Type of empiric antibiotics
- Route of administration
How is risk stratification of CAP decided?
Pneumonia severity index (PSI)
CURB-65
IDSA/ATS criteria
How is PSI scoring used to
stratify patients?
Class I and II (0-70): Outpatients
Class III (71-90): Short hospitalization / observations
Class IV / V (91 and above): Inpatient
How is CURB-65 used to stratify patients?
0-1: Outpatient
2: Inpatient
>3: Inpatient and severe (i.e. consider ICU)
How is the IDSA/ATS criteria used to determine severe CAP?
It is severe CAP if more than 1 major criteria or more than 3 minor criterias are achieved
What are the major and minor criteria of IDSA/ATS criteria?
Major: mechanical ventilation, septic shock requiring vasoactive medications
Minor: RR> 30 bpm, PaO2/FiO2 < 250, multilobar infiltrates, confusion, uremia, leukopenia, hypothermia, hypotension requiring aggressive fluid resuscitation
How is an antibiotic chosen?
Risk stratification
Any comorbidities
MRSA/ P.Aeruginosa risk factors
What is the empiric therapy for outpatients with no comorbidities? What is the pathogen of concern?
PO Amoxicillin 1g q8h
- Pathogen: S.Pneumoniae
If allergic, take levofloxacin / moxifloxacin
What is the empiric therapy for outpatients with comorbidities? What is the pathogen of concern?
PO Amoxicillin clavulanate / cefuroxime + clarithromycin/azithromycin/doxycycline
- Pathogen: S.Pneumoniae, H.Influenzae, Atypical microorganisms
If allergic take levofloxacin / moxifloxacin
What are some of the possible MDRO risk factors to consider for patients with CAP ?
MRSA
- Resp isolation of MRSA in last 1 year
- Hospitalization/ parenteral antibiotics in last 90 days + MRSA PCR positive
Pseudomonas aeruginosa
- Resp isolation of P.Aeruginosa in last 1 year
What empiric antibiotics to consider adding for those with Pseudomonas and MRSA risk factors?
MRSA: IV Vancomycin/ PO Linezolid
Pseudomonas Aeruginosa:
- Piperacillin tazobactam
- Cefepime
-Meropenem
- Levofloxacin
What is the empiric therapy for inpatients non severe CAP? What is the pathogen of concern?
PO Amoxicillin clavulanate / cefuroxime + clarithromycin/azithromycin/doxycycline
- Pathogen: S.Pneumoniae, H.Influenzae, Atypical microorganisms
If allergic take levofloxacin / moxifloxacin
Why are respiratory fluoroquinolones generally not recommended?
Increase adverse effects
Development of resistance
Preserve activity for other gram-negative infections
Delay diagnosis of tuberculosis
What is the empiric therapy for inpatients severe CAP? What is the pathogen of concern?
Amoxicillin clavulanate / Penicillin G + Ceftazidime + Clarithromycin / Azithromycin
Alternative: Levofloxacin / Moxifloxacin + Ceftazidime
Pathogens: S.Pneumoniae, H.Influenzae, Atypicals, S.Aureus, Burkholderia pseudomallei
Is there a need for P.Aeruginosa coverage for inpatient and severe cases?
Not really as current regimen already covers Pseudomonas aeruginosa
What are some special considerations to consider with regards to empiric therapy?
Anaerobic coverage
Additional influenza management
Adjunctive corticosteroid therapy
What are the indications of anaerobic coverage?
Lung abscess and emphysema
Current regimen already cover amoxicillin clavulanate and ceftazidime
If regimens do not cover clarithromycin metronidazole
What is the influenza management for current treatment regimens?
Providing influenza management which is best within 48h, up to 5 days.
Consider discontinuing antibiotics at 48-72 hours if no evidence of bacterial pathogen
What are the indications for adjunctive corticosteroid therapy?
Shock refractory to fluid resuscitation
Vasopressor support
When should deescalation of therapy?
Hemodynamically stable
- resolution of vital signs abnormalities
- baseline mental status
Improving clinically
Able to ingest oral
What is the ideal duration of therapy?
5 - 7 days (longer if suspected MRSA/ P.Aeruginosa)
When should longer courses of antibiotics be considered?
CAP complicated with deep-seated infections
Infection with other less common pathogen
How should monitoring of response be done for CAP?
Clinical stability in first 48-72 hours
No need microbiological test clearance
Advice ADR of antibiotics
What are the risk factors of HAP/ VAP?
Patient factors: elderly, smoking, COPD, cancer, immunosuppression, prolonged hospitalization, coma, impaired consciousness and malnutrition
Infection control related: lack of hand hygiene compliance, contaminated respiratory care devices
Healthcare related: Prior antibiotic use, sedative, opioid analgesics, mechanical ventilation and supine position
What are some preventive techniques to counter HAP/ VAP?
Practise consistent hand hygiene
Use of antibiotics and medications with sedative effects
Limit duration of mechanical ventilation and deep levels of sedation
Elevate head of bed by 30 deg
How are the pathogens for HAP/VAP identified? What pathogens need to be covered for HAP/ VAP?
Each hospital have different microbiota
Coverage should be done for Pseudomonas aeruginosa and S.Aureus
When should I consider for double antipseudomonal therapy in HAP/ VAP?
Prior IV antibiotics use in last 90 days
Isolation of MRSA in last 1 year
Hospitalization in unit where >20% S.Aureus are MRSA
Prevalence of MRSA in hospitals not known but patient at high risk of mortality
What are some anti-pseudomonal beta lactams?
Piperacillin tazobactam
Cefepime
Ceftazidime (Avoid if no MRSA risk)
Meropenem
Imipenem
What are the anti-pseudomonal fluoroquinolones to consider for double antipsuedomonal therapy?
Levofloxacin
Ciprofloxacin
