LRTI (Bronchitis & CAP) Flashcards
What are the 2 types of LRTIs?
Acute bronchitis and Pneumonia
Define acute bronchitis
Acute cough < 3w due to inflammation of trachea and lower airways
How does acute bronchitis generally start? (viral/ bacterial)?
Is it self-limiting? How long does it usually last for?
> 92% of cases are viral
Self-limiting, lasts up to 1-3w, giving symptomatic relief is enough
Do we use abx for acute bronchitis?
No
When should pt with acute bronchitis see a doctor?
Pt should see a doctor if they develop:
- Fever
- SOB
- Chest pain
- Cough ↑ in extent or frequency/ cough persists beyond 3w
Is pneumonia typically a viral or bacterial infection?
Normally a bacterial infection
What are the risk factors for pneumonia? (4)
- Smoking
- Chronic lung conditions (eg COPD, asthma, lung cancer)
- Immune suppression (eg HIV, sepsis, glucocorticoids, chemotherapy)
- Exposure to pathogen via inhalation, aspiration, contiguous or haematological mechanism
Systemic and localised s/sx of pneumonia?
What is a s/sx that the elderly may experience?
Systemic s/sx:
- Fever
- Chills
- Malaise
- Mental status changes* (elderly)
- Tachycardia
- Hypotension
Localised s/sx:
- Cough
- Chest pains
- SOB
- Tachypnoea
- Hypoxia
- Increased sputum production
What results of a physical examination will result in the diagnosis of pneumonia? (2)
- Diminished breath sounds over affected area
- Inspiratory crackles during lung expansion
What type of test is NEEDED for diagnosis of pneumonia?
What are the findings of the test that are indicative of pneumonia?
CXR/ lung CT/ lung ultrasonography
Diagnosis of pneumonia requires evidence of NEW infiltrates or dense consolidations
What are the laboratory findings for pneumonia? (non-specific signs of systemic infection)
Signs of systemic infection (non-specific to pneumonia):
- WBC (normal: 4-10 x 109/L)
- C-reactive protein (infection > 40mg/L)
- Procalcitonin ≥ 0.25μg/L
On which type of pts do we perform urinary antigen tests?
What bacterial pathogens does it test for?
Limitations of urinary antigen tests?
Recommended for severe CAP or hospitalised pts
Streptococcus pneumonia
Legionella pneumophila
Limitation: may just indicate exposure to respective pathogens & remains +ve for days - weeks despite abx Tx
What are the different types of respiratory gram-stain and cultures that we can do for pneumonia? (3)
Comment on each of them
- Sputum
- Low yield
- Contamination by oropharyngeal secretions - Lower respiratory tract samples
- Invasive sampling
- Less contamination - Blood cultures
- To rule out bacteremia
- Esp done for hospitalised pts
What are the 2 types of pts we should obtain pre-treatment blood and respiratory gram-stain and cultures for pneumonia?
Pts managed in the hospital who are:
- Classified as severe CAP
- Have risk factors for drug-resistant pathogens like MRSA and P. aeruginosa
What are the risk factors for drug-resistant pathogens like MRSA and P. aeruginosa
- Empirically treated for MRSA or P. aeruginosa
- Previously infected with MRSA or P. aeruginosa in last 1 year
- Hospitalised or received parenteral abx in last 90 days (weak, low quality of evidence)
Define CAP
Onset in community or < 48h after hospital admission
What are the risk factors of CAP? (4)
- History of pneumonia
- Smoking
- Chronic respiratory diseases
- Immunosuppression
Prevention of CAP? (2)
- Smoking cessation
- Immunisations (influenza, pneumococcal)
List the CURB-65 criterions (5- 1 point each)
- New onset confusion
- Urea > 7 mmol/L
- RR ≥ 30 breaths/min
- Blood pressure (SBP < 90 mmHg or DBP ≤ 60 mmHg)
- Age ≥ 65 y/o
What are the scores for CURB-65? (which scores mean outpatient, inpatient etc)
Score: 0 or 1 → outpatient
Score: 2 → inpatient
Score: ≥ 3 → inpatient, consider ICU
Other than CURB-65, what is another risk stratification guideline that is more preferred to categorise pts into outpatient/ inpatient?
Name the different classes and what they mean
Pneumonia Severity Index (PSI)
Class I and II: outpatient
Class III: short hospitalisation or observation (can be managed as outpatient)
Class IV and V: inpatients
What is the risk stratification method for severe CAP? (2 major and 8 minor criteria)
How many major or minor criterias are needed for diagnosis of severe CAP?
Major criteria:
- Mechanical ventilation
- Septic shock requiring vasoactive medications
Minor criteria:
- RR ≥ 30 breaths/min
- PaO2/ FiO2 ≤ 250
- Multilobar infiltrates
- Confusion/ disorientation (esp elderly)
- Uremia (urea > 7 mmol/L)
- Leukopenia (WBC < 4 x 109/L)
- Hypothermia (temp < 36°C)
- Hypotension requiring aggressive fluid resuscitation
Severe CAP: ≥ 1 major criterion or ≥ 3 minor criteria
Key pathogens for outpatient CAP, no co-morbidities? (1)
Streptococcus pneumoniae
Do we give IV or PO abx for outpatient CAP (non-severe and severe?)
Give PO
Empiric regimen for outpatient CAP, no co-morbidities?
β-lactam:
- PO amoxicillin 1g tds
OR
Respiratory FQ (if penicillin allergy):
- PO levofloxacin 750mg od
- PO moxifloxacin
What are the type of co-morbidities that CAP outpatients may have which warrants greater abx coverage and Tx?
- Chronic heart, lung, liver, renal disease
- DM
- Alcoholism
- Malignancy
- Asplenia
What pathogens must we cover for outpatient CAP with comorbidities (chronic heart, lung, liver, renal disease, DM, alcoholism, malignancy, asplenia)? (3 types)
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypicals (Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila)
Empiric regimen for outpatient CAP, with co-morbidities?
What ADRs must you take note of for doxycycline?
β-lactam:
- PO amoxicillin-clavulanate 625mg tds
- PO cefuroxime 500mg bd
PLUS
Macrolide or Tetracycline:
- PO clarithromycin 500mg bd
- PO azithromycin 500mg od
- PO doxycycline 100mg bd (ADRs: esophagitis (concerning, make sure pt can stay upright and drink a lot of water to flush down drug), photosensitivity)
OR
Respiratory FQ:
- PO levofloxacin 750mg od
- PO moxifloxacin
Key pathogens for CAP inpatient, non-severe? (3)
Without MRSA or P. aeruginosa risk factors yet
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypicals (Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila)
Do we give PO or IV for CAP inpatient, non-severe?
Can initiate IV, step down to PO later
May also give PO if pt well
Tx for CAP inpatient, non-severe?
Without MRSA or P. aeruginosa risk factors yet
What must you take note of for doxycycline?
β-lactam:
- IV amoxicillin-clavulanate 1.2g tds
- IV cefuroxime 500mg bd
- IV ceftriaxone 1-2g od
PLUS
Macrolide or Tetracycline:
- IV clarithromycin 500mg bd
- IV azithromycin 500mg od
- PO Doxycycline 100mg bd (ADRs: esophagitis (concerning, make sure pt can stay upright and drink a lot of water to flush down drug), photosensitivity)
OR
Respiratory FQ:
- IV levofloxacin 750mg od
- IV moxifloxacin
What are the MRSA risk factors to consider for CAP inpatient non-severe? (2)
How is it different from CAP inpatient severe?
MRSA risk factors:
1. Resp isolation of MRSA in last 1 year
2. Hospitalisation or parenteral abx use in last 90 days PLUS MRSA PCR screen +ve
Different regarding factor no. 2: inpatient non-severe need the additional MRSA PCR screen +ve test but inpatient severe don’t need
For inpatient CAP non-severe, Tx for additional MRSA coverage?
Add on:
- IV vancomycin 25-30mg/kg loading dose, 15mg/kg bd-tds
- IV/PO linezolid 600mg bd
What are the P. aeruginosa risk factors to consider for CAP inpatient non-severe? (1)
P. aeruginosa risk factors:
Resp isolation of P. aeruginosa in last 1 year
For inpatient CAP non-severe, Tx for additional P. aeruginosa coverage?
Modify regimen to include P. aeru coverage:
- Piperacillin-tazobactam
- Ceftazidime
- Cefepime
- Meropenem
- Levofloxacin
Key pathogens for CAP inpatient severe?
All of outpatient:
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypicals (Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila)
AND
- Staphylococcus aureus
- Other gram -ve (Klebsiella pneumonia, Burkholderia pseudomallei*)
Do we give PO or IV for CAP inpatient, severe?
- Initiate IV, step down to PO later
- May give PO if pt well
Tx for CAP inpatient severe?
Without MRSA or P. aeruginosa risk factors yet
- β-lactam:
- IV amoxicillin-clavulanate 1.2g tds
- Penicillin G
PLUS
- IV ceftazidime 2g tds (covers burkholderia)
PLUS
Macrolide:
- IV clarithromycin 500mg bd
- IV azithromycin 500mg od
OR
- Respiratory FQ:
- IV levofloxacin 750mg od
- IV moxifloxacin
PLUS
- IV eftazidime 2g tds
What are the MRSA risk factors to consider for CAP inpatient severe? (2)
MRSA risk factors:
1. Resp isolation of MRSA in last 1 year
2. Hospitalisation or parenteral abx use in last 90 days
(unlike inpatient non-severe, don’t need MRSA PCR +ve screen test)
For inpatient CAP severe, Tx for additional MRSA coverage?
Add on:
- IV vancomycin
- IV/PO linezolid
What are the P. aeruginosa risk factors to consider for CAP inpatient severe? (2)
- Resp isolation of P. aeruginosa in last 1 year
- Hospitalisation or parenteral abx use in last 90 days
For inpatient CAP severe, Tx for additional P. aeruginosa coverage?
Ensure regimen includes P. aeru coverage:
- Ceftazidime
- Levofloxacin
For CAP, when do we modify empiric Tx to include anaerobic cover?
If CT scan reports lung abscess/ empyema
What can we give to include anaerobic cover for CAP? (in the case CT scan reports lung abscess/ empyema)
First-line:
- Add IV/PO metronidazole
If metronidazole contraindicated:
- Add IV/PO clindamycin
What to take note of regarding use of respiratory FQs in Tx for CAP?
Respiratory FQs are not first-line for CAP:
- ↑ ADEs (eg tendonitis/ tendon rupture, neuropathy, QTc prolongation, CNS disturbances, hypoglycemia)
- If overuse → resistance
- Undesirable monoTx if pt ends up having TB
- Preserve activity for other gram -ve infections (Levo and cipro → alternative P. aeruginosa coverage for severe penicillin allergies +
Only PO options for P. aeruginosa)
What Tx should we add if we suspect that the pt has influenza?
When is the best time to initiate?
- Add PO Oseltamivir if suspicious for influenza
- Initiate ASAP (best within 48h, up to 5 days) of s/sx onset
Tx duration for suspected influenza?
If positive influenza PCR:
- Complete 5 day course
- Consider discontinuing abx at 48 - 72h if no evidence of bacterial pathogen (ie -ve cultures, low procalcitonin levels, early clinical stability)
Comment on the use of adjunctive corticosteroid Tx for CAP (what it does + whether we should add)
- ↓ lung inflammation
- DO NOT routinely add, only if shock refractory to fluid resuscitation and vasopressor support
No benefit for non-severe CAP
Conflicting mortality benefit in severe CAP
Duration of Tx for CAP?
When are longer courses of abx needed?
- Minimum 5 days Tx
- 7 days if suspected MRSA or P. aeruginosa
Longer courses of abx for:
- CAP complicated with other deep-seated infections (eg meningitis, lung abscess)
- Infection with less common pathogens (Burkholderia pseudomallei, Mycobacterium tuberculosis, endemic fungi)
When can we de-escalate Tx of CAP? (3)
When pt is:
- Hemodynamically stable (labs, vital signs)
- Improving clinically
- Able to ingest PO
How should we de-escalate Tx for CAP following a positive culture?
Use AST to guide selection of lower spectrum abx
How should we de-escalate Tx for CAP following no positive culture?
- Empiric cover for MRSA, P. aeruginosa or Burkholderia pseudomallei can be stopped in 48h if pathogen not isolated + pt improving
- IV-to-PO: use same abx or same class abx
How long do most pts take to achieve clinical stability for CAP?
Should we escalate abx in the first 72 hours?
Most pts achieve clinical stability within first 48 - 72h (hence should not escalate abx in the first 72 hours unless culture-directed or significant clinical deterioration)
Elderly/ pts with co-morbs may take longer
