LRTI; CAP

Question 1

What are 3 ways bacteria can enter the LRT through various mechanisms? (KIV, not in learning outcome)

Answer 1

1. Aspiration of oropharyngeal secretions
2. Inhalation of aerosols
3. Haematogenous spreading

Question 2

What is the S&S clinical presentation of pneumonia?

Answer 2

• Cough, chest pains, SOB, hypoxia
• Fever >38oC, chills
• Tachypnoea, Tachycardia, Hypotension
• Leukocytosis
• Fatigue, anorexia, nausea, changes in mental status

Question 3

What is the Physical Examination clinical presentation of pneumonia?

Answer 3

• Diminished breath sounds over the affected area

- Inspiratory crackles during lung expansion

Question 4

What is the Radiographic findings (clinical presentation and diagnosis) of pneumonia?

Answer 4

• Chest XR (CXR) or CT

- New infiltrates or dense consolidation

Question 5

What is the Lab findings (clinical presentation and diagnosis) of pneumonia?

Answer 5

• CRP, procalcitonin
• non-specific
• limited discriminatory potential
• not recommended for routine use to guide ABx initiation or discontinuation

Question 6

What should we take note for respiratory cultures?

Answer 6

• Sputum:
  ~ low yield; frequent contamination oropharyngeal secretions
  ~ Quality sample: >10 neutrophils and <25 epithelial cells per low-power field
• Lower RT samples:
  ~ Less contamination
  ~ invasive sampling (e.g. bronchoalveolar lavage (BAL)

Question 7

What should we take note for blood cultures?

Answer 7

Rule out bacteremia

Question 8

What should we take note of urinary antigen tests?

Answer 8

• Organisms that we are are looking for: Streptococcus pneumonia, Legionella pneumophilia
• Limitations: indicate exposure to the respective pathogens, remain positive for days-weeks despite Abx treatment
• NOT routinely used

Question 9

What is the classification of CAP?

Answer 9

Onset in community or <48 hours after hospital admission

Question 10

What are the risk factors for CAP?

Answer 10

1. Age >/= 65yo
2. Previous hospitalisation for CAP
3. Smoking
4. COPD, DM, HF, cancer, immunosuppression

Question 11

What are some preventions for CAP?

Answer 11

Smoking cessation

immunisations (influenza, pneumococcal)

Question 12

What are the risk stratification for major criteria?

Answer 12

• Mechanical ventilation

- Septic shock requiring vasoactive medications

Question 13

What are the risk stratification for minor criteria of CAP?

Answer 13

• RR > or = 30 breaths/min
• PaO2/FiO2 < or = 250
• Multi-lobar infiltrates
• Confusion/disorientation
• Uremia (urea >7mmol/L)
• Leukopenia (WBC <4 X 10^9/L)
• Hypothermia (core temp <36oC)
• Hypotension requiring aggressive fluid resuscitation

Question 14

How many major/minor criteria to determine severe CAP?

Answer 14

>/= 1 major criteria OR
>/= 3 minor criteria

Question 15

What are the potential organisms for standard regimens in outpatient CAP?

Answer 15

• Streptococcus pneumoniae
• H. influenzae
• Atypical organisms (MC)

Question 16

What is the empiric therapy for patients who are generally healthy for outpatient standard regimen CAP?

Answer 16

b-lactam (amoxicillin)
OR
Resp FQ (levo/moxi) - for pen allergy

all PO

Question 17

What is the empiric therapy for patients with chronic heart, lung, liver or renal diseases, DM, alcoholism, malignancy or asplenia in OUTpatient CAP standard regimen?

Answer 17

b-lactam (Augmentin OR Cefuroxime) + Macrolide (Clarithro/Azithro) OR Doxy

OR

Resp FQ (levo/moxi)

all PO

Question 18

What are the organism present in inpatient non-severe CAP?

Answer 18

• Streptococcus pneumoniae
• H. influenzae
• Atypical organisms (MCL)

Question 19

What is empiric therapy for inpatient non-severe CAP?

Answer 19

b-lactam (augmentin OR ceftriaxone) + Macrolide (clarithro/azithro) OR Doxy

OR

Resp FQ (levo/moxi)

b-lactam and FQs adm IV (step down to PO later)
Macrolide and doxy adm PO (if there is no N/V, can tolerate)

Question 20

What are the organisms present in inpatient severe CAP?

Answer 20

• Streptococcus pneumoniae
• H. influenzae
• Atypical organisms (MCL)
• S. aureus
• Other gram-ve bacilli (e.g. K. pneumoniae, BURKHOLDERIA PSEUDOMALLEI) B.P.

Question 21

What is empiric therapy for inpatient severe CAP?

Answer 21

b-lactam (augmentin + CEFTAZIDIME) + Macrolide (clarithro/azithro) OR Doxy

OR

Resp FQ (levo/moxi) + CEFTAZIDIME

b-lactam and FQs adm IV (step down to PO later)
Macrolide and doxy adm PO (if possible)

Question 22

What if pt has pen allergy? What if allergy to Ceftazidime?

Answer 22

Evaluate the severity of penicillin allergy
E.g. Simple rash, most can tolerate; 3rd gen, low cross reactivity
E.g. If anaphylaxis, omit ceftazidime and other b-lactams and just give resp FQs; we know that it doesnt cover B.P. but no choice. Monitor and see if need to cover B.P.

Question 23

What is the indications for anaerobic coverage and what anaerobes are present (inpatient only) ?

Answer 23

• any one of them: Lung abscess and/or empyema

- common species: Bacteriodes fragilis, Prevotella spp, Porphyromonas spp, Fusobacterium spp.

Question 24

Which Abx to add for anaerobic activity? (except for which situations?)

Answer 24

• Clindamycin (IV/PO) OR Metronidazole (IV/PO)

Augmentin and moxifloxacin in standard regimen have already anaerobic coverage, so don’t need to add Clinda/Metro if augmentin/ moxi is given
(pip-tazo as well)

Question 25

What are the indications for MRSA and what Abx would be provided to cover MRSA?

Answer 25

- Any one of these: Prior respiratory isolation of MRSA in the last 1 year and/or Severe CAP only: hospitalisation and received IV ABx within last 90days (and locally validated risk factors) Abx added to standard regimenP - Vancomycin IV - Linezolid (PO/IV)

Question 26

What is the indication for pseudomonal coverage and what are the Abx covered for Pseudomonas?

Answer 26

Prior respiratory isolation of Pseudomonas in the last 1 year Modify standard regimen, add: - Pip/Tazo (IV) - Ceftazidime IV (alr in standard regimen for inpatient severe) - Cefepime IV - Meropenem IV (reserve for ESBL) - Levo (IV/PO) (alr in standard regimen outpt and inpt)

Question 27

Why FQs are not 1st line therapy?

Answer 27

- inc adv effects - collateral damage - preserve activity for other gram-ve infections - FQs only PO options covering P. aeruginosa - Delay diagnosis of TB

Question 28

Is adjunctive corticosteroid therapy recommended?

Answer 28

NO

Question 29

What is the safety and efficacy for monitoring CAP?

Answer 29

Safety: adv effects of Abx (diarrhoea, rash), renal fn Efficacy: - clinical improvement expected in 48-72 hours (dec cough, chest pain, SOB, fever, WBC, tachypnoea, etc.; elderly w multiple comorbidities may take longer) - Should not escalate Abx therapy in 1st 72 hours (unless culture-directed or sig clinical deterioration) - Radiographic improvement lags behind, up to 4-6wks for resolution (repeat only if clinical deterioration)

Question 30

When to modify treatment for empiric coverage for MRSA/ P. aerugionsa?

Answer 30

STOP coverage in 48hrs if no MRSA/P. aeruginosa is found on culture and pt is improving

Question 31

When to step down to PO?

Answer 31

ALL criteria must be met: - Haemodynamically stable - Clinically improved/improving - Afebrile >/= 24hrs - Normal GIT function - Able to ingest PO med if there are positive cultures: use susceptibility results to guide selection of PO abx if no +Ve cultures: use same Abx or another ABx of same class; empiric coverage with PO step-down therapy for MRSA/P. aeruginosa/B. pseudomallei usually irrelevant

Question 32

e.g. if ceftriaxone + clarithromycin was given at first for inpatient non-severe IV, how do we step down to PO?

Answer 32

Ceftriaxone (IV) --> cefuroxime (PO) clarithro was alr in PO

Question 33

How long is the treatment? exceptions?

Answer 33

- at least 5 days (until clinical stability is achieved, i.e., afebrile, able to take PO, normal vital signs, O2 saturation and mental status) - most achieve stability within 48-72 hrs - Exceptions: - MRSA, P. aeruginosa ~ 7 days - B.P. ~ 3-6 months