LRTI; CAP Flashcards
What are 3 ways bacteria can enter the LRT through various mechanisms? (KIV, not in learning outcome)
- Aspiration of oropharyngeal secretions
- Inhalation of aerosols
- Haematogenous spreading
What is the S&S clinical presentation of pneumonia?
- Cough, chest pains, SOB, hypoxia
- Fever >38oC, chills
- Tachypnoea, Tachycardia, Hypotension
- Leukocytosis
- Fatigue, anorexia, nausea, changes in mental status
What is the Physical Examination clinical presentation of pneumonia?
- Diminished breath sounds over the affected area
- Inspiratory crackles during lung expansion
What is the Radiographic findings (clinical presentation and diagnosis) of pneumonia?
- Chest XR (CXR) or CT
- New infiltrates or dense consolidation
What is the Lab findings (clinical presentation and diagnosis) of pneumonia?
- CRP, procalcitonin
- non-specific
- limited discriminatory potential
- not recommended for routine use to guide ABx initiation or discontinuation
What should we take note for respiratory cultures?
- 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)
What should we take note for blood cultures?
Rule out bacteremia
What should we take note of urinary antigen tests?
- 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
What is the classification of CAP?
Onset in community or <48 hours after hospital admission
What are the risk factors for CAP?
- Age >/= 65yo
- Previous hospitalisation for CAP
- Smoking
- COPD, DM, HF, cancer, immunosuppression
What are some preventions for CAP?
Smoking cessation
immunisations (influenza, pneumococcal)
What are the risk stratification for major criteria?
- Mechanical ventilation
- Septic shock requiring vasoactive medications
What are the risk stratification for minor criteria of CAP?
- 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
How many major/minor criteria to determine severe CAP?
>/= 1 major criteria OR >/= 3 minor criteria
What are the potential organisms for standard regimens in outpatient CAP?
- Streptococcus pneumoniae
- H. influenzae
- Atypical organisms (MC)
What is the empiric therapy for patients who are generally healthy for outpatient standard regimen CAP?
b-lactam (amoxicillin)
OR
Resp FQ (levo/moxi) - for pen allergy
all PO
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?
b-lactam (Augmentin OR Cefuroxime) + Macrolide (Clarithro/Azithro) OR Doxy
OR
Resp FQ (levo/moxi)
all PO
What are the organism present in inpatient non-severe CAP?
- Streptococcus pneumoniae
- H. influenzae
- Atypical organisms (MCL)
What is empiric therapy for inpatient non-severe CAP?
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)
What are the organisms present in inpatient severe CAP?
- Streptococcus pneumoniae
- H. influenzae
- Atypical organisms (MCL)
- S. aureus
- Other gram-ve bacilli (e.g. K. pneumoniae, BURKHOLDERIA PSEUDOMALLEI) B.P.
What is empiric therapy for inpatient severe CAP?
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)
What if pt has pen allergy? What if allergy to Ceftazidime?
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.
What is the indications for anaerobic coverage and what anaerobes are present (inpatient only) ?
- any one of them: Lung abscess and/or empyema
- common species: Bacteriodes fragilis, Prevotella spp, Porphyromonas spp, Fusobacterium spp.
Which Abx to add for anaerobic activity? (except for which situations?)
- 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)
What are the indications for MRSA and what Abx would be provided to cover MRSA?
- 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)
What is the indication for pseudomonal coverage and what are the Abx covered for Pseudomonas?
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)
Why FQs are not 1st line therapy?
- inc adv effects
- collateral damage
- preserve activity for other gram-ve infections
- FQs only PO options covering P. aeruginosa
- Delay diagnosis of TB
Is adjunctive corticosteroid therapy recommended?
NO
What is the safety and efficacy for monitoring CAP?
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)
When to modify treatment for empiric coverage for MRSA/ P. aerugionsa?
STOP coverage in 48hrs if no MRSA/P. aeruginosa is found on culture and pt is improving
When to step down to PO?
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
e.g. if ceftriaxone + clarithromycin was given at first for inpatient non-severe IV, how do we step down to PO?
Ceftriaxone (IV) –> cefuroxime (PO)
clarithro was alr in PO
How long is the treatment? exceptions?
- 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
