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Antibiotic > Pneumonia > Flashcards

Pneumonia Flashcards

1
Q

Most common organisms

causing pneumonia

A
  1. Streptococcus pneumoniae (~ 65%)
  2. Haemophilus influenzae (~ 10%)
  3. Mycoplasma pneumoniae, Legionella sp. and Chlamydia pneumoniae (~ 20%)
  4. Mycobacterium tuberculosis
  5. Viruses
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2
Q

other organism that cause pneumonia

A
  1. Staphylococcus aureus
  2. Gram negative bacilli – Burkholderia pseudomallei (meloidosis), Klebsiella pneumoniae
  3. Anaerobic bacteria – Peptococcus, Peptostreptococcus a. Cause aspiration pneumonia
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3
Q

Risk factor for

CAP

A

A. Host factors

  1. Increasing age
  2. Male sex

B. Modifiable risk factors

  1. Smoking
  2. Malnutrition
  3. Low vitamin D level

C. Underlying lung disease

  1. COPD, asthma
  2. Preceding viral respiratory infection

D. Chronic medical conditions

  1. Stroke
  2. Diabetes
  3. Renal disease
  4. Dysphagia

E. Immune suppression 1. TNFα inhibitors
2. HIV infection

F. Medications

  1. PPI’s
  2. Inhaled steroids

G. Socioeconomic factors

  1. Low-income household
  2. Crowded living conditions
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4
Q

Clinical presentation CAP

A

A. Usual presentation 1. Fever
2. Cough – productive 3. Shortness of breath 4. Tachypnea

Non-specific

  • N/V/HA
  • myalgia

B. Clinical signs and symptoms cannot reliably be used to predict the microbial etiology of community-acquired pneumonia.

C. Physical examination findings - Lungs

  1. Decreased breath sounds
  2. Inspiratory crackles 3. Dullness on percussion

D. Elderly and patients with co-existing illnesses may not present with usual signs and symptoms

  1. May present with poor feeding, drowsiness, no fever
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5
Q

Diagnosis of CAP

A

A. Clinical presentation
B. Chest X-ray
1. Changes that may indicate pneumonia – consolidation, infiltrate 2. Assess pre-existing lung disease
3. Baseline assessment – monitor response to therapy

C. White blood cell count
1. Aid in the diagnosis of infection, in general

D. Other
1. Electrolytes
2. Renal function
3. C-reactive protein (CRP) – Not specific for infection
4. Procalcitonin
- Released in response to bacterial toxins and inflammatory mediators - Aids in differential diagnosis of viral vs. bacterial infection
- Non-ICU patients
> 0.25mcg/L or ICU patients > 0.5mcg/L → can aid in decision to start antibiotic therapy

E. Microbiologic

  1. Aid selection of antibiotic therapy
    a. Use drug active against organism
    b. Narrow down spectrum of drug
    c. Use lower cost drug
  2. Identify unusual pathogens
  3. Gram stain sputum
    a. Sputum vs. saliva
    i. < 10 epithelial cells
    ii. > 25 neutrophils
    b. Technique and operator dependent
  4. Sputum culture
    a. Takes at least 48 – 72 hours to get results
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6
Q

Diagnosis

  1. Blood culture
    a. Bacteremia in ~ 11% of patients
    b. Infection can spread from blood to lungs, or lungs to blood
    c. Associated with higher mortality
    d. Selected hospitalized patients
    i. severe pneumonia
    ii. immunocompromised
  2. Urine culture
A

Diagnosis

  1. Blood culture
    a. Bacteremia in ~ 11% of patients
    b. Infection can spread from blood to lungs, or lungs to blood
    c. Associated with higher mortality
    d. Selected hospitalized patients
    i. severe pneumonia
    ii. immunocompromised
  2. Urine culture
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7
Q

Diagnosis

  1. Urine antigen tests (hard to grow on culture)
    a. Legionella, Strep. pneumoniae
    b. Only indicates that there has been exposure to the organism and an immunologic response
  2. Polymerase chain reaction (PCR) assays (blood)
    a. Selected organisms - Legionella, Mycoplasma, Strep. pneumoniae, Chlamydia and Viruses
    b. Higher sensitivity and specificity compared to urine antigen tests
A

Diagnosis

  1. Urine antigen tests
    (hard to grow on culture)
    a. Legionella, Strep. pneumoniae
    b. Only indicates that there has been exposure to the organism and an immunologic response
  2. Polymerase chain reaction (PCR) assays (blood)
    a. Selected organisms - Legionella, Mycoplasma, Strep. pneumoniae, Chlamydia and Viruses
    b. Higher sensitivity and specificity compared to urine antigen tests
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8
Q

F. Guidelines on CAP are conflicting for recommendations on extent and importance of diagnostic work-up
1. Performing diagnostic tests should never delay the start of antibiotic therapy

A

F. Guidelines on CAP are conflicting for recommendations on extent and importance of diagnostic work-up
1. Performing diagnostic tests should never delay the start of antibiotic therapy

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9
Q

Risk stratification for CAP (IN OR OUT PT tx )

A

1) pneumonia seerity index (PSI)
- Need lots of data
- Complicated
(Lvl 1-3 = low
lvl 4 = moderate
lvl 5 = high)

2) CURB-65 severity score. 
Based on 
- Confusion ( =<8 
                  score)
- Urea >7mmol/L
- Respiratory rates >= 30/min
  • BP (SBP<90mmhg; DBP<= 60mmhg)
  • Age >= 65yo

Group 1
= 0/1 score
= LOW mortality
= outpatient

Group 2
= 2 score 
= intermediate mortality
= Consider hospital supervised tx 
( a: Short stay inpatient
  b: Hospital supervised outpatient)

Group 3
= >=3 score
= High mortality
= managed in hospital as severe pneumonia
= Asess for ICU admission especially if CURB-65 score = 4or5

3) social issue
a. Caregiver support at home
b. Likelihood of compliance with outpatient therapy and follow-up

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10
Q

B. Other factors to consider in choosing initial empiric antibiotic therapy
1. Adverse reactions or allergies to antibiotics 2. Co-existing illnesses

A

B. Other factors to consider in choosing initial empiric antibiotic therapy
1. Adverse reactions or allergies to antibiotics 2. Co-existing illnesses

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11
Q 
Target organism 
outpatient 
PSI  = I or II
 OR 
CURB-65 = 0 - 1
A

strep. pneumonia

Atypical organisms

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12
Q 
Empiric therapy for CAP 
outpatient 
PSI  = I or II
 OR 
CURB-65 = 0 - 1
A

Erythromycin
500mg PO QDS
OR 800mg BD (EES)

OR 
Clarithromycin 
500mg PO BD
OR
Azithromycin 
500mg PO OM
OR
Doxycycline 
100mg PO BD

OR in sever case
Macrolide/Doxycycline

PLUS 
amoxicillin/clavulanate 
625mg po TDS
OR
Ampicillin/sulbactam 
750 po BD
OR
Cefuroxime 
250-500mg po BD
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13
Q

Inpatient (Non-ICU) PSI = III or IV
OR
CURB-65 = 2

Target organism

A

Strep. pneumoniae Haemophilus influenzae Atypical organisms

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14
Q

Inpatient (Non-ICU) PSI = III or IV
OR
CURB-65 = 2

empiric tx

A

Amo/clavu IV/PO
1.2g IV q8hr

OR

Ampi/sulbactam IV/PO
1.5g IV q6hr

OR 
ceftriaxone
1g IV q12h 
OR 
2g IV q24hr
PLUS 
Clarithromycin PO
500mg BD
OR 
Azithromycin PO 
500mg OM

OR in penicillin allergy
levofloxacin
750mg IV/PO q24hr

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15
Q

Inpatient (Severe pneumonia, ICU)

PSI = V
OR
CURB-65 ≥ 3

Target organism

A

Strep. pneumoniae Atypical organisms

Burkholderia pseudomallei

Klebsiella pneumoniae

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16
Q

Inpatient (Severe pneumonia, ICU)

PSI = V
OR
CURB-65 ≥ 3

empiric tx

A

Penicillin 4MU IV q6h
OR
amo/clavu 1.2g IV q6h

PLUS 
Azithromycin 
500mg IV q24h
PLUS
Ceftazidime 
2g IV q8h
OR 
Levofloxacin 
750mg IV q24hr
PLUS 
Ceftazidime
2g IV q8h
17
Q

Respiratory fluoroquinolones, anti-pneumococcal fluoroquinolones

Not recommended as first-line treatment (local practice)

A
  • Concerns about development of resistance with overuse
  • Concerns about inappropriate use for other respiratory infections
  • Use has been associated with delays in diagnosis and treatment of pulmonary TB
18
Q

CAP Need for empiric coverage of atypical organisms

A

Legionella sp., Mycoplasma pneumoniae, Chlamydophila pneumoniae

β-lactam plus macrolide or fluoroquinolone monotherapy had better outcomes compared to β-lactam alone

19
Q

CAP Early initiation of antibiotics for hospitalized patients

A

Early initiation of antibiotics for hospitalized patients

i. Early initiation (within 8 hours) results in better outcomes
ii. Start therapy in emergency department rather than wait until patient is on ward

20
Q

duration of therapy for CAP

A

Traditionally = 7 – 14 days

ii. Rationale for shorter courses of therapy
- Decrease development of resistance
- Reduce costs
- Decrease adverse reactions

ii. New agents with long serum and tissue half-lives may be able to give shorter course (3 – 5 days)

iii. IDSA/ATS guidelines (2007)
- Treat for minimum of 5 days
- Should be afebrile for 48-72 hours and clinically stable before discontinuation of therapy

iv. Levofloxacin dosing - Recent guidelines specify 750mg once daily x 5 days

21
Q

e. Adjunctive corticosteroid therapy CAP

A

i. Rationale - Inflammatory response in lungs
ii. Only studied in patients who were hospitalized due to CAP

iii. Outcomes
- May decrease need for mechanical ventilation, length of stay and time to clinical stability
- Some evidence to show decreased mortality

22
Q

Monitoring response to therapy CAP

A
  1. Goals of therapy
    a. Cure of infection
    b. Eradication of organism
  2. Time course of response
    a. Should start to see improvement in signs and symptoms in 48 – 72 hours
    b. Elderly and patients with co-existing illnesses may be slower to respond

c. Should not change antibiotics within first 72 hours
- Unless patient is deteriorating or culture results available

23
Q

Monitoring parameters CAP

A

a. Efficacy i. Chest X-ray
- Changes are slow to resolve
– 4-6 weeks or longer - Repeat if patient deteriorates

WBC count
temperature 
CRP 
Cough SOB
HR

Toxicity

24
Q

conversation from IV to oral

A

1) benefits
- discharged
- cheaper

2) Criteria for switching a. Vital signs stable for 24 hours (Afebrile)
b. Able to take oral diet and oral medications
c. Others
- WBC count decreasing
- Improvement in signs and symptoms

3) Can be discharged the same day as convert to oral

25
Q

Patients who do not respond to initial therapy CAP

A
  1. Incorrect diagnosis (e.g., heart failure, pulmonary embolus)
  2. Correct diagnosis a. Drug-related issues
    i. Compliance
    ii. Drug interactions
    iii. Wrong dose
    iv. Wrong drug

b. Pathogen-related issues
i. Unusual pathogen
ii. Resistant organism

26
Q

HAP definition

A
  • Development of a pneumonia at least 48 hours after hospital admission
  • Not incubating (present) at the time of admission
27
Q

HAP Prolongs hospital stay 7 – 9 days

A

HAP Prolongs hospital stay 7 – 9 days

28
Q

Risk Factors for HAP

A

A. Patient-related factors 1. Age > 70 years

  1. Coma or impaired consciousness
  2. Prolonged hospitalization
  3. Malnutrition
  4. Cigarette smoking
  5. Co-existing illnesses
    a. COPD
    b. Diabetes mellitus
    c. Renal failure
    i. Associated with impaired lung function and defenses

B. Infection control-related factors

  1. Transmission of bacteria from hands of healthcare workers to patients
  2. Use of contaminated respiratory care equipment

C. Intervention-related factors

  1. Drugs
    a. Sedatives, narcotic analgesics
    b. Antibiotics
    c. Steroids and immunosuppressive agents
  2. Nasogastric tubes
  3. Intubation/mechanical ventilation (ventilator-associated pneumonia)
29
Q

HAP GRAM +ve

A
  1. Streptococcus pneumoniae
  2. Methicillin-sensitive Staphylococcus aureus (MSSA)
  3. Methicillin-resistant Staph aureus (MRSA)
30
Q

HAP GRAM -ve

A
  1. Escherichia coli
  2. Haemophilus influenzae
  3. Proteus species
  4. Serratia marcescens 5. Enterobacter species 6. Klebsiella pneumoniae (including MDR and ESBL-producing)
  5. Acinetobacter species (including MDR and ESBL-producing)
  6. Pseudomonas aeruginosa (including MDR)
31
Q

HAP
A. Up to 50% of cases do not identify an organism
B. Cannot wait to start antibiotics until culture results are available
1. Studies show that mortality can be reduced with early initiation of appropriate empiric therapy

A

HAP
A. Up to 50% of cases do not identify an organism
B. Cannot wait to start antibiotics until culture results are available
1. Studies show that mortality can be reduced with early initiation of appropriate empiric therapy

32
Q

HAP categories of pt

A
  1. Not at high risk of mortality and no risk factors increasing likelihood of MRSA
  2. Not at high risk of mortality, but with risk factors increasing likelihood of MRSA
  3. High risk of mortality or receipt of IV antibiotics in prior 90 days
33
Q

Initial empiric therapy for HAP

Not at high risk of mortality and no risk factors increasing likelihood of MRSA

A

Piperacilin/tazobactam
4.5g IV q6h

OR

Cefepime
1-2g IV q8hr

OR
Levofloxaccin
750mg IV q24hr

OR
imipenem
500mg IV q6hr

OR
meropenam
1g IV q8hr

34
Q

Not at high risk of mortality, but with risk factors increasing likelihood of MRSA

Initial empiric therapy for HAP

A

Piperacilin/tazobactam
4.5g IV q6h

OR

Cefepime
1-2g IV q8hr

OR
Levofloxaccin
750mg IV q24hr

OR
imipenem
500mg IV q6hr

OR
meropenam
1g IV q8hr

OR

Ceftazidime
1-2g IV q8hr

OR
ciprofloxacin
400mg IV q8-12hr

OR
Aztreonam
1-2g IV q8h

PLUS

vancomycin
15-20mg/kg IV q8-12hr
(target trough = 15-20mg/L)

OR
linezolid
600mg IV q12h

35
Q

Initial empiric therapy for HAP

High risk of mortality or receipt of IV antibiotics in prior 90 days

A

Piperacilin/tazobactam
4.5g IV q6h

OR

Cefepime
1-2g IV q8hr

OR
imipenem
500mg IV q6hr

OR
meropenam
1g IV q8hr

OR

Ceftazidime
1-2g IV q8hr

PLUS

ciprofloxacin
400mg IV q8-12hr

OR
Levofloxaccin
750mg IV q24hr

OR
Aztreonam
1-2g IV q8h

OR
Amikacin
7.5mg/kg IV q12hr
OR 15mg/kg IV q24hr

OR
Gentamicin
1-2mg/kg IV q8h or
5-7mg/kg IV q24h

PLUS

vancomycin
15-20mg/kg IV q8-12hr
(target trough = 15-20mg/L)

OR
linezolid
600mg IV q12h

36
Q

Indications for empiric MRSA coverage

HAP

A
  1. Prior IV antibiotic use within 90 days
  2. Hospitalization in a unit where > 20% of Staph aureus isolates are methicillin-resistant
  3. Where the prevalence of MRSA is not known
37
Q

Risk factors for mortality HAP

A
  1. Need for ventilatory support due to the pneumonia 2. Septic shock
38
Q

Duration of therapy for HAP

A

a. Historically = 14-21 days
b. Optimal duration not clearly established from clinical trials
c. More recent recommendations for shorter duration (i.e., 5 – 7 days)
- Patient is responding to therapy
- No multidrug-resistant organism isolated

d. IDSA/ATS guidelines (2016) = 7 days

39
Q

Monotherapy vs. Combination therapy

HAP

A
  • Synergistic activity
  • Prevent development of resistance
  • Broader spectrum of coverage
  • More expensive
  • Increased risk of adverse effects

Combination therapy recommended

  • High risk of mortality
  • Receipt of IV antibiotics in prior 90 days
  • Pseudomonas aeruginosa as causative organism
    i. Patients in septic shock or at high risk for death

Monotherapy sufficient if

  • Gram positive organism as cause of pneumonia
  • Mild to moderate infection

Antibiotic (21 decks)

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