Respiratory tract infection

By Dr.Preaw(General medicine )

Scope

Diagnosis : CAP , HCAP , VAP

Pathophysiology

Investigation

Management and treatment

Community-acquired pneumonia (CAP)

Diagnosis

1. Temperature > 38 ºC

2. Purulent secretion

3. Leucocytosis or leucopenia

IDSA/ATS Guidelines for CAP in Adults • CID 2007:44 (Suppl 2)

Moderate recommendation; level III evidence.

Pathophysiological modes of spreading

Aerosols inhalation Mycoplasma pneumoniae Chlamydophila psittaci Chlamydophila pneumoniae Legionella pneumophila

Orophryngeal secretions Streptococcus pneumoniae

Aspiration Haemophilus influenzae anaerobes , gram- negative bacilli

Hematogenous spread Staphylococcus aureus

Reactivation of latent Mycobacterium tuberculosismicroorganism Pneumocystis jirovecci

Mechanism Example

Pathophysiology :Failure of defences mechanisms

1. Alteration of normal oropharyngeal flora.

2. Depressed Cough and glottis reflexes.

3. Altered consciousness.

4. Impaired mucociliary apparatus mechanism.

5.Alveolar macrophage dysfunction.

6. Immune dysfunction.

Classification of pneumonia (based on anatomical part )

Bronchopneumonia : terminal bronchiole ( patchy consolidation)-Streptococci-Staphylococcus aureus-B Haemolytic streptocci-Haemophilus influenzae-Klebsiella pneumonia-Pseudomonas

Lobar pneumonia -Streptococci pneumoniae-Staphylococcus aureus-B Haemolytic streptocci

Interstitialpneumonia : without alveolar exudates-virus: Respiratory syncytial virus Influenza virus Adenoviruses Cytomegaloviruses-Mycoplasma pneumoniae

Pathologic Stages of Pneumococcal Lobar Pneumonia

Stage onset Affected lobe

congestion 1-2 day-proteinaceous fluid -neutrophils and many bacteria in aveoli

red hepatisation 2-4 day -red, firm and liver like consistency-proteinaceous fluid -> fibrin strands

gray hepatisation 4-7 day

-dry,firm and gray (lysed red cells)-neutrophils and bacteria also reduces-macrophages are seen

resolution over 3 wk( in normal )

-fibrinous matter

-macrophage ( major cells)

Criteria for severe community-acquired pneumonia.

confusion /disorentation

V/S RR> 30/min ,T < 36 ºC , hypotension

multilobar infiltration

Lab : BUN > 20 mg/dL , WBC < 4,000 cells/mm3 , platelet count <100,000 cells/mm3

PaO2/FiO2 ratio > 250

Minor criteria

Major criteria

Investigation and management

Evidence level Definition

Level I (high) well-conducted,RCT

Level II ( moderate)well -designed,controlled trials without

randomization

Level III ( low) case studies and expert opinion

Diagnosis testing remain controversial

InvestigationModerate

recommendation

hemocultureOPD case :level IIIIPD case : level I

sputum gram stain and culture level II

urine antigen for Legionella pneumophila and streptococcus pneumoniae level II

chest x ray level III

Sensitivity 69%false negative

1.dehydration2. early onset of PCP3. neutropenic patient

sensitivity 15-100%specificity 11-100%Adequate sputum PMN >25 cells/LPF

epithelium < 10 cells/LPF

sensitivity 70-90 %specificity 99 %

Classification of pneumonia (based on anatomical part )

Lobar pneumonia

Bronchopneumonia

Interstitial pneumonia

Gram : positive dipplococci :Streptococcus pneumoniae

Gram : negative bacilli

Management and treatment :hospital admission decision

CURB -65 score

strong recommendation :level I evidence

PSI score

Stratification of risk score

risk risk class score mortality

low Ibased on algorithm

0.1%

outpatient treatment

low II <70 0.6%

low III 71-90 0.9%

moderate IV 91-130 9.3%hospital

admissionhigh V >130 27%

PSI score

CURB-65 Treatment PSI scores Treatment

012345

OPDOPDIPDICUICUICU

-IIIIIIIVV

-OPDOPD

observe or hospitalizationIPDIPD

Summary

PIRO score for CAP

Factor Point Scores Risk

P

COPD or immunosuppresive 1

0-2low risk (1 in 30 )for ICU

mortalityAge > 70 yr 1

I

bacteremia

13

Mild risk (1 in 8) for ICU mortality

multilobar opacity 1

R

shock1

4high risk ( 2 in 5) for ICU

mortalitysevere hypoxia 1

O

ARDS1

5-8very high risk (3 in 4)

for ICU mortalityacute renal failure

1

Predisposition

Insult

Response

Organ dysfunction

ICU case

Management

Management : outpatient

setting antibiotic drugs recommendation

previous healthy (no use ABO in 3 month)

macrolide ordoxycycline

level I(strong)level III(weak)

comorbiditiesimmunosuppressing

conditon

respiratory fluoroquinolone orB-lactam +macrolide

level I(strong)level I(strong)

region with high rate (>25%)infection with high level ( MIC>16

mcg/ml)macrolide-resist streptococcus pneumoniae

ceftriaxone, cefuroxime doxycycline

level II (moderate)

C.pneumoniae (29%)M.pneumoniae(20%)S.pneumoniae(8%)

unknown (30%)

Management : inpatient

setting antibiotic drugs recommendation

non-ICU-respiratory quinolone or-B -lactam+macrolide or level I

ICU -B-lactam +azithromycin -respiratory quinolone

level IIlevel I (penicillin allergic patient)

levofloxacin,moxifloxacin ,gemifloxacin

cefotaxime , ceftriaxone,ampicillin-sulbactam

-gram negative bacilli(20%)-S.pneumoniae(19%)-C.pneumoniae(19%)-M.pneuminiae(9%)

-unknown (31%)

-S.pneumoniae(24%)-gram negative bacilli(20%)-

C.pneumoniae(15%)-unknown (31%)

Special condition

special concerns antibiotic drugs recommedation

Pseudomonas

-B-lactam+ ciprofloxacin or levofloxacin or

-B-lactam +aminoglycoside+azithromycin or

-B-lactam +aminoglycoside+fluoroquinolone

level III(moderate)

*CA-MRSA add vancomycin or linezolidlevel III

(moderate)

*CA-MRSA:community-acquired methicillin-resistant staphylococcus aureus

piperacillin-tazobactamcefepime,imipenem

meropenem

Criteria for clinical stability

Temperature < 37.8 ºCHeart rate < 100 beats/minRespiratory rate < 24 breaths/minSystolic blood pressure > 90 mmHgAterial oxygen saturation > 90 % or PaO2 > 60 mmHg on RAAbility to maintain oral intakeNormal mental status

Hospital-acquired pneumonia(HAP) :definition Presence of new chest X-ray infiltration plus one of the three clinical variables-fever > 38 ºC-leukocytosis or leukopenia (WBC >12,000 cells/mm3 or < 4,000 cells/mm3 )-purulent secretionsPneumonia that occurs 48 hours or more after admission

●

●

Ventilator-associated pneumonia : definition

Pneumonia that occurs 48 hours or more after intubation of endotracheal tube until 48 hours after extubation

Definition:HAP, VAP, HCAP

Healthcare-associated pneumonia(HCAP)

- Any patient who was hospitalized in acute care hospital for > 2 days within

90 days of the infection

- Resided in a nursing home or long-term care facility

- Received recent IV antibiotic therapy, chemotherapy or wound care within

the past 30 days of the current infection

- Attended a hospital or hemodialysis clinic

Hospital-acquired pneumonia(HAP)

Early onset pneumonia (within < 4 days of hospital admission)pathogens -> S.aureus -> S.pneumoniae -> H.influenzae

Late onset pneumonia ( > 4days of hospital admission)pathogens ->MRSA ->drug-resistant GNEB ->P.aeruginosa ->A.baumannii

HAP : pathogenesis

-Microaspiration:from oropharynx to lungs-Aspiration from stomach to lungs-Colonization of ET tube with bacteria encased in biofilm result into alveoli during suctioning or bronchoscope-Inhalation of pathogens form contaminated aerosols direct inoculation -Hematogenous spread

Risk factor for multidrug-resistant pathogens causing

HAP, HCAP, VAP

-Antimicrobial therapy in preceding 90 days-Current hospitalization of 5 days or more-High frequency of antibiotic resistance in the community or in the specific hospital unit-Presence of risk factor for HCAP Hospitalization for 2 days or more in preceding 90 days Residence in a nursing home or extended care facility Home infusion therapy ( including antibiotics) Chronic dialysis within 30 days Home wound care Family member with multidrug- resistant pathogen-Immunosuppressive disease and/or therapy

Assessment of nonresponders

wrong organismdrug-resistant pathogeninadequate antimicrobial

therapy

wrong diagnosisARDS

atelectasispulmonary emboli

pulmonary hemorrhageneoplasm

underlying disease

complicationempyema or lung abcess

Clostridium difficile coliitisoccult infection

drug fever

Summary

Diagnosis :

CAP

HCAP

VAP

Summary

CURB-65

PSI score

PIRO score

Summary

-Management-Prevention-Accessment of nonresponder