Understanding Respiratory Infection- Their Causes, Symptoms, Prevention, and Treatment. For more information, please contact us: 9779030507.

1. Respiratory
Infections
Pneumonia

2. An inflammation of the mucous membranes of your
mouth, nose, airways and/ or lung parenchyma
brought on by a virus or bacteria is known as a
respiratory infection.

3. I. Upper Respiratory Infections: Infections in the mouth,
nose and throat - Sinusitis, Tonsillitis, Pharyngitis, Laryngitis
etc.
II. Lower Respiratory Infections: Infections of the trachea,
bronchi and lung parenchyma - Tracheo-bronchitis, Chronic
bronchitis, Pneumonias, Lung abscess, Bronchiectasis
III. Pleural Infections: Pleurisy, Pleural effusion, Empyema

4. Pneumonia – Alveolar infection resulting from the
invasion and overgrowth of microorganisms in lung
parenchyma.
Classification
Anatomical- Depending upon the part of the lung
involved: Lobar / segmental
Bronchopneumonia
Microbiological – Depending upon the type of organism
responsible for infection
Empirical – Depending upon the setting of occurrence of
pneumonia

5.  Community-acquired pneumonia - infection in a non-
hospitalized population.
 Health-Care associated pneumonia (HCAP)
 Hospital-acquired pneumonia
 Ventilator-associated pneumonia
 Pneumonia in an Immunosuppressed individual.

6. A. Bacterial: Pneumococal, H. influenzae, Atypical,
Staphylococcal, Gram –ve, Anaerobic, and others
B. Mycobacterial: Caused by Tubercle bacillus
C. Viral: Respiratory Syncytial Virus, Corona, others
D. Fungal: Aspergillus, Mucor, Cryptococcus, others
E. Chemical: Inhalation of acid and other chemical
vapours

7.  Infection occurs whenever there is
disturbance in the ‘homeostasis’
normally maintained by the
interaction between the:
 Host
 Pathogen and
 Environment

8. ENVIRONMENT
Infected air, water,
fomites, instruments
Cross-contamination
HOST
Impaired immune function
Comorbid illness
Prior surgery/antibiotics
PATHOGEN
- Inoculum
- Virulent strain (MDR)

9. Increased prevalence/ occurence
 Comorbidities: DM, CAD, CHF, neurologic
disease, Immunosuppression, active malignancies,
HIV infection, Cortico-steroid use
 Increasing age, Age > 65 yrs,
 Recent influenza, Bacteraemia, leukopenia,
 Alcoholism, Tobacco-smoking, Air-pollution
 Exposure/s to child in a day care centre

10. Risk for enteric gram –ve infections
Recent antibiotic therapy
Underlying cardiopulmonary disease
Resident of a nursing home
Multiple medical co-morbidities
Risk for P. aeruginosa
Structural lung disease (Bronchiectasis, CF)
BSA therapy for > 7 days in the past month
Corticosteroids (at least 10 mg predn/day)
Malnutrition

11. Symptoms
 General: Fever, pains, night sweats
 Respiratory: Cough/sputum, dyspnea, chest pain,
hemoptysis, others
Signs
 General: Rash, hemorrhage
 Chest: Normal, crackles, bronchial, wheeze
 Systemic: Meningitis, carditis

12.  Pulmonary tuberculosis
 Pulmonary infarction
 Vasculitis
 Eosinophilic pneumonia
 Collapse, Malignancy
 Loculated effusion
 Uncommonly: ILD, Organizing Pneumonia

13. Pulmonary: Para-pneumonic effusion
 Empyema, Broncho-Pleural Fistulae
 Cavitation, Lung abscess, Pneumothorax
 Sputum impaction, collapse
 ARDS, Respiratory failure
Systemic: Deep vein thrombosis, Ectopic abscesses,
Pericarditis, Myocarditis, Renal failure Hepatitis, Meningo-
encephalitis
Multi-organ failure

14.  CXR
 CT chest only in those with non-resolution or for
assessment of complications
 Bl. Culture in hospitalized patients
 Sputum/BAL smear and culture for hospitalized
patients
 Sputum for AFB
Diagnosis of Community Acquired Pneumonia is
largely clinical and CXR based in the out-patient
setting.

15.  Leucocytosis (polymorphonuclear)
 Raised ESR
 Arterial blood gases
 S. electrolytes; liver & renal function tests
 Blood sugar
 H.I.V. serology
 Blood cultures
 Others

16.  New infiltrates / opacities
 Alveolar shadows – consolidation
Lobar / segmental / others
 Pleural effusion / pneumothorax
 Air cysts / cavities
 Interstitial / miliary shadows
 Hilar L.N. ± infiltrates

19. False-negative
 Interstitial lung dis
 PJP pneumonia
 Miliary TB
 Dehydration
 Neutropenia
False-positive
 Early course
 Vasculitis
 Atelectasis
 CHF
 Pulmonary infarcts
 Malignancies
 Miscellaneous

20. • Blood culture- Positive in around 25%; indicator of
severity
• Sputum smear and culture- Rapid, inexpensive,
variable sensitivity & specificity
• Serology- Initial testing only if onset > 7 days, or
severe or unresponsive to -lactams
• Legionella urine antigen- Highly specific & sensitive;
intubated patients with severe disease

21.  Sputum / induced sputum
 Bronchoscopic
- Washings
- Bronchial / bronchoalveolar lavage
- Biopsy (bronchial / TBLB)
- Needle aspiration
 Transthoracic needle biopsy
 Transtracheal aspiration
 Pleural aspirate / biopsy
 Thoracoscopic specimens

22. 1. Routine Clinical Assessment
2. Host factors
3. General indicators: Fever, Leucocytosis, blood
cultures, C Reactive Protein
4. Clinical Scoring System
5. Micro organism pattern
6. Biomarkers

23.  CURB – 65, CRB
 Pneumonia Severity Index (PSI)
 Apache scoring system (APACHE II)
 Others

24. Inflammatory biomarker
Acute phase reactant primarily produced by liver in
bacterial infections
Inhibited by viral related cytokines
Increased PCT: helps to identify patients who:
- Benefit from antibiotics
- Increased risk of death
PCT-guided group had significantly less antibiotic use
and duration of therapy

25.  Anti-microbial therapy - Antibiotics
 Supportive & symptomatic therapy: Fever, Dehydration,
Systemic symptoms
 Stabilization of severity parameters: De-oxygenation, Organ
failure, Shock
 Treatment of complications: Empyema, Cavitation, BP
Fistulae
 Management of drug-toxicities
 Preventive strategies

26.  Presence of comorbid medical conditions
 Chronic heart, lung, liver or renal disease
 Diabetes mellitus
 Alcoholism
 Malignancies
 Use of antimicrobials within the previous 3 months
 Severe CAP with or without comorbidities

27. I. No cardiopulmonary disease / No disease
modifying factors
 β-lactam, macrolide, doxycycline
II. Cardiopulmonary disease / disease
modifying factors
 Beta lactam + macrolide (or doxy)

28. I. Non-severe CAP
 β-lactam or macrolide
II. Severe CAP/No risk factor for Pseudomonas
 IV Beta lactam + azithromycin
III. Severe CAP/Risk factor for Pseudomonas
 IV anti-pseudomonal β-lactam + anti-pseudomonal
fluoroquinolones
 IV antipseudomonal β-lactam + amino-glycoside + azithromycin
Fluoroquinolones should be used judiciously

29. Duration of therapy
 Pneumococcus, Gram negative bacteria - 7 to 10 d
 M. pneumoniae & C. pneumoniae - 10 to 14 d
 Legionella, Pseudomonas, Staph. aureus – 14 to 21 d
Switch to Oral Therapy
 Improvement in cough and dyspnea, afebrile (< 100 F) on two
occasions 8 h apart, WBC count decreasing, functioning GIT with
adequate oral intake

30. Antimicrobial failure
 Patient noncompliance, improper dosing regimen,
resistant pathogen, unusual or unsuspected pathogen
Infectious complications
 Empyema, endocarditis, super-infection
Incorrect diagnosis
 Malignancy, pulmonary embolism, other noninfectious
etiologies

31.  Death
 Need for mechanical ventilation
 RR > 25 / min
 SaO2 < 90%; PaO2 < 55 mmHg
 Hemodynamic instability
 Less than 1oC decline in admission temp. of > 38.5oC
 Altered mental state

32. Antimicrobial failure
 Patient noncompliance, improper dosing regimen,
resistant pathogen, unusual or unsuspected pathogen
Infectious complications
 Empyema, endocarditis, superinfection
Incorrect diagnosis
 Malignancy, pulmonary embolism, other noninfectious
etiologies

33. Pneumococcal & influenza vaccine
 Immune-competent patients > 65 yr
 Persons < 65 yr - CHF, COPD (not asthma), diabetes
mellitus, alcoholism, chronic liver disease, asplenia etc.
 Immunosuppressed states (HIV infection, leukemia-
lymphoma, immunosuppressive therapy etc.)
 Can be given immediately (after CAP)

34.  Hospital-acquired pneumonia - pneumonia 48
hours or more after admission, and was not
incubating at the time of admission
 Ventilator-associated pneumonia - pneumonia
that arises more than 48-72 hours after
endotracheal intubation

35.  Hospital Acquired Pneumonia (HAP)
◦ ≥48 h after hospital admission (excluding an incubating infection)
◦ Early onset HAP vs Late onset HAP
 Ventilator Associated Pneumonia (VAP)
◦ ≥48-72 h after endotracheal intubation
◦ Early onset VAP vs Late onset VAP
 Health Care Associated Pneumonia (HCAP)
i. hospitalized in an acute care hospital ≥ 2days in
preceding 90 days;
ii. nursing home or long-term care facility resident;
iii. recent iv chemotherapy, or wound care within past 30 days
iv. attended a hospital or hemodialysis clinic

36. Clinical + Chest X ray + Microbiology
• New onset fever
• Purulent expectoration
• Tachycardia, Tachypnoea
• Leukocytosis / Leukopenia
• Need of higher FiO2
•Clinical diagnosis: high
sensitivity, low specificity
•empiric treatment
Microbiology
•to identify etiology
•de-escalate therapy
•decide duration of
therapy

37.  Sicker inpatient population
 Immuno-compromised patients
 New procedures & instrumentation
 Emerging pathogens
 Complacency regarding antibiotics
 Ineffective infection control and compliance
 Increased antibiotic use

38. HAP, VAP or HCAP suspected
Obtain lower respiratory tract (LRT) sample for culture (quantitative or semi-
quantitative) and microscopy
Begin empiric antimicrobial therapy using local
microbiological data
Days 2 and 3: check cultures and assess clinical response: (temperature, WBC, chest X-ray,
oxygenation, purulent sputum, haemodynamic changes and organ function)
Clinical improvement at 48–72 hours
No Yes
Cultures +
Cultures – Cultures- - Cultures +
Adjust antibiotic
therapy, search for
other pathogens,
Search for other
pathogens,
complications etc
Consider
stopping
antibiotics
De-escalate
antibiotics,
if possible,

39.  Community Acquired Pneumonia are common, mostly diagnosed on
clinical and radiological criteris.
 Hospital aquired pneumonias are associated with excess mortality
initiate prompt appropriate & adequate therapy
 Pathogens for HAP are distinct from one hospital to another, specific
sites within the hospital, and from one time period to another
 Avoid overuse of antibiotics, focus on accurate diagnosis, tailor
therapy to recognized pathogen and shorten duration of therapy to
the minimum effective period
 Apply prevention strategies aimed at modifiable risk factors