COMMUNITY ACQUIRED PNEUMONIA : COMMUNITY ACQUIRED PNEUMONIA Dr. MAULIK SHAH
ICU REGISTRAR
CRITICAL CARE DEPT.
Pneumonia : Pneumonia Definition : It is defined as the infection of lung parenchyma.
Types :
CAP (Community acquired pneumonia)
HAP (Hospital acquired pneumonia)
VAP (Ventilator associated pneumonia)
PNEUMONIA : PNEUMONIA CAP
ETIOLOGY : ETIOLOGY Agent Factors
Typical pathogens : Streptococcus pneumoniae
Haemophilus influenza
S. aureus
GNB – Klebsiella Pneumoniae
Pseudomonas aeruginosa
Slide 5: Atypical pathogens :
Chlamydiaophila pneumoniae
Mycoplasma pneumoniae
Legionella spp.
Respiratory viruses – Influenza
Adeno
RSV
Slide 6: Rare pathogens :
Fungi
Protozoa
New viruses - Hantavirus
Metapneumovirus
Coronavirus (SARS)
Changing trends : MDR strains of GNB and CA – MRSA can cause necrotising pneumonia
HOST FACTORS : HOST FACTORS Breach of mechanical or immunological defences makes a host susceptible to infection
POSSIBLE ETIOLOGICAL AGENT ACCORDING TO SUSCEPTIBILITY : POSSIBLE ETIOLOGICAL AGENT ACCORDING TO SUSCEPTIBILITY Alcoholism - Klebsiella pneumoniae, oral
anaerobes,S Pneumoniae, M. Tb
COPD and/or Smoking – H. influenza, Moraxella catarrhalis,Pseudomonas, S. Pneumoniae
Structural lung disease – Pseudomonas aeruginosa,Burkholderia cepacia,S. aureus
Decreased level of consciousness – Oral anaerobes, gram neg bacilli
Slide 9: Exposure to birds – Chlamydia psittaci
H. capsulatum
Stay in hotel or on cruise ship in previous 2 weeks – Legionella
PATHOPHYSIOLOGY : PATHOPHYSIOLOGY Host defences trigger inflammatory response which lead to clinical syndrome of pneumonia
Inflammatory mediators from macrophages and neutrophils create alveolar capillary leak equivalent to that seen in ARDS.
PATHOLOGY : PATHOLOGY Intact immunity or typical pathogen– Localisation of infection and so lobar pneumonia pattern
4 Stages :
Edema
Red Hepatization-Erythrocytes
Gray Hepatization-neutrophils
Resolution-Macrophages
Immunocompromised or atypical pathogens- Bronchopneumonia pattern
CLINICAL MANIFESTATIONS : CLINICAL MANIFESTATIONS CAP can vary from mild diseases to fatal in severity
Symptoms : Cough, dyspnea, chestpain if parietal pleura involved
Others : Fever, constitutional symptoms
Signs
DIAGNOSIS : DIAGNOSIS Clinical
Radiological
Etiological : Gram stain and culture of sputum
Blood cultures
Antigen tests
PCR
Serology
DIFFERENTIAL DIAGNOSIS : DIFFERENTIAL DIAGNOSIS Acute exacerbation of COPD
Heart Failure
Pulmonary embolism
Radiation Pneumonitis
Acute Bronchitis
TREATMENT : TREATMENT Principles :
Decide according to severity whether the patient is a candidate for outpatient or inhospital treatment
Try to cover organism as per local epidemiological pattern
Keep in mind the drug resistance patterns
IV drugs when hospitalised
Cover for pseudomonas and MRSA when suspected
Inhospital/Outpatient treatment decided as per PSI/CURB-65 criteria : Inhospital/Outpatient treatment decided as per PSI/CURB-65 criteria PSI (Pneumonia Severity Index) variables : 20 in number
CURB variables :
C-Confusion
U-Urea(>7 mmols)
R-Respiratory rate (>30)
B-Blood pressure (<90 sys or <60 diastolic)
Slide 18: Outpatient treatment – PSI class 1&2
CURB score 0
Inhospital treatment – PSI class 4&5
CURB score >2
ANTIBIOTIC GROUPS : ANTIBIOTIC GROUPS Macrolides-Covers atypical org. but DRSP cases ineffective
B-Lactams-No atypical coverage but DRSP cases effective
Fluroquinolones-Less resistance and covers both
Aminoglycosides-Add on drug for pseudomonas
Drugs for MRSA
Slide 21: Bacteremic Pneumococcal Pneumonia – Dual therapy preferred
Definitive Treatment : Definitive Treatment What if organism isolated sensitive to Penicillins and we have started with B lactum+Macrolide or Fluroquinolones
What if no response and drug resistant to FQ+Macrolides+Penicillins (MDR)
DURATION OF THERAPY : DURATION OF THERAPY Uncomplicated CAP : 5-day course suffices
Bacteremic CAP/Virulent organism – 10-14 days
Response to treatment in otherwise uncomplicated CAP: : Response to treatment in otherwise uncomplicated CAP: Fever- Falls in 2 days
Leucocytosis-decreases in 4 days
Physical findings persist slightly longer
Chest radiographic abnormalities may take 4-12 weeks to resolve
What if patient fails to improve? : What if patient fails to improve? Consider –
Noninfectious condition
Resistance to drug
Superinfection with new nosocomial pathogen
COMPLICATIONS : COMPLICATIONS Seen usually when MDR pathogens present
Respiratory Failure
Shock and Multiorgan failure with DIC
Metastatic infection
Lung Abscess
Complicated pleural effusion
PROGNOSIS : PROGNOSIS Depends on – Age
Presence of co-morbidities
Site of treatment
PREVENTION : PREVENTION Immunocompromised/Susceptible –Vaccination
Community outbreak – Chemoprophylaxis+Vaccination
Slide 29: I hope I was not boring !!!!!