COMMUNITY ACQUIRED PNEUMONIA

• Acute infection of pulmonary parenchyma

• Causative Organism :

Streptococcus pneumoniae (pneumococci) - most common

Haemophilus influenzae - 2nd most common

Mycoplasma pneumonia

Chlamydia pneumonia

• Rare :

Legionella

Staphylococcus aureus

Gram negative organism ( klebsiella , pseudomonas)

virus (adenovirus , meta pneumo virus)

• In India :

- 20% cases of CAP - Tuberculosis

- 40% cases of CAP - Not established

PATHOLOGY :

Initially there is a inhalational of bacteria into the lungs results in phase of Edema 

↓ 

proteinaceous exudates developed in the alveoli

(so there can be a crepitation, crackles of  bronchial breathing in the patient and subsequently patients enter into the following phases)

• Red hepatization - RBC + Neutrophils (3-4 days)

• Grey hepatization - RBC lysis + Neutrophils (it signifies successful)(5 -7 days)

• Resolution - here Macrophages predominantly present because these cells restore the normal tissue

Typical / lobar pneumonia :

• Lobar consolidation
• causative organism ;

- Pneumococci

- H. influenza

- staph aureus

- Klebsiella

- pseudomonas

• Alveolar exudates in air spaces
• high grade fever
• productive cough
• hemoptysis
• pleuritic chest pain
• x-ray - large areas of consolidation

Atypical / Interstitial / broncho pneumonia :

• Patchy interstitial inflammation
• Causative organism :

- chlamydia

- mycoplasma

• Interstitial involvement
• lymphocytic
• low grade fever
• Dry cough
• Scanty sputum
• Extrapulmonary manifestation

- cold agglutinin disease

- erythema multiforme

- Arthralgia + adenopathy

- Guillain barre syndrome

- myocarditis / pericarditis

- encephalitis

- Bullous meningitis

• x-ray - Interstitial pattern

clinical feature :

1. Fever
2. Breathlessness
3. Cough
4. Hemoptysis 
5. Chest pain : due to pleuritis
6. Nausea and vomiting
7. Abdominal pain
8. Headache
9. Myalgia

on examination :

• Respiratory rate - increased
• Use of accessory respiratory muscles 

- Scalenus

- Sternocleidomastoid muscle

 - Alae nasi

• Trachea is central

• Vocal fremitus increased because lung has become solid as Bronchophony

- sometimes vocal fremitus is lesser due to parapneumonic pleural effusion at bottom of one side of the lung

• ON PERCUSSION : Dull due to consolidation (usually finds resonant in normal lungs)

• ON AUSCULTATORY : findings in pneumonia is Breath sounds of bronchial breathing not crepitation or crackles. there is gap between inspiration and expiration component.

WORKUP :

• Complete blood counts (CBC) : TLC increased (Neutrophils counts are increased)
• Sputum evolution : important work up for choice of antibiotics

- Culture

- Gram stain

• Blood culture :
• Urine antigen :

- Legionella pneumophilia

- pneumococcus

• Chest X - ray : consolidation

- Lobar

- Round

- Bronchopneumonia

- Parapneumonic effusion

• Biomarkers = CRP( C reactive proteins) , Procalcitonin (helps to identify infective process in the body)

TREATMENT :

• CURB - 65 Score : Parameters used for the need for hospitalization

 Empirical treatment of CAP :

OPD treatment

• previous health or not received antibiotics in last 3 months - MACROLIDES (Clarithromycin / Azithromycin)

or

Doxycycline (if macrolides is not available)

• Co - morbid condition or antibiotics in last 3 months - MOXIFLOXACIN

 or

 β LACTAM + MACROLIDES

IPD treatment

• ICU  or non ICU - I.V β LACTAM + I.V MACROLIDES

If pseudomonas - add MEROPENEM

If s. aureus - add LINEZOLID

VENTILATOR ASSOCIATED PNEUMONIA  (VAP)

• MDR (MULTI DRUG RESISTANT)

- Pseudomonas

- Community Acquired MRSA (methicillin resistant staphylococcus aureus)

- Acinetobacter

↓

Treatment

- PIPERACILLIN - TAZOBACTUM

- AMIKACIN

- LINEZOLID (for MRSA)

• NON - MDR 

- Pneumococcus

Treatment

- PIPERCILLIN - TAZOBACTUM

LOBAR PNEUMONIA

ROUND PNEUMONIA

 

Ventilator associated pneumonia