This document discusses pneumonia, including its definition, classifications, pathogenesis, predisposing factors, clinical features, investigations, differential diagnosis, and assessment of severity. Pneumonia is an acute infection of the lungs, usually bacterial, that causes inflammation and consolidation visible on imaging. It can be classified anatomically by location in the lungs or empirically based on where it was acquired. Risk factors include smoking, viral infections, alcohol use, medications, age, and underlying lung disease. Diagnosis involves identifying the infecting organism through sputum or blood tests as well as chest imaging.

1. PNEUMONIA
Dr. Manu Mohan K
Associate Professor
Pulmonary Medicine

2. Definition
 Syndrome caused by acute infection, usually
bacterial
 Clinical and radiological signs of
consolidation
 Pneumonitis – chemical , radiation

3. Classification
 Anatomist
 Lobar, segmental, subsegmental,
Bronchopneumonia
 Empiricist’s
 Community – acquired, Hospital-acquired,
Aspiration, Immunocompromised host
 Behaviorist’s
 Easy, Difficult

4. Pathogenesis
 Predisposed by conditions that
 Reduces or suppresses cough
 Impair mucociliary activity
 Reduces phagocytic activity
 Impair immunoglobulin production

5. Factors that predispose to
pneumonia
 Cigarette smoking
 Upper respiratory tract infections
 Alcohol
 Corticosteroid therapy
 Old age
 Recent influenza infection
 Pre-existing lung disease
 HIV
 Indoor air pollution

6. Pathogenesis
 Aspiration and micro aspiration
 Inhalation
 Colonization
 Blood spread

7. Pathology
 Congestion
 Red Hepatization
 Grey Hepatization
 Resolution

8. Clinical features
 Symptoms
 Constitutional
 Dyspnea
 Cough
 Hemoptysis
 Pleuritic chest pain
 Signs

9. Investigations
 Laboratory identification of infecting
organisms
 Sputum Microscopy
 Sputum immunodetection
 Sputum culture
 Invasive methods for obtaining respiratory
secretions
 Blood culture

10. Investigations
 Pneumococcal antigen detection
 Standard acute and convalescent serological
testing
 Newer microbiological technologies – PCR
 Pleural fluid
 Chest radiography
 Arterial oxygen saturation and blood gas
analysis

11. Investigations
 Other laboratory findings
 WBC counts
 Cold agglutinins – mycoplasma
 Biochemical abnormalities
 SIADH – hyponatremia
 Urine - serology

12. Differential diagnosis
 Pulmonary infarction
 Pulmonary or pleural tuberculosis
 Pulmonary edema
 Pulmonary eosinophilia
 Malignancy: Bronchoalveolar cell carcinoma
 Rare disorders – Bronchiolitis obliterans
organizing pneumonia (BOOP)

13. Assessing severity