1. Pneumonia
Dr. Gerrard Uy

2. Definition infection of the pulmonary parenchyma
often misdiagnosed, mistreated, and underestimated
community-acquired pneumonia (CAP) or health care–associated pneumonia (HCAP)
hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP)

3. Pathophysiology
proliferation of microbial pathogens at the alveolar level and the host's response
aspiration from the oropharynx – most common mode of entry
inhaled as contaminated droplets
hematogenous spread or contiguous extension

4. Pathophysiology Host defense: hairs and turbinates of the nares
branching architecture of the tracheobronchial tree traps particles on the airway lining
Mucociliary clearance
Local antibacterial factors
gag reflex and the cough mechanism
normal flora adhering to mucosal cells of the oropharynx
resident alveolar macrophages

5. host inflammatory response, rather than the proliferation of microorganisms, triggers the clinical syndrome of pneumonia
inflammatory mediators, such as interleukin (IL) 1 and tumor necrosis factor (TNF), results in fever

6. Pathology Edema Red hepatization Gray hepatization Resolution
presence of a proteinaceous exudate
Red hepatization
erythrocytes in the cellular intraalveolar exudate
Gray hepatization
neutrophil is the predominant cell, fibrin deposition is abundant, and bacteria have disappeared
Resolution
Macrophage is the dominant cell type

7. Etiology Typical: Atypical:
S. pneumoniae, Haemophilus influenzae, S. aureus and gram-negative bacilli such as Klebsiella pneumoniae and Pseudomonas aeruginosa
Atypical:
Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella spp. as well as respiratory viruses such as influenza viruses, adenoviruses, and respiratory syncytial viruses (RSVs

8. Risk factors
CAP:alcoholism, asthma, immunosuppression, institutionalization, and an age of 70 years versus 60–69 years

9. Clinical Manifestations
frequently febrile, with a tachycardic response, and may have chills and/or sweats and cough
pleura is involved, the patient may experience pleuritic chest pain
fatigue, headache, myalgias, and arthralgias
Crackles, bronchial breath sounds

10. Management Diagnosis CLINICAL XRAY – suggests etiology
pneumatoceles suggest infection with S. Aureus
upper-lobe cavitating lesion suggests tuberculosis
Sputum Gram stain and culture
Blood culture

11. Management Treatment : CAP Site of Care Antibiotics Home Hospital
Empiric
Previously healthy and no antibiotics in past 3 months
A macrolide [clarithromycin (500 mg PO bid) or azithromycin (500 mg PO once, then 250 mg od)] or Doxycycline (100 mg PO bid)