1. Lower Respiratory Tract Infection

2. Pneumonia Common with high morbidity and mortality rates. Acute respiratory infection with focal chest signs and radiographic changes. Classification; 1. Community-acquired pneumonia. 2. Hospital-acquired pneumonia (nosocomial). 3. Pneumonia in the immunocompromised.

3. Community-acquired Pneumonia Epidemiology; Worldwide disease, common in the winter months. Clinical features; 1. Symptoms; malaise, fever, and shortness in breath; productive cough, pleuritic chest pain, tachycardia. 2. Chest X-ray; lobar, patchy consolidation, or diffuse shadowing.. Complications. Septicaemia and empyaema

4. . Laboratory diagnosis; 1.Sputum specimens for microscopy (Gram stain) and culture. 2.Bronchial-alveolar lavage specimens. 3.Blood cultures. 4.Serology (viruses, mycoplasma, chlamydia, coxiella, Legionella).

5. Causes of Community- acquired Pneumonia

6. S. pneumonia 30-50% of community-acquired pneumonia. Occurs in all age groups. Risk group; patients with chronic lung disease, splenectomized patients and immunocompromised patients. X-rays; shows lobar consolidation. Laboratory diagnosis; by sputum and blood cultures. Treatment; penicillin or erythromycin.

7. Mycoplasma pneumoniae 1-20% Occur primarily in young adults. X-ray shows diffuse changes. Laboratory diagnosis is by serology. Treatment; erythromycin.

8. Haemophilus influenzae <10% of all community acquired cases. Common in infants <5 years. Diagnosis by sputum culture.

9. Staphylococcus aureus Very rare Post-influenza pneumonia Laboratory diagnosis; sputum culture.

10. Legionella pneumophila L. pneumophila is transmitted via aerosols particularly from contaminated air- conditioning systems. <5% Elderly and immunocompromised are in particular risk. Specimen; culture, serology, direct immunofluorescence.

11. C. pneumoniae 10% Young adults have high incidence. Diagnosis by serology.

12. C. psittaci Contact with birds Serology

13. Hospital-acquired (nosocomial) pneumonia

14. Symptoms appears >2 days after admission. Common nosocomial infection Risk factors include assisted respiration, immunocompromised and pre-existed pulmonary disease. Aetiology; S. pneumoniae, H. influnzae, Gram negative organisms like E. coli, Klebsiella.

15. Pneumonia in the immunocompromised

16. Infected with classical chest pathogen like S. pneumoniae M. pneumoniae…etc Or with opportunistic pathogens; 1.Actinomyceteae 2.Atypical mycobacteria 3.Legionella pneumophila.

17. Whooping cough (pertussis)

18. Tuberculosis