1. Dr. Meg-angela Christi Amores
Infectious Diseases
Dr. Meg-angela Christi Amores

2. Infectious Diseases Tuberculosis Leprosy AIDS Syphilis
Viral Infections
Pneumonia
Herpes

4. TUBERCULOSIS one of the oldest diseases to affect humans
caused by bacteria of the Mycobacterium tuberculosis complex
Usually affects the lungs
untreated, the disease may be fatal within 5 years in 50–65% of cases
airborne spread of droplet nuclei

5. M. Tuberculosis
rod-shaped, non-spore-forming, thin aerobic bacterium measuring 0.5 um by 3 um
Neutral on gram staining
Acid-fast (once stained, cannot be decolorized by acid alcohol)
Acid fastness is due to the organisms high content of mycolic acid

7. Epidemiology
More than 5 million new cases of tuberculosis were reported to the WHO in 2005
> 90% are from developing countries
The WHO estimated that 8.8 M new cases of tuberculosis occurred worldwide in 2005
Asia: 4.9 M
Africa 2.6 M
Middle East 0.6 M
Latin America 0.4 M

8. From exposure to infection
M. tuberculosis is common transmitted through droplet nuclei, which are aerosolized by coughing, sneezing or speaking
Determinants of the likelihood of transmission includes:
Intimacy and duration
Degree of infectiousness
Shared environment

9. From exposure to infection
Patients whose sputum contains AFB are most likely to transmit infection
Most infectious patients have cavitary disease

10. From infection to disease
the risk of developing disease after being infected depends largely on endogenous factors, such as the individual's immunity and the level of function of cell mediated immunity
primary tuberculosis –
Clinical illness directly following infection
common among children up to 4 years of age and among immunocompromised persons
Not associated with high level transmissibility

11. secondary (or postprimary) tuberculosis
Dormant bacilli persisting for years before reactivating
Mostly in adults
Pulmonary findings

12. secondary (or postprimary) tuberculosis
Age is an important determinant of the risk of disease after infection
Risk is highest among late adolescent and early childhood
Women are more prone to acquire infection than men in early adolescence
The most potent factor for M tuberculosis infection is HIV co-infection

13. Pathogenesis and Immunity
Infection and Macrophage Invasion
Virulence of Tubercle Bacilli
Innate Resistance to Infection
The Host Response
phagosomes and lysosomes occurs
bacilli begin to multiply, ultimately killing the macrophage

14. Pathogenesis and Immunity
Granuloma Formation (Tubercles)
macrophages
The Macrophage-Activating Response
Caseous necrosis
The Delayed-Type Hypersensitivity Reaction
Role of Macrophages and T lymphocytes
Mycobacterial Lipids and Proteins

15. Immunity Skin Test Reactivity PPD Skin test:
Due to delayed-type sensitivity
Coincident with immunity
Mainly due to previously sensitized CD4 T lymphocytes
Positive Tuberculin Skin Test (TST): wheal
> 5mm on un-vaccinated persons
>10 mm on vaccinated persons
After 72 hours

16. Clinical Manifestations
PULMONARY
EXTRA-PULMONARY

17. Pulmonary TB Primary Mostly seen in children
most inspired air is distributed to the middle and lower lung zones, these areas of the lungs are most commonly involved in primary tuberculosis
In majority of cases, lesion heals spontaneously and may later be evident as a small calcified nodule (Ghon lesion)
immunocompromised persons develop miliary TB

18. Pulmonary TB Secondary (Postprimary) adult-type, reactivation
localized to the apical and posterior segments of the upper lobes, where the substantially higher mean oxygen tension favors mycobacterial growth
small infiltrates to extensive cavitary disease

20. Clinical Manifestations
fever and night sweats, weight loss, anorexia, general malaise, and weakness
cough eventually develops—often initially nonproductive and subsequently accompanied by the production of purulent sputum, sometimes with blood streaking
Hemoptysis may also result from rupture of a dilated vessel in a cavity (Rasmussen’s aneuruysm)
Often with no physical findings
The most common hematologic finding is mild anemia and leukocytosis

21. Extrapulmonary TB Lymph-Node Tuberculosis Pleural TB
frequent among HIV-infected patients
historically referred to as scrofula
Pleural TB
TB of upper airways
Genitourinary TB
TB Meningitis and Tuberculoma
Gastrointestinal TB

22. Extrapulmonary TB Skeletal TB
reactivation of hematogenous foci or to spread from adjacent paravertebral lymph nodes
spine in 40% of cases, the hips in 13%, and the knees in 10%
Spinal tuberculosis (Pott's disease or tuberculous spondylitis)
With advanced disease, collapse of vertebral bodies results in kyphosis (gibbus)

23. Extrapulmonary TB Miliary TB Disseminated TB
yellowish granulomas 1–2 mm in diameter that resemble millet seeds
chest radiography reveals a miliary reticulonodular pattern

24. Diagnosis High index of suspision XRAY consistent with TB
AFB microscopy:
Sputum exam
Tissue biopsy
Culture
Gold standard

25. Treatment
DOTS ( Direct Observed Treatment Strategy)
Treatment partner