3. Introduction
Tuberculosis (TB) - leading cause of death - world.
1.8 billion people/year-equal to one-third of the entire world
population.
In 2014,- 9.6 million cases - active TB - resulted in 1.5 million
deaths.
Curable and preventable
4. HISTORY
Tuberculosis-Ancient Disease- Spinal Tuberculosis -Egyptian
Mummies
History dates to 1550 – 1080 BC
Identified by PCR
Robert Koch- M. Tuberculosis - discovered - 24 March
1882.
Received-Nobel Prize -1905.
5. Classification of
mycobacteriumCultivable
1. Tubercle bacilli
a) Human – MTB
b) Bovine – M. bovis
c) Murine – M. microti
d) Avian – M. avium
e) Cold blooded – M. marinum
2. Mycobacteria causing skin ulcers
a) M. ulcerans
b) M. belnei
3. Atypical Mycobacteria (Runyon Groups)
a) Photochromogens
b) Scotochromogens
c) Nonphotochromogens
d) Rapid growers
4. Johne’s bacillus
M. paratuberculosis
5. Saprophytic mycobacteria
a) M. butyricum
b) M. phlei
c) M. stercoralis
d) M. smegmatis
e) Others
Non cultivable
1. Lepra bacilli
a) Human – M. leprae
b) Rat – M. leprae murium
6. Mycobacterium differ from other routinely
isolated Bacteria
Slow-growing-12 to 18 hours ( 20-30 min E.coli).
Hydrophobic-high lipid content in the cell wall.
Tend to clump together - impermeable to the usual stains, e.g. Gram's
stain
Acid-fast bacilli - lipid-rich cell walls-relatively impermeable -
various basic dyes unless the dyes-combined with phenol.
Sensitive to heat & UV light
7. Pulmonary
Tuberculosis
• lung
parenchyma-
usually involves-
middle or lower
lung area.
Extra
pulmonary TB
• Other parts-
body- Meninges,
kidneys, bone,
joints,
pericardium, GI
tract & lymph
nodes.
Bovine
tuberculosis
• Disease-affects
animals-cattle -
may sometimes be
transmitted to
man.
Forms of TB
12. Primary Tuberculosis
Initial response
Events of Primary complex
1. Bacilli are engulfed - Alveolar Macrophages
2. Multiply & give raise-Sub pleural focus TB involve lower
lobes & lower part of upper lobes-Ghon’s focus & primary
complex .
13. Primary complex
The patient will heal & a scar - infected area
Few viable bacilli/spores may remain(particularly - lung).
Bacteria-this time goes into-dormant state, as long as- person's
immune system remains active & functions normally.
14. Reactivation
When a person's immune system-depressed., a secondary reactivation
occurs.
85-90% -cases seen -secondary reactivation type occurs in the lungs
Infection activated in Immunosuppressed conditions Eg. HIV infections
and AIDS
Can produce Meningitis, Miliary tuberculosis, other disseminated
Tuberculosis.
15. No progression
Healing by fibrosis & calcification
Ghons complex after undergoing progressive
fibrosis-radiologically detectable
calcification-Ranke complex
Progressive primary tuberculosis
Primary miliary tuberculosis
Dissemination to organs like liver, spleen, kidney, ..etc.
FATE OF PRIMARY TUBERCULOSIS
16. SECONDARY PULMONARY TUBERCULOSIS
The upper parts of both lungs Showed:
• Gray-white areas of caseation
• Multiple areas of softening and cavitation
17. Lesion may heal-fibrous scarring & calcification
Lesions may coalesce together - form large area - TB pneumonia &
produce progressive secondary pulmonary tuberculosis
Producing pulmonary & extra pulmonary lesions:
Tuberculous caseous pneumonia
Fibrocaseous tuberculosis
Miliary tuberculosis
FATE OF SECONDARY PULMONARY TB
18. Extensive infection via hematogenous spread
In lung: lesions - either microscopic or small, visible foci (2mm) of yellow white-
scattered through out lung parenchyma.
Miliary pulmonary disease can cause pleural effusion, tuberculous empyema or
obliterative fibrous pleuritis.
Extra pulmonary miliary tuberculosis - most prominent - liver, spleen, bone
marrow, adrenals, meninges, kidneys, fallopian tubes & epididymis but can involve
any organ
MILIARY TUBERCULOSIS
20. Oral manifestations
Oral lesions- any site- tongue most common
Other-palate, buccal mucosa, lips, gingiva & floor of the
mouth.
Irregular, painful, multiple ulcers with undermined border
granulating floor usually covered by grey-yellowish exudate,
inflamed surrounding tissue.
23. Five patterns of the disease are recognised:
I) pulmonary diseas-m. Kansasii or M. Aviumintracellulare.
Ii) lymphadenitis - m. Avium-intracellulare or M.Scrofulaceum.
Iii) ulcerated skin lesions - m. Ulcerans or M. Marinum.
Iv) abscesses - m.Fortuitum or M. Chelonae.
V) bacteraemias - m. Avium-intracellulare-seen-
Immunosuppressed patients / AIDS
Atypical mycobacteria
Atypical mycobacteria-acquired-directly from environment,
unlike person-to-person transmission -classical TB-disease
produce-atypical mycobacteriosis
Similar-tuberculosis but-less virulent.
Lesions produced-granulomas, nodular collection of foamy cells,
or acute inflammation.
25. HIV Considerations
HIV -strongest risk factor-progression to active disease
HIV kills CD4+ T Helper cells which normally inhibit M.
tuberculosis.
HIV interferes with PPD skin test.
26. Assessment and Diagnostic aids
1. A complete history and physical examination.
2. Histopathological examination
3. Tuberculin skin test (Mantoux test)
4. Chest x-ray
5. Acid-fast bacillus smear & sputum culture -diagnose TB.
6. Smear-ZN - mycobacterium.
7. Bone Marrow Culture
27. Histopathological features
Granulomatous inflammation forms both caseating
and non caseating tubercles
Tuberculous granuloma has the following criteria:
1. Rounded outlines
2. Central caseous necrosis
3. Transformed macrophages termed epithelioid cells
4. Lymphocytes, plasma cells, & fibroblasts
5. Multinucleated giant cells
TB - HISTOPATHOLOGICAL EXAMINATION
28. GRANULOMA OF TUBERCULOSIS
Collar of
lymphocytes,
plasma cells
Central caseated necrosis
Giant multinucleated
cells (langhans type
Epithliod cells
29. Mantoux test
Tubercle bacillus extract (tuberculin), purified protein derivative (PPD)-
injected-intradermal layer of the inner aspect - forearm, approx-4 inches-
elbow.
Result is read 48 to 72 hrs after injection.
30.
31. Culturing Acid Fast Bacilli
Slow to grow ,
Generation time is 14 – 15 hours
Grows at 370c do not grow
below 250c
Ph between 6.4 to 7.0
32. CULTURE MEDIA
SOLID MEDIA
Egg-based Media:
Lowenstein-Jensen (LJ)
Medium
Dorset Medium
Serum containing Media:
Loeffler’s Medium
Potato-based Media:
Pawlowsky’s Medium
Blood containing Media:
Tarshi’s Medium
Agar-based Media:
Middlebrook 7H10
Middlebrook 7H11
Middlebrook Biplate
(7H10/7H11 S Agar).
33. CULTURE MEDIA
LIQUID MEDIA
BACTEC 12 B Medium
BACTEC 460 TB
BACTEC 9000 MB
BACTEC MGIT 960
EPS Culture System II
Middlebrook 7H9 Broth
SeptiChek AFB
Dubo’s Medium
Tween 80
(Sorbitol Mono oleate)
Continuous Monitoring
system
34. TB-L.J MEDIUM
M.tuberculosis appear dry,
rough raised irregular colonies
Appear wrinkled
Creamy white to yellowish
M.bovis appear as flat smooth,
moist, white and break up easily
35. ZN-Stain
• Zn stain-demonstrate-AFB
• Appear-straight /curved
rods – single, pairs or
clumps
• Technique is simple &
inexpensive
• Limited sensitivity(46-78%)
• Specificity 100%
36. Biochemical Reactions:
Niacin Test
Arylsulphatase Test
Neutral Red Test
Catalase-Peroxidase Test
Tween 80 Hydrolysis Test
Amidase Test
Nitrate Reduction Test
Thiophene 2-Carboxylic acid
Hydrazide (TCH) Test
Tellurite Reduction Test
39. Immuno-prophylaxis
Intradermal injection - live attenuated vaccine (BCG).
Strain causes self limited lesion & induces hypersensitivity &
immunity.
Coverts tuberculin negative person to positive reactor.
Immunity lasts for 10-15 years. Immunity 60-80%
Some studies proved BCG is doubtful value in prevention of
Tuberculosis.
40. Incidence of oral lesions in TB cases is very less, so each and
every persistent and atypical oral lesion must be examined
carefully to intercept & prevent the disease early will increase
the morbidity and mortality of the patient.
Conclusion
41. References
Text book of oral pathology, Shafer’s, 7th Edition
Text book of Oral & maxillofacial pathology Neville, Damm, Allen,
Bouquot.,1st south asia edition.
Text book of clinical medicine, DR. S N CHUGH, 3rd edition
Text book of microbiology, C P Baveja, 4th edition
Text book of essential pathology for dental students, harsh mohan
3rd edition.
Editor's Notes
The size of the indurations determines the significance of the reaction.
A reaction of 0 to 4 mm is considered not significant; a reaction of 5 mm or greater may be significant in individuals who are considered at risk.
In duration of 5mm or more than in diameter indicates positive reaction and need for anti tuberculosis treatment for latent TB infection in high risk group.
In duration of 10 mm or more in diameter indicates a positive reaction and need for treatment of latent TB infection in person at risk.