Tuberculosis is caused by Mycobacterium tuberculosis and can manifest in active or latent forms. It is transmitted through airborne droplets when an infected person coughs or sneezes. There are three main types - primary TB occurs when the initial infection becomes active, post-primary TB occurs when latent TB reactivates, and latent TB occurs in 90% of infected individuals who never develop symptoms. Radiological findings can help diagnose and characterize TB types. Primary TB often shows lymphadenopathy, consolidation, pleural effusions or milliary nodules. Post-primary TB typically has cavitary lesions and upper lung involvement. Latent TB has fibrotic changes in the upper lungs.

2. INTRODUCTION
• Tuberculosis is an airborne infectious disease caused by
Mycobacterium tuberculosis and is a major cause of
morbidity and mortality, particularly in developing countries
especially among immunocompromised patients.
• Tuberculosis manifests in active and latent forms.

3. • Transmission: Airborne mycobacteria are
transmitted by droplets 1–5 µm in diameter,
which can remain suspended in the air for
several hours when a person with active
tuberculosis coughs, sneezes, or speaks.

4. PRIMARY, POST-PRIMARYAND LATENT
TB
• Not all tuberculosis-
exposed individuals get infected.
• The risk of transmission to another person
depends on the infectiousness of the source
of tuberculosis,the climate and length of the
exposure, and the immune status of the
individual being exposed.
• PRIMARYTB: Once the organism infects
alveolar macrophages, In about 5% of
people:The immune system is unable to
regulate the initial infection, and in the
first 1-2 years, active tuberculosis grows.
• This is referred to as PrimaryTB.

5. • The immune system is successful at
managing the original infection in another
5 percent of infected individuals, but viable
mycobacteria stay latent and reactivate at
a later time; this type is referred to as
Postprimary or Reactivation tuberculosis.
• The remaining 90% of individuals will never
develop symptomatic disease and will harbor
the infection only at a subclinical level, which
is referred to as latent tuberculosis
infection.

7. PRIMARYTUBERCULOSIS

8. • Common Symptoms:
• Productive cough
• Hemoptysis
• Weight loss
• Fatigue
• Malaise
• Fever
• Night sweats

9. In the initial assessment of patients suspected of
having active tuberculosis, imaging plays an
significant role. The figure presented here provides
an algorithm for the evaluation of such a patient.
In HIV-positive patients radiographic findings may
be normal, despite active disease.

10. RADIOLOGICAL FINDINGS IN PRIMARY
TB
• LYMPHADENOPATHY
• CONSOLIDATION
• PLEURAL EFFUSION
• MILIARY NODULES

11. LYMPHADENOPATHY
• Mediastinal and hilar
lymphadenopathy is the most
common radiologic manifestation
of primary tuberculosis .

12. Axial contrast-enhanced chest CT image shows
necrotic mediastinal lymphadenopathy (arrow)
and a small right-sided pleural effusion.

13. Chest radiograph shows a bulky left hilum and
a right paratracheal mass, findings that are
consistent with lymphadenopathy and are
typical in pediatric patients.

14. PARENCHYMAL DISEASE
• Manifests as consolidation depicted as an area of opacity
in a segmental or lobar distribution
• Cavitation occurs in a subset of primary tuberculosis
patients, and it is regarded as a progressive primary
disease when cavitation occurs.
• Difference from Post-PrimaryTB:This cavitation occurs
within existing consolidation and thus does not
demonstrate an upper lung zone predominance
• Bacterial pneumonia frequently looks similar to
parenchymal disease, but the appearance of
lymphadenopathy may be a clue that points to primary
tuberculosis.

15. Radiograph of the left lung demonstrates
extensive upper lobe and lingular consolidation.

16. PA Chest Radiograph showing nodules
and consolidations(arrows),
predominately in the bilateral apical
and upper lung zones.

17. This PA radiograph shows consolidation of
the upper zone with ipsilateral hilar
enlargement due to lymphadenopathy.

18. PLEURAL EFFUSION
• In about 25 percent of primary
tuberculosis cases in adults, pleural
effusion is seen, with the
overwhelming majority of such
effusions being unilateral.

19. Tuberculous empyema in a 40-year-old woman
presenting with weight loss, malaise, and chills.
Axial contrast-enhanced chest CT image shows a
loculated right-sided pleural effusion with thickened,
enhancing pleura (arrows) as well as infiltration of
the extrapleural fat (arrowhead).

20. AIRWAY DISEASE
• In primary and postprimary tuberculosis,
the involvement of the bronchial wall can
be seen, although it is more frequent in
the former.
• The main radiographic features of
proximal airway involvement are indirect,
including segmental or lobar atelectasis ,
lobar hyperinflation, mucoid impaction,
and postobstructive pneumonia.
Chest Radiograph showing right upper
lobe collapse(arrow)

21. MILIARYTB
• Miliary tuberculosis results from
hematogenous transmission,
especially in immunocompromised
and paediatric patients.

22. Axial chest CT image shows numerous
micronodules in a random distribution. Note
subpleural (arrowhead) and centrilobular (arrow)
nodules.

23. HEALED PRIMARYTB
Following an immune response to primary infection, a caseating granuloma forms
which calcifies over time – this is known as a ‘Ghon focus’

24. GHON’S FOCUS + LYMPHADENOPATHY:
GHON’S COMPLEX
HEALED PRIMARYTB

25. POST-PRIMARYTB
• Usually, postprimary tuberculosis is
thought to result from the reactivation
of infection with dormant M
tuberculosis, but may also result from a
second infection with a different strain,
especially in endemic areas.
• Cavitation is a typical finding in
postprimary tuberculosis, seen on chest
radiographs in 20 percent–45 percent of
patients.The largest dimension of
cavities can be several centimetres and
can form dense and irregular walls.
Cavitary lesions are frequently found in
consolidation areas and can be
multifocal.

26. PA Chest Radiograph showing
patchy airspace opacity (arrows) in
right upper lobe with a cavitary
lesion(arrowheads)

28. Axial chest CT image shows right upper
lobe consolidation (arrows) with
associated cavitation (arrowheads).

29. Chest Radiograph shows two left sided
cavitary lesions(arrows) with an ir fluid
level in the larger lesion(arrowhead)
and scattered reticulonodular
opacities.
The presence of an air-fluid level within
a cavity may be related to the
tuberculosis itself or to bacterial
superinfection

30. Chest radiograph demonstrates the
characteristic bilateral upper lobe
fibrosis associated with postprimary
tuberculosis.

31. High-resolution CT scan shows the
typical apical cavitation of
postprimary tuberculosis.

32. High-resolution CT scan
demonstrates multiple small,
centrilobular nodules connected to
linear branching opacities.This so-
called tree-in-bud appearance is
typically seen in postprimary
tuberculosis.

33. LATENT INFECTION
• Definition: Radiographic or clinical
evidence of previous tuberculosis but
no evidence of currently active
tuberculosis.
• Characterized by fibronodular
changes in the apical and upper lung
zones such as peribronchial fibrosis,
bronchiectasis, architectural
distortion and nodular opacities.

34. Chest radiograph shows upper lobe
fibrosis(arrowhead) and volume loss with a
residual cavity(arrow).

35. Axial CT image shows
peribronchial fibrosis
(arrowhead) and
architectural distortion
in the lung apices, with a
residual cavity (arrow).

36. THANKYOU