Tuberculosis
Primary
Pulmonary Tuberculosis
§ Upper lobes affected
slightly more than lower
§
Alveolar infiltrate
§
Cavitation is rare
§ Lobar pneumonia is
almost always associated with lymphadenopathy—therefore, lobar
pneumonia associated with hilar or mediastinal adenopathy at any age should
strongly suggest TB
§ Mostly unilateral hilar
and/or paratracheal, usually right
sided, rarely bilateral
§ Differentiates primary
from postprimary TB—it does not occur in postprimary TB
§
Much more common in
children
·
Airway
· Atelectasis classically
affects the anterior segments of the upper lobes or the medial segment of the
RML
·
Pleura
§
Pleural effusion as a
manifestation of primary TB occurs more often in adults than children
§
With appropriate
treatment, it carries the best prognosis of all patterns of TB and is the
least likely to develop complications
§ The fluid accumulates
slowly and painlessly—therefore, patients
with TB are seldom seen with a small amount of pleural fluid
§
Parenchymal disease will
almost never be present with a pleural effusion although lymphadenopathy may
§ Apical pleural scarring
is rarely tuberculous in origin
Postprimary Tuberculosis (“Reactivation TB”)
Patterns
of distribution
§
Almost always affect the
apical or posterior segments of the upper lobes or the superior segments of
the lower lobes—bilateral upper lobe disease is very common
§
May present as pneumonia
§
Cavitation may result:
the cavity is usually thin-walled, smooth on the inner margin with no
air-fluid level
![cavitary tb](../../notes/chestnotes/TBcavitaryx2.jpg)
Tuberculosis, Cavitary. There are large cavities in both apices (white arrows) and airspace disease at the left base (yellow arrow) on the chest radiograph. On the coronal CT, the thin-walled upper lobe cavities without air-fluid levels are again seen (blue arrows) as is the consolidation at the left base (green arrow). Nodular densities are scattered throughout both lungs.
§
Transbronchial
spread may
occur—from one upper lobe to opposite lower or to another lobe
§
Miliary
spread (below)
§
Bronchiectasis—usually
asymptomatic
§
Bronchostenosis due to fibrosis and stricture: fibrosis may cause distortion of a bronchus and
atelectasis many years after the initial infection—“middle lobe
syndrome”
§
Solitary pulmonary
nodule—the tuberculoma—may occur
in either primary or postprimary disease; round or oval lesions with small,
discrete shadows in the immediate vicinity of the lesion—the “satellite” lesion
-
Formation
of a pleural effusion in postprimary TB almost always means direct spread
of the disease into the pleural cavity and should be regarded as an empyema—this carries a graver prognosis than the pleural
effusion of the primary form
-
Direct
extension into the ribs or sternoclavicular joints is uncommon
Miliary Tuberculosis
-
Older
men, Blacks and pregnant women are susceptible
-
Onset
is insidious
-
Fever,
chills, night sweats are common
-
Takes
weeks between the time of dissemination and the radiographic appearance of
disease
-
Considered
to be a manifestation of primary TB–although clinical appearance of
miliary TB may not occur for many years after initial infection
-
When
first visible, they measure about 1 mm in size; they can grow to 2-3mm if
left untreated
-
When
treated, clearing is rapid—miliary TB seldom, if ever, produces
calcification
TB and Other Diseases
-
There
is an association between TB and silicosis, TB and HIV
-
There
may be an association between TB and sarcoid
-
There
is no association between TB and bronchogenic carcinoma
HIV and
TB
-
No
matter what form of TB the patient has, it tends to look like 1° TB
-
Hilar
and mediastinal adenopathy are common
-
Cavitation
is less common
-
There
is no predilection for the apices
-
MAI
(mycobacterium avium-intracellulare) is more common in HIV than TB
![tuberculosis](../../images/chestimages1/tb-active-chest.jpg)
Tuberculosis, post-primary. There are large cavities in both apices and smaller cavities scattered throughout the lungs. The lungs are over-aerated and there is already scarring present. Dilated bronchi (tuberculous bronchiectasis) is present throughout the lungs.
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