A) primary tuberculosis:

NEET PG Pathology
#1

TUBERCULOSIS

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✅a/k/a KOCH’s disease

✅acid fastness – due to MYCOLIC ACID

✅Virulence factor — “CORD factor”

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A) PRIMARY TUBERCULOSIS:

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✳️Most commonly seen in children

✳️a/w unsensitised and unexposed individuals

✳️source of organism— exogenous

✳️most commonly starts as “LATENT DISEASE”

✳️unilateral hilar lymph enlargement

  1. GHON’S FOCUS:-

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✅ Subpleural fibrocaseous lesion (CONSOLIDATION) of lung parenchyma.

✅microscopically contains epitheloid granulomatous inflammation

  1. GHON’S COMPLEX:-

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❇️Consists of Subpleural ghon’s focus and involved lymph nodes.

❇️Ghon’s complex found below clavicle.

  1. RANKE’S COMPLEX :-

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✅Ghon’s focus alongwith FIBROSIS and CALCIFICATION known as RANKE’S COMPLEX.

✅Calcification

✅Pleural effusion

✅Erythema nodosum

✅Phlyctenular conjunctivitis

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B ) POST-PRIMARY

(=SECONDARY)PULMONARY TUBERCULOSIS

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✳️Seen in previously sensitized host due to reactivation of latent primary lesions

✳️ frequently a/w decreased immune status

  1. PUHL’S LESION:-

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✅ Lesion in lung apex.

✅ No lymph node involvement

  1. SIMON FOCUS :

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❇️it is a tuberculous (TB) nodule formed in lung apex.

❇️Due to spread of primary TB infection from elsewhere in the body to lung apex via bloodstream.

❇️Simon focus nodules are often calcified.

3 ) ASSMAN FOCUS:-

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✅infraclavicular lesion of chronic pulmonary T.B.

✅Lymph node involvement is RARE.

secondary TB more likely to cavitate than primary TB.

✅Endobronchial spread along nearby airways is relatively common finding, resulting in relatively well-defined 2-4 mm nodules or branching lesions TREE-IN-BUD APPEARANCE on CT scan.

🔵#tuberculoma formation and miliary TB are also recognised patterns of secondary TB.

C) MILIARY PULMONARY TUBERCULOSIS

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❇️Miliary tuberculosis is uncommon but carries a poor prognosis.

❇️It represents haematogeneous dissemination of an uncontrolled tuberculous infection.

❇️seen both in primary and post-primary tuberculosis.

❇️lungs are usually the easiest location to image.

❇️Miliary deposits appear as 1-3 mm diameter nodules.

1 ) RICH FOCUS :-

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✳️It is a tuberculous granuloma occurring on brain cortex that ruptures into subarachnoid space, causing tuberculous meningitis.

2 ) WEIGERT’S FOCUS :-

✅Subintimal foci in pulmonary vein. ( d/t metastatic caseous TB.)

3 ) SIMMOND’S FOCUS:-

❇️Localized TB foci in liver.

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🔴CONGENITAL TUBERCULOSIS🔴

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✅Infection with tubercle bacilli either during intrauterine life or before complete passage through birth canal is termed as congenital tuberculosis.

✅Three possible modes of infection of fetus:-

  1. Hematogenous infection via umbilical vein

  2. fetal aspiration of infected amniotic fluid

  3. fetal ingestion of infected amniotic fluid

✅Most common “site” and most common "site of primary complex " both is — LIVER ( primary complex in liver is suggestive of congenital TB)

✅Prognosis is poor.

🔵 Revised criteria for diagnosis of congenital tuberculosis ( by Cantwell )

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✅Proven tuberculosis lesions in the infant plus one of the following:-

  1. Lesions occurring in the first week of life.

  2. A primary hepatic complex

  3. Maternal genital tract or placental tuberculosis, and

  4. Exclusion of postnatal transmission by thorough investigation of contact.