Characterized by a chronic wave-like course with the formation of a thick-walled cavern or caverns with pronounced perifocal scarring (extensive fibrosis)
Etiology
Fibrocavernous tuberculosis is primarily caused by infection with the bacterium Mycobacterium tuberculosis
Pathogenesis
TB
Infection occurs when person inhales droplet nuclei containing tubercle bacilli that reach the alveoli of the lungs
The first contact of the Mycobacterium organism with a host leads to manifestations known as primary tuberculosis.
This primary TB is usually localized to the middle portion of the lungs, and this is known as the Ghon focus of primary TB.
In most infected individuals, the Ghon focus enters a state of latency. This state is known as latent tuberculosis
Tuberculosis is a classic example of a cell-mediated delayed type IV hypersensitivity reaction:
By stimulating the immune cells (the helper T-Lymphocyte, CD4+ cells), Mycobacterium tuberculosis induces the recruitment and activation of tissue macrophages. This process is enhanced and sustained by the production of cytokines, especially interferon-gamma.
Two main changes involving macrophages occur during this process, namely, the formation of multinucleated giant cells and the formation of epithelioid cells
The aggregation of giant cells surrounding the Mycobacterium particle and the surrounding lymphocytes and other cells is known as a granuloma
In addition to interferon-gamma (IFN-gamma), the following cytokines play important roles in the formation of a tuberculosis granuloma, Interleukin-4 (IL-4), Interleukin-6 (IL-6), and tumor necrotic factor-alpha (TNF-alpha).
The appearance of the granuloma in tuberculosis has been described as caseous or cheese-like on gross examination. This is principally explained by the rich mycolic acid content of the mycobacterium cell wall
Acute cavernous TB
Develops due to lysis of caseous necrosis and is characterized by formation of a cavity
Symptoms
Persistent cough that could last for weeks or months
May be productive with sputum
Hemoptysis
Chest pain
SOB
Weight loss
Fatigue
Night sweats
Fever
Physical exam
Percussion
Dullness to hyperresonant sound dependant on whether cavities are full or filled
Auscultation
Diminished breathing sounds in places of fibrosis and pleural thickening
Diagnosis
Macroscopically- massive fibrosis in the lung, thick-walled cavities, and multiple foci in the pulmonary parenchyma
CXR- fibrotic cavity with thick fibrous walls and pleural stratification
Mostly seen in upper parts of lungs
Upper parts reduced in volume
Sputum samples for culture
Blood tests
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