197. Secondary tuberculosis: its forms, clinical and morphological characteristics, complications.

Secondary, or reinfective, tuberculosis develops in the body of an adult who has previously suffered a primary infection, which provided him with relative immunity, but did not protect him from repeated disease — post-primary tuberculosis.

There are 8 forms of secondary tuberculosis, each of which represents a further development of the form preceding it. In this regard, the forms of secondary tuberculosis are at the same time phases of its development:

– acute focal tuberculosis;

– fibrotic focal tuberculosis;

– infiltrative tuberculosis;

– tuberculosis;

– caseous pneumonia;

– acute cavernous tuberculosis;

– fibrous-cavernous tuberculosis;

– cirrhotic tuberculosis.

Acute focal tuberculosis. Morphologically, it is characterized by 1-2 foci in the I–II segment of the right (less often left) lung — foci of Abrikosov's reinfect. Specific inflammation of the bronchioles passes to the pulmonary parenchyma, acinous or lobular curd bronchopneumonia develops, around which a shaft of epithelioid cells with an admixture of lymphoid and giant Pirogov–Langhans cells is rapidly formed. Reactive nonspecific inflammation develops in the lymph nodes of the lung root. With timely treatment, and most often spontaneously, the process subsides, the exudative tissue reaction is replaced by a productive one, foci of caseous necrosis are encapsulated and petrified, Aschoff-Pulev foci of reinfect appear, and the process ends there.

Fibrotic focal tuberculosis is a phase of the course of acute focal tuberculosis, when, after a period of subsiding of the disease (healing of the foci of Abrikosov), inflammation flares up again. During the healing of Abrikosov foci, rather large encapsulated and partially petrified foci appear.The process remains one–sided, does not go beyond the I-II segment.

Infiltrative tuberculosis develops with the progression of acute focal or exacerbation of fibrous-focal tuberculosis, and exudative changes around caseous foci go beyond the lobule and even the segment. Perifocal inflammation prevails over minor caseous changes. Such a focus is called an early Assmann–Redeker infiltration. The nonspecific perifocal inflammation resolves, and during the healing period only one or two small caseous foci remain, which are further encapsulated, and the disease again acquires the character of fibrotic focal tuberculosis.

Tuberculoma is a form of secondary tuberculosis that occurs as a peculiar phase of the evolution of infiltrative tuberculosis, when perifocal inflammation resolves and a focus of curd necrosis remains, surrounded by a capsule. Often, during X-ray examination, due to its rather well-defined boundaries, it is mistaken for peripheral lung cancer.

Caseous pneumonia is usually observed with the progression of infiltrative tuberculosis, as a result of which caseous changes begin to prevail over perifocal ones. Acinous, lobular, segmental caseous-pneumonic foci are formed, which, when merged, occupy large areas of the lungs and even the entire lobe. Lobar pneumonia has a caseous character, which developed against the background of lobitis. The lung with caseous pneumonia is enlarged, dense, yellow in the incision, fibrinous overlays on the pleura.

Acute cavernous tuberculosis is a form of secondary tuberculosis, which is characterized by the rapid formation of a decay cavity, and then a cavity at the site of an infiltrate or tuberculoma focus. The decay cavity is formed as a result of purulent melting and liquefaction of caseous masses, which are released together with sputum. This creates a danger of bronchogenic contamination of the lungs and the release of mycobacteria into the environment. The wall of the cavity is heterogeneous: its inner layer consists of caseous masses, the outer layer consists of compacted lung tissue as a result of inflammation.

Fibrous-cavernous tuberculosis, or chronic pulmonary consumption, develops from acute cavernous tuberculosis if it takes a chronic course. The cavity wall is dense and has three layers: the inner one is pyogenic (necrotic), rich in decaying leukocytes; the middle one is a layer of tuberculous granulation tissue; the outer one is connective tissue, and areas of lung atelectasis are visible among the layers of connective tissue. The inner surface is uneven, with beams crossing the cavity of the cavity; each beam is an obliterated bronchus or thrombosed vessel. The cavern occupies one or two segments. Various foci are identified around it, depending on the type of tissue reaction, bronchiectasis. Over time, the process passes through the bronchi to the opposite lung.

Cirrhotic tuberculosis is a variant of the development of fibrous-cavernous tuberculosis, when a powerful formation of connective tissue occurs around the cavity, a linear scar forms in place of the healed cavity, pleural adhesions appear; the lung is deformed, dense and sedentary, bronchiectasis appears.

Complications of tuberculosis

In secondary tuberculosis, the greatest number of complications is associated with the cavity: bleeding, rupture of the contents of the cavity into the pleural cavity, which leads to pneumothorax and purulent pleurisy (empyema of the pleura). Due to the long course of the disease, any form of tuberculosis is complicated by amyloidosis, especially often with fibrous-cavernous tuberculosis.