Extrapulmonary tuberculosis

Extrapulmonary tuberculosis is tuberculosis (TB) within a location in the body other than the lungs. This occurs in 15–20% of active cases, causing other kinds of TB. These are collectively denoted as "extrapulmonary tuberculosis". Extrapulmonary TB occurs more commonly in immunosuppressed persons and young children. In those with HIV, this occurs in more than 50% of cases. Notable extrapulmonary infection sites include the pleura (in tuberculous pleurisy), the central nervous system (in tuberculous meningitis), the lymphatic system (in scrofula of the neck), the genitourinary system (in urogenital tuberculosis), and the bones and joints (in Pott disease of the spine), among others.

Spread to lymph nodes is the most common. An ulcer originating from nearby infected lymph nodes may occur and is painless, slowly enlarging and has an appearance of "wash leather".

When it spreads to the bones, it is known as "osseous tuberculosis", a form of osteomyelitis. Tuberculosis has been present in humans since ancient times.  A potentially more serious, widespread form of TB is called "disseminated tuberculosis", also known as miliary tuberculosis. Miliary TB currently makes up about 10% of extrapulmonary cases.

Tuberculous peritonitis
There are three forms of tuberculous peritonitis:
Wet type presents with abundant and relatively increased density ascites (20-45 HU), smooth peritoneal thickening and omental smudge. Thickened strands with crowded vascular bundles in the mesentery are characteristic.
Fixed fibrotic form- With imaging appears as omental mass, matted bowel loops and nodular / irregular thickening of bowel and mesentery, and sometimes with loculated ascites. This form is considered as great mimic of peritoneal carcinomatosis.
The dry or plastic form causes a fibrous reaction in the peritoneum results in adhesion of bowel loops and caseous lymph nodes.

Other findings in the abdomen such as miliary microabscesses in the liver or spleen, splenomegaly, splenic or lymph
node calcification, inflammatory thickening of the terminal ileum and caecum, patulous I-C junction and low attenuation
lymphadenopathy may help suggest tuberculosis as the etiology of diffuse peritoneal disease.

Like tuberculosis, Crohn's disease can result in granulomatous peritonitis. Smooth and regular peritoneal thickening is more in favor of granulomatous peritonitis.

References

Category:Tuberculosis