Tuberculosis in AIDS Patients

AIDS is a major risk factor for the development of tuberculosis. This phenomenon is partly related to the fact that HIV adversely affects macrophage function and also destroys CD4 lymphocytes, both of which are part of the normal host defense mechanisms involved in combating MTb. The radiographic manifestations of MTb in patients with AIDS depend on the CD4 count. Patients with relatively preserved immunity (CD4 counts above 200 cells/µl), usually present with the typical postprimary pattern of MTb infection seen in immunocompetent patients. These findings include upper lobe consolidation, cavitation, and nodules, usually without pleural effusion or lymphadenopathy. Patients that are comparatively immunosuppressed, usually with CD4 counts less than 200 cells/µl, present with a pattern of disease resembling primary MTb infection. Such findings include consolidation associated with lymphadenopathy.

Figure 1A. MTb in a Patient with a CD4 Count of 100 Cells/µl

Frontal chest radiograph shows left lower lobe consolidation and a left pleural effusion.

 

 

 

Figure 1B. Axial Thoracic CT

Note extensive left lower lobe consolidation. MTb was recovered in the sputum.

Often the lymphadenopathy is the dominant or only finding, and on CT, affected lymph nodes may show low central attenuation with peripheral enhancement following contrast administration.

lymph

Figure 2A. MTb in a Patient with a CD4 Count of 80 Cells/µl

Frontal chest radiograph shows right paratracheal lymphadenopathy.

Find the paratracheal lymphadenopathy.

 

 

Figure 2B. Axial Contrast-Enhanced CT Image

Note lymphadenopathy anterior and posterior to the superior vena cava. The lymph nodes show central low attenuation, consistent with necrosis and characteristic of MTb in HIV-infected patients with CD4 counts below 200 cells/µl.

HRCT commonly shows centrilobular nodules, often with tree-in-bud patterns. Pleural effusions may also occur. Normal radiographs may occasionally be encountered in patients with AIDS and MTb, and extrapulmonary dissemination is also more frequent in this setting than in immunocompetent patients.

node1node2

 

Figure 3A. Extrapulmonary Dissemination of MTb in AIDS

Axial CT image through the upper abdomen shows necrotic lymphadenopathy in the retroperitoneum.

Find necrotic lymph nodes.

 

 

 

 

Figure 3B

Axial CT image through the upper abdomen shows numerous foci of low attenuation throughout the spleen, consistent with dissemination of MTb infection.

 

References: To return to reference section after viewing abstract, click here before clicking on "abstract".

Jasmer R, Gotway M, Creasman J, Webb W, Edinburgh K, Huang L. Clinical and radiographic predictors of the etiology of computed tomography-diagnosed intrathoracic lymphadenopathy in HIV-infected patients. J Acquir Immune Defic Syndr 2002; 31:291-298. Abstract

Jasmer R, Edinburgh K, Thompson A, Gotway M, Creasman J, Webb W, Huang L. Clinical and radiographic predictors of the etiology of pulmonary nodules in HIV-infected patients. Chest 2000; 117:1023-1030. Abstract

Leung A, Brauner M, Gamsu G, Mlika-Cabanne N, Ben Romdhane H, Carette M, Grenier P. Pulmonary tuberculosis: comparison of CT findings in HIV-seropositive and HIV-seronegative patients. Radiology 1996;198:687-691 Abstract

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Necrotic lymph node

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