This document discusses tuberculosis (TB) in immunosuppressed individuals, particularly those with HIV. It notes that TB is a common opportunistic infection in HIV patients, as HIV impairs cell-mediated immunity and increases the risk of developing active TB from latent TB infection. In HIV patients, active TB often presents atypically with extra-pulmonary involvement, nonspecific chest x-ray findings, or even a normal chest x-ray. The degree of immunosuppression also affects clinical presentation and radiographic patterns of TB. Advanced immunosuppression is associated with less typical radiographic presentations and increased risk of extra-pulmonary and disseminated disease. A CD4 count can provide guidance on the likelihood of TB versus other

1. TB In The Immunosuppressed
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201002414

2. Normal Chest X-ray

3. Introduction
 TB is the most common opportunistic infection
 By producing a progressive decline in cell-mediated immunity,
 HIV alters the pathogenesis of TB,
 greatly increasing the risk of disease from TB in HIV-co-infected individuals
 and leading to more frequent extra-pulmonary involvement,
 atypical radiographic manifestations,
 and paucibacillary disease, which can impede timely diagnosis

4.  In HIV-infected patients with LTBI, active TB develops in about 5 to 10%/yr,
whereas in people who are not immunocompromised, it develops in about
the same percentage over a lifetime
 a chest x-ray may show a nonspecific pneumonia or even be normal.
 Smear-negative TB is more common when HIV coinfection is present.
 Because smear-negative TB is common, HIV-TB coinfection is often
considered a paucibacillary disease state.

5. Immunity

6. Impact of HIV Infection on the Pathogenesis of
Tuberculosis
 Defective macrophages function in response to TB infection
 HIV impairs the host's ability to contain new TB infection
 etc

8.  The presentation of TB also is affected by the extent of HIV-related
immunosuppression.
 In patients with CD4 counts of >350 cells/µL, the clinical and radiographic
presentation is similar to that of patients without HIV infection.
 However, as immunosuppression advances, the radiographic presentation
becomes less typical and extra-pulmonary and disseminated disease
become more common…

9. Radiographic Findings
 Upper-lobe infiltrates and cavities are the typical findings in reactivation TB,
whereas intra-thoracic lymphadenopathy and lower-lobe disease are seen in
primary TB.
 In HIV-infected persons with higher CD4 counts (ie, >200 cells/µL), the
radiographic pattern tends to be one of reactivation disease with upper-lobe
infiltrates with or without cavities.
 In HIV-infected persons who have a greater degree of immunosuppression (ie,
CD4 count <200 cells/µL), a pattern of primary disease with intra-thoracic
lymphadenopathy and lower-lobe infiltrates is seen.
 As chest radiographs may appear normal in up to 21% of those with culture-
positive TB and CD4 counts of <50 cells/µL,(51) a high index of suspicion must
be maintained in evaluating an HIV-infected patient with symptoms suggestive
of TB

10. Without Pleural Effusion

11. With Pleural Effusion

12. CD4 Count Significance
 In AIDS patients, a mycobacterial illness that develops while the CD4 count
is ≥ 200/μL is almost always TB. By contrast, depending on the probability of
TB exposure, a mycobacterial infection that develops while the CD4 count is
< 50/μL is usually due to M. avium complex

13. MAC

14. Milliary TB
IMMUNOCOMPETENT IMMUNOSUPPRESSED

18. Thank You
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