Chapter 5-15: Pulmonary Tuberculosis (TB) in AIDS Patients

TEXTBOOK PRESENTATION

Pulmonary TB typically presents subacutely with cough and fever that have gone on for over a week (and often much longer) and systemic symptoms of night sweats and weight loss are common¹. In patients with CD4TL > 200 cells/mcL, the chest radiographic pattern is similar to the one seen in non–HIV-infected patients—that is, with apical, cavitary, or nodular infiltrates. In patients with CD4TL < 200 cells/mcL, the pattern on chest radiograph is often atypical: lower lobe infiltrates, miliary infiltrates, and lymphadenopathy are more common. Extrapulmonary TB is also more common in AIDS.

DISEASE HIGHLIGHTS

1. There are currently more worldwide cases of TB than at any time in human history: per CDC data, in 2017, there were an estimated 10.0 million people with new TB and 1.3 million TB-related deaths worldwide. Latent TB infection affects a quarter of the world population.

2. HIV-infected persons are at highest risk for TB (170 times higher incidence).

   1. Risk increases further in patients from endemic areas and among IDUs.

   2. 9000 TB cases were reported in 2017 in the United States, a 1.6% decrease from 2016.

3. TB in turn increases both HIV replication and the risk of death.

4. Worldwide, TB accounts for 30% of HIV-related deaths.

5. Epidemic in sub-Saharan Africa and parts of Asia

6. 50% of cases secondary to recent infection (progressive primary TB)

7. TB may be the first manifestation of HIV infection and is an AIDS-defining illness.

   All patients with TB should be tested for HIV.

8. Clinical characteristics

   1. Early HIV infection: pulmonary TB is fairly typical.

   2. Advanced HIV infection

      1. Extrapulmonary TB more frequent

         1. More common in the AIDS population (30%) than in patients without AIDS (15%)

         2. Most common sites of extrapulmonary TB include blood, lymph nodes, bone marrow, genitourinary tract, CNS, and liver. 19% of patients had cervical or supraclavicular lymph node involvement.

         3. Other syndromes seen in these patients include weight loss, fever of unknown origin, and TB meningitis.

      2. Chest radiographic pattern more frequently atypical (see below).

Extrapulmonary TB is common in HIV-­infected patients and extrapulmonary sites of infections may provide a target for diagnostic procedures.

EVIDENCE-BASED DIAGNOSIS

1. Prolonged fever (> 7 days) is more common in HIV-infected persons with pulmonary TB than in PJP or bacterial pneumonia (sensitivity, 56%; specificity, 78%; LR+, 2.5; LR–, 0.57).

2. Weight loss is also more common with pulmonary TB than with PJP or bacterial pneumonia (sensitivity, 67%; specificity, 68%; LR+, 2.1; LR–, 0.49).

3. Standard tests in patients with suspected pulmonary TB should include chest radiograph (with posteroanterior and lateral views), 3 sputum AFB stains and cultures, PPD or IGRA, and blood and urine cultures.

4. Chest radiography

   1. Certain radiographic findings, including cavitary lesions, hilar lymphadenopathy, and nodular lesions, are infrequent but suggestive of pulmonary TB (Table 5-7).

      The chest radiograph in HIV-infected patients with ...