Routine screening of my patient suspected of having tuberculosis (TB) shows that he is HIV seropositive. Does HIV affect the clinical manifestation of TB?

Patients with newly-diagnosed TB are ~20 times more likely to be coinfected with HIV than those without TB. Unfortunately, the diagnosis of TB in HIV-infected patients is often delayed in part related to its atypical presentation1.

In HIV-infected patients with high CD4 counts, clinical manifestations of TB are usually similar to those without HIV infection (eg, subacute fever, weight loss, cough) with CXR often showing upper lobe infiltrates and/or cavitations typically seen in reactivation TB.

Lower CD4 counts, however, are associated with atypical CXR findings, including pleural effusions, lower or middle lobe infiltrates, mediastinal adenopathy, and lack of cavitary lesions1,2.  A normal CXR has been reported in 21% of patients with CD4 <200 cells/μl (vs 5% in those with higher counts)2.

Advanced immune suppression in HIV infection is also associated with negative sputum smears for acid-fast bacilli, concurrent extra-pulmonary disease, and immune reconstitution symptoms after initiation of anti-TB therapy1.

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References

  1. Kwan CK, Ernst JD. HIV and tuberculosis: a deadly human syndemic. Clin Microbiol Rev 2011;24:351-376. https://cmr.asm.org/content/24/2/351
  2. Greenberg, SD, Frager D, Suster B, et al. Active pulmonary tuberculosis in patients with AIDS: spectrum of radiographic findings (including a normal appearance). Radiology 1994;193:115-9. https://pubs.rsna.org/doi/abs/10.1148/radiology.193.1.7916467
Routine screening of my patient suspected of having tuberculosis (TB) shows that he is HIV seropositive. Does HIV affect the clinical manifestation of TB?

When should I seriously consider active tuberculosis (TB) in my newly-admitted HIV-negative patient with a cough?

Active TB should be suspected based on a combination of epidemiological (eg, exposure, travel to, or residence in a high prevalence area, history of prior TB), clinical (eg, cough lasting 2-3 weeks or longer, fever, night sweats, weight loss, fatigue, less commonly, chest pain, dyspnea, and hemoptysis), chest radiograph abnormalities (eg, infiltrates, fibrosis, cavitation), and histopathologic (eg, caseating granuloma)1.

Among HIV-negative patients, the highest prevalence of TB is found those who have been incarcerated, use intravenous drugs, have alcohol use disorder, or are immunocompromised (including diabetes mellitus)2,3

Patients suspected of TB based on clinical criteria should undergo chest radiography.  Reactivation pulmonary TB (~90% of TB in adults) classically presents with upper lobe and/or the superior segment of the lower lobe disease.  Remember that up to 5% of patients with active pulmonary TB have normal chest radiograph, however4.  

All hospitalized patients suspected of having active TB should be placed on appropriate isolation precautions.

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References

  1. Sia IG, Wieland ML. Current concepts in the management of tuberculosis. Mayo Clin Proc. 2011;86:348-361. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068897/
  2. Center for Disease Control. Tuberculosis: Data and Statistics. https://www.cdc.gov/tb/statistics/default.htm. Accessed October 3, 2016.
  3. World Health Organization. Tuberculosis. http://www.who.int/mediacentre/ factsheets/fs104/en/. Accessed October 3, 2016.
  4. Marciniuk, D, McNab, BD, Martin WT, Hoeppner, VH. Detection of pulmonary tuberculosis in patients with a normal chest radiograph. Chest 1999;115:445-452. https://journal.chestnet.org/article/S0012-3692(15)50590-4/abstract

 

 

Contributed by Charles C. Jain MD, Medical Resident, Massachusetts General Hospital

 

When should I seriously consider active tuberculosis (TB) in my newly-admitted HIV-negative patient with a cough?