Fever night sweats weight loss hemoptysis apical

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fever, night sweats, weight loss, hemoptysis, apical lesion on chest x-ray) – and the suspected patient should be placed in isolation until the diagnosis is made or disproven. TB is prevalent in certain populations (see slide titled High Risk Populations). Among foreign-born persons, active TB usually arises from infection acquired years earlier. Among US-born persons, it often indicates recent infection. The tuberculin skin test indicates past infection, not active disease. It is negative in infected patients who have defective CMI for any reason, and in 10-20% of infected patients for no apparent reason. It is most useful for detecting “latent” TB infection (LTBI). By contrast, the diagnosis of active tuberculosis is best made by identifying acid-fast bacteria (by smear or culture) in bodily samples or by demonstrating granulomas (preferably with caseation) on biopsies. However, other diseases may cause granulomas and some other microbes are acid-fast so that, short of actually growing the microorganisms in culture, the diagnosis must be made on the basis of high probability rather than proof. Interpretation of a positive PPD in the patient with suspected latent TB is complicated and depends on the a priori likelihood of TB and the presumed ability of the patient to mount a delayed hypersensitivity reaction. As little as 5 mm of induration is indicative of latent TB in HIV-infected patients, close contacts of patients with active TB, patients with upper lobe scarring, or patients on chronic prednisone. Ten mm is required in patients with moderate risk of exposure (born in endemic area, homeless, injection drug user, health care worker) or some potential impairment of CMI (steroids, malnutrition, certain medical illnesses such as ESRD, DM). Other patients should not be tested at all or, if tested, require 15 mm of induration to qualify as having latent TB.
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  • Fall '10
  • JoyStewart
  • Anatomy, CMI

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