UMEM Educational Pearls

Title: Tuberculosis: Testing and Treatment

Keywords: Tuberculosis, infectious disease, drug resistance, treatment (PubMed Search)

Posted: 7/15/2015 by Jon Mark Hirshon, MD, MPH, PhD
Click here to contact Jon Mark Hirshon, MD, MPH, PhD

Tuberculosis (TB) remains a deadly scourge killing approximately 1.5 million each year (see Pearl from 7/2/2105). Recognition by astute clinicians in the emergency department is key, as there is no readily available rapid test.

Current testing options:

1) Tuberculin skin test (also known as the Mantoux tuberculin skin test). A small amount of fluid (tuberculin purified protein derivative) is placed intradermally, usually in the left forearm. A positive test means the person was infected with TB. (Alternatively, if they grew up outside the US, they could have been vaccinated with Bacillus Calmette–Guérin or BCG.) A positive test is determined by the size of the reaction, but this can vary depending on the patient’s immune status.

2) Two interferon-gamma release assays or IGRA blood tests are approved for TB. While not readily available in all institutions, this is the preferred method for someone vaccinated with BCG.

Diagnosis of TB disease is based upon:

Medical history
Physical exam
A positive TB test
Chest radiograph
Other appropriate laboratory test (such as acid fast bacilli on sputum smear followed by culture)

Treatment:

TB treatment depends on the susceptibility of the organism and the immune status of the patient. For a susceptible organism in a non-HIV patient, the first-line anti-TB agents regimens include

isoniazid (INH),
rifampin (RIF),
ethambutol (EMB), and
pyrazinamide (PZA).

Typical treatment has an initial phase of 2 months, followed by a choice of several options for the continuation phase of either 4 or 7 months. Further information can be found at the CDC website on tuberculosis

Bottom Line

As stated previously, in the emergency department, maintain a strong clinical awareness for tuberculosis for someone with night sweats, cough, chest pain, and intermittent fever lasting for 3 weeks or longer. In particular, consider this diagnosis for someone from a low- or middle-income country or if he or she is HIV positive.

References

http://www.cdc.gov/tb/topic/testing/default.htm

http://www.cdc.gov/tb/publications/factsheets/testing/diagnosis.htm

http://www.cdc.gov/tb/publications/factsheets/treatment/treatmenthivnegative.htm