Plague Symptoms, Causes, Treatment - How is plague diagnosed? on MedicineNet

Plague (cont.)

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Medical Author:

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Medical Editor:

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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How is plague diagnosed?

The history and physical exam is an important first step in the diagnosis of plague. The patient's exposure to animals (and the fleas that accompany them) or exposure to humans that have plague or the symptoms of plague, or have visited or reside in a plague-endemic area can help trigger the medical caregivers' ability to do further tests for plague. In addition, if buboes develop in about three to seven days after exposures listed above, bubonic plague may be presumptively diagnosed. Unless septicemic or pneumonic plague develop directly from the bubonic form, the presumptive diagnosis is somewhat more difficult to make; sometimes because plague is seen so infrequently by many doctors (for example, see reference 1). However, a good patient history can help make a more timely presumptive diagnosis. In addition, bleeding under the skin and other septicemic symptoms may be helpful. Laboratory tests are usually based on the detection of the F1 antigen of Y. pestis and can provide both a presumptive and definitive diagnosis of plague. The CDC currently (2011) provides the following guidelines for diagnosis of plague:

SUSPECTED PLAGUE SHOULD BE CONSIDERED IF THE FOLLOWING CONDITIONS ARE MET:

1. Clinical symptoms that are compatible with plague, i.e., fever and lymphadenopathy in a person who resides in or recently traveled to a plague-endemic area.

2. If small gram-negative and/or bipolar-staining coccobacilli are seen on a smear taken from affected tissues, e.g.:

Bubo (bubonic plague)
Blood (septicemic plague)
Tracheal/lung aspirate (pneumonic plague)

PRESUMPTIVE PLAGUE SHOULD BE CONSIDERED WHEN ONE OR BOTH OF THE FOLLOWING CONDITIONS ARE MET:

Yersinia pestis

CONFIRMED PLAGUE IS DIAGNOSED IF ONE OF THE FOLLOWING CONDITIONS IS MET:

*Agglutination testing must be shown to be specific to Y. pestis F1 antigen by hemagglutination inhibition.

Definitive diagnosis of plague has also been done by PCR tests to detect the genetic material of Y. pestis antigens in animal, flea, and human tissues.

Reviewed by Mary D. Nettleman, MD, MS, MACP on 4/13/2012

Next: What is the treatment for the plague? What is the prognosis of the plague?