Pathology Associates Of Lexington, P.A.
Pathology Associates Of Lexington, P.A.
Pathology Associates Of Lexington, P.A.
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        Anthrax
      

In October 2001, this agent became a terrorist threat in the USA by way of tainted postal letters. Until then, cutaneous lesions were sometimes seen, inhalation cases rarely seen, and GI cases essentially never seen. Cutaneous cases were among those working with imported animal hides and fur (especially goats) or livestock workers in places such as southwestern Texas where anthrax is found naturally in the dusty soil (and where ranchers may have stopped vaccinating livestock against anthrax). There are quite a number of Gram positive members of the Bacillus genus in the environment. Bacillus anthracis is the specie which causes anthrax.

Our doctor offices and CMCs are all able to obtain anterior nasal swabs as samples for testing in the main hospital lab. The anthrax organism is readily cultureable & cultures may become positive in 24 hours; blood cultures may become positive sooner. Nasal washing "flu tests" (available in our main lab) are relatively ineffective because real flu (influenza) is not prevalent, and the tests are relatively insensitive (although pretty specific...accurate...when positive). It is a great advantage to have any "r/o anthrax" specimen labeled to that effect!

Skin anthrax:

  1. red spot develops a blister which dries and becomes black (malignant pustule)

  2. a small percentage can become systemically ill and die if not treated

Inhalation anthrax:

  1. Initial phase (1-4 days): variable URI/flu-like symptoms & no way to differentiate from viral URI in this phase. The bacteria invade airway and go to mediastinal and paratracheal nodes which prominently enlarge.

  2. chest x-ray shows the mediastinal and hilar node enlargement, and then lobulated mediastinal widening due to necro-hemorrhagic lymphadenitis with mediastinal hemorrhage (hemorrhagic mediastinitis...the most characteristic finding, not pneumonia3).

  3. as sepsis ensues, the bacillary toxin injures vessels and get intra-pulmonary hemorrhage and "hemorrhagic pneumonia"

  4. can get further lesions of severe bacterial sepsis, such as hemorrhagic meningitis

Gastrointestinal anthrax:

  1. usually follows eating of undercooked meat; no cases recognized in USA

References & update sources:

  1. The College of American Pathologists web site CAP

  2. The U. S. Government's Communicable Diseases Center web site

  3. Anthrax 101, Charles S. Bryan, MD, (senior infectious disease internist, Columbia, SC), The Recorder, Nov. 2001, page 9.

(posted Nov. 2001)
 
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