Anthrax other diagnostic studies: Difference between revisions

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Latest revision as of 20:25, 29 July 2020

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]

Overview

Several studies are used for the diagnosis and monitoring of anthrax. The polymerase chain reaction (PCR) test is ordered to confirm the virulence of the organism. In addition, lumbar puncture should be performed on admission when it is not contraindicated to search for the organism in the cerebrospinal fluid (CSF) and to to exclude other alternative diagnoses. Other diagnostic studies include an electrocardiogram and an echocardiogram to assess possible complications of anthrax such as atrial fibrillation and pericardial effusion.

Diagnostic Studies

Shown below is a table summarizing studies used to diagnose and monitor anthrax infection and its potential complications.^[1]^[2]^[3]

**Laboratory findings**
Test	Initial Findings	Serial Monitoring
PCR	Confirms virulence of organism by search for virulence factor genes Primers to the toxin gene Primer for the enzyme of capsule formation gene
Lumbar puncture	At admission unless contraindicated	Headache Confusion Other neurologic symptom If meningitis, meningeal signs will only be present at a later stage
Other imaging	As relevant to site of exposure Evaluate edema Evaluate inflammation Evaluate necrosis	For headache, confusion or other neurologic symptom If meningitis, meningeal signs will only be present at a later stage
EKG	Atrial fibrillation with rapid ventricular response
Echocardiogram	Evaluate for pericardial effusion Evaluate for myocardial dysfunction

References

↑ Hendricks, Katherine A.; Wright, Mary E.; Shadomy, Sean V.; Bradley, John S.; Morrow, Meredith G.; Pavia, Andy T.; Rubinstein, Ethan; Holty, Jon-Erik C.; Messonnier, Nancy E.; Smith, Theresa L.; Pesik, Nicki; Treadwell, Tracee A.; Bower, William A. (2014). "Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults". Emerging Infectious Diseases. 20 (2). doi:10.3201/eid2002.130687. ISSN 1080-6040.
↑ "Anthrax in Humans and Animals" (PDF).
↑ "Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults".

[HendricksWright2014-1] Hendricks, Katherine A.; Wright, Mary E.; Shadomy, Sean V.; Bradley, John S.; Morrow, Meredith G.; Pavia, Andy T.; Rubinstein, Ethan; Holty, Jon-Erik C.; Messonnier, Nancy E.; Smith, Theresa L.; Pesik, Nicki; Treadwell, Tracee A.; Bower, William A. (2014). "Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults". Emerging Infectious Diseases. 20 (2). doi:10.3201/eid2002.130687. ISSN 1080-6040.

[WHO-2] "Anthrax in Humans and Animals" (PDF).

[CDC-3] "Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults".

[1]

[2]

[3]

@@ Line 1: / Line 1: @@
 __NOTOC__
 {{Anthrax}}
+{{CMG}}; {{AE}} {{JS}}
 ==Overview==
+Several studies are used for the [[diagnosis]] and monitoring of anthrax.  The [[polymerase chain reaction]] ([[PCR]]) test is ordered to confirm the [[virulence]] of the organism.  In addition, [[lumbar puncture]] should be performed on admission when it is not contraindicated to search for the organism in the [[cerebrospinal fluid]] ([[CSF]]) and to to exclude other alternative diagnoses.  Other diagnostic studies include an [[electrocardiogram]] and an [[echocardiogram]] to assess possible complications of anthrax such as [[atrial fibrillation]] and [[pericardial effusion]].
-Various techniques are used for the direct identification of ''B. anthracis'' in clinical material.  Firstly, specimens may be [[Gram stain]]ed.  ''Bacillus'' spp. are quite large in size (3 to 4 μm long), they grow in long chains, and they stain Gram-positive.  To confirm the organism is ''B. anthracis'', rapid diagnostic techniques such as [[polymerase chain reaction]]-based assays and [[Immunofluorescence|immunofluorescence microscopy]] may be used.<ref>{{cite book |author=Levinson, W. |title=Review of Medical Microbiology and Immunology |year=2010 |edition=11th}}</ref>
-All ''Bacillus'' species grow well on 5% sheep blood agar and other routine culture media. Polymyxin-lysozyme-EDTA-thallous acetate can be used to isolate ''B. anthracis'' from contaminated specimens, and bicarbonate agar is used as an identification method to induce capsule formation.  ''Bacillus'' spp.  usually grow within 24 hours of incubation at 35°C, in ambient air (room temperature) or in 5% CO<sub>2</sub>. If bicarbonate agar is used for identification, then the medium must be incubated in 5% CO<sub>2</sub>.  ''B. anthracis'' colonies are medium-large, gray, flat, and irregular with swirling projections, often referred to as having a "[[Medusa|medusa head]]" appearance, and are not hemolytic on 5% sheep blood agar. The bacteria are not motile, susceptible to penicillin, and produce a wide zone of lecithinase on egg yolk agar. Confirmatory testing to identify ''B. anthracis'' includes gamma bacteriophage testing, indirect hemagglutination, and enzyme linked immunosorbent assay to detect antibodies.<ref>{{cite book |author=Forbes, B.A. |title=Bailey & Scott's Diagnostic Microbiology |year=2002 |edition=11th}}</ref> The best confirmatory precipitation test for anthrax is the [[Alberto Ascoli|Ascoli]] test.
 ==Diagnostic Studies==
+Shown below is a table summarizing studies used to diagnose and monitor anthrax infection and its potential [[complications]].<ref name="HendricksWright2014">{{cite journal|last1=Hendricks|first1=Katherine A.|last2=Wright|first2=Mary E.|last3=Shadomy|first3=Sean V.|last4=Bradley|first4=John S.|last5=Morrow|first5=Meredith G.|last6=Pavia|first6=Andy T.|last7=Rubinstein|first7=Ethan|last8=Holty|first8=Jon-Erik C.|last9=Messonnier|first9=Nancy E.|last10=Smith|first10=Theresa L.|last11=Pesik|first11=Nicki|last12=Treadwell|first12=Tracee A.|last13=Bower|first13=William A.|title=Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults|journal=Emerging Infectious Diseases|volume=20|issue=2|year=2014|issn=1080-6040|doi=10.3201/eid2002.130687}}</ref><ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref><ref name=CDC>{{cite web | title = Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults | url = http://wwwnc.cdc.gov/eid/article/20/2/13-0687_article }}</ref>
-===Hemolysis===
+{| style="border: 2px solid #DCDCDC; font-size: 90%"
+|+ '''Laboratory findings'''
-B. anthracis was shown to be haemolytic on blood agar made with sheep red cells that had been washed with buffered saline containing calcium and magnesium. Similarly, the anthrolysin is presumably haemolytic. Reports are also occasionally encountered of haemolysis in blood or on agar containing blood of certain species, including human.<ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref>
+|-
+! style="width: 100px; background: #4479BA; text-align: center;"|{{fontcolor|#FFF|Test}}
-===Lecithinase===
+! style="width: 200px; background: #4479BA; text-align: center;"| {{fontcolor|#FFF|Initial Findings}}
-B. anthracis either produces lecithinase to a lesser extent than its close relatives, B. cereus and B. thuringiensis, or produces a lecithinase with a lower activity. In the lecithinase test on egg yolk agar, the zone of opalescence or “halo” almost always seen around colonies or areas of growth of B. cereus and B. thuringiensis is only sometimes visible around B. anthracis, probably only becoming apparent at 48 hours (35-37 °C) and usually in a narrow band when present. Opalescence should be looked for under the colony/area of growth by scraping away some of the colony material. It can be seen here after 24 hours incubation at 35–37 °C. While B. anthracis grows well on conventional egg yolk agar, it grows less well than B. cereus on Kendall’s BC egg yolk-mannitol agar; the growth of B. anthracis on this medium (24–48 hours) is greyish as compared to the deep purple of B. cereus and, in contrast to B. cereus, a zone of opalescence does not form around the growth of B. anthracis. once again, colony material must be scraped away to see the underlying LV (lecithovitellin) reaction.<ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref>
+! style="width: 200px; background: #4479BA; text-align: center;"| {{fontcolor|#FFF|Serial Monitoring}}
+|-
-===Motility===
+| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''PCR'''
-Although examination for motility is always listed as one of the primary identification tests for B. anthracis, it is doubtful that the test is often done on new isolates or checked more than rudimentarily and occasionally on culture collection cultures. Certainly, the first obvious appearance for diagnostic test purposes is lack of motility, but in view of the existence of genes associated with motility, and even one recent report that includes electron micrographs showing flagella, perhaps the “absoluteness” of non-motility in B. anthracis should be revisited.<ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref>
+| style="background: #DCDCDC; padding: 5px; text-align: center;" colspan=2| Confirms [[virulence]] of [[Bacillus anthracis|organism]] by search for [[virulence factor]] [[genes]]<br>[[Primers]] to the [[toxin]] [[gene]]<br>[[Primer]] for the [[enzyme]] of [[capsule]] formation [[gene]]
+|-
-==PCR==
+| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''Lumbar puncture'''
-PCR is becoming more widely available as a means of confirming the presence of the virulence factor (capsule and toxin) genes, and hence that an isolate is, or is not, virulent B. anthracis. For routine purposes, primers to one of the toxin genes (usually the Protective Antigen gene) and to one of the enzymes mediating capsule formation are adequate. In laboratories not equipped for PCR tests, if doubt remains to the definitive identity of a suspect B. anthracis isolate, inoculation into a mouse or guinea-pig may be the only way remaining to determine conclusively if it is virulent B. anthracis. However this should be a last resort procedure and confined to situations where a definitive identification is essential.
+| style="background: #DCDCDC; padding: 5px;"| At admission unless contraindicated
+| style="background: #DCDCDC; padding: 5px;"| [[Headache]]<br>[[Confusion]]<br>Other neurologic symptom<br>If [[meningitis]], [[meningeal signs]] will only be present at a later stage
+|-
+| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''Other imaging'''
+| style="background: #DCDCDC; padding: 5px;"| As relevant to site of exposure<br>Evaluate [[edema]]<br>Evaluate [[inflammation]]<br>Evaluate [[necrosis]]
+| style="background: #DCDCDC; padding: 5px;"| For [[headache]], [[confusion]] or other [[neurologic]] symptom<br>If [[meningitis]], [[meningeal signs]] will only be present at a later stage
+|-
+| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''EKG'''
+| style="background: #DCDCDC; padding: 5px; text-align: center;" colspan=2| [[Atrial fibrillation]] with rapid [[ventricular]] response
+|-
+| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''Echocardiogram'''
+| style="background: #DCDCDC; padding: 5px; text-align: center;" colspan=2| Evaluate for [[pericardial effusion]]<br>Evaluate for [[myocardial]] dysfunction
+|-
+|}
 ==References==
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 {{reflist|2}}
-[[Category:Needs content]]
+[[Category:Disease]]
+[[Category:Bacterial diseases]]
+[[Category:Biological weapons]]
+[[Category:Livestock]]
+[[Category:Zoonoses]]
+[[Category:Medical disasters]]
+[[Category:Emergency mdicine]]
+[[Category:Up-To-Date]]
+[[Category:Infectious disease]]
+[[Category:Dermatology]]
+[[Category:Pulmonology]]
+[[Category:Gastroenterology]]

Anthrax other diagnostic studies: Difference between revisions

Latest revision as of 20:25, 29 July 2020

Overview

Diagnostic Studies

References

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