Brief Checklist Facilitates Triage After Anthrax Mass Exposure Event

By Will Boggs MD

March 19, 2019

NEW YORK (Reuters Health) - A brief checklist of signs and symptoms accurately distinguishes anthrax from other conditions and identifies individuals requiring treatment or diagnostic testing after a mass exposure event, researchers report.

"I think physicians may be surprised by the fact that the majority of anthrax cases in our study were detected by evaluating just two vital signs (very high heart rate and high breathing rate) and two neurological conditions (confusion and severe headache)," Dr. Nathaniel Hupert from the Cornell Institute for Disease and Disaster Preparedness and Weill Medical College in New York City told Reuters Health by email.

In the event of a wide-area aerosol release of Bacillus anthracis spores (Ba-WAAR), health care providers would need a rapid, efficient way of separating anthrax case patients needing combination intravenous antimicrobials from individuals who could be given oral antimicrobials for uncomplicated cutaneous illness or postexposure prophylaxis (PEP).

Dr. Hupert and colleagues used data from published clinical reports of adult patients with anthrax from 1880 through 2013 and clinical features of individuals presenting for evaluation after 2 US anthrax attacks in 2001 to develop a screening checklist for rapidly triaging patients after Ba-WAAR.

They identified nine consistently significant independent predictors of anthrax, but they excluded two of them (fever and chills) because of their high prevalence among control individuals.

During paramedical evaluation, the presence of any one of four major signs (tachypnea, extreme tachycardia, altered mental status, or severe headache) quickly identified 58% of the case patients requiring hospitalization with 94% specificity, according to the March 18th Annals of Internal Medicine online report.

Additional potential case patients were identified on formal medical evaluation by the presence of abnormal lung sounds, increasing abdominal girth, or characteristic skin lesions.

Paramedical and medical approaches combined identified 95% of individuals requiring intravenous therapy and 76% of those who could be given oral treatment or PEP.

Additional diagnostic testing increased overall specificity from 76% to 89% but had no impact on sensitivity. In this data set, up to half of case patients and one quarter of control patients would reach the medical evaluation, but only 5% and 15%, respectively, or less would have diagnostic testing recommended.

Overall, 104 of 304 case patients and 13 of 644 control patients had incomplete data. Of these, 49 case patients and 5 control patients could be assigned to a treatment category or diagnostic testing on the basis of other clinical information, but 55 case patient and 8 control patients could not be classified.

In sensitivity analyses, diagnostic testing rarely improved checklist sensitivity but was useful for decreasing false-positive results. Exclusion of asymptomatic controls decreased specificity, thus increasing the importance of diagnostic testing.

Dr. Hupert said, "At the end of the day, we would like medical professionals to know two things from our research: first, that it's possible to make informed decisions about patient care after an anthrax spore exposure even without using any diagnostic tests; and second, that it's just as important to find those without anthrax in order to give them reassurance - backed up by evidence - that they do not need to go to the hospital. Preserving hospital capacity for those who truly need it is an important goal in situations like this."

"We believe that preparedness tools like our new checklist will lead to better patient outcomes if they are part of an ongoing, regularly exercised, and community-based emergency response program," he added.


Ann Intern Med 2019.