New culture-independent tests are much more
sensitive than traditional diagnostic methods in detecting the cause of
infectious diarrhea.
a significant problem that leads to nearly 500,000
hospitalizations and more than 5,000 deaths in the United States every
year. But because these tests are so sensitive and may detect multiple
organisms, infectious disease expertise may be necessary to interpret
the clinical significance and facilitate appropriate public health
surveillance, according to new infectious diarrhea guidelines released
by the Infectious Diseases Society of America (IDSA) and published in
the journal Clinical Infectious Diseases.
Designed to guide primary care physicians and other healthcare
providers who see most children and adults with diarrhea, the guidelines
note that the majority of people with diarrhea do not need to be
tested.
Those who should be tested include children younger than five, the
elderly, people who are immune-compromised and those with bloody
diarrhea, severe abdominal pain or tenderness or signs of sepsis
(life-threatening response to infection).
"Diagnostic testing combined with clinical expertise is helpful in
identifying a cluster of infections that may signal an outbreak," said
Andi L. Shane, MD, MPH, MSc, lead author of the guidelines and associate
professor of pediatric infectious diseases, Emory University School of
Medicine and Children's Healthcare of Atlanta. "However, even if they
don't need to be tested, most people will benefit from rehydration
therapy while waiting for the infection to run its course."
Diarrhea is defined by the World Health Organization as three or more
loose or liquid stools in 24 hours, or more frequently than is normal
for the person. Diarrhea is often -- but not always -- infectious,
meaning that it is thought to be caused by a microbe such as a virus,
bacterium or parasite that can spread from person to person. However,
overall the most common causes of infectious diarrhea (also known as
acute gastroenteritis) is are unknown. When new molecular tests are
used, pathogenic E. coli and norovirus is are among the microbes most
frequently identified in people with diarrhea. While infectious diarrhea
is most common in children younger than 5 years of age, its incidence
has decreased in the last decade since vaccines for rotavirus were
introduced.
New culture-independent diagnostic tests developed in the last
several years are more sensitive than the culture-based tests
traditionally used. However, they may detect organisms with which most
physicians are unfamiliar, or detect more than one microbe. In those
cases, consultation with an infectious diseases physician may be
beneficial, the guidelines note.
The guidelines include seven tables that busy clinicians can quickly
reference for information about the various ways people acquire the
microbes, exposure conditions, post-infectious symptoms and clinical
presentation, as well as recommended antimicrobial, fluid and
nutritional management. The tables also help clinicians assess when a
person with diarrhea should be tested and provide treatment
considerations. Physicians should ensure that children with mild to
moderate dehydration, and children and adults with acute diarrhea and
those with mild to moderate dehydration associated with vomiting or
severe diarrhea be given oral rehydration solution if tolerated,
progressing to intravenous rehydration if oral rehydration is not
tolerated.
The guidelines also underscore the vital role primary care clinicians can play in identifying an outbreak.
"We need the frontline clinicians to be astute and notice if they are
seeing patients with an unusual infection, or a number of similar
infections from a specific location such as a child care center, nursing
home or eating facility and then work closely with the state and local
health authorities," said Larry Pickering, MD, a co-author of the
guidelines and adjunct professor of pediatrics at Emory University
School of Medicine and Children's Healthcare of Atlanta. "This is the
optimal way to develop community awareness and use an integrated
approach to identify and contain an outbreak."
The new infectious diarrhea guidelines provide an update of the 2001
guidelines. While the guidelines mention travel-associated diarrhea and
Clostridium difficile diarrhea, other more-specific guidelines on those
topics provide detailed guidance and are referenced.
An related accompanying editorial in the same issue of Clinical Infectious Diseases
notes that other organizations such as the American College of
Gastroenterology have provided additional specific criteria for
diagnostic testing for acute diarrhea, such as individuals with
moderate-to-severe symptoms or illness lasting more than 7 days.
"Culture-independent diagnostic tests are a game changer. A specific
diagnosis can direct appropriate therapy and provide information
regarding the likely course of illness," writes Ferric C. Fang, MD and
Robin Patel, MD, CID editors and authors of the commentary. "Moreover, a
specific diagnosis can facilitate public health surveillance efforts."
Story Source:
Materials provided by Infectious Diseases Society of America
