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 Brainerd Diarrhea
What is Brainerd diarrhea?
Brainerd diarrhea is a
syndrome of acute onset of watery diarrhea (3 or more loose stools per
day) lasting 4 weeks or longer, which can occur in outbreaks or as
sporadic cases. It is named after Brainerd, Minnesota, the town where the
first outbreak occurred in 1983. Patients typically experience 10-20
episodes per day of explosive, watery diarrhea, characterized by urgency
and often by fecal incontinence. Accompanying symptoms include gas, mild
abdominal cramping, and fatigue. Nausea, vomiting, and systemic symptoms
such as fever are rare, although many patients experience slight weight
loss.
What causes Brainerd diarrhea?
Despite extensive
clinical and laboratory investigations, the cause of Brainerd diarrhea has
not yet been identified. Although it is thought to be an infectious agent,
intensive searches for bacterial, parasitic, and viral pathogens have been
unsuccessful so far. The possibility remains that Brainerd diarrhea is
caused by a chemical toxin, but no such toxin has yet been found.
How can Brainerd diarrhea be
diagnosed?
Because the etiologic
agent is unknown, there is no laboratory test that can confirm the
diagnosis. Brainerd diarrhea should be suspected in any patient who
presents with the acute onset of nonbloody diarrhea lasting for more than
4 weeks, and for whom stool cultures and examinations for ova and
parasites have been negative. Care should be taken to exclude other causes
of chronic diarrhea, both infectious and noninfectious (e.g., lymphocytic
colitis, collagenous colitis, tumors, drug reactions) Brainerd diarrhea is
not characterized by any specific laboratory abnormalities. On colonoscopy,
petechiae, aphthous ulcers and erythema may be observed. Microscopic
examination of colonic tissue biopsy specimens often reveals mild
inflammation, with an increased number of lymphocytes, particularly in the
ascending and transverse colon. The stomach and small intestine generally
appear normal.
How can Brainerd diarrhea be
treated?
There is no known
curative treatment for Brainerd diarrhea. A variety of antimicrobial
agents have been tried without success, including
trimethoprim-sulfamethoxazole, ciprofloxacin, doxycycline, ampicillin,
metronidazole, and paromomycin. Neither has there been any response to
steroids or antiinflammatory agents. Approximately 50% of patients report
some relief in symptoms with high doses of opioid antimotility drugs, such
as loperamide, diphenoxylate, and paregoric.
Are there long term
consequences to Brainerd diarrhea?
Brainerd diarrhea is a
self-limited illness. Symptoms may last a year or more, and typically have
a waxing and waning course. Long-term follow-up studies have shown
complete resolution in virtually all patients by the end of 3 years. There
have been no known cases of sequelae or relapse once the illness has
completely resolved.
How common is Brainerd
diarrhea?
Seven outbreaks of
Brainerd diarrhea have been reported since 1983. Six occurred in the
United States, five of which were in rural settings. One outbreak occurred
on a South American cruise ship based in the Galapagos Islands. The
original Brainerd outbreak, which involved 122 persons, was the largest
outbreak. An outbreak that occurred in Henderson County, Illinois,
involved 72 persons; the Galapagos Islands outbreak involved 58. A survey
of gastroenterologists suggested that many patients who are not associated
with a recognized outbreak seek treatment for illness compatible with
Brainerd diarrhea. Further work needs to be done to establish the
incidence of sporadic cases of Brainerd diarrhea.
How do people get Brainerd
diarrhea?
In the original
Brainerd outbreak, raw (unpasteurized) milk was implicated as the vehicle
for disease transmission. Contaminated and inadequately chlorinated or
unboiled water has been identified as a source of Brainerd diarrhea in
several other outbreaks. For example, illness was strongly associated with
drinking untreated well water in the Henderson County outbreak. Persons
who drank the same water after it was boiled did not get sick.
Contaminated water was also implicated in the Galapagos Island outbreak.
The diarrheal illness does not spread contagiously from one person to the
next.
What can a person do to prevent
this illness?
Avoiding drinking raw (unpasteurized)
milk and water that has not been properly chlorinated or boiled will help
reduce the risk for Brainerd diarrhea and many other diseases. Once the
cause of Brainerd diarrhea is identified, more specific prevention
measures can be formulated
What is being done about
Brainerd diarrhea?
Outbreaks of Brainerd
diarrhea have been extensively investigated by Centers for Disease Control
and Prevention and state health departments. Laboratory investigation
continues at CDC to try to identify the etiologic agent.
The following references
contain more information about Brainerd diarrhea:
- Osterholm MT,
MacDonald KL, White KE, et al. An outbreak of a newly recognized
chronic diarrhea syndrome associated with raw milk consumption. JAMA
1986; 256: 484-490.
- Parsonnet J, Trock
SC, Bopp CA, et al. Chronic diarrhea associated with drinking
untreated water. Ann Intern Med 1989; 110: 985-991.
- Parsonnet J, Wanke
C, Hack H. Idiopathic chronic diarrhea. In: Infections of the
Gastrointestinal Tract. MJ Blaser, PD Smith, JI Ravdin, HB
Greenberg, RL Guerrant, editors. Raven Press, Ltd. New York 1995;
311-323.
- Janda R, Conklin J,
Mitros F, Parsonnet J. Multifocal colitis associated with an epidemic
of chronic diarrhea. Gastroenterology 1991; 100: 458-464.
- Afzalpurkar RG,
Shiller LR, Little KH, Santangelo WC, Fortran JS. The self-limited
nature of chronic idiopathic diarrhea. N Engl J Med 1992; 327:
1849-52.
- Mintz ED, Parsonnet
J, Osterholm M. Chronic idiopathic diarrhea (letter). N Engl J Med
1993; 328: 1713-1714.
- Bryant DA, Mintz ED,
Puhr N, Griffin P, Petras R. Colonic epithelial lymphocytosis
associated with an epidemic of chronic diarrhea. Am J Surg Pathol
1996; 20:1102-1109.
This fact sheet is for
information only and is not meant to be used for self-diagnosis or as a
substitute for consultation with a health care provider. If you have any
questions about the disease described above or think that you may have a
parasitic infection, consult a health care provider.
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