-IBIS-1.5.0-
tx
digestive system
dysentery
diagnoses
definition and etiology
definition:
an acute bacillary infection of the intestines
etiology:
S. sonnei is the most often implicated species of Shigella in dysentery in the U.S. Its only significant reservoir is in humans. The disease is spread by the fecal-oral route and is a particular problem in overcrowded conditions where the sanitation is poor (day-care centers, geriatric wards, mental institutions, cruise ships, etc.) The bacteria are virulent and as little as a hundred organisms can cause human disease.
signs and symptoms
signs and symptoms: The onset of symptoms is usually sudden, about 1-7 days after exposure. Children are normally afflicted much more seriously than adults.
watery stools: developing into stools containing blood, pus and mucus
high fever: usually in children; may also have convulsions, delirium, nuchal rigidity
nausea and vomiting
diffuse abdominal pain and distention
tenesmus: may cause rectal prolapse and/or incontinence of stool
myalgias
chills
backache and headache
dehydration and weight loss: usually in children
urgency to defecate and gripping pains: usually in adults
lab findings:
culture stools on selective media
Shigella bacillus is found in 75% of stools, rectal swabs may be cultured
WBC increased mildly, or normal
decreased plasma carbon dioxide
proctoscopic exam may show characteristic ulcers
blood, mucus, leukocytes and erythrocytes in stool
blood culture negative
serologic tests not useful
course and prognosis
In adults, the disease usually is self-limiting in 3-8 days (mild cases) and 3-6 weeks (severe cases). Although the overall mortality rate in the U.S. is only 0.1%, the highest risk of fatality is in infants under 2 years old, the elderly, and debilitated adults, usually from dehydration and severe electrolyte loss and imbalance.
differential diagnosis
ulcerative colitis
viral diarrhea
celiac disease
cholera
amebiasis and parasites
other inflammatory gastrointestinal conditions
footnotes