-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