Medicine Fifth Stage – G:E shigellosis
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Bacillary dysentery (shigellosis)
Bacillary dysentery (shigellosis):
is an acute infectious colitis that
involves predominantly the rectosigmoid colon. Clinically, a disease
characterized by diarrhea that is frequently grossly bloody, abdominal
cramping, tenesmus, and fever.
Firstly, discovered by Japanese microbiologist Shiga in 1897 during a large
epidemic dysentery.
Shigellae are Gram-negative rods, closely related to E. coli, that invade the
colonic mucosa. There are four main groups: Sh. dysenteriae, flexneri,
boydii and sonnei
Spread may occur via contaminated food or flies, but transmission by
unwashed hands after defecation is by far the most important factor.
Clinical features
Disease severity varies from mild Sh. sonnei infections to more severe Sh.
Flexneri infections, while those due to Sh. dysenteriae may be fulminating
and cause death within 48 hours.
In a moderately severe illness, the patient complains of diarrhea, colicky
abdominal pain and tenesmus. Stools are small, contain blood and purulent
exudate with little faecal material. Fever, dehydration and weakness occur,
with tenderness over the colon.
Arthritis or iritis may occasionally complicate bacillary dysentery (Reiter’s
syndrome), associated with HLA-B27.
The "gold standard" for the diagnosis of Shigellae infection remains the
isolation and identification of the pathogen from fecal material.
Management and prevention
Oral rehydration therapy or, if diarrhea is severe, intravenous replacement
of water and electrolyte loss is necessary.
Antibiotic therapy with ciprofloxacin (500 mg twice daily for 3 days) is
effective. The use of antidiarrheal medication should be avoided.
The prevention of faecal contamination of food and the isolation of cases
may be difficult. Hand-washing is very important.