Dysentery Flashcards
Stool features in dysentery
Scant volume with blood, mucus, WBC, and tissue invasion
Site affected in dysentery
Large intestine
Causal organisms of dysentery
Shigella
Entamoeba histolytica
EIEC
Non-motile gram negative rod enterobacteriaceae, non-lactose fermenter, and resistant to acid
Shigella
Shigella species most frequently seen in US
S sonnei
Shigella species most frequently seen in developing countries
S flexneri
Infective dose of Shigella
10-100 organisms
Very low –> highly infective
Transmission of Shigella
Feco-oral, humans are only host
4 virulence factors of Shigella
LPS endotoxin
Shiga-toxin/verotoxin-1
Plasmid encoded type III secretion system
Hemolysin
Shigella virulence factor that induces membrane ruffling on target cell and engulfment of bacteria
Plasmid encoded type III secretion system (Ipa A-D)
Cell targeted in mucosal invasion of Shigella
M cell
Pt complains of fever, abdominal cramps, tenesmus, and diarrhea that was initially bloody, but has became bloody. MacConkey agar shows NLF colonies and salmonella-shigella agar has transparent colonies with no black center.
Shigellosis
Incubation period of Shigella
1-4 days
Complications of shigellosis
Reiter’s syndrome
Hemolytic uremic syndrome
Stool microscopy findings in shigellosis
Plenty of inflammatory cells with RBCs and mucus
Antibiotics used in treating shigellosis
Trimethoprim-sulfamethoxazole
Ciprofloxacin
Protozoans that cause dysentery
Entamoeba histolytica
Balantidium coli
Histologic finding in non-diarrheal stools in entamoeba histolytica infection
4 nuclei cysts
Histologic findings in lesions and diarrheal stools in entamoeba histolytica
Motile trophozoites with single nucleus
Protozoan causing dysentery with virulence factors specific lectin GAL/GalINAc, amoebapores, cysteine proteinases
Entamoeba histolytica
Gradual onset of bloody diarrhea, abdominal pain, and tenderness that lasts for several weeks that may be accompanied by RUQ pain because of liver involvement
Amebic colitis
Complications of entamoeba histolytica infection
Amebic liver abscess
Cerebral amebiasis
Pleuropulmonary amebiasis
Where amebulae accumulate in liver abscess in entamoeba histolytic
Edge of abscess
Treatment of asymptomatic amebiasis
Luminal agent –> lodoquinol, paromomycin, or diloxanide furoate
Treatment for symptomatic amebiasis
Metronidazole first, followed by luminal agent
Treatments for Balantidium coli
Metronidazole
Lodoquinol
Tetracycline
Nitazoxanide
