Snapshot A 6-year-old girl is brought in to the emergency department for a 2-day history of fever and watery diarrhea. This morning, the diarrhea contained some blood. She had just traveled to Bangladesh to visit relatives. According to her family, an uncle there recently had bloody diarrhea as well. On physical exam, she is febrile, has hyperactive bowel sounds, and abdominal tenderness to palpation. A stool culture and Gram stain reveals lactose-fermenting, gram - rods. She is admitted for immediate rehydration and treatment. Introduction Classification Shigella spp. a non-flagellated, non-lactose-fermenting gram - rod oxidase - and does not produce H2S produces endotoxin and Shiga toxin transmission fecal-oral transmission organisms S. dysenteriae (produces the most toxin) S. flexneri S. boydii S. sonnei (most common in the United States and least severe) Epidemiology incidence more common in developing countries demographics more common in children risk factors ingestion of contaminated or uncooked food/water travel poor hygiene crowding Pathogenesis infects gastrointestinal track through invasion of Peyer patch M cells resistant to gastric acid does not spread hematogenously Shiga toxin (enterotoxin) "A" subunit inactivates 60S ribosome kills intestinal cells by inhibiting protein synthesis neurotoxic, cytotoxic, and enterotoxic produced by S. dysenteriae Associated conditions shigellosis (bacillary dysentery) reactive arthritis Prognosis symptoms occur a few days after exposure Presentation Symptoms fatigue malaise anorexia tenesmus watery diarrhea precedes bloody diarrhea bloody and mucoid stools abdominal pain or cramping Physical exam fever hyperactive bowel sounds abdominal tenderness signs of dehydration Studies Labs stool culture Making the diagnosis based on clinical presentation and laboratory studies Differential Enteroinvasive Escherichia coli (EIEC) distinguishing factor clinically very similar to shigellosis but typically less contagious and less severe distinguish based on culture or polymerase chain reaction Treatment Management approach antibiotics will shorten duration of dysentery choice of antibiotics ultimately depends on regional resistance patterns anti-motility drugs should be avoided, as they may worsen symptoms Conservative rehydration indication all patients modalities oral intravenous Medical antibiotics indication severe cases drugs ciprofloxacin ceftriaxone trimethoprim-sulfamethoxazole (TMP-SMX) zinc indication young children outcomes shortens duration of disease in children also improves weight gain Complications Reactive arthritis (Reiter syndrome) classic triad of conjunctivitis, urethritis, and arthritis Febrile seizures