Snapshot A 40-year-old woman presents to an urgent care clinic for multiple days of watery and bloody diarrhea and fever. She is currently homeless and has been staying at crowded homeless shelters. She also describes abdominal cramping throughout the day. On physical exam, she has sunken eyes, delayed skin turgor, and delayed capillary refill. Her abdomen is tender to palpation. A stool culture is sent and she is empirically started on antibiotics for the suspected disease. 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) Associated conditions shigellosis (bacillary dysentery) reactive arthritis 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 ETIOLOGY 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 is neurotoxic, cytotoxic, and enterotoxic produced by S. dysenteriae 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 Prognosis Symptoms occur a few days after exposure