dysentery

Dysentery is a form of inflammatory diarrhea characterized by blood and mucus in the stool, often accompanied by fever and abdominal cramps. It results from invasion of the colonic mucosa by pathogens or from inflammatory bowel disease or other colitis, but in common medical usage refers to infectious dysentery caused by certain bacteria or protozoa.

Two major etiologies: bacillary dysentery caused by invasive bacteria such as Shigella, certain strains of Escherichia coli, Campylobacter, or Salmonella, and amoebic dysentery caused by Entamoeba histolytica. Less commonly, other pathogens can cause dysentery. Transmission is usually fecal-oral via contaminated food or water, person-to-person contact, or poor sanitation.

Symptoms include abrupt onset of abdominal cramps, tenesmus, fever, and frequent stools containing blood and mucus; dehydration may occur, particularly in children and older adults.

Diagnosis is based on clinical presentation, with stool tests for blood and leukocytes; stool cultures for bacterial pathogens; antigen tests or PCR for Shigella and Entamoeba histolytica; and microscopy for trophozoites or cysts.

Treatment emphasizes rehydration and electrolyte management. Antibiotic therapy is used for certain bacterial dysentery and may shorten illness or reduce transmission, depending on local resistance patterns. Amoebic dysentery requires metronidazole or tinidazole followed by a luminal agent such as paromomycin. Anti-motility agents are generally avoided in invasive disease.

Prevention relies on safe drinking water, good sanitation, hand hygiene, and proper food handling.

Prognosis ranges from full recovery with treatment to serious complications in vulnerable groups, including dehydration, electrolyte disturbances, sepsis, perforation, or toxic megacolon in rare cases.