Stages of Dysentery

Dysentery is not formally staged like cancer or kidney disease, but a typical untreated illness follows a recognizable arc - and knowing the arc explains why doctors push for early treatment rather than "let it run its course."

Incubation. After the germs are swallowed, there is a quiet gap: about 1-3 days for Shigella, anywhere from days to several weeks for amoebiasis. Nothing is felt yet, but the infection is establishing in the bowel.

Invasion - the acute stage. The germs burrow into the bowel wall, and the full picture erupts: cramping pain, fever (with bacillary dysentery), frequent small bloody-mucoid stools and relentless tenesmus. This is the stage of maximum fluid loss and maximum misery - and the stage where treatment changes the course most. Dehydration is the immediate threat, especially in children; the invasion itself is the reason anti-motility drugs are forbidden.

The turning point. With proper treatment - antibiotics for shigella, the two-drug sequence for amoebiasis, plus ORS and zinc for children - fever settles within days and stools normalize over about a week. Without treatment, bacillary dysentery often still self-limits in healthy adults, but longer, harder, and with the patient contagious the whole time; untreated amoebiasis may quiet down without truly clearing.

Complication territory (the reason not to wait). Untreated, the infection can progress to severe dehydration and shock, toxic dilation of the colon, bowel perforation (rare but lethal), bloodstream infection, and - specific to amoebiasis - the liver abscess that can announce itself weeks later with fever and right-sided abdominal pain. Children add the risks of malnutrition after prolonged illness and, occasionally, post-infectious reactive arthritis.