In chronic bacillary dysentery, according to Rogers, the lesions are limited to the lower portion of the large gut and rarely extend above the descending colon.
In this region one finds serpiginous ulcerations separated by islands of mucosa. Willmore and Savage have noted autopsy findings of what was practically a large granulating surface over the whole large intestine, in cases which had apparently recovered, with the exception of a prolonged convalescence.
Symptomatology
Bacillary dysentery usually runs an acute course, rarely relapsing and but occasionally going on to a chronic condition. The period of incubation is usually from two to seven days although accidental infection with bacilli in the laboratory has given an incubation period approximating twenty-four hours. Periods of incubation longer than a week can probably be explained as for cholera, such cases being in those who are healthy carriers, but by reason of some gastro-intestinal upset the quiescent bacilli take on pathogenic activity.
In temperate climates and in particular when the infecting organism is a Flexner type the case may appear as a watery diarrhoea associated with colicky pains and anorexia. The stools soon become more scanty in amount, frequent in number and associated with straining. This is followed by mucous stools more or less tinged with blood. The temperature is normal or but slightly elevated and the patient does not seem ill.
In the tropics and in temperate climates where the Shiga type bacillus is the infecting organism the onset is usually rather sudden with malaise, abdominal pain and a diarrhoea, which only temporarily relieves such pain. This initial diarrhoea is soon followed by the characteristic dysentery stool and the pains, which latter tend to centre about the umbilicus and to become continuous. There is usually loss of appetite and slight nausea and the patient may at times show a very slight tendency to flightiness. The mind however is usually clear. Fever of moderate degree is not uncommon and it may be quite marked,—up to 104°F. Ingestion of food or drink or any movement of the body brings on a desire for defecation.
The number of stools, which in mild cases number 15 to 30, may become excessive, even more than one hundred in twenty-four hours, and the tenesmus most torturing, so that excoriations around the anus and at times prolapse of the bowel intensify the distressing clinical picture. In acute cases the stool may be almost pure blood with only an admixture of mucus.
Vesical tenesmus may be present and the urine may be diminished in amount.
There is a toxic effect on the heart so that the pulse tends to become accelerated and weak. Bacillary dysentery may show a moderate leucocytosis with increased polymorphonuclear percentage instead of a large mononuclear one as with amoebic dysentery.