Rogers has called attention to the importance of bearing in mind a chronic condition as well as the acute one. In these chronic cases the ulcerations are usually located in the descending colon, sigmoid flexure or rectum and give rise to frequent stools containing blood and mucus and causing a progressive loss of strength and weight. There is marked digestive disorder and the patient becomes weak, anaemic and neurasthenic.
Diagnosis
In the presence of the dysenteric syndrome of tormina, tenesmus, frequent scanty stools of muco-purulent or muco-sanguinolent character, one must keep in mind the various conditions which may give rise to such manifestations of dysentery and not diagnose a bacillary dysentery until we have excluded tuberculous, cancerous and syphilitic processes as well as those connected with schistosome or other helminthic infections.
Clinical Diagnosis.—Amoebic dysentery is differentiated clinically from bacillary dysentery by the usual absence of manifestations of toxaemia and by its insidious onset and chronic course.
It is important however to remember that either bacillary or amoebic dysentery may show gangrenous manifestations and in such cases the clinical picture of the typhoid state is the same whether the process is amoebic or bacillary. Fulminant bacillary dysenteries may greatly resemble cholera in its algid stage.
Tropical liver abscess is a complication exclusively occurring in the amoebic form of dysentery while joint manifestations and evidences of multiple neuritis may be noted in some epidemics of bacillary dysentery. Again, the toxins of the dysentery bacilli have a tendency to damage the myocardium. At present we consider the good effects of the administration of emetine as important in the diagnosis of amoebic dysentery.
It is important to remember that chronic dysentery may result from bacillary as well as amoebic infections, although a chronic process is more a feature of amoebic dysentery.
The muco-purulent stool of bacillary dysentery is more of a milky whiteness and flecked or streaked with blood or a very viscous bright blood-tinged mucus rather than the homogeneous, grayish brown, gelatinous mixture of disintegrated blood and mucus of the amoebic one. The odour is apt to be foetid in amoebic stools but rather albuminous with bacillary dysentery ones.
Laboratory Diagnosis.—The chief point is to determine whether we are dealing with an amoebic or bacillary infection. While these two kinds of dysentery may coexist it is practical to consider a case in which amoebae with long, rapidly extruded, finger-like pseudopodia and containing red blood cells are found, as one of amoebic dysentery.