CAN YOU DIAGNOSE "CHRONIC INTESTINAL AMOEBIASIS" ?
Hon. Visiting Physician, Jaslok Hospital and Bombay Hospital, Mumbai, Ex. Hon. Prof. of Medicine, Grant Medical College and JJ Hospital, Mumbai 400 008.
Before I answer this question, I would like to make it clear that the word "chronic" has been coined by some clinician who has never visited the post mortem room! At the autopsies supervised by me on hundreds of patients who have died of amoebiasis (by complications of colonic ulcers and liver abscess), not a single case was observed who had "chronic" intestinal disease. It was always "acute". Yet, in practice you may see "recurrence" of the disease (occurring again and again). Even this is unlikely with the introduction of modem drugs like metronidazole or tinidazole. Such patients are likely cases of "ulcerative colitis" if they are passing blood and mucus in the stools. If not, then they are cases of irritable colon, for which there is no permanent cure.
Patients whose stools show cysts of E. histolytica may be carriers only. But then how to exclude "active" amoebic disease in such patients?
Sigmoidoscopy should be done to see ulcers in the terminal colon. If seen, a "biopsy" must be done. Only if amoebic necrosis and amoeba are seen in the biopsy report, should a diagnosis of amoebiasis be considered. (Of course it should respond dramatically to drugs!) Serological tests for amoebiasis (like IHA test or CIEA) though more often positive in hepatic amoebiasis may also be positive in cases of intestinal amoebiasis. But remember, like "Widal Test" serological tests for amoebiasis can also be very often misguiding (unless you have read very well about their interpretation including their "anamnestic" reaction like response). Ideally combination of 2 to 3 serological tests reports, including fluorescence Antibody Test, should be more decisive in the diagnosis. This is not practical in private practice specially from cost effectiveness point of view. It would be much cheaper to try a therapeutic test with metronidazole (proper dose for intestinal amoebiasis is 800 mg. tds for 5 days) or tinidazole!!!
But unfortunately (or fortunately!) these drugs are "poly therapeutic" drugs. They also show very good results in
1 . Patients of irritable colon like many other drugs or placebos
2. Patients of giardiasis
3. Infection with anaerobic organisms of the intestines (Ideal drugs)
4. Infection by the organism - helicobacter pyloridis which is one of the known causes of "Peptic Ulcer" - a common, differential diagnosis of a colonic pain! (Remember peptic ulcer syndrome and irritable colon are often present in the same patient).
Finally, how can you diagnose amoebiasis as the cause of a patient's complaint - when majority of E. histolytica seen in stools have been shown to be benign!! Only types 11, X1 and XII out of 18 Zymodomes, are the ones which can produce disease. In India, the investigations to "subtype" these amoebae are not available just now. Even then, do you think doc, that your patients will be able to pay for these costly tests in the pathological labs!! Amoebiasis is a disease of poor people. In a rich, young man or woman, passing blood and mucus in the stools, in the modem times of stress, ulcerative colitis should be the first diagnosis!! (In older diabetics and hypertensives - ischaernic colitis).
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