Diseases List

ID 41
Name INTESTINAL AMOEBIASIS
Cause
Signs Symptoms
Diagnosis
Investigations Investigations: 1. Examination of stool (standard procedure- collect 3 specimens at 2-day intervals): Mucus. Trophozoites (Trophozoites, predominently found in liquid stools and cysts in fromed stools. As trophozoites rapidly autolyze, stool should be examined within 30 minutes or just after mixed with preservatives).! RBC may be present. Motile trophozoites containing RBC is diagnostic. 2. Sigmoidoscopy may reveal typical ulcers- flask shaped ulcer may be seen. 3. Serologic testing & ELISA methods are also useful ways of detecting amoebiasis now a day
Management
Introduction Intestinal amoebiasis is the infection of the large gut by the pathogenic species of the protozoan parasite Entamoeba histolytica. It was formerly thought that, there was one parsite of varying virulence, but recent view is that, there are two separate species- (i) E. dispar, a non-pathogenic avirulent species present in the colon as a stable commensal, and (ii) E. histolytica, a pathogenic species (about 10%) present in the colon and may also be carried by the blood to the liver (hepatic amoebiasis or hepatic abscess) & rarely other organs (e.g lungs, brain etc). Cysts of these two species are structurally identical, but can be differentiated by molecular techniques, isoenzyme studies or monoclonal antibody typing after culture of the trophozoites.
History
Etiology
Clinical Features Clinical features: 1. In mild to moderate cases- there may be recurrent loose or semiformed stools with abdominal cramps; mucus is usually present, but blood is initially absent. As the severity is progressing, streaks of blood with mucus is present. Stools often have an offensive odour. 2. Severe acute cases may present as bloody mucoid diarrhoea with features closely resembling that of bacillary dysentery. There may be systemic manifestations, such as nausea, vomiting, anorexia, headache, mild fever, fatigue etc. and even patient may become prostrate & toxic. 3. In chronic amoebic dysentery periods of diarrhoea alternating with constipation are frequent feature. 4. Tenesmus (painful straining to empty the bowels without resultant evacuation) usually present. 5. On palpation of the abdomen there may be tenderness along the line of the colon, (usually more marked over the caecum and pelvic colon)
Preventions
Treatment Treatment: 1. Mild to moderate intestinal infection: Drugs ofchoice- Metronidazole 500mg 3 times daily orally after meal, (or 500mg i.v 6 hourly) for 5-10 days. Or, Tinidazole 2gm in a single dose for 3 days, or Nitaxozanide 500mg 12-hourly for 3 days (is an alternative drug). Plus-Diloxanide furoate 500mg 3 times daily with meals for 10 days (to eliminate luminal cysts). Alternative drugs of choice- Tetracycline 250mg 4 times daily for 10 days; in severe dysentery, give 500mg 4 times daily for the first 5 days, then 250mg 4 times daily for 5 days. Plus-Diloxanide furoate or iodoquinol (dosage as stated above). 2. Severe intestinal amoebiasis: Drugs of choice- Metronidazole 500mg 3 times daily after meal for 10 days. Or, Tinidazole 2gm or ornidazole 2gm daily orally in a single dose for 3 days. Plus- Diloxanide furoate 500mg 3 times daily with meals for 10 days. Or, Iodoquinol (diiodohydroxyquin) 650mg 3 times daily for 21 days. Or, If parenteral therapy is needed initially- metronidazole 500mg i.v 6 hourly until oral therapy can be started. Then give oral metronidazole, plus diloxanide furoate or iodoquinol (dosage as stated above.) Alternative drugs ofchoice- Tetracycline 250mg 4 times daily for 10 days; in severe dysentery, give 500mg 4 times daily for the first 5 days, then 250mg 4 times daily for 5 days. Or, Inj. Dehydroemetine 60mg in 1ml of water (or Img/kg) i.m or subcutaneously daily for 3-5 days. Plus-Diloxanide furcate or iodoquinol (dosage as stated above). 3. General measures in acute stage -a. Bed rest b. Adequate amount of fluid intake, c. Non-residual diet e. g. Dhai and Chera. N.B: In case of child patient, dosage should be adjusted accordingly.
Complications
Prognosis
Types
Classification
Observation
Pathology Pathology: E. histolytica, outside the human body survive as cysts, which are very infectious. Since, humen are the only established host, when they ingest cysts with contaminated food or water, these overcome & survive gastric acidity and in the colon vegetative trophozoites are usually developed. In the lumen and mucosal crypts of the large bowel E. histolytica exists in two forms- cysts and motile trophozoites. Trophozoites invade the colonic mucosa by means of their amoeboid movement and proteolytic secretions and induce necrosis to form the characteristic flask-shaped ulcers surrounded by healthy mucosa, which can occur any where in the large bowel and sometimes in the terminal ileum but predominates in the caecum, descending colon, and the rectosigmoid junction- areas of greatest faecal stasis. Rarely, a localized granuloma (amoeboma) may develop in the rectum or colon presenting as palpable mass-may be mistaken for a colonic carcinoma. The incubation period varies from 2 weeks to many years.
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