Amoebiasis: causes, symptoms, diagnosis and treatment

Amoebiasis is a parasitic disease caused by an amoeba sistolicescoy and flowing with intestinal and extraintestinal manifestations. Intestinal amoebiasis is characterized by abundant mucous stools mixed with blood, abdominal pain, tenesmus, weight loss, anemia; extraintestinal – forming liver abscesses, lung, brain, etc.

Diagnosis of amebiasis is based on clinical data, sigmoidoscopy, colonoscopy, examination of the smear of the contents of abscesses, serology, radiography.

In the treatment of amoebiasis used medicines (luminal and systemic tissue amebicide, antibiotics), surgical techniques (opening and drainage of abscesses, resection of the intestine).


Amoebiasis is a protozoal infection, manifested by ulcerative process in the colon and damage internal organs with the formation of abscesses. Amoebiasis is most widespread in regions with tropical and subtropical climate; the mortality among parasitic infections, it ranks second in the world after malaria.

In recent years, in connection with considerable growth of migration and international tourism has increased the number of imported cases of amebiasis in Russia. Amoebiasis is recorded in the form of sporadic cases and epidemic outbreaks are rare. Amebiasis primarily affects patients of middle age.

Causes of amebiasis

The causative agent of amoebiasis – histolytica amoeba (Entamoeba histolytica) is pathogenic to the simplest and has two stages of life cycle: the dormant stage (cyst) and vegetative (trophozoite), replacing each other depending on the conditions of existence. Vegetative forms of amoebae (Prezista, translucent, large vegetative and tissue) is very sensitive to changes in temperature, humidity, pH, so they die quickly in the environment. Cysts show considerable stability outside the human body (in the soil is stored up to 1 month, to 8 months).

Mature cysts, once in the lower GI, transformirovalsya to non-pathogenic luminal form, inhabiting the lumen of the colon, feeding on detritus and bacteria. A stage of asymptomatic carriage of amoeba. In the future, translucent shape or insisterede, or converted into a large vegetative form, which is due to the presence of proteolytic enzymes and specific proteins embedded in the epithelium of the intestinal wall, passing in a fabric form. A large vegetative and tissue forms of the pathogens detected in acute amoebiasis.

Tissue form is parasitic in the mucous and submucosal layers of the colon wall, causing destruction of the epithelium, disturbance of microcirculation, the formation of microabscesses with subsequent tissue necrosis and multiple ulcerative lesions. The pathological process in the intestines in amebiasis is distributed most often on the blind and the ascending part of the colon, less frequently in the sigmoid and rectum. Histolytica amoeba as a result of hematogenous dissemination is able to get into liver, lungs, brain, kidneys, pancreas with the formation of these abscesses.

The main source of infection with ameba – patients with chronic form of amoebiasis in remission, as well as convalescents, and carriers of cysts. Carriers of cysts of amoebae can be flies. Patients with acute or recurrent chronic amoebiasis do not represent epidemiological danger, as isolated unstable in the external environment vegetative forms of amoebas. Infection occurs by the fecal-oral route when released into the gastrointestinal tract of a healthy person is infected Mature cysts of food and water, as well as household through contaminated hands. In addition, the possible transmission of amebiasis in anal sexual intercourse mainly among homosexuals.

Risk factors of infection with amoebiasis are poor personal hygiene, low socio-economic status, living in areas with a hot climate. The development of amoebiasis can be induced by immunodeficiency, dysbiosis, an unbalanced diet, stress.

The symptoms of amebiasis

The incubation period of amebiasis lasts from 1 week to 3 months (usually 3-6 weeks). According to the severity of the symptoms of amoebiasis may be asymptomatic (90% cases) or manifestum; duration of the disease – acute and chronic (continuous or recurrent), the severity of light, moderate, heavy. Depending on the clinical picture distinguish 2 forms of amebiasis: intestinal and extraintestinal (amoebic liver abscesses, lung, brain, urogenital and cutaneous amoebiasis). Amoebiasis can manifest in the form of mixed infection with other protozoan or bacterial intestinal infections (e.g. dysentery), helminthiasis.

Intestinal amoebiasis is the basic, most common form of the disease. The main symptom of intestinal amoebiasis becomes diarrhea. Stool copious, fluid, at first fecal in nature with mucus to 5-6 times a day; then bowel movements take the form of gelatinous masses mixed with blood, and the frequency of defecation is increased to 10-20 times a day. Characterized by constant increasing pain in the abdomen, in the iliac region, more on the right. With the defeat of the rectum bothering painful tenesmus, with the defeat of the Appendix – there are symptoms of appendicitis. May be mild fever, asthenovegetative syndrome. The severity of the process in intestinal amoebiasis subsides within 4-6 weeks, followed by a long remission (weeks or months).

Spontaneous recovery is very rare. Without treatment again develops fever, and intestinal amebiasis becomes chronic relapsing or continuous (lasting up to 10 years or more). Shigellosis is accompanied by disorders of all types of metabolism: vitamin deficiencies, exhaustion, up to cachexia, edema, hypochromic anemia, endocrinopathy. In debilitated patients, young children and pregnant women may develop a fulminant form intestinal amoebiasis with extensive ulcerations of the colon, toxic syndrome and fatal outcome.

Of the extraintestinal manifestations of amebiasis is the most common amebic liver abscess. Characterized by single or multiple abscesses without pyogenic sheath, localized most often in the right lobe of the liver. The disease begins acutely with chills, hectic fever, sweating, pain in the right hypochondrium, aggravated by coughing, change of body position. The condition of patients heavy, the liver is sharply enlarged and painful; the skin is of earthy tint, and sometimes develop jaundice.

Amoebiasis of the lung occurs in the form of pleuropneumonia or lung abscess with fever, chest pain, cough, hemoptysis. In amoebic brain abscess(amoebic meningoencephalitis) occurs and cerebral focal neurological symptoms, severe intoxication. Cutaneous amoebiasis occurs secondary immunocompromised patients is manifested by formation of little painful erosions and ulcers with an unpleasant odor in the perianal region, on the buttocks, in the area of the perineum, the abdomen, around the fistulous openings, and postoperative wounds.

Intestinal amoebiasis may occur with various complications: perforation intestinal ulcers, bleeding, necrotic colitis, amoebic appendicitis, and purulent peritonitis, stricture of the colon. If extraintestinal localization does not exclude the breakthrough of abscess in the surrounding tissues with the development of peritonitis, empyema, pericarditis or fistula formation. In chronic amoebiasis in the intestinal wall around the ulcer is formed by specific tumor formation of granulation tissue – ameboma leading to obstructive intestinal obstruction.

Diagnosis of amebiasis

In the diagnosis of intestinal amebiasis accounted for the clinical signs, epidemiological data, results of serological studies (Phragmites, REEF, ELISA), sigmoidoscopy and colonoscopy. Endoscopically, when amoebiasis detected characteristic ulcers of the intestinal mucosa at different stages of development in chronic forms of cicatricial stricture of the colon. Laboratory confirmation of intestinal amebiasis is the detection of tissue and large vegetative forms of amoeba in the faeces of the patient and detachable bottom ulcers. The presence of cysts, luminal and precystic forms of the pathogen indicates amoebic carriers. Serological tests indicate the presence of specific antibodies in the serum of patients with amoebiasis.

Extraintestinal amebic abscesses helps to visualize complex instrumental examination, including ultrasound of the abdomen, radionuclide scanning, radiography of the thorax, brain CT scan, laparoscopy. Detection in the contents of abscesses pathogenic forms of the causative agent is proof of its amoebic origin. Differential diagnosis of amebiasis is carried out with dysentery, campylobacteriosis, balantidiozom, schistosomiasis, Crohn’s disease, ulcerative colitis, pseudomembranous colitis, tumors of the colon; in women with endometriosis of the colon. Amoebic abscesses extraintestinal localization differencesbut from abscesses of other etiology (echinococcosis, leishmaniasis, tuberculosis).

Treatment of amebiasis

Treatment of amebiasis outpatient basis, hospitalization is necessary in severe and extraintestinal manifestations. For the treatment of asymptomatic carriage and relapse prevention, apply translucent amebicide direct action (etofamide, diloxanide furoate, iodine, monomitsin). In the treatment of intestinal amebiasis and abscesses of different localization system effective tissue amebicide (metronidazole, tinidazole, Ornidazole). For the relief of kriticheskogo syndrome, acceleration of reparative processes and elimination of pathogenic forms of the amoeba prescribe ethnoracial. Intolerance of metronidazole demonstrates the use of antibiotics (doxycycline, erythromycin). The combination of drugs, their doses and duration of treatment depends on the form and severity of disease.

In the absence of effect of conservative tactics and the threat of a breakthrough of the abscess may require surgical intervention. At small amoebic abscesses may conduct puncture under ultrasound guidance with aspiration of contents or an autopsy abscess drainage and the subsequent introduction into its cavity and amebotsidnym antibacterial drugs. When expressed necrotic lesions around amoebic ulcers or intestinal obstruction perform a bowel resection with colostomy.

Forecast and prevention of amoebiasis

With timely specific treatment, in most cases, the prognosis of intestinal amebiasis favorable. In case of late diagnosis of amoebic abscesses of other organs, there is a risk of death. Prevention of amebiasis includes early detection and proper treatment of patients and Aeronavale, observance of sanitary-hygienic regime in the home, providing quality water and wastewater treatment, food safety, health education

One thought on “Amoebiasis: causes, symptoms, diagnosis and treatment

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