Opisthorchiasis in children: causes, symptoms, diagnosis, treatment

Opisthorchiasis is a chronic helminthiasis with predominant damage to the biliary system and pancreas. In children - native inhabitants of highly endemic foci, the invasion usually proceeds subclinically and is realized in adulthood or old age. In the endemic area, in visitors from areas non-endemic for opisthorchiasis, an acute stage of the disease of varying severity develops with subsequent transition to chronic.

ICD-10 code

B66.0 Opisthorchiasis.

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Epidemiology of opisthorchiasis

Opisthorchiasis is a natural focal invasion, widespread among fish-eating animals, but in endemic foci the main source of infection is humans. Infection occurs when eating raw, frozen, lightly salted, dried fish of the carp family - ide, dace, chub, roach, bream, carp, etc. The incidence of opisthorchiasis among the indigenous population of the North reaches 80-100% and is associated with the traditional consumption of thermally untreated highly infested fish. The incidence of opisthorchiasis in children in the north of Western Siberia reaches 80-100% by the age of 8. In the Kama Basin, opisthorchiasis is detected in children of indigenous people from the age of 1-3 years, by the age of 14-15 the incidence reaches 30-40%. The incidence of the local Russian population is somewhat lower.

Pathogenesis of opisthorchiasis

During digestion of the infested fish in the stomach and duodenum, the metacercariae are released from the shell and move through the common bile duct into the intrahepatic bile ducts within 3-5 hours. In individuals with a combined outlet of the common bile and Wirsung ducts, the metacercariae also invade the pancreas. The metabolites secreted by the parasite during migration and maturation have a direct toxic effect on the epithelium of the ducts, activate the release of endogenous inflammatory factors by lymphoid and macrophage elements, epithelial cells, and have a sensitizing effect. Clinical manifestations of the invasion depend on the massiveness of the infection, the age of the child, and the level of immunity. The proliferative-exudative process in the mucous membranes of the gastrointestinal tract, respiratory tract, urinary system, and the production of antibodies determine a widespread allergic reaction. Cell proliferation in the walls of microvessels, the stroma of internal organs leads to the development of dystrophic processes in the liver, myocardium. An imbalance in the production of peptide hormones - gastrin, pancreozymin, cholecystokinin - plays a significant role in the disruption of the digestive organs. In children of the indigenous peoples of the North - Khanty, Mansi, Komi, Permyaks, the early stage of the disease is subclinical, which is associated with transplacental immunization with parasite antigens, the receipt of protective antibodies with mother's milk.

The pathogenesis of the chronic stage of opisthorchiasis in the foci of invasion is largely determined by repeated multiple infections with persistent cell proliferation in the walls of the ducts, the stroma of the organs with the development of cholangitis, pericholangitis, canaliculitis with elements of fibrosis, and disruption of the glandular apparatus of the upper gastrointestinal tract. Dysregulation of the production of peptide hormones leads to dyskinetic and dystonic disorders of the biliary system, stomach, duodenum with pain syndrome, cholestasis, and stool disorders. Allergic phenomena in the chronic stage of the disease are expressed insignificantly. Immunodepression phenomena prevail, which contributes to the complicated course of bacterial, viral infections, and the development of bacterial carriage.

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Symptoms of opisthorchiasis

In children living in highly endemic foci of invasion, opisthorchiasis usually has a primary chronic course. Clinical symptoms develop in middle and even old age, provoked by concomitant diseases, intoxications. In foci of average endemicity, the acute stage of the disease is recorded in children aged 1-3 years in the form of subfebrile temperature, pain in the right hypochondrium, epigastrium, sometimes exudative or polymorphic rashes on the skin, catarrh of the upper respiratory tract, bowel disorder. Lymph nodes, liver enlargement, blood eosinophilia up to 12-15%, hypoalbuminemia are determined.

The primary manifestations are followed by an increase in ESR to 20-25 mm/h, an increase in the level of alpha2-globulins, a tendency to anemia, and developmental delays. At the age of 4-7 years, allergic symptoms are more pronounced, eosinophilia reaches 20-25% against the background of leukocytosis up to 10-12x10 ⁹ /l. In middle-aged and older children, 2-3 weeks after massive invasion, fever, skin rash, pulmonary syndrome in the form of "flying" infiltrates or pneumonia, pronounced dystrophic changes in the myocardium develop, and in particularly severe cases, allergic hepatitis with jaundice and hepatosplenomegaly. Eosinophilia reaches 30-40%, ESR - 25-40 mm/h, alpha ₂ - and gamma globulins of serum increase, transaminase activity increases, to a greater extent - alkaline phosphatase, serum bilirubin concentration increases to 25-35 μmol/l due to the conjugated fraction. Acute symptoms can develop gradually, reaching a maximum within 1-2 weeks.

The chronic stage of opisthorchiasis in children in the endemic focus is manifested mainly by severe cholepathia, less often by gastroenteropathic syndrome, in about 1/3 of children, asthenic syndrome predominates. In young children, there is a slowdown in physical development, decreased nutrition, unstable stool, loss of appetite, moderate liver enlargement, rarely its tenderness on palpation, eosinophilia up to 5-12%, a tendency to anemia. Due to repeated infections, clinical symptoms reach a maximum by 10-12 years. Complaints of heaviness, pain in the right hypochondrium, nausea, unstable stool, lack of appetite predominate, which is determined by the transition of hypertensive dyskinesia of the gallbladder to hypotonic. Eosinophilia up to 5-12% often persists, a tendency to anemia, hypoalbuminemia is revealed. By the age of 14-15, clinical manifestations of the invasion are often compensated, laboratory parameters are normalized, dyskinetic disorders of the biliary system rarely occur, which is apparently associated with the development of immunity to parasite antigens.

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Classification of opisthorchiasis

In children with acute opisthorchiasis, asymptomatic, latent and clinical forms of the disease with cholangitic, hepatocholangitic, typhoid-like and bronchopulmonary variants are distinguished, and among chronic opisthorchiasis - latent and clinically expressed forms with phenomena of cholepathy (angiocholitis, angiocholecystitis, hepatoangiocholecystitis) and gastroduodenopathy (chronic gastroduodenitis). The development of liver cirrhosis in children with opisthorchiasis invasion is rightly associated with a previous viral infection.

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Diagnosis of opisthorchiasis

Acute opisthorchiasis is diagnosed based on the epidemiological history (consumption of raw fish of the carp family), a characteristic clinical picture (the appearance of an acute febrile disease or high subfebrile condition with skin rashes, myalgia, arthralgia, catarrhal phenomena, pneumonia, jaundice, hepatosplenomegaly with intoxication, eosinophilic leukocytosis) and positive serological reactions (RNGA, ELISA) with an opisthorchiasis diagnosticum. Opisthorchis eggs are detected in feces and bile no earlier than 1.5 months after infection.

In the chronic stage, the diagnosis of opisthorchiasis is also made on the basis of the epidemiological history, clinical picture of cholepathy or gastroenteropathy with exacerbations and remissions and accompanied by asthenia, in children - with blood eosinophilia up to 5-12%. The diagnosis is confirmed by detecting parasite eggs in feces and duodenal contents (with low intensity of invasion only in the latter). Ultrasound reveals biliary dyskinesia, mainly of the hypertensive type in young children and hypotonic in older children.

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Treatment of opisthorchiasis

Treatment of opisthorchiasis in the acute stage with high fever and organ damage begins with detoxification therapy, prescription of antihistamines, calcium salts, in severe cases, glucocorticoids are given orally or administered parenterally in moderate doses for 5-7 days with rapid drug withdrawal, and cardiovascular agents. After the fever has ceased, the ECG has begun to show positive dynamics (it is better if it has normalized), and focal changes in the lungs have disappeared within 24 hours, treatment is carried out with praziquantel (azinox, biltricid) at a dose of 60-75 mg/kg in 3 doses with intervals of at least 4 hours between them. The drug is given after meals, diet No. 5 is preferable, and restriction of coarse fiber and fats is mandatory. Laxatives are not prescribed. Treatment is carried out against the background of antihistamines, administration of calcium salts, and ascorbic acid.

The effectiveness of the treatment is monitored after 3 and 6 months by a 3-fold study of feces using the Kato method and duodenal contents. If parasite eggs are detected after 6 months, a repeated course of treatment with Azinox can be administered. Outpatient observation of children and, if necessary, pathogenetic therapy are administered for 3 years after the last course of treatment.

Prevention of opisthorchiasis

The main method of preventing opisthorchiasis in children remains the consumption of carp fish only in thermally processed form. In foci of invasion, hygienic education of parents is necessary, especially older family members (it is unacceptable to feed young children raw fish, or to use it as a pacifier). General preventive measures include preventing sewage from entering river basins, destroying mollusks, intermediate hosts of opisthorchiasis, and monitoring fish infestation in production and in the retail network.

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