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Opistorchiasis - Symptoms
Last reviewed: 04.07.2025
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The incubation period for opisthorchiasis is 2-6 weeks after eating infected fish. Symptoms of opisthorchiasis are characterized by polymorphism.
There is no single classification of opisthorchiasis. An acute phase of invasion is distinguished, which may be asymptomatic or erased in native inhabitants of endemic regions during reinvasion or superinfection. A clinically expressed form of the acute phase is observed in persons who arrived in an endemic region. The chronic phase of the disease in the absence of symptoms of the acute phase is assessed as primary-chronic: if it is preceded by an acute phase - as secondary-chronic. Organ lesions (biliary tract, pancreas, stomach and duodenum) can persist even after the body is freed from opisthorchiasis, so some authors distinguish a residual phase of the disease.
The acute phase of asymptomatic invasion is diagnosed by parasite eggs found in duodenal contents and feces, by slight eosinophilia and increased IgM levels.
The latent form, in addition to these criteria, is characterized by short-term subfebrile temperature.
The clinically expressed form manifests itself with sudden fever, pain in the right hypochondrium, myalgia, arthralgia, skin rashes, enlarged spleen and liver, leukocytosis and hypereosinophilia of the blood.
In mild forms, fever (about 38 °C) lasts up to 2 weeks, abdominal pain of unspecified localization, diarrhea, moderate leukocytosis and eosinophilia are possible.
Moderate opisthorchiasis is characterized by fever (38-39.5 °C) of a remittent, constant or irregular type lasting up to 3 weeks, urticarial rashes on the skin, myalgia and arthralgia, pain in the right hypochondrium, and in some cases moderate diarrhea and vomiting. The liver and spleen are enlarged; asthmatic bronchitis is possible.
Severe opisthorchiasis is characterized by high fever, severe intoxication (headache, insomnia, lethargy or agitation, tachycardia), polymorphic skin rashes. Hepatitis symptoms are expressed: pain in the right hypochondrium, liver enlargement, jaundice, increased bilirubin levels, increased aminotransferase and alkaline phosphatase activity. Some patients develop erosive-ulcerative gastroduodenitis with severe pain in the epigastric region, nausea, vomiting, flatulence, diarrhea. Chest pain, shortness of breath, cough, and volatile pulmonary infiltrates are possible. Cases of myocarditis are known. Hyperleukocytosis is characteristic (20-60x10 9 /l), eosinophilia within 10 to 80-90%, increased ESR.
Symptoms of opisthorchiasis in the acute phase last from 2-3 weeks to 2 months, after which the clinical signs subside and the disease enters the chronic phase, the signs of which appear after several months and even years and are characterized by significant polymorphism.
Most often, the hepatobiliary system is affected. Patients report heaviness in the right hypochondrium and epigastric region, loss of appetite, nausea, vomiting, and diarrhea. The liver is slightly enlarged, sensitive to palpation, and dense. Functional parameters are usually unchanged. The gallbladder is enlarged, the point of the gallbladder is painful; attacks of colic pain are possible. During duodenal intubation, the amount of bile is increased, and the content of leukocytes in it is elevated.
When the pancreas is affected, pains of a girdle nature are noted. Development of chronic gastritis, gastroduodenitis, ulcerative lesions of the mucous membrane of the stomach and duodenum are possible.
Patients often suffer from headaches, dizziness, insomnia, and sometimes depression.
The acute stage of the disease lasts up to two months, after which the clinical symptoms of opisthorchiasis gradually disappear, and the disease enters the chronic stage, characterized by various clinical manifestations, which often develop only after several years. In some patients, opisthorchiasis may manifest itself only with symptoms of cholangitis and cholecystitis, in others - with signs of insufficiency of digestive enzymes, in others - with general toxic and allergic lesions.
Most often, the chronic stage of the disease manifests itself with symptoms of damage to the hepatobiliary system. Patients complain of a feeling of heaviness, distension in the epigastric region and right hypochondrium, sometimes radiating to the back and left hypochondrium. Appetite decreases, nausea, vomiting appear, dyspeptic disorders are common. In most patients, the liver is slightly enlarged and compacted, moderately painful on palpation. However, biochemical indices of liver function often remain within normal limits. The gallbladder is enlarged, painful when pressed. In patients with hypertensive and hyperkinetic types of biliary dyskinesia, biliary (calculus-free) colic syndrome is often expressed, while the size of the gallbladder is not enlarged. Body temperature, as a rule, does not increase. During duodenal intubation, it is difficult to obtain a reflex from the gallbladder. The amount of bile, especially portion "B", is increased. Microscopic examination of bile reveals leukocytes and epithelial cells. Cholecystography and ultrasound methods often determine dyskinesia of the biliary tract and gallbladder.
When the pancreas is affected, pains of a girdle nature occur with irradiation to the left half of the chest, back, left shoulder. Hyperglycemia periodically appears on an empty stomach and the content of digestive enzymes decreases.
Patients with chronic opisthorchiasis often experience disorders of the secretory and enzymatic functions of the stomach and duodenum; chronic gastritis, duodenitis, gastroduodenitis, and even ulcers develop. As a result of damage to the central nervous system, headaches, dizziness, sleep disorders, emotional instability, depression, irritability, frequent mood swings, paresthesia, and increased sweating occur.
In chronic opisthorchiasis, in some cases, damage to the cardiovascular system may be observed, manifested by pain or discomfort behind the breastbone, palpitations. The borders of the heart may be expanded, the tones are muffled, tachycardia and arterial hypotension occur. Diffuse dystrophic changes in the myocardium are detected on the ECG.
Often the course of opisthorchiasis is complicated by the addition of a secondary infection of the biliary tract. Patients have an elevated body temperature, liver function is impaired, and the liver significantly increases in size. Sometimes short-term jaundice is observed. Pathogenic microflora is detected when bile is cultured. Leukocytosis, a band shift in the leukocyte formula are noted in the blood, ESR increases, hyperproteinemia, gamma globulinemia are detected, bilirubin levels increase, and transaminase activity increases.
Long-term invasion can lead to the development of chronic hepatitis syndrome, and subsequently to the development of liver cirrhosis and even hepatocellular carcinoma and liver cancer. This is why the International Agency for Research on Cancer has classified O. viverrini as a Group I human carcinogen.
[ Complications of opisthorchiasis
In the chronic phase of the disease, purulent cholangitis and cholecystitis, acute and chronic pancreatitis, gastric ulcer and duodenal ulcer, peritonitis, and cholangiocarcinoma are often detected.
The course of the invasion is long (up to 20 years or more), but benign. Fatal outcomes are rare and are associated with complications (peritonitis, cholangiocarcinoma).