Opisthorchiasis - Clinicals, Diagnosis, and Management

Infectious diseases

Clinicals - History

Fact Explanation
Abdominal discomfort Opisthorchiasis is caused by trematode Opisthorchis felineus and Opisthorchis viverrini. Infection of humans occurs by ingestion of infected fish.
After ingestion, the metacercariae encysted in the duodenum. Some adults reside in the duodenum and many ascend the biliary tract through the ampulla of Vater. Presence and attachment to the biliary and intestinal mucosa causes an abdominal
discomfort or pain in the upper quadrant or the epigastrium. It is insidious in onset, dull and intermittent in nature. This may accompanied by
other nonspecific symptoms such as fever and chills, as well as fatigue, anorexia, nausea and vomiting. The abdominal discomfort may be attributed to enlargement of the liver, and very rarely cholangitis or cholangiocarcinoma which develop as complications.
Abdominal discomfort
Opisthorchiasis is caused by trematode Opisthorchis felineus and Opisthorchis viverrini. Infection of humans occurs by ingestion of infected fish.
After ingestion, the metacercariae encysted in the duodenum. Some adults reside in the duodenum and many ascend the biliary tract through the ampulla of Vater. Presence and attachment to the biliary and intestinal mucosa causes an abdominal
discomfort or pain in the upper quadrant or the epigastrium. It is insidious in onset, dull and intermittent in nature. This may accompanied by
other nonspecific symptoms such as fever and chills, as well as fatigue, anorexia, nausea and vomiting. The abdominal discomfort may be attributed to enlargement of the liver, and very rarely cholangitis or cholangiocarcinoma which develop as complications.
Diarrhea Watery diarrhea may also develop in some cases. It is usually mild and owing to the localized inflammatory reaction of the intestinal mucosa. Diarrhea
Watery diarrhea may also develop in some cases. It is usually mild and owing to the localized inflammatory reaction of the intestinal mucosa.
Jaundice Intraductal flukes cause mechanical obstruction. This causes obstructive jaundice in the initial stage. Patient's eyes and mucous membranes get yellowish. Jaundice
Intraductal flukes cause mechanical obstruction. This causes obstructive jaundice in the initial stage. Patient's eyes and mucous membranes get yellowish.
Complications Mechanical Irritation of bile ducts and toxic secretions by the adult fluke causes enlargement of liver and thickening and dilatation of bile ducts. Eventually, this may result in fibrosis and destruction of liver tissues, impairment of liver functions and proliferation of biliary epithelium. Very rarely, some biliary epithelial hyperplasia may result in malignant changes such as cholangitis or cholangiocarcinoma. Complications
Mechanical Irritation of bile ducts and toxic secretions by the adult fluke causes enlargement of liver and thickening and dilatation of bile ducts. Eventually, this may result in fibrosis and destruction of liver tissues, impairment of liver functions and proliferation of biliary epithelium. Very rarely, some biliary epithelial hyperplasia may result in malignant changes such as cholangitis or cholangiocarcinoma.
At risk population Ingestion of undercooked, salted, pickled, or smoked freshwater fish specially in endemic areas such as Japan, Korea, Vietnam and China poses a greater risk. Incidences are higher in fishermen, fishmongers, workers in processing fish products, officials than in those with other occupations. At risk population
Ingestion of undercooked, salted, pickled, or smoked freshwater fish specially in endemic areas such as Japan, Korea, Vietnam and China poses a greater risk. Incidences are higher in fishermen, fishmongers, workers in processing fish products, officials than in those with other occupations.

Clinicals - Examination

Fact Explanation
Jaundice Yellowish discoloration is attributed to the mechanical obstruction of the biliary tract by adult fluke. Jaundice
Yellowish discoloration is attributed to the mechanical obstruction of the biliary tract by adult fluke.
Abdominal tenderness Tender hepatomegaly is caused by mechanical obstruction of bile ducts. Abdominal tenderness
Tender hepatomegaly is caused by mechanical obstruction of bile ducts.

Investigations - Diagnosis

Fact Explanation
Full blood count Acute phase is characterized by high degree of eosinophilia. Leukocytosis may occur. Full blood count
Acute phase is characterized by high degree of eosinophilia. Leukocytosis may occur.
Liver function tests Elevated levels of gamma-glutamyl transpeptidase, ALT, alkaline phosphatase, and bilirubin may suggest cholestatic liver injury. Liver function tests
Elevated levels of gamma-glutamyl transpeptidase, ALT, alkaline phosphatase, and bilirubin may suggest cholestatic liver injury.
Microscopic examination Microscopic demonstration of eggs in the stool or in duodenal aspirate is the most practical diagnostic method. These are small operculated eggs sized 27 to 35 µm by 11 to 20 µm. The operculum is convex and rests on a visible "shoulder", at smaller end of the egg. where a small knob or hook- like protrusion is often visible at the opposite (larger, abopercular) end. The miracidium is visible inside the egg. Microscopic examination
Microscopic demonstration of eggs in the stool or in duodenal aspirate is the most practical diagnostic method. These are small operculated eggs sized 27 to 35 µm by 11 to 20 µm. The operculum is convex and rests on a visible "shoulder", at smaller end of the egg. where a small knob or hook- like protrusion is often visible at the opposite (larger, abopercular) end. The miracidium is visible inside the egg.
Ultrasonography Ultrasound scan may aid the diagnosis. The characteristic findings include diffuse and uniform dilatation of the peripheral intrahepatic bile ducts with no or minimal dilatation of the extrahepatic bile duct and without focal obstructing lesions in the larger bile ducts. Ultrasonography
Ultrasound scan may aid the diagnosis. The characteristic findings include diffuse and uniform dilatation of the peripheral intrahepatic bile ducts with no or minimal dilatation of the extrahepatic bile duct and without focal obstructing lesions in the larger bile ducts.

Management - Supportive

Fact Explanation
Patient education and prevention Avoidance from having raw, undercooked or pickled wish is the best preventive method. Using molluscicides for snail (a host) control have been successful. Patient education and prevention
Avoidance from having raw, undercooked or pickled wish is the best preventive method. Using molluscicides for snail (a host) control have been successful.

Management - Specific

Fact Explanation
Praziquantel Praziquantel as a single dose (25 mg/kg or less) is the current treatment of choice. Frequently occurring side effects are dizziness, headache, and malaise. Approximately 90% of all patients have abdominal pain or cramps with or without nausea and vomiting. Other drugs used to treat infestation include triclabendazole, bithionol, albendazole, levamisole and mebendazole. Praziquantel
Praziquantel as a single dose (25 mg/kg or less) is the current treatment of choice. Frequently occurring side effects are dizziness, headache, and malaise. Approximately 90% of all patients have abdominal pain or cramps with or without nausea and vomiting. Other drugs used to treat infestation include triclabendazole, bithionol, albendazole, levamisole and mebendazole.

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