History

Fact Explanation
Abdominal discomfort Clonorchiasis is caused by trematode Clonorchis sinensis (Chinese/ oriental liver fluke) .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. [1,2,3,4,5]
Diarrhea Watery diarrhea may also develops in some cases. It is usually mild and owing to the localized inflammatory reaction of the intestinal mucosa. [1,2,3]
Jaundice Intraductal flukes cause mechanical obstruction. This causes obstructive jaundice in the initial stage. Patient's eyes and mucous membranes get yellowish. [2,3,4]
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. [1,2,3,4]
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. [2,3,4,5]
References
  1. QIAN MB, CHEN YD, YAN F. Time to tackle clonorchiasis in China. Infect Dis Poverty [online] 2013 Feb 19, 2(1):4 [viewed 10 August 2014] Available from: doi:10.1186/2049-9957-2-4
  2. HARTLEY JP, DOUGLAS AP. A case of clonorchiasis in England. Br Med J [online] 1975 Sep 6, 3(5983):575 [viewed 10 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/1174828
  3. CHOI BI, HAN JK, HONG ST, LEE KH. Clonorchiasis and cholangiocarcinoma: etiologic relationship and imaging diagnosis. Clin Microbiol Rev [online] 2004 Jul, 17(3):540-52, table of contents [viewed 10 August 2014] Available from: doi:10.1128/CMR.17.3.540-552.2004
  4. WANG KX, ZHANG RB, CUI YB, TIAN Y, CAI R, LI CP. Clinical and epidemiological features of patients with clonorchiasis. World J Gastroenterol [online] 2004 Feb 1, 10(3):446-8 [viewed 10 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/14760777
  5. LIM JH. Liver flukes: the malady neglected. Korean J Radiol [online] 2011 May-Jun, 12(3):269-79 [viewed 10 August 2014] Available from: doi:10.3348/kjr.2011.12.3.269

Examination

Fact Explanation
Jaundice Yellowish discoloration is attributed to the mechanical obstruction of the biliary tract by adult fluke. [1,2,3]
Abdominal tenderness Tender hepatomegaly is caused by mechanical obstruction of bile ducts. [2,3]
References
  1. QIAN MB, CHEN YD, YAN F. Time to tackle clonorchiasis in China. Infect Dis Poverty [online] 2013 Feb 19, 2(1):4 [viewed 10 August 2014] Available from: doi:10.1186/2049-9957-2-4
  2. CHOI BI, HAN JK, HONG ST, LEE KH. Clonorchiasis and cholangiocarcinoma: etiologic relationship and imaging diagnosis. Clin Microbiol Rev [online] 2004 Jul, 17(3):540-52, table of contents [viewed 10 August 2014] Available from: doi:10.1128/CMR.17.3.540-552.2004
  3. WANG KX, ZHANG RB, CUI YB, TIAN Y, CAI R, LI CP. Clinical and epidemiological features of patients with clonorchiasis. World J Gastroenterol [online] 2004 Feb 1, 10(3):446-8 [viewed 10 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/14760777

Differential Diagnoses

Fact Explanation
Schistosomiasis Schistosomiasis is caused by parasitic worms of the Schistosoma type. It may infect the urinary tract or intestines. Symptoms may include abdominal pain, diarrhea, bloody stool, or blood in the urine. In those who have been infected a long time, liver damage, kidney failure, infertility, or bladder cancer may occur. In children it may cause poor growth and learning difficulty. [1]
Fascioliasis Fasciola hepatica or the sheep liver fluke is a common parasite of sheep and cattle kept on damp pastures in many parts of the world, but is only occasionally found in men. Most cases have been reported from from sheep rearing countries such as South America, Europe and North America. People usually become infected by eating raw watercress or other water plants contaminated with immature parasite larvae. From the ingestion of metacercariae to the appearance of the first symptoms, it may take few days to 3 months. The immature larval flukes migrate through the intestinal wall, the abdominal cavity, and the liver tissue, into the bile ducts, where they develop into mature adult flukes. Symptoms like abdominal pain, dyspepsia and nausea are caused by localized and or generalized toxic and allergic reactions triggered by this migration. In the chronic phase, abdominal pain may be attributed to painful enlargement of the liver secondary to the adult flukes in the bile ducts which cause obstruction, inflammation and hyperplasia of its epithelium (cholangitis and cholecystitis). This abdominal pain is a biliary colic characterized by an intermittent and often severe pain in the epigastrium or right upper quadrant, and at times between the scapula. [2]
Fasciolopsiasis Fasciolopsiasis is caused by the trematoda called Fasciolopsis buski or the "Intestinal fluke". It is Found naturally in pigs, humans and dogs. The parasite infects an amphibious snail after being released by infected feces. Metacercaria released from the snails encyst on the fruits and roots of water plants such as water caltrop, water chestnut and lotus. These cysts will be ingested along with the edible water plants which are eaten raw by pigs and humans. The adult parasite normally develops and inhabits the duodenal and jejunal mucosa. Clinical features are related to the parasitic load. Most infections are mild and asymptomatic. Heavy infection causes extensive intestinal and duodenal erosion, ulceration, haemorrhage, abscess and catarrhal inflammation as the adult parasites attach to intestinal mucosa using their ventral suckers. These pathologies cause insidious onset diarrhea. These are usually watery in nature. Diarrhea may be alternating with constipation and hunger pangs. Malabsorption may lead to steatorrhea as well. [3]
Viral hepatitis Viruses are the commonest cause for hepatitis. The viraemia causes the patient to feel unwell with nonspecific symptoms that include nausea, anorexia and a distaste for cigarettes. Many recover at this stage and remain anicteric. After 1 or 2 weeks some patients become jaundiced and symptoms often improve. Persistence of nausea, vomiting or any mental confusion warrants assessment in hospital. As the jaundice deepens, the urine becomes dark and the stools pale owing to intrahepatic cholestasis. The liver is moderately enlarged and the spleen is palpable in about 10% of patients. [4]
References
  1. GOMES LI, ENK MJ, RABELLO A. Diagnosing schistosomiasis: where are we? Rev Soc Bras Med Trop [online] 2014 Jan-Feb, 47(1):3-11 [viewed 10 August 2014] Available from: doi:10.1590/0037-8682-0231-2013
  2. GULSEN MT, SAVAS MC, KORUK M, KADAYIFCI A, DEMIRCI F. Fascioliasis: a report of five cases presenting with common bile duct obstruction. Neth J Med [online] 2006 Jan, 64(1):17-9 [viewed 27 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16421437
  3. BHATTACHARJEE HK, YADAV D, BAGGA D. Fasciolopsiasis presenting as intestinal perforation: a case report. Trop Gastroenterol [online] 2009 Jan-Mar, 30(1):40-1 [viewed 27 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/19624087
  4. MATHENY SC, KINGERY JE. Hepatitis A. Am Fam Physician [online] 2012 Dec 1, 86(11):1027-34; quiz 1010-2 [viewed 27 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23198670

Investigations - for Diagnosis

Fact Explanation
Full blood count Acute phase is characterized by high degree of eosinophilia. Leukocytosis may occur. [1,2]
Liver function tests Elevated levels of gamma-glutamyl transpeptidase, ALT, alkaline phosphatase, and bilirubin may suggest cholestatic liver injury. [1,2,3]
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 at smaller end of the egg and rests on a visible "shoulder". At the opposite end which is large &, abopercular, a small protrusion (knob or hook- like) is often visible. Visible inside the egg is the the miracidium. [1,2,3,4,5]
Ultrasonography Ultrasound scan may aid the diagnosis. The characteristic findings of clonorchiasis 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. [2,3,4]
References
  1. QIAN MB, CHEN YD, YAN F. Time to tackle clonorchiasis in China. Infect Dis Poverty [online] 2013 Feb 19, 2(1):4 [viewed 10 August 2014] Available from: doi:10.1186/2049-9957-2-4
  2. LIM JH. Liver flukes: the malady neglected. Korean J Radiol [online] 2011 May-Jun, 12(3):269-79 [viewed 10 August 2014] Available from: doi:10.3348/kjr.2011.12.3.269
  3. WANG KX, ZHANG RB, CUI YB, TIAN Y, CAI R, LI CP. Clinical and epidemiological features of patients with clonorchiasis. World J Gastroenterol [online] 2004 Feb 1, 10(3):446-8 [viewed 10 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/14760777
  4. HARTLEY JP, DOUGLAS AP. A case of clonorchiasis in England. Br Med J [online] 1975 Sep 6, 3(5983):575 [viewed 10 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/1174828
  5. CHOI BI, HAN JK, HONG ST, LEE KH. Clonorchiasis and cholangiocarcinoma: etiologic relationship and imaging diagnosis. Clin Microbiol Rev [online] 2004 Jul, 17(3):540-52, table of contents [viewed 10 August 2014] Available from: doi:10.1128/CMR.17.3.540-552.2004

Management - General Measures

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. [1,2]
References
  1. QIAN MB, CHEN YD, YAN F. Time to tackle clonorchiasis in China. Infect Dis Poverty [online] 2013 Feb 19, 2(1):4 [viewed 10 August 2014] Available from: doi:10.1186/2049-9957-2-4
  2. LIM JH. Liver flukes: the malady neglected. Korean J Radiol [online] 2011 May-Jun, 12(3):269-79 [viewed 10 August 2014] Available from: doi:10.3348/kjr.2011.12.3.269

Management - Specific Treatments

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. [1,2,3]
References
  1. QIAN MB, CHEN YD, YAN F. Time to tackle clonorchiasis in China. Infect Dis Poverty [online] 2013 Feb 19, 2(1):4 [viewed 10 August 2014] Available from: doi:10.1186/2049-9957-2-4
  2. LIM JH. Liver flukes: the malady neglected. Korean J Radiol [online] 2011 May-Jun, 12(3):269-79 [viewed 10 August 2014] Available from: doi:10.3348/kjr.2011.12.3.269
  3. HARTLEY JP, DOUGLAS AP. A case of clonorchiasis in England. Br Med J [online] 1975 Sep 6, 3(5983):575 [viewed 10 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/1174828