Epidemiologic features that may be helpful in diagnosis:
(1) residence or travel to an endemic area
(2) eating raw watercress or other risk factors
(3) involved in an outbreak of similar cases
Phases of infection:
(1) acute (larval migration)
(2) chronic (adult within the biliary system)
Features of the acute infection (first 2 or 4 months):
(1) hepatitis with abnormal liver function tests and hepatomegaly
(2) fever
(3) eosinophilia
(4) right upper quadrant pain
(5) anorexia and weight loss
(6) nausea and vomiting
(7) diarrhea or change in bowel habits
(8) urticaria
(9) malaise
(10) night sweats
(11) splenomegaly
(12) weakness
(13) anemia
(14) cough, dyspnea, chest pain and right pleural effusion (lung migration)
(15) cutaneous larva migrans
Features of the chronic phase (within the biliary system):
(1) may be asymptomatic
(2) right upper quadrant pain
(3) nausea and vomiting
(4) hepatomegaly with abnormal liver function tests
(5) eosinophilia
(6) cholangitis with dilatation and reactive changes in the bile ducts
(7) acalculous or calculous cholecystitis
(8) obstructive jaundice with pruritis and malabsorption
(9) ascites (in severe cases)
(10) intrahepatic abscess
Cholangiocarcinoma does not develop.
The diagnosis may be made by:
(1) stool examination for ova and parasites, but false negatives are a problem (may be absent in the acute phase and in low numbers during the chronic phase)
(2) examination of duodenal aspirate or bile
(3) serologic tests
(4) visual identification at surgery or ERCP
(5) imaging studies with ultrasonography or CT scanning (hypodense areas)
(6) epidemiologic findings during an outbreak
Differential diagnosis:
(1) viral hepatitis
(2) cholangitis and/or cholecystitis
