subject: Clonorchiasis Aetiology clinical features and management [print this page] Clonorchiasis Aetiology clinical features and management
Transmission ana incidence Fishponds into which human faeces are poured as fishfeed are an important source of infection, as eggs, snails.and fish are conveniently found together. The diseaseoccurs in Asian countries. Dogs and cats are also importanthosts.
Pathology The worms obstruct small branches of the biliary tree, andbile accumulates in cysts proximal to the obstruction.Hypertrophy of the bile epithelium with adenomatous proliferationoccurs. Later there is cellular infiltrate of the bileduct wall with chronic inflammatory cells. Pigment stonesand biliary sludge form. Flukes obstructing the pancreaticducts can cause pancreatitis. Long-standing heavy infectionsare associated with malignant change in the adenomatous hyperplasia, leading to cholangiocarcinoma.
Clinical features Clinical features relate to the worm burden. Mild infectionscause no symptoms. Upper abdominal discomfort,diarrhoea and weakness occur with heavier infections;with the heaviest worm burdens upper abdominal pain,diarrhoea, weight loss, obstructive jaundice, hepatomegaly,cholangitis and Gram-negative septicaemia occur.
Diagnosis The eggs are found in faeces or in duodenal aspirate.Eosinophilia is usual in the peripheral blood. Endoscopicretrograde cholangiopancreatography or percutaneoustranshepatic cholangiography shows dilated branches ofthe biliary tree, and the worms appear as filling defects.
Management Praziquantel is the treatment of choice, giving 25 mg/kg onthree occasions 4 hours apart on one day. When thereis obstructive jaundice with cholangitis and septicaemia,relief of biliary obstruction, vigorous treatment of the bacterialinfection and circulatory support for the patient areneeded.
Prevention and control Transmission can be interrupted by safe disposal of faecalwastes. Usually this involves a major change in socialhabits, which is difficult to achieve. Thorough cooking offish before it is eaten prevents infection, as does freezingfish, -10C for 5 days, and salting in 10% saline.
