Schistosoma mansoni and S. japonicum affect the liver, but S. haematobium rarely does so. During their life-cycle the ova reach the liver via the venous system and obstruct the portal branches, producing granulomas, fibrosis and inflammation but not cirrhosis. Clinically there is hepatosplenomegaly and presinusoidal portal hypertension, which is particularly severe with S. mansoni.
Investigations show a raised alkaline phosphatase, and ova can be found in the stools (centrifuged deposits) and in rectal and liver biopsies. Skin tests and other immunological tests often have false results and may also be positive because of past infection.
Treatment is with praziquantel, but fibrosis still remains with a potential of portal hypertension.
Cysts caused by Echinococcus granulosus are single or multiple. They usually occur in the lower part of the right lower lobe. The cyst has three layers: an outside layer derived from the host, an intermediate laminated layer, and an inner germinal layer that buds off brood capsules to form daughter cysts.
Clinically there may be no symptoms or a dull ache and swelling in the right hypochondrium. Investigations show a peripheral eosinophilia and usually a positive hydatid complement-fixation test or haemagglutination. The Casoni skin test is no longer used because of its lack of specificity. Plain abdominal X-ray may show calcification of the outer coat of the cyst. Ultrasound and CT scan demonstrate a space-occupying lesion and may show diagnostic daughter cysts.
Fine-needle aspiration under ultrasound control with chemotherapeutic cover is now used therapeutically. Surgery can be performed with removal of the cyst intact if possible after first sterilizing the cyst with formalin or alcohol. Medical treatment, e.g. with albendazole, which penetrates into large cysts, can result in reduction of cyst size. Chronic calcified cysts can be left. Complications include rupture, secondary infection and involvement of other organs. The prognosis without any complications is good, although there is always the risk of rupture. Preventative measures are important, including deworming of pet dogs and prevention of pets from eating infected carcasses where possible.
The liver is often involved but rarely causes significant morbidity or mortality. H1V itself is probably not thecause of the liver abnormalities. The following are seen:
PRE-EXISTING/COINCIDENTAL VIRAL HEPATITIS (HBV, HCV, HDV)
NEOPLASIA-Kaposi’s sarcoma and non-Hodgkin’s lymphoma
OPPORTUNISTIC INFECTION, e.g. Mycobacterium tuberculosis, Mycobacterium avium intracellulare, Cryptococcus, Candida albicans
Clinical hepatomegaly is common in 60% of patients.