INFECTIONS OF THE LIVER

1. Bacterial hepatitis

   1. Leptospira are spirochaetes that can cause leptospirosis. They are found in urine of animals, and make their way into the human bloodstream. This is the spiraemic phase. After 1 week, the immune phase occurs with production of IgM antibodies. Leptospira ictero-haemorrhagiae causes infectious jaundice (Weil’s disease).

   2. Treponema pallidium is the spirochaete that causes syphilis. 2^nd syphilis (bacteraemic stage) is caused by this organism. Congenital syphilis occurs when pregnanct mother is infected with Treponema pallidium.

2. Liver abscess

   1. Pyogenic: A pyogenic abscess just means that the abscess is usually caused by complication of other abscesses in body. The organism reaches the liver by: 1) portal vein, 2) arterial supply, 3) ascending cholangitis, 4) direct invasion from nearby source. The culprits are usually anaerobes such as: Strep milleri, Enteric gram neg rods, enterococci. If abscess occurs haematogenically, you will see multiply lesions rather than a solitary lesion. Clinical features: fever, jaundice (ascending cholangitis), tender RUQ + hepatomegaly. Diagnosis: clinical, ultrasound, CT scan, aspiration + culture (identify organism). Treatment: aminopenicillins, 3^rd generation cephalosporins, metronidazole.

3. Amoebic

   1. E. histolytica: After invading the colonic mucosa, it enters the portal circulation and travels to the liver to form abscesses. From here it can penetrate the diaphragm to cause lung abscesses.

   2. Diagnosis: clinical: RUQ pain, palpable mass, hepatomegaly, fever, dysentery, serology, CT scan. Treatment: metronidazole, + chloroquine.

4. Hydatidosis (need to know).

   1. This is caused by the cestode (tapeworm) Echinococcus granulosum and multilocularis. Eggs are found in dogs and sheep. They are released in faeces ≫ ingested by humans (or sheep) ≫ form larvae in intestines and penetrate the intestinal mucosa. They then migrate to the liver to form abscesses (can form in brain, kidney, lungs etc). These abscesses contain hydatid fluid that is extremely allergic to humans ≫ CAN BE FATAL. With E. multilocularis the abscesses can laterally bud≫ therefore forming new cysts (often mistaken for a slow growing tumour).

   2. Diagnosis: clinical: hepatomegaly, palpable mass, rural history, CAT scan, serology. DO NOT BIOPSY OR ASPIRATE. Treatment: praziquante; + niclosamide, surgery. This disease is dangerous, and so is the treatment. So focus on prevention and control (i.e.: hygiene etc). This is not a common disease but in the 60’s, Tassie had highest incidence in the world.

5. Other parasitic infections of the liver:

   1. Kala azar: Caused by leishmania donovani – Phlebotomus. It causes fever and hepatosplenomegaly. Diagnosis is by liver/spleen biopsy and serology. Treatment is by retronidazole, and pentamidine.

   2. Malaria (falciparum, vivax, ovale, malariae): All species cause hepatosplenomegaly + fever. Do blood slides at appropriate times. Treatment is by chloroquine, mefloquine, quinine, malarone.

   3. Liver flukes:

   4. Schistosomiasis: Basically it causes fibrosis of vessels≫ portal hypertension. Remember treatment for blood flukes is: praziquantel. (What is the treatment for nematodes and cestodes?).

   5. Toxocariasis:

   6. Ascarisis: causes obstructive jaundice.

Just stick to the main ones which are: cholecystitis, cholangitis, bacterial hepatitis, hydatid disease, liver abscess, and amoebic hepatic abscess.

Category: Pathology Notes