The LIVER may be extensively diseased without any obviously serious symptoms, unless the circulation through it is impeded, the outflow of BILE obstructed, or neighbouring organs involved. JAUNDICE is a symptom of several liver disorders, and is discussed under its separate heading. ASCITES, which may be caused by interference with the circulation through the portal vein of the liver, as well as by other reasons, is also considered separately. The presence of gall-stones is a complication of some diseases connected with the liver, and is treated under GALL-BLADDER, DISEASES OF. For hydatid cyst of the liver, see TAENIASIS. Liver diseases in a tropical environment are dealt with later in this section.
or HEPATITIS, may occur as part of a generalised infection or may be a localised condition. Infectious hepatitis, which is the result of infection with a virus, is one of the most common forms. Many different viruses can cause hepatitis, including that responsible for glandular fever (see MONONUCLEOSIS). Certain spirochaetes may also be a cause, particularly that responsible for LEPTOSPIROSIS, as can many drugs. Hepatitis may also occur if there is obstruction of the BILE DUCT, as by a gall-stone.
So-called because fat droplets accumulate in liver cells, this is the commonest reason why an individual is found to have abnormal LIVER FUNCTION TESTS. About 1 in 5 persons are thought to have NAFLD (and 7 in 10 of those with Type 2 DIABETES MELLITUS), far more than those with alcoholic liver disease. The main risk factor is OBESITY. While most have no symptoms and are diagnosed only because they happen to have had liver function tests done, a minority will progress to CIRRHOSIS. Treatment designed to prevent this progression depends on offering guidance on healthy eating and exercise and encouraging obese individuals to lose weight.
A disorder caused by chronic damage to liver cells. The liver develops areas of FIBROSIS and in response, the remaining normal liver cells increase and form regeneration nodules. Those islands of normality, however, suffer from inadequate blood supply, thus adversely affecting liver function. Alcohol is the most common cause of cirrhosis in the developed world with 10–20% of chronic heavy drinkers developing the condition; in the last 50 years there has been a 400% increase in alcohol related liver disease in the UK. In Africa and many parts of Asia, infection with hepatitis B virus is a common cause. Non-alcoholic fatty liver disease can progress to cirrhosis and certain drugs – for example, PARACETAMOL – may damage the liver if taken in excess. Unusual causes of cirrhosis include defects of the bile ducts, HAEMOCHROMATOSIS (raised iron absorption from the gut), CYSTIC FIBROSIS, cardiac cirrhosis (the result of heart failure causing circulatory congestion in the liver), and WILSON'S DISEASE (raised copper absorption).
In early cirrhosis, most people have no signs or symptoms and the disease may be diagnosed only at a routine medical examination. Eventually, the condition is likely to decompensate and the person develops jaundice, OEDEMA (including ascites – fluid in the abdomen), fever, confusion, HAEMATEMESIS (vomiting blood) from oesophageal varices (see PORTAL HYPERTENSION), loss of appetite and lethargy. On examination, cirrhotic patients often have an enlarged liver and/or SPLEEN, and HYPERTENSION. Liver function tests, cholangiography (X-ray examination of the bile ducts) and ultrasonic imaging techniques such as transient elastography and acoustic radiation force impulse, where available, mean that a diagnosis can often (though not always) be reached without having to take a BIOPSY of the liver.
Nothing can be done to repair a cirrhosed organ, but the cause, if known, must be removed and further advance of the process thus prevented. A high-protein, high-carbohydrate, low-fat diet is given, supplemented by liver extract and vitamins B and K. Complete abstinence from alcohol is essential. If endoscopy shows oesophageal varices are present, the patient is offered LIGATION of the affected veins. Those with ASCITES may be offered prophylactic antibiotics because of the risk of PERITONITIS. Regular monitoring by ultrasound is recommended by the National Institute for Health & Care Excellence (NICE) to detect liver cancer. In patients with liver failure and a poor prognosis, liver TRANSPLANTATION may be needed.
When an ABSCESS develops in the liver, it is usually a result of amoebic DYSENTERY, appearing sometimes late in the disease – even after the diarrhoea is cured (see below). It may also follow upon inflammation of the liver due to other causes. In the case of an amoebic abscess, treatment consists of oral metronidazole.
is a destructive and often fatal disease of the liver which is very rare. It may be due to chemical poisons, such as carbon tetrachloride, chloroform, phosphorus and industrial solvents derived from benzene. It may also be the cause of death in cases of poisoning with fungi. Very occasionally, it can be a complication of acute infectious hepatitis.
is not uncommon, although it is rare for the disease to begin in the liver – usually it has spread from the stomach or bowels. Cancer originating in the liver is more common in Asia and Africa. It usually arises in a fibrotic (or cirrhotic) liver and in carriers of the hepatitis B virus. The liver is much enlarged, and its margin and surface are rough, being studded with hard cancer masses of varying size, which can often be felt through the abdominal wall. There is great emaciation, which increases as the disease progresses. Pain, jaundice and oedema often occur.
The hepatitis viruses (A-F) are of paramount importance. Hepatitis E (HEV) often produces acute hepatic failure in pregnant women; extensive epidemics – transmitted by contaminated drinking-water supplies – have been documented. HBV, especially in association with HDV, also causes acute liver failure in infected patients in several tropical countries: however, the major importance of HBV is that the infection leads to chronic liver disease (see below). Other hepatotoxic viruses include the EPSTEIN BARR VIRUS, CYTOMEGALOVIRUS (CMV), the flavivirus causing YELLOW FEVER, Marburg/Ebola viruses, etc. Acute liver disease also occurs in the presence of several acute bacterial infections, including Salmonella typhi, brucellosis, leptospirosis, syphilis, etc. The complex type of jaundice associated with acute systemic bacterial infection – especially pneumococcal PNEUMONIA and pyomyositis – assumes a major importance in many tropical countries, especially those in Africa and in Papua New Guinea. Of protozoan infections, PLASMODIUM falciparum malaria, LEISHMANIASIS, and TOXOPLASMOSIS are causes. Ascaris lumbricoides (the roundworm) can produce obstruction to the biliary system.
Long-term disease is dominated by sequelae of HBV and HCV infections (often acquired during the neonatal period), both of which can cause chronic active hepatitis, cirrhosis, and hepatocellular carcinoma (‘hepatoma’) – one of the world's most common malignancies. Chronic liver disease is also caused by SCHISTOSOMIASIS and acute and chronic alcohol ingestion. Furthermore, many local herbal remedies and also orthodox chemotherapeutic compounds (e.g. those used in tuberculosis and leprosy) can result in chronic liver disease. HAEMOSIDEROSIS is a major problem in southern Africa. Hepatocytes contain excessive iron – derived primarily from an excessive intake, often present in locally brewed beer; however, a genetic predisposition seems likely. Indian childhood cirrhosis – associated with an excess of copper – is a major problem in India and surrounding countries. Epidemiological evidence shows that much of the copper is derived from copper vessels used to store milk after weaning. Veno-occlusive disease was first described in Jamaica and is caused by pyrrolyzidine alkaloids present in bush-tea. Several HIV-associated ‘opportunistic’ infections can give rise to hepatic disease (see AIDS/HIV).
A localised (focal) form of liver disease in all tropical/subtropical countries results from invasive Entamoeba histolytica infection (amoebic liver ‘abscess’); serology and imaging techniques assist in diagnosis. Hydatidosis also causes localised liver disease, one or more cysts usually involving the right lobe of the liver. Hepato-biliary disease is also a problem in many tropical/subtropical countries. In south-east Asia, Clonorchis sinensis and Opisthorchis viverini infections cause chronic biliary-tract infection, complicated by adenocarcinoma of the biliary system.