The early symptoms are loss of appetite and energy and a feeling of nausea. The waste pigment from old blood cells (bilirubin) builds up in the blood, turning the skin and the eyes yellow. If the liver is badly damaged the steady accumulation of wastes causes progressive disturbance of the body's internal chemistry, and on rare occasions this may eventually lead to unconsciousness and even death. The more usual outcome is complete recovery after an illness lasting as little as a few days or as long as several months. In a few cases the hepatitis grumbles on continuously; this chronic hepatitis causes progressively more damage and eventually may lead to liver failure.
What, then, are the causes of hepatitis? A Frenchman who is feeling unwell often claims to be suffering from a crise de foie and a few old-fashioned Englishmen still complain of being liverish when they feel off colour. There may be a guilty suspicion in the minds of the invalids that their livers have been upset by too much alcohol. In fact alcohol rarely causes hepatitis until the liver has been poisoned by years of really heavy drinking and its resistance has been further lowered by a poor, vitamin-deficient diet. The morning-after symptoms of nausea and inability to face food are more likely to be caused by alcoholic irritation of the stomach lining than liver damage.
The main causes of hepatitis are virus infections and chemical damage. A few industrial processes are associated with liver damage, but (at least in Western countries) precautions are now taken to protect the workforce. Nowadays the main chemical hazard to the liver comes from medicinal drugs. Some anaesthetics, drugs for high blood pressure, tranquillisers and anti-depressants, and even oral contraceptives may cause hepatitis in a small fraction of those who take them in normal doses. These sensitivity reactions are unpredictable, and may occasionally be life threatening.
Some drugs, on the other hand, will cause hepatitis in almost everyone who takes them in very high dosage. The most notorious example is the pain-reliever paracetamol; death from overdosage of this drug is usually due to hepatitis causing liver failure. Hepatitis may also be caused by poisonous fungi.
Hepatitis A is transmitted in urine and sewage and is common in countries with poor sanitation. The viruses that cause hepatitis B and C are carried in the blood and other body fluids and are transmitted by sexual intercourse, transfusion of contaminated blood, or sharing of needles by intravenous drug users. Because these are the same modes of transmission as for HIV, the relative rarity of hepatitis in Western countries has caused some scientists to question the most gloomy forecasts of the spread of Aids. Yet worldwide, virus hepatitis is one of the most common causes of chronic sickness. Fortunately, an effective vaccine is now available against hepatitis B.