Causes of liver disease
The causes of liver disease can be categorised as follows:
Congenital causes of liver disease
As the liver plays such a critical part in ridding the body of toxins, and extracting and storing nutrients for the body to use, children born with a congenital liver disease usually become ill as young infants.
Some of the most common congenital diseases that can damage the liver are:
- Biliary atresia – a condition in which bile ducts don’t develop normally.
- Haemochromatosis – a condition in which iron accumulates in the body, especially the liver.
- Wilson’s disease – the inability to excrete copper, leading to accumulation in the liver and brain.
- Gilbert’s syndrome – elevated levels of unconjugated bilirubin in the bloodstream (not a disease as such).
- Alpha 1-antitrypsin deficiency – a metabolic disorder and the most common genetic liver disease.
- Glycogen storage diseases – excess glycogen accumulates in the liver tissue.
Causes of acquired liver disease
1. Alcohol-related liver disease
The biggest risk factor for alcoholic liver disease is drinking excessive amounts of alcohol, although the exact amount of alcohol intake that puts a person at risk isn’t known.
UK Public Health advises no more than 14 units of alcohol per week as a “safe” drinking limit for women, and 21 units a week for men. One unit is about 10g of alcohol. (Read the labels on wine or beer bottles carefully. Alcohol is quoted as %w/v. For example, 5% w/v on a beer bottle means 5g of alcohol per 100ml of beer and 14% w/v on a wine bottle means 14g of alcohol per 100ml of wine.)
Alcoholic liver disease doesn’t only occur in people who are alcoholics, or who have an alcohol-dependency problem. In fact, the severity of the disease doesn’t always correlate with the amount of alcohol intake. This is because there are other factors such as genetics and lifestyle that also play a part in the disease.
Other risk factors for alcoholic liver disease include:
- Gender. Women are at higher risk because their bodies process alcohol differently from men.
- Obesity. Heavy drinkers who are overweight are at higher risk, and are also more likely to progress to cirrhosis.
- Genetic factors. Studies suggest that genetic factors can make some people more prone to developing alcoholic liver disease than others.
Other liver diseases, such as having concomitant chronic hepatitis B or C infection, can also increase your risk for alcoholic liver disease. If your liver is already damaged by another disease, drinking alcohol will damage it further or accelerate damage.
There are three stages to alcohol-related liver damage:
- Hepatic steatosis (fatty liver)
- Alcoholic hepatitis
- Alcoholic cirrhosis
Once the disease has reached the cirrhosis stage, the damage is irreversible.
There’s no universally agreed definition of moderate drinking, but in South Africa, the recommended amount is no more than one drink (12g of alcohol) per day for women and no more than two drinks per day for men.
However, research by the World Health Organization (WHO) shows that the prevalence of heavy drinking in South Africa is quite high. On a scale of 1 to 5, with 1 being least risky and 5 being most risky, we score a 4.
2. Viral hepatitis
Hepatitis is a term used for inflammation of the liver. Viral hepatitis has become a leading cause of death and disability in the world, and is now killing more people globally per year than HIV/AIDS.
Deaths from infection, liver disease and cancer caused by viral hepatitis increased by 63% from 890,000 in 1990 to 1.45 million in 2013, according to a review of data collected in 183 countries. By comparison, there were 1.3 million deaths from HIV/AIDS, 1.4 million from tuberculosis and 855,000 from malaria in 2013, according to the report published in The Lancet.
There are five main types of viral hepatitis: A, B, C, D and E.
Hepatitis D is found in other parts of the world where hepatitis B is prevalent (such as South America and the Mediterranean), and is rare in South Africa. Hepatitis D infection occurs only simultaneously or as super-infection with hepatitis B.
Hepatitis E is found in India and South-East Asia, where it sometimes occurs in large outbreaks linked to contaminated water. Hepatitis A is most commonly found in developing countries. A study conducted in South Africa in 1994 showed that over 90% of black people had been infected with hepatitis A by adulthood.
By comparison, only about 50% of white adults had antibodies indicating past infection. This probably reflects the different socio-economic circumstances and sanitary conditions historically available to these groups. However, this is changing with changing socio-economic trends.
Hepatitis B is widespread in sub-Saharan Africa and South Africa. It’s estimated that about 2.5 million people in South Africa are living with chronic hepatitis B, and the infection is more common in the Eastern Cape Province and KwaZulu-Natal.
Hepatitis C infections are less common in South Africa, with less than 1% of adults being infected. There’s a cumulative risk of exposure over a lifetime, and so more infections are seen in older age groups. Also, hepatitis C is more strongly linked to high-risk groups for blood-borne diseases.
The hepatitis A virus is found in the faeces of an infected person. It’s usually acquired from hands soiled after using the toilet or changing a nappy, or by swallowing water or food that’s been contaminated by human faeces. Uncooked shellfish and raw vegetables contaminated by sewage can also be a route of infection.
By contrast, hepatitis B and C are blood-borne viruses. Hepatitis B is highly infectious – in fact, it’s estimated to be about 50 times more infectious than HIV. It’s mostly spread by very close contact with an infected person, which allows for the exchange of minute quantities of blood through tiny grazes or cuts.
This sort of spread can occur through:
- Rough play among children
- Sharing toothbrushes or razors
- Direct contact with, for example, a bleeding wound
Here are a few more specific high-risk circumstances where the spread of hepatitis B can occur:
- Tattooing or tribal scarification with unsterile implements.
- Between intravenous drug abusers who share needles and syringes.
- Between patients and staff in hospital settings, e.g. haemodialysis units.
- Potentially by blood transfusion. Since all blood donations are screened for hepatitis B and C prior to use in South Africa, the risk of acquiring viral hepatitis from a blood transfusion is low – in the region of 1 in 10,000 or less.
The ways in which hepatitis C are spread are believed to be similar to those associated with hepatitis B, but hepatitis C is far less infectious. Hepatitis B and C can also be passed from an infected mother to her baby. Note that, despite the fact that hepatitis B and C are found in the blood, there’s no convincing evidence that these viruses are spread through mosquitoes or other biting insects.
When any of the hepatitis viruses reach the liver, they infect the liver cells and multiply inside them. The body's immune system can recognise these virus-infected cells and will attempt to destroy them. This immune attack by white blood cells causes liver cell damage and inflammation.
Hepatitis A isn’t a chronic condition, while both hepatitis B and C can become chronic. If untreated, it can cause irreversible liver damage.
3. Non-alcoholic fatty liver disease (NAFLD)
When there’s fat build-up in the liver (steatosis), as is often the case in obese or overweight people, the functioning of the liver is affected. In those who also have severe inflammation and progressive scarring (steatohepatitis), this can lead to cirrhosis of the liver.
All individuals with NAFLD are at risk of increased cardiovascular problems. NAFLD individuals typically also have diabetes and high cholesterol. In its early stages, this disease can be arrested by severely reducing fat intake, losing weight and exercising regularly.
4. Medication-induced liver problems
Many medications can be toxic to the liver, so it’s important to always follow the dosage instructions on the packaging.
For example, paracetamol is found in more than 600 different prescription and over-the-counter medicines. When they’re used as directed, these medicines are safe and effective, but taking more than the prescribed dose, or intentionally overdosing, can lead to acute liver damage.
Illegal drugs, including cocaine and inhalants, can also do serious damage to your liver. Some herbal and traditional medicines can also be liver toxins. Make sure you know what you’re taking and ask a doctor or pharmacist for advice if you’re unsure about the medicine’s safety.
5. Autoimmune liver disease
This includes a range of conditions in which the body’s own immune system sets up inflammation against the liver, leading to damage.
Risk factors for liver disease
Factors that may put you at risk for liver disease include:
- Excessive alcohol use
- Overexposure to certain drugs and/or toxins (e.g. anabolic steroids, herbal remedies)
- Eating foods that haven’t been sufficiently cleaned
- Injecting drugs and using shared needles
- Your gender – women are at higher risk for alcoholic liver disease, while men are more likely to develop liver cancer
- Travelling to areas associated with a high risk for hepatitis infection
- Being exposed to blood products
- A family history of liver disease
Diagnosing liver disease
Reviewed by Dr Mark Sonderup, B Pharm, MB ChB, FCP (SA). Senior Specialist, Division of Hepatology, Department of Medicine, University of Cape Town and Groote Schuur Hospital. March 2018.