Liver disease is a common term that includes any condition that affects the liver. There is a spectrum of diseases that can affect the organ.
These conditions develop due to different causes but affect the liver to produce liver damage and a profile of symptoms and signs that suggests liver involvement.
Brief About Structure and Function of Liver
The liver is present in the abdominal cavity, below the right lung separated from it by the lower boundary of the thoracic cavity and diaphragm.
It is the largest solid organ in the body and weighs about 1.5 kgs.
It measures on average, about 20 cm horizontally, and 17 cm vertically, and is 12 cm thick and is an irregularly shaped, dome-like solid structure.
There are two lobes in the liver, a larger right lobe, and a smaller left lobe. There are two minor lobes as well.
Just to get an idea, the upper border of the right lobe is at the level of the top of the 5th rib or about half inch below nipple. The normal liver can only be palpated during inspiration when it is pushed down by the diaphragm and the lower edge of the liver descends below the margin of the lowest rib.
Ducts carry liver secretions to the gall bladder and gall bladder is also connected by a different duct to the intestines.
The bile made by the liver travels to the gallbladder which temporarily stores it before discharging into the intestines at meal aid in the digestion.
The liver directly receives the blood that comes from the intestines (portal blood) and can readily process nutrients absorbed from food as well as other contents of the portal blood.
The main functions of the liver are
- Manufacture of essential proteins
- Participates in the metabolism of fats and carbohydrates.
- Eliminate harmful biochemical waste products
- Detoxification of toxins like alcohol, certain drugs, and environmental toxins.
- Forms and secretes bile
Common Liver Diseases
The liver can be damaged by
- Viral infection
- Prescription drugs
- Herbal supplements
- Hepatotoxic drugs
- Alcohol intake
- Metabolic diseases
- Immune (defense) system
- Genetic (hereditary) abnormalities
Many conditions can affect your liver. Here’s a look at some of the main ones.
Hepatitis means inflammation of the liver. It can be caused by viral infection and ingestion of toxins which cause harm to the liver.
Because of inflammation and damage, the function of the liver is affected.
Hepatitis caused by viruses is called viral hepatitis. There are five types of hepatitis viruses which commonly cause hepatitis – A, B, C, D, and E.
- Hepatitis A
- Spreads through contaminated food or water
- Mild to severe
- May resolve within a few weeks
- Does not cause chronic hepatitis
- Hepatitis B
- Spreads through bodily fluids such as blood and semen
- An acute episode may be followed by a chronic episode
- Chronic hepatitis cannot be cured and the person may transmit the virus
- Leads to cirrhosis
- Vaccination is available and recommended for at-risk people
- Hepatitis C
- Spreads through contact with blood from a person with hepatitis C
- Can cause both acute and chronic hepatitis
- Leads to cirrhosis
- Hepatitis D
- Infects only people with preexisting hepatitis D
- Could be acute or chronic
- Hepatitis E
- Spreads by intake of contaminated water or food
- Like hepatitis A, it is self-resolving
- Has a predilection for pregnant females
Noninfectious hepatitis is caused by drugs or other toxic agents.
Alcoholic liver disease and non-alcoholic steatohepatitis (NASH)
Alcohol is converted into fat which is stored in the liver. This leads to alcoholic fatty liver or alcoholic steatohepatitis.
Over the period this could lead to cirrhosis.
Nonalcoholic fatty liver disease is caused by nonalcoholic factors that are not entirely clear though.
Diet and other lifestyle changes can improve liver function in both cases.
These are the diseases where there are antibodies are formed against the body’s own cells.
Autoimmune diseases can cause liver diseases too.
- Autoimmune hepatitis
- Hepatitis resulting from damage of liver cells by autoimmune antibodies
- Primary biliary cirrhosis or primary biliary cholangitis
- The damage is done to the bile ducts and this causes bile to build up in the liver leading to cirrhosis over time.
- Primary sclerosing cholangitis
- This is an inflammatory disease that leads to scarring of bile ducts and eventually blocking them. This can lead to cirrhosis or liver failure.
Several genetic conditions can affect the liver.
Read more about Genetic inheritance – Modes and Significance
In this disease, the liver stores more iron than required. The iron is deposited in many organs, including the liver.
The liver stores excess of copper which eventually leads to liver damage.
This protein is formed in the liver and this protein helps to prevent enzymatic breakdown by enzyme trypsin. This condition can lead to liver and lung disease.
Liver cancers which either primarily develop in the liver or metastasize to liver would lead to liver damage.
Hepatocellular carcinoma is the most common type of liver cancer.
Complications of other liver diseases, especially those that aren’t treated, may contribute to the development of liver cancer.
Symptoms and Signs of Liver Disease
All the diseases that affect the liver would lead to an identifiable pattern of clinical presentation.
It must be noted that small insults of the liver may not be noted as the liver has a large capacity of tissue and it could be that some amount of destruction has already occurred when the symptoms show.
Following symptoms collectively indicate the presence of a liver disease
- Yellowing of skin, sclera, etc
- Deposition of bilirubin pigment due to raised levels in the blood, poor metabolization or poor excretion of the pigment
- (yellow skin) that can occur when the liver is unable to properly metabolize or secrete the yellow pigment bilirubin in bile
- Bleeding or easy bruising
- Decrease in clotting factors due to decreased synthesis by the liver
- Swelling of legs
- Due to decrease in protein levels
- Occurs in late stages
- Dark urine
- Pale, bloody, or black stool
- Nausea, vomiting
- Decreased appetite
- Pruritis [itchy skin]
Diagnosis of Liver Disease
The clinical picture could give an idea about liver involvement and the next logical step is to confirm that by doing tests for liver functions.
Liver function tests include
- Serum bilirubin level
- Direct bilirubin
- Indirect bilirubin
- Alanine aminotransferase (ALT) or serum glutamic pyruvic transaminase (SGPT)
- Aspartate aminotransferase (AST) or serum glutamic oxaloacetic transaminase (SGOT)
- Serum total proteins
- Serum Albumin
- Serum Globulin
- Albumin: Globulin ratio
- Serum Alkaline Phosphatase
- Gamma-glutamyl transferase (GGT)
If bleeding disorders are present, coagulation studies including prothrombin time, International normalized ratio (INR) and activated partial thromboplastin time (APTT) are also done.
Investigations are also able to suggest if the cause of the problem is liver parenchyma or external to the liver.
Sometimes, the pattern of liver blood test abnormalities provides a clue as to the type of liver disease. For example, an AST to ALT ratio greater than two (as long as both are less than nine times normal) suggests alcoholic hepatitis or cirrhosis of any type.
If liver functions are deranged further tests for etiology confirmation are done.
For example, in viral hepatitis viral markers are done to check the type of virus and the extent of infection.
Similarly, in primary biliary cirrhosis antimitochondrial antibodies are done and for hemochromatosis, iron studies are conducted. For cancers, tumor markers are assessed.
Other biochemical tests and complete blood count are also done to provide further guidance.
Liver biopsy is done in selected cases where the diagnosis is uncertain. The biopsy is a procedure where a piece of tissue is removed for histopathological studies.
Read more about Liver Biopsy-Types, Indications, and Procedure
Read more about Types of Biopsies and their applications
Who is at Risk for Liver Disease?
Some kinds of liver diseases can affect any individual. However, other diseases affect people with certain behaviors.
Heavy drinking is one such behavior.
People who share needles or get tattooed with non-sterile needles are more likely to be infected with hepatitis B virus. Healthcare workers are also exposed to needle injuries and should take appropriate precautions.
Diabetes, obesity, exposure to toxins or the use of drugs that affect the liver are also risk factors.
The drugs are given for the symptoms and supplementing the deficiencies
- Drugs to target specific symptoms, such as itchy skin
- Vitamins and supplements to boost liver health
For the liver manifestation of the cause, the treatment involves dietary and lifestyle changes.
These might include:
- Limiting alcohol
- Maintaining a healthy weight
- Drinking more water
- A diet with plenty of fiber and reduced fat, sugar, and salt
Definitive treatment, if available, aims at treatment of the underlying cause.
In the case of a lesion, surgery may be needed.
Antiviral drugs are used to treat hepatitis.
Therapeutic phlebotomy may be required for hemochromatosis.
In the case of fibrosis and liver failure, liver transplant needs to be considered.