An overview of hepatitis: part 1

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The Pharmaceutical Journal
Vol 280 No 7496 p411-414
5 April 2008

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Continuing professional development

An overview of hepatitis: part 1
The UK is the only major developed country showing an increase in the number of deaths from all forms of liver disease, including hepatitis. In part 1, Gareth Nickless focuses on non-viral hepatitis and drug use in liver dysfunction
Continuing professional development articles	Hepatitis series

Gareth Nickless, PgClinDip, MRPharmS, is lead clinical liaison tutor at Liverpool John Moores University and Wirral University Hospitals NHS Foundation Trust

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Liver

The liver performs numerous essential functions

SUMMARY

The liver is the largest internal organ of the human body and has a dual blood supply. The hepatic portal vein delivers blood from the intestine to be processed before being returned to the general circulation while the hepatic artery, which branches from the aorta, supplies the liver with oxygen.

The individual functional units of the liver are called lobules. These are hexagonal arrangements of tissue formed around a central vein. A branch of the hepatic artery, a branch of the hepatic portal vein and a bile duct are situated at each edge of these lobules.

Blood from each lobule flows into large capillary spaces (sinusoids), which are connected to the central vein.

The liver performs numerous essential functions of metabolism, synthesis and storage, including:

• Detoxifying waste products (eg, nitrogenous waste), hormones, drugs and other xenobiotics

• Producing plasma proteins (eg, albumin) and clotting factors

• Storing glycogen, fats, iron and vitamins

However, despite these numerous functions, there is little cellular specialisation — hepatocytes perform a wide variety of metabolic and secretory roles, and phagocytic activities are carried out by Kupffer cells.

When the liver comes into contact with toxins or viruses, it undergoes inflammatory (hepatitis) or fatty (steatosis) changes, or both (steatohepatitis). These changes are usually reversible — the liver can regenerate — but if the cause of the initial insult is not addressed damage can progress to fibrosis (scarring and thickening of the smooth liver tissue) and cirrhosis of the liver (see Definitions panel), which result in complications, such as ascites (fluid in the abdomen), portal hypertension and oesophageal varices.

Varices form when blood from the intestine cannot flow through the hardened liver and can result in internal bleeding (indicated by vomiting blood or tarry stools) if they burst.

Definitions

Cholestasis Impaired bile flow. This can be intra- or extra-hepatic (eg, gallstones blocking the bile duct) and may or may not be associated with hepatitis.

Cirrhosis of the liver A progressive disease of the liver (as a result of diffuse damage to hepatic parenchymal cells) associated with fibrosis, nodular formation and altered architecture. There is associated failure of hepatocyte function and resistance to hepatic blood flow.

Compensated liver disease Where a patient has known chronic liver damage but is asymptomatic, either because of prescribed medicines or because there is enough healthy liver tissue to carry our normal functions.

Decompensated liver disease Where a patient with compensated liver disease suddenly develops symptoms.

Cirrhosis of the liver also increases the chances of a patient developing hepatocellular carcinoma, a condition with a life expectancy of no more than six months.

Use of the term “hepatitis” needs to be qualified because numerous factors can trigger inflammation, including:

• Alcohol
• Viruses (A-E)
• Drugs (including herbal remedies)
• Auto-antibodies
• Insulin resistance

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