Liver infections - Hepatitis

HEPATITIS (Micro made easy pp 180)

Hepatitis just means inflammation of liver. There are 5 known hepatitis RNA viruses: A, C, D, E, G. There is only 1 hepatitis DNA virus: B.

Refer to overview in lecture – pg 1. Hep C virus was called NANB (non-A non-B virus). All of these viruses except A & E are transmitted parenterally (G not included). A & E are transmitted via faecal oral route (they are found in faeces). Also, all parenterally transmitted viruses can cause chronic hepatitis.

FUNCTIONS OF LIVER (Lecture notes)

Major functions of the liver include: 1) storage of: glycogen, vitamins, iron, 2) disposal of metabolic wastes, 3) metabolism of sugar, fat, protein, 4) production of clotting factors, 5) filters toxic substances.

SYMPTOMS OF LIVER INFECTION

Most infections of the liver may be asymptomatic because they may not disrupt the function to the extent that “loss of function” occurs. Symptoms include cardinal diarrhoea symptoms, jaundice, dark urine, pruritus, rash/arthritis (deposition of immune complexes), hepatic encephalopathy ≫ coma ≫ death.

SIGNS

Signs include: None, jaundice, hepatomegaly/hepatosplenomegaly, hepatic encephalopathy.

INVESTIGATIONS

There are two enzymes that hepatocytes produce: AST, ALT. If hepatocytes are damaged, then they will release these enzymes ≫ elevated enzymes is cause for concern. Bilirubin is conjugated in the liver. If hepatocytes are damaged, then there is back up of bilirubin in blood ≫ hyperbilirubinemia. If you suspect a hepatitis infection, then you can use serological assays to see which hepatitis virus is causing the infection. You can also look at platelet clotting time ≫ if increased, then you have problem in liver.

ACUTE VIRAL HEPATITIS PANEL (Lecture notes)

There are four serological assays that can be measured which give an idea of what type of virus is causing the infection: 1) anti-HAV IgM/IgG, 2) HBsAg, 3) anti-HBc IgM, 4) anti-HCV.

VIRAL HEPATITIS (Micro made easy pp 180)

There are two major types of viral hepatitis. 1) acute viral hepatitis: infection causes illness and then completely resolves, 2) chronic viral hepatitis: infection is asymptomatic or produces symptoms for a long time (BCD types are involved).

Acute viral hepatitis is as a result of the virus growing in the hepatocytes. The first few days, the patient has flue like symptoms. The hepatocytes necrose and release transaminases ALT, ASP. The patient is jaundiced about 1-2 weeks later because bilirubin is not cleared by the liver, because the liver swells and blocks the bile canaliculi.

Chronic viral hepatitis is more difficult because the patient is often asymptomatic with mildly elevated liver enzymes.

Category: Pathology Notes