2. Acute viral hepatitis (aetiology, pathomorphology, complicated forms)

What is viral hepatitis?

The inflammation of the liver parenchyme

- due to viral infection

Which viruses can cause hepatitis?

- Hepatitis viruses (A-E)

- EBV

- CMV

Which viruses can cause chronic hepatitis?

- Hepatitis B

- Hepatitis C

"Become Chronic"

Symptoms of acute hepatitis?

- Hepatic jaundice

- Dark urine

- Fever

- Malaise

- Nausea

- Elevated liver enzymes (ALT, AST - and ALT will be higher than AST)

For how long can acute hepatitis last? when does it become "chronic"?

Lasts for less than 6 months

- if the infection lasts for longer = chronic

How is the acute and chronic forms of hepatitis distinguished?

- Partly based on duration

- Partly based on the pattern of cell injury

Which clinical syndromes can an infection from hepatitis viruses result in?

- Asymptomatic acute infection, where there is only serologic evidence

- Acute hepatitis

- Fulminant hepatitis = massive hepatic necrosis and liver failure

- Chronic hepatitis, which may progress into cirrhosis

- Chronic carrier state, where the disease is asymptomatic

Microscopic changes of the parenchyma in acute hepatitis?

- Ballooning degeneration of hepatocytes

- Necrosis of hepatocytes

- Loss of normal architecture in the liver

- Regenerative changes, like hepatocyte proliferation

- Accumulation of phagocytosed cellular debris in Kupffer cells

- Infiltration of mononuclear cells like macrophages and monocytes

Hepatitis caused by HAV and HEV?

Usually benign and self-limiting

- cant progress into chronic hepatitis or carrier state

How is HAV and HEV transmitted?

Transmitted through fecal-oral route

- ingestion of contaminated water or foods

Symptoms of HAV and HEV?

- Fever, nausea and vomiting during the first 1-2 weeks

- After 2 weeks = icteric phase: jaundice, dark urine and pale stool

Only for who is HEV infection dangerous?

Pregnant women

How is HEV infection dangerous for pregnant women?

Can develop fulminant hepatitis, where the whole liver becomes necrotic and dies

= Yellow liver atrophy

How is HBV transmitted?

- Sex

- Blood

- Body fluids

- Vertically

What does HBV infection cause?

Cause acute hepatitis

- approx. 20% of these cases progress into chronic hepatitis

What are the three HBV antigens?

- HBsAg

- HBeAg

- HBcAg

HBsAg?

Hepatitis B surface antigen

- protein on the surface of the virus

Anti-HBs?

Antibody against HBVsAg

- indicates immunity to HBV due to resolved infection or vaccination

HBcAg?

Hepatitis B core antigen

- protein of the capsule

Anti-HBc?

Antibody agains HBVcAg

- IgM antibodies show recent or ongoing infection

- IgG antibodies show resolved or chronic infection

HBeAg?

Hepatitis B envelope antigen

- protein secreted by the virus, which indicates viral replication and infectivity

After exposure to the virus, which three phases will the patient progress through?

1. Incubation period

2. Acute disease phase

3. Convalescence (resolving)

Incubation period? how long is this period?

During the end of the incubation period, HBsAg appears in the serum

- the patient starts to experience symptoms like nausea, fever and abdominal pain

- can take 1-6 months

Acute disease phase?

HBsAg, HBeAG and IgM anti-HBc is present in the serum

- icterus develops

Convalescence phase?

All antigens have disappeared from the blood

- IgG anti-HBs and anti-HBc remain

What happens with the antigens if the disease progresses into chronic hepatitis?

HBsAg and HBeAg will remain in the blood

- No IgG anti-HBs

What is the case if there only is anti-HBs in the serum? No anti-HBc?

That the person is vaccinated

Hepatitis C?

This type of hepatitis can resolve by itself after an acute inflammation, but it progresses into chronic hepatitis in most cases

How is HCV transmitted?

Blood

- intravenous drug use

How is HCV detected during acute infection?

Viral RNA in the blood

Hepatitis D?

Cant cause infection without being capsulated by HBsAg

- can only cause infection during a HBV coinfection

Two settings where you can get infected from HDV?

- Coinfection; being exposed to both HBV and HDV simultaneously

- Superinfection; getting infected by HDV when you already have HBV