Hepatitis A virus (HAV)

Epidemiology:

Most common type of viral hepatitis occurring worldwide, often in epidemics

The disease is commonly seen in the autumn and affects children and young adults

Spread of infection is faeco-oral and arises from the ingestion of contaminated food or water (e.g. shellfish)

In the UK, it is a notifiable disease

Clinical features:

Non-specific features:

Malaise

Anorexia

Distaste for cigarettes

Many recover at this stage and remain anicteric

After 1-2 weeks, some pts become jaundiced and symptoms often improve

As the jaundice deepens, the urine becomes dark and the stools pale (owing to intra-hepatic cholestasis)

There is organomegaly in ~10% of pts

Thereafter, the jaundice lessens and (in the majority of cases) the illness is over within 3-6 weeks.

Extra-hepatic complications are rare include:

Arthritis

Vasculitis

Myocarditis

Renal failure

Investigations:

LFTs:

In the prodromal stage:

Normal serum bilirubin

Bilirubinuria

Increased urinary urobilinogen

Raised serum AST or ALT (sometimes very high) precedes the jaundice

In the icteric stage:

The serum bilirubin reflects the level of jaundice

Serum AST reaches a maximum 1-2 days after the appearance of jaundice (may rise > 500IU/L)

Serum ALP is usually < 300IU/L

Post-icteric stage:

The aminotransferases may remain elevated for some weeks after and, occasionally, for up to six months

Haematology:

Raised ESR

Raised PT (in severe cases)

Hepatitis A virus (HAV)

Viral markers:

An anti-HAV IgM = acute infection

Course and prognosis:

The prognosis is excellent, with most pts making a complete recovery

The mortality in young adults is ~ 0.1%, but it increases with age

Death is due to fulminant hepatic necrosis

HAV never progresses to chronic liver disease