Introduction
Hepatitis A is usually a self-limiting viral illness spread through the faecal-oral route that primarily causes inflammation of the liver. It usually presents with flu-like symptoms, right upper abdominal pain and nausea, diarrhoea and vomiting. Jaundice can later develop. There is normally no specific treatment for hepatitis A but it is a notifiable disease, and immunisation is also recommended if travelling to high-risk countries.
Epidemiology
- Incidence: 1.20 cases per 100,000 person-years
- Peak incidence: 40-50 years
- Sex ratio: more common in males 2:1
| Condition | Relative incidence |
|---|---|
| Hepatitis C | 13.33 |
| Hepatitis A | 1 |
| Hepatitis B | 0.67 |
| <1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Clinical features
Hepatitis A is usually a self-limiting viral illness. In some cases, patients may remain asymptomatic (especially children under 5-years of age). There are usually four stages of infection:
- Incubation phase
- This is the time period between coming into contact with the virus and developing symptoms.
- Approximately 28 days (range 15 to 50 days).
- Prodromal phase
- This refers to period where early symptoms develop before onset of fully-developed acute illness.
- Typically lasts 3 to 10 days.
- Symptoms include flu-like illness, gastrointestinal symptoms (such as appetite loss, right upper abdominal pain, nausea, vomiting and diarrhoea) and low-grade temperatures up to 39oC.
- Usually no specific signs on examination.
- Icteric phase
- This refers to period of established infection.
- Typically lasts 1 to 3 weeks, but can last up to 12 weeks.
- Symptoms include jaundice, pale stools and dark urine, pruritis (40% of those with jaundice), fatigue, anorexia, vomiting.
- There may be hepatomegaly (85%), splenomegaly (15%) and hepatic tenderness on examination.
- Convalescent phase
- This refers to period of recovery after acute illness.
- May last up to 6 months.
- Features include muscle weakness, malaise, anorexia and hepatic tenderness.
Investigations
If hepatitis A is suspected, current NICE CKS guidance recommends the following investigations should be performed:
Public Health England (PHE) define possible cases of hepatitis A using a case definition, defined as:
Probable and confirmed cases are then defined by PHE using this case definition as in the table below:
- Hepatitis serology
- First line is the PCR test for hepatitis A RNA.
- If this is not available, hepatitis A virus immunoglobulin M (HAV-IgM) and hepatitis A virus immunoglobulin G (HAV-IgG) blood tests should be performed. These should be repeated in one to two weeks if taken within ten days of symptom onset.
- Positive HAV-IgM and positive HAV-IgG suggests acute hepatitis A infection.
- Negative HAV-IgM and positive HAV-IgG suggests past hepatitis A infection or immunity.
- A high IgG reactivity and a moderate level of IgM suggests recent infection rather than acute infection.
- Liver function tests
- Typically shows significantly raised alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels.
- Bilirubin may be elevated, as well as pro-thrombin time.
- Alkaline phosphatase may be elevated but generally less than 2 times upper limit of normal.
Public Health England (PHE) define possible cases of hepatitis A using a case definition, defined as:
- A person presenting with acute illness with onset of suggestive features and jaundice; or
- A person presenting with acute illness with onset of suggestive features and raised AST levels.
Probable and confirmed cases are then defined by PHE using this case definition as in the table below:
| Probable case | Confirmed case |
|---|---|
| Meets case definition (above) and has had contact with a confirmed hepatitis A case | Meets case definition and has HAV-IgM and HAV-IgG antibodies |
| Meets case definition and has HAV-IgM antibodies | Has hepatitis A RNA (HAV-RNA) detected regardless of clinical features |
| Asymptomatic and no recent immunisation but has anti HAV-IgM and has had contact with confirmed hepatitis A case |
Management
The majority of hepatitis A cases are usually mild and self-limiting and require no specific treatment. Severely unwell patients should be admitted to hospital.
For those who have been in contact with someone with known hepatitis A infection, the local health protection unit should be contacted for advice on further management including vaccination.
- Generally symptom management is all that is required. Current NICE CKS guidance advises a patient should:
- Rest and stay hydrated.
- Use pain relief as required, with dose adjustment if liver impairment.
- Use anti-emetics as required, including metoclopramide or cyclizine unless impaired liver function.
- For itch, use simple measure such as loose clothing and avoiding hot baths and showers and chlorphenamine if required unless impaired liver function.
- Avoid alcohol.
- Ensure good personal hygiene practices and avoid food preparation, and sexual intercourse for 7 days after symptom onset.
- Patients should avoid work or school for 7 days after symptom onset.
- Patients should be followed-up every 1-2 weeks, and liver function tests repeated until amino-transferase levels are within normal levels.
For those who have been in contact with someone with known hepatitis A infection, the local health protection unit should be contacted for advice on further management including vaccination.
Complications
The majority of patients with hepatitis A make a full recovery within six-months.
- Rarely (15%) of patients may have a relapsing course of illness lasting several months.
- Very rare complications (0.4%) include fulminant liver failure and other rare complications. Other rare complications include:
- Acalculous cholecystitis
- Pancreatitis
- Aplastic anaemia
- Post-viral encephalitis
- Reactive arthritis.