Acute Viral Hepatitis

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 Acute Viral Hepatitis 

(Hepatitis A and Hepatitis E)

Acute Viral Hepatitis is a systemic infection afecting the liver. Almost all cases of acute viral Hepatitis are caused by one of five viral agents: Hepatitis A (HAV), Hepatitis B (HBV), Hepatitis C (HCV), the HBV-associated delta agent or Hepatitis D Virus (HDV) and Hepatitis E (HEV). All these human hepatitis viruses are RNA viruses, except for hepatitis B, which is a DNA virus but replicates like a retrovirus. While hepatitis A and E are often the cause for sporadic or outbreaks of hepatitis, hepatitis B and C can either clear spontaneously or can lead to chronic infection

Mode of Transmission 


Hepatitis A: HAV is a non-enveloped RNA virus belonging to the picornavirus family, with four genotypes belonging to one serotype. This agent is transmitted almost exclusively by the fecal-oral route. It is an outbreak prone disease with an incubation period of around four weeks. Person-to-person transmission of HAV is enhanced by poor personal hygiene and overcrowding. Excretion in the stool occurs after seven-14 days of onset of the clinical illness and is diagnostic of an acute HAV infection. No carrier state has been identified. Hepatitis E: HEV is a non-enveloped single stranded RNA virus belonging to Hepevirus. This agent is transmitted almost exclusively by the fecal oral route. It is an outbreak prone disease with an incubation period of around two-ten weeks


Complications 

Hepatitis A: The case fatality is extremely low (~0.1%) but increases in advanced age and in the presence of underlying debilitating diseases. Hepatitis E: Acute liver failure may be seen in a small proportion (0.4-5%) usually higher in pregnant women, normally within a week of onset of symptoms. Persons with pre-existing liver disease and immunosuppression are also at a higher risk for severe diseases following HEV infection.

Signs and Symptoms


Hepatitis A: The incubation period for HAV ranges from 15-45 days. The prodromal symptoms of Aacute Viral Hepatitis are systemic and quite variable. Constitutional symptoms of lowgrade fever, anorexia, nausea and vomiting, fatigue, malaise, arthralgias, myalgias, headache, photophobia, pharyngitis, cough and coryza may precede onset of jaundice by one-two weeks. Dark urine and clay colored stools may be noticed by the patient one-five days before the onset of clinical jaundice. With the onset of clinical jaundice, the constitutional prodromal symptoms usually diminish. The liver becomes enlarged and tender and may be associated with right upper quadrant pain and discomfort. During recovery phase the constitutional symptoms disappear, but usually some liver enlargement and abnormalities in liver biochemical tests are still evident. Hepatitis E: The illness usually begins after an incubation period of 14-70 days as an acute viral syndrome with mild fever, marked loss of appetite, aversion to food, upper abdominal discomfort, nausea and/vomiting. Within a few days after onset of these non-specific symptoms, onset of jaundice is visible and non-specific symptoms decline. Jaundice usually persists for one-six weeks and then gradually resolves. In children, most HEV infections occur without any symptom or as a mild illness without jaundice. In contrast, in adults, acute Hepatitis E may have a prolonged cholestatic phase with significant itching







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