Hepatitis: General Principles

Maria Grazia Clemente; Kathleen Schwarz

doi:10.1542/pir.32-8-333

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Maria Grazia Clemente, MD, PhD*
Kathleen Schwarz, MD^†

^*Senior Research Specialist, Pediatric Liver Center, Johns Hopkins School of Medicine, Baltimore, MD.
^†Professor of Pediatrics, Director, Pediatric Liver Center, Johns Hopkins University School of Medicine, Baltimore, MD.

Author Disclosure

Dr Clemente has disclosed that she is coinventor of a diagnostic technique for detecting F-actin immunoglobulin A antibodies. Dr Schwarz has disclosed no financial relationships relevant to this article. This commentary does contain a discussion of an unapproved/investigative use of a commercial product/device.

Objectives

After completing this article, readers should be able to:

Describe the procedure and interpretation of the laboratory evaluation of hepatitis.
Recognize the signs and symptoms of acute and chronic hepatitis.
Describe the immediate and long-term complications of hepatitis.
List the multiple causes of hepatitis in an older child.

Introduction

Hepatitis is a term for inflammatory diseases of the liver, grossly subdivided into infectious and noninfectious, which are characterized by a wide variety of clinical and histologic manifestations, ranging from mild and self-limited to severe and progressive forms leading to liver failure, cirrhosis, or hepatocellular carcinoma.

Laboratory Evaluation

The liver typically has a similar response to any inflammatory injury, with some differences. The injury may be mostly hepatocellular (necrotic) or if it affects primarily the bile ducts and consequently the bile flow, cholestatic. In spite of injury, liver function is not necessarily compromised, and signs of liver failure might not appear until most of the hepatic cells are destroyed in the necrotic process. Disease-specific laboratory tests are available to diagnose the different causes of hepatitis.

Tests Reflecting Hepatocellular Necrosis

Serum aspartate aminotransferase (AST) and serum alanine aminotransferase (ALT) are released from necrotic liver cells into the circulation, causing elevated serum concentrations. Usually, serum ALT values are higher than serum AST values unless cirrhosis already is present. Serum AST and ALT concentrations may rise dramatically with the progression of acute liver damage and subsequently decline to the normal range through depletion of their content in the liver. In the case of very slowly progressing chronic liver injury that results in cirrhosis, ALT and AST …