The term hepatitis refers to inflammation of the liver. From toxins to infections, the differential diagnosis is quite broad, however, much can be learned from history which can narrow down the differential. Recent travel, medication overdose, history of alcoholism, IV drug use… History can provide a significant amount of valuable information. This Daily Doodle features one of the infectious causes of hepatitis – Hepatitis C.

There are five categories of viral hepatitis: A, B, C, D, and E. All the hepatitis viruses are RNA viruses except for hepatitis B, which is an enveloped DNA virus. Hepatitis C (HCV) is the most prevalent hepatitis virus worldwide and there are at least six distinct genotypes as well as over 50 subtypes within those genotypes.

Unlike HAV and HEV which are excreted in the feces and transmitted by the fecal-oral route (water/food transmitted infections), HBV, HCV and HDV are transmitted parenterally. Transmission of HCV is mainly through blood, however, it can be transmitted through sexual contact. Vertical transmission (from mother to fetus) is quite low. HCV was the main cause of post-transfusion hepatitis prior to 1992, however, routine screening of blood donors has greatly reduced this risk. Currently, HCV is the most common cause of hepatitis in IV drug users.

The intubation period for HCV is 1-5 months with the average being 7-8 weeks. Patients with acute HCV are typically asymptomatic. They may present with nausea, jaundice, dark urine and right upper quadrant pain. Other symptoms include anorexia, pruritus, mood disturbances and low-grade fever and chills.

Laboratory tests show a variable elevation in aminotransferase levels which can be greater than 10-20 times the upper limit of normal. Bilirubin levels may also be elevated.

Diagnosis of acute HCV involves testing for the presence of HCV RNA and antibodies in the blood.

Serologic Markers for HCV include:

1. Anti-HCV – antibodies to a group of recombinant HCV peptides. Positive on average 12 wks after exposure; not protective. Antibody testing by enzyme linked immunosorbent assay (ELISA).
2. HCV RNA – infectious viral genomic material – reflects ongoing infection, level inversely linked to treatment response. Tested through polymerase chain reaction (PCR) and can be first detectable in serum within days to 8 weeks following exposure.

For a patient presenting after a known exposure to HCV, such as a needle-stick injury, the following tests are recommend by Uptodate [4]:

• Immediately/baseline: Anti-HCV antibody, HCV RNA, and serum aminotransferases
• Four weeks after exposure: HCV RNA and serum aminotransferases
• Three months after exposure: Anti-HCV antibody, HCV RNA, and serum aminotransferases
• Six months after exposure: Anti-HCV antibody

This Daily Doodle also shows hepatocellular carcinoma (liver cancer), a potential risk of hepatitis C. The risk of developing hepatocellular carcinoma once cirrhosis has developed is approximately 0-3% a year and the risk is greater for genotype 1b [4].

References:

1. S. Agabegi and E. Agabegi. “Step-Up to Medicine”. Third Edition. Lippincott Williams and Wilkins. 2013
2. Fauci, Braunwald, Kasper, Hauser, Longo, Jameson, Loscalzo. “Harrison’s Principles of Internal Medicine”. 17th Edition. McGraw Hill Medical. 2008.
3. Andreoli, Carpenter, Griggs, Benjamin. “Cecil Essentials of Medicine”. 7th edition. Saunders Elsevier. 2007
4. Reinhard and Stefan. “Clinical manifestations, diagnosis, and treatment of acute hepatitis C in adults”. Uptodate. July 2014: http://www.uptodate.com/contents/clinical-manifestations-diagnosis-and-treatment-of-acute-hepatitis-c-in-adults