Types of Hepatitis for the Physician Assistant Exam
On the Physician Assistant Exam (PANCE), you’ll likely be asked to discern not only the pattern of liver injury based on the labs and clinical exam but also the cause and prognosis of that cause. Many of the causes of hepatitis that you’ll see on the test are viral hepatitis.
Hepatitis A is a viral form of hepatitis that has a fecal-oral route of transmission and is usually spread through eating contaminated food or water, or coming into direct contact with a person who has hepatitis A. This usually gets better on its own and doesn’t turn into a chronic form of hepatitis. IgM antibodies to hepatitis A indicate an acute infection. No specific treatment is needed, other than avoiding other hepatotoxins.
Hepatitis A usually occurs in younger individuals, most commonly in people who travel to countries where it may be endemic.
If you’re traveling to an area where there’s a high prevalence of this condition, then vaccination with a hepatitis A vaccine is recommended.
Anyone with any other form of hepatitis should be immunized to hepatitis A.
Hepatitis B is a viral form of hepatitis that’s transmitted through body fluids, usually from sexual contact or a blood transfusion. It can also be transmitted through sharing needles.
As with other forms of hepatitis, most people actively infected with hepatitis B feel tired and weak, and may have jaundice. Hepatitis B can present acutely and resolve. In some people, it develops into a chronic form. In a few people, it can turn into fulminant liver failure.
For the test, be familiar with the antibody and antigen tests for hepatitis B:
Envelopes: There are two envelope tests: the hepatitis B envelope antigen and the hepatitis B envelope antibody. The hep B envelope antigen means that the virus is actively replicating and that the person is highly infective. The hep B envelope antibody means that the virus is replicating and the person is infective but to a lesser degree.
Surface dudes: You again have two surface tests: the hepatitis B surface antigen and the hepatitis B surface antibody. The hep B surface antigen means that the person is still dealing with an active infection. The hep B surface antibody is what you test for after someone has been immunized against hep B. The surface antibody also means the person is immune to any infection.
Core: In one special case, the hep B surface antigen isn’t the first antigen positive in the setting of an infection. Sometimes the body does such a good job of clearing the virus initially that the only test that’s positive is the hep B core antibody. Because the infection is acute, this is an IgM antibody, not an IgG antibody.
In many people, hepatitis B resolves, and they develop antibodies against it. In some cases, someone develops a chronic hepatitis secondary to hep B. If the hepatitis B surface antigen stays elevated for 6 months or longer, that person is said to have a chronic hepatitis. Usually the ALT level stays elevated in that regard.
Hep B is a DNA virus, so you can always order a quantitative hepatitis B DNA level to see how much the virus is replicating. Chronic hepatitis B is associated with the development of hepatocellular carcinoma; often you need to order a liver biopsy.
Hepatitis D is next, ahead of hepatitis C. This isn’t because we’re rebels who want to go out of order but because hepatitis D is associated with hepatitis B. A person can be infected with both B and D at the same time, or hepatitis D can infect someone already diagnosed with hepatitis B.
Three things you need to know about hepatitis D:
It can make the hepatitis B much worse.
It’s associated with many of the same risk factors as hepatitis B, especially the part about sharing needles.
It’s also known as the delta agent and can’t replicate without hepatitis B.
Hepatitis C is like hepatitis B in a couple of ways. First, the route of transmission is the same, and a primary way that hep C spreads is through blood transfusions. Like hep B, hep C can be an acute hepatitis that resolves, develops into a chronic hepatitis, or develops into fulminant liver failure.
Unlike hep B, hep C is an RNA virus, not a DNA virus. And unlike hep B, you don’t have six freakin’ antibodies to worry about. If a person has hep C, the antibodies to hep C are positive. Hepatitis C antibodies don’t show up until about 4 months after the initial exposure.
You need to quantitate the hep C RNA to determine the viral load. If the viral load is significant, then the person has an ongoing infection. You can follow the viral load and the ALT levels over time. Sometimes, the liver can clear the viral load with resolution of the infection. Most people develop a chronic infection and thus is associated with development of liver cancer.
The therapy for hep C involves pegylated interferon and ribavirin. Both of these can have serious side effects. The interferon can cause a flu-like illness as well as depression. Ribavirin can wreak havoc on the blood count and cause pancytopenia.
Other types of hepatitis
Epstein-Barr virus causes infectious mononucleosis. It’s also associated with hepatitis. Liver function tests can be associated with mononucleosis at the time of diagnosis. This virus also causes a hemolytic anemia. The treatment is supportive, the key being to recognize the initial presentation. Remember that with mono, one can have cervical adenopathy, exudative pharyngitis, and splenomegaly.
Cytomegalovirus-induced hepatitis is a rarer sort of infection. Almost everyone already has IgG antibodies to the cytomegalovirus. Cytomegalovirus can cause hepatitis, and it can also cause colitis or retinitis. The treatment is either ganciclovir (Cytovene) and/or valganciclovir (Valcyte).