The A, B, Cs of Viral Hepatitis

Air Line Pilot, September 2001, p. 24
By Quay Snyder, MD, MSPH, and Tom Yasuhara, MD, MPH

The term "hepatitis" implies an inflammation and impaired function of the liver. Among the many causes of hepatitis are several infectious agents, toxic substances including alcohol and medicines, and mechanical blockages of the liver’s drainage system. Most commonly, the layperson’s use of the word hepatitis implies one of the infectious virus-caused diseases. Our discussion of this subject is confined to a few of the more common infectious causes.

The liver is a large organ located in the upper right quadrant of the abdomen. Tremendous amounts of blood pass through the liver to be filtered and detoxified. In broad terms, the liver is similar to a recycling center for the body.

The liver and the kidney process most of the bloodborne toxins in the body and either eliminate the hazards or convert them into a less hazardous form. The liver eliminates hazards and passes them into the stool, while the kidney eliminates hazards into the urine.

Most medications are "metabolized" or changed to a different form in the liver. These different forms of a medication may be either more or less active than the original form.

The liver also processes nutrients and helps convert food to nutrients. In this role, the liver may convert sugars into more complex substances that the body, using insulin, will use slowly. It also converts dietary cholesterol and fats into the healthy and unhealthy forms of cholesterol. The liver helps the body digest fat by producing bile which is stored in the adjacent gall bladder.

The liver is an essential organ for the body’s daily functioning.

Small virus particles may infect the liver and impair its ability to function. When this occurs, individuals may feel acutely fatigued, feverish, and nauseated, and lose their appetite. The urine may become very dark as the body tries to excrete a breakdown product of blood called bilirubin through the urine instead of through the normal pathway of the liver into the stool. The skin may turn yellow (jaundice) due to bilirubin deposition in the skin.

In addition to the illness caused in the individual by hepatitis, a significant danger lies in its ability to be transmitted to other people.

Chronic forms of hepatitis that lead to liver failure and liver cancer may develop. Of the many forms of infectious hepatitis, the most common are hepatitis A, hepatitis B, and hepatitis C.

Hepatitis A infects approximately 180,000 people in the United States each year, and 33 percent of the U.S. population will be infected during their lifetime. The virus is found in contaminated food, water, milk, and shellfish. It is primarily related to overcrowding, poor sanitation, and poor personal hygiene. Contamination occurs when the virus excreted in the stool of an infected individual gets into drinking water or food. The most common scenarios occur with poor water processing facilities and poor hand washing in preparing food. A single individual can infect hundreds of people in a very short period of time. Major outbreaks have recently occurred in the United States. Raw seafood, particularly oysters, which concentrate wastes dumped into the ocean, may also transmit the condition without an infected individual directly handling the food.

Hepatitis A may range in severity from a person’s having almost no symptoms to being very ill. Symptoms include fatigue, fever, chills, headaches, nausea, vomiting, weight loss, jaundice, and darkened urine as discussed earlier. The condition is usually not fatal in otherwise healthy individuals. Symptoms occur from 15 to 45 days after the exposure to the virus. The symptoms usually last from one to 2 weeks with complete recovery within 2 months. No specific treatment exists other than supportive care and avoiding such liver toxins as alcohol. Once recovery is complete, the individual gains some immunity against future infection by that strain of virus.

The diagnosis is made by testing the blood for antibodies to the hepatitis A virus and followed by monitoring blood enzymes from the liver. Elevated liver enzymes generally return to normal as the individual recovers, although this is not always the case.

Very rarely, death from hepatitis A results from a fulminant infection, a very aggressive and often fatal form of the disease.

Fortunately, hepatitis A is usually easy to prevent. Exceptions can occur when a person unsuspectingly consumes hepatitis-A–contaminated food in an area in which transmission risk is usually very low (e.g., North America or Western Europe).

When traveling to areas with poor hygiene, using the same steps one would use to avoid traveler’s diarrhea are fairly effective in preventing hepatitis A.

You should avoid uncooked foods and eat only fruits and vegetables that you personally peel. Avoid water or ice. Even "bottled" water may be contaminated if not obtained from a reliable clean source.

In the past, people traveling to high-risk areas were given "gamma globulin" or immune serum globulin, which gave a partial temporary immunity. These painful shots conveyed passive immunity, a transient protection gained from the serum of individuals who had recovered from an earlier infection.

Recently, vaccines for hepatitis A (Havrix and Vaqta) have been developed. They are much more effective in conveying a lifelong active (produced by your own body) immunity. The vaccine series is given as a two-shot series, with the second shot given 6 months after the first for adults. Significant immunity occurs within several weeks of the first immunization. These shots are usually very well tolerated and relieve the need for repeated painful gamma globulin injections. See the practice guidelines recommended by the Advisory Committee on Immunization Practices for preventing hepatitis A.

The vaccine is highly recommended for individuals traveling to high-risk areas. Information concerning high-risk areas of the world may be obtained from the Centers for Disease Control and Prevention.

Household members who come into contact with an individual who is infected with hepatitis A should consider immunization and administration of immune globulin, and the individual should practice excellent personal hygiene and avoid preparing food to significantly decrease the risk of transmitting the disease.

Hepatitis B

Hepatitis B is a bloodborne infection transmitted through contaminated body fluids. It annually affects 0.1 to 0.5 percent (128,000+) of low-risk people in the United States and 200 million individuals worldwide. Hepatitis B is the primary cause of liver cancer worldwide and is responsible for more cancer deaths than any other agent in developing countries. In areas that have adopted Western lifestyles, hepatitis B is less prevalent, and cigarettes are a much more common cause of other fatal cancers. People at risk for hepatitis B include intravenous drug users, those with high-risk sexual behavior, infants of mothers with hepatitis, and health care workers exposed to infected blood and body fluids. Blood used for transfusion in the United States is screened for infectious hepatitis.

Hepatitis B also has a wide range of symptoms but is a potentially much more serious disease than hepatitis A. As many as 10 percent of infected people, more than 1 million in the United States, develop a chronic infection that is contagious (90 percent of infected infants). This condition also puts the individual at risk for hepatic carcinoma (liver cancer). A small percentage of people develop chronic, active hepatitis, a situation in which recovery is incomplete. This may require long-term treatment with medication that some people will tolerate poorly and may disqualify a pilot from flying. Finally, approximately 0.1–1.0 percent of those infected individuals develop fulminant infection. Nearly 6,000 deaths per year in the United States are attributed to hepatitis B.

Immunizations for hepatitis B (Engerix-B and Recombivax-HB) are also available in a three-shot series given as an initial dose followed by doses at 1 and 6 months. For those not engaging in high-risk behavior, the risk of acquiring the disease is not significant. Those who may be exposed to blood or body fluids of infected persons, usually through sexual contact, should receive the immunization series.

Chronically infected individuals may benefit from treatment with interferon. The treatment requires frequent injections and is often accompanied by a flu-like syndrome. This treatment must be reported to and cleared by the FAA before an individual may fly.

Hepatitis C is a relatively newly discovered form of liver disease that has recently received considerable public attention and media coverage. The virus was not discovered until 1988 and reliable testing did not exist until 1992. Unfortunately, the virus has infected many people before that time. Approximately 4 million Americans (2 percent of the population) are infected with hepatitis C, and 10,000 will die of the disease each year. The current medical costs in the United States associated with treating the disease are greater than $600 million annually.

Worldwide, 170 million people are infected. Like hepatitis B, hepatitis C is transmitted through contaminated blood and body fluids. High-risk behaviors such as intravenous drug use and unprotected sexual intercourse with infected individuals account for most of the transmission. Blood transfusions before improved testing of the blood supply, which began in 1992, account for about 7 percent of the infections.

The clinical picture of hepatitis C, at least in the early stages, is quite different from hepatitis A or B. People infected with hepatitis C rarely have any symptoms for 10 to 30 years. They appear perfectly healthy, yet carry the disease and can infect others. Approximately 80 percent of people infected will develop chronic inflammation of the liver in 10 to 30 years, and 20 percent will develop cirrhosis that destroys the liver, resulting in the need for a liver transplant to prevent death. For a wealth of articles on hepatitis C, see the Medscape hepatitis C Resource Center at http://www.medscape.com/Medscape/features/ResourceCenter/HepC/public/RC-index-HepC.html.

Other forms of hepatitis caused by viruses include hepatitis D, E, and G. Transmission for most is similar to that of hepatitis B—through infected blood. Hepatitis E is transmitted by contact with infected stool similar to hepatitis A.

No vaccine exists for hepatitis C. Prevention is limited to avoiding blood and body fluids of infected individuals. The blood supply is now tested for hepatitis C, but individuals who received blood transfusions before 1992 may consider getting a simple blood test to screen for the disease. Those who are infected should avoid substances that may harm the liver, particularly alcohol, but also some medications.

Some people advocate nutritional therapy to boost the immune system, though this has not been studied enough to be of proven benefit.

Symptomatic people infected with hepatitis C may benefit from treatment with interferon-alpha and ribavirion, a recently FDA-approved combination for the condition. The treatment is expensive and improves symptoms in only some individuals. It does not cure the disease and has significant side effects—fatigue, fever, muscle aches, flu-like symptoms.

The FAA recently changed its policy and now will certify pilots using alpha interferon for the treatment of hepatitis C. A minimum observation period of 3 weeks is required before submitting requests for medical certification to the FAA. Pilots who do not have any significant side effects or serious consequences of hepatitis may have their medical certificates reinstated. Periodic reports to the FAA are required to maintain medical certification.

The acute forms of hepatitis are disqualifying for flying duties. If the condition resolves spontaneously, an individual may return to flying after clearance from the treating physician and when the pilot feels confident he or she can perform all required duties. This condition may be reported to the FAA at the time of the pilot’s next FAA physical examination.

Chronic hepatitis conditions requiring the use of medication must be cleared by the FAA before the pilot may exercise the privileges of the aeromedical certificate. Certification is dependent upon minimal symptoms from the disease and tolerance of the medications. Periodic reports from the treating physician are required for continued certification.

The term hepatitis covers a broad spectrum of diseases affecting the liver. Infectious forms of hepatitis are relatively common and can cause serious illness and death. Prevention is the key to avoiding the consequences of the disease.

Medical certification of pilots with hepatitis depends on the seriousness of the disease and the method of treatment. After review and approval of appropriate medical documentation, the FAA may medically certify pilots whose disease is well controlled and who tolerate medication well. Many credible resources for additional information on hepatitis exist.