HEPATITIS A VIRUS (HAV)
HAV accounts for 20% to 25% of cases of clinical hepatitis in the developed world. Hepatitis A, formerly called infectious hepatitis, is caused by an RNA virus of the Enterovirus family. The mode of transmission of this disease is the fecal–oral route, primarily through the ingestion of food or liquids infected by the virus. The virus has been found in the stool of infected patients before the onset of symptoms and during the first few days of illness. Typi-cally, a child or a young adult acquires the infection at school by poor hygiene, hand-to-mouth contact, or close contact at play. The virus is carried home, where haphazard sanitary habits spread it through the family. It is more prevalent in developing countries or in areas with overcrowding and poor sanitation. An infected food handler can spread the disease, and people can contract it by consuming water or shellfish from sewage-contaminated waters. Outbreaks have occurred in day care centers and institutions for the developmentally delayed because of lapses in hygiene. It is rarely, if ever, transmitted by blood transfusions. Hepatitis A can be transmitted during sexual activity; this is more likely with oral–anal contact, anal intercourse, and a greater number of sex partners (CDC, 2002).
The incubation period is estimated to be 15 to 50 days, with an average of 30 days (O’Grady et al., 2000). The illness may be prolonged, lasting 4 to 8 weeks. It generally lasts longer and is more severe in those older than 40 years of age. Recovery is the rule; hepatitis A rarely progresses to acute liver necrosis or fulmi-nant hepatitis, terminating in cirrhosis of the liver or death. Hepatitis A confers immunity against itself, but the person may contract other forms of hepatitis. The mortality rate of hep-atitis A is approximately 0.5% for those under 40 years of age and increases to 1% to 2% for those over 40. No carrier state exists, and no chronic hepatitis is associated with hepatitis A. The virus is present only briefly in the serum; by the time jaundice occurs, the patient is likely to be noninfectious (O’Grady et al., 2000).
Many patients are anicteric (without jaundice) and symptomless. When symptoms appear, they are of a mild, flu-like upper respi-ratory tract infection, with low-grade fever. Anorexia, an early symptom, is often severe. It is thought to result from release of a toxin by the damaged liver or by failure of the damaged liver cells to detoxify an abnormal product. Later, jaundice and dark urine may become apparent. Indigestion is present in varying degrees, marked by vague epigastric distress, nausea, heartburn, and flat-ulence. The patient may also develop a strong aversion to the taste of cigarettes or the presence of cigarette smoke and other strong odors. These symptoms tend to clear as soon as the jaundice reaches its peak, perhaps 10 days after its initial appearance. Symptoms may be mild in children; in adults, the symptoms may be more severe and the course of the disease prolonged.
The liver and spleen are often moderately enlarged for a few days after onset; otherwise, apart from jaundice, there are few physical signs. Hepatitis A antigen may be found in the stool a week to 10 days before illness and for 2 to 3 weeks after symptoms appear. HAV antibodies are detectable in the serum, but usually not until symptoms appear. Analysis of subclasses of immunoglobulins can help determine whether the antibody represents acute or past infection.
A number of strategies exist to prevent transmission of HAV. Patients and their families need to be made aware of these and encouraged to consider them if recommended by their primary health care provider.
In February 1995, the Food and Drug Administration ap-proved the first vaccine against hepatitis A for use in the United States. Effective and safe HAV vaccines include Havrix and Vagta (Koff, 2001). It is recommended that the two-dose vac-cine be given to adults 18 years of age or older, with the second dose 6 to 12 months after the first. Protection against hepatitis A develops within several weeks after the first dose of the vac-cine. Children and adolescents 2 to 18 years of age receive three doses, with the second dose 1 month after the first and the third dose 6 to 12 months later. It is estimated that protection against hepatitis A may last for at least 20 years (CDC, 1999). No country has as yet recommended universal vaccination against hepatitis A. Hepatitis A vaccine is recommended for travelers to locations where sanitation and hygiene are unsatisfactory. Vac-cination is also recommended for those from other high-risk groups (homosexual men, injection/intravenous drug users, staff of day care centers, and health care personnel) (CDC, 2002). The vaccine has also been used to interrupt community-wide out-breaks. As with other vaccinations, precautions must be taken to ensure prevention, detection, and treatment of hypersensitivity reactions to the vaccine.
Type A hepatitis can be prevented in those not previously vaccinated by the intramuscular administration of globulin dur-ing the incubation period, if given within 2 weeks of exposure. This bolsters the person’s antibody production and provides 6 to 8 weeks of passive immunity. Immune globulin may suppress overt symptoms of the disease; the resulting subclinical case of hepatitis A would produce active immunity to subsequent episodes of the virus.
Immune globulin is also recommended for household members and sexual contacts of people with hepatitis A. Susceptible people in the same household as the patient are usually also infected by the time the diagnosis is made and should receive immune globulin. Day care center and restaurant workers with exposure to or infected with hepatitis A should also receive immune globulin to provide passive immunity (CDC, 1999). Although rare, systemic reactions to immune globulin may occur. Caution is required when anyone who has previously had angioedema, hives, or other allergic reac-tions is treated with any human immune globulin. Epinephrine should be available in case a systemic, anaphylactic reaction occurs.
Preexposure prophylaxis is recommended for those traveling to developing countries and settings with poor or uncertain sanita-tion conditions but who do not have sufficient time to acquire protection by administration of hepatitis A vaccine (CDC, 1999). Community interventions for preventing hepatitis A are outlined in Chart 39-6.
Bed rest during the acute stage and a diet that is both acceptable to the patient and nutritious are part of the treatment and nurs-ing care. During the period of anorexia, the patient should receive frequent small feedings, supplemented, if necessary, by IV fluids with glucose. Because this patient often has an aversion to food, gentle persistence and creativity may be required to stimulate the appetite. Optimal food and fluid levels are necessary to counter-act weight loss and slow recovery. Even before the icteric phase, however, many patients recover their appetites (Chart 39-7).
The patient’s sense of well-being as well as laboratory test re-sults are generally appropriate guides to bed rest and restriction of physical activity. Gradual but progressive ambulation seems to hasten recovery, provided the patient rests after activity and does not participate in activities to the point of fatigue.
The patient is usually managed at home unless symptoms are se-vere. Therefore, the nurse assists the patient and family in coping with the temporary disability and fatigue that are common in hepatitis and instructs them to seek additional health care if the symptoms persist or worsen.
The patient and family also need specific guidelines about diet, rest, follow-up blood work, and the importance of avoiding alcohol, as well as sanitation and hygiene measures (particularly hand washing) to prevent spread of the disease to other family members.
Specific teaching to patients and families about reducing the risk of contracting hepatitis A includes good personal hygiene, stressing careful hand washing (after bowel movements and be-fore eating), and environmental sanitation (safe food and water supply, as well as effective sewage disposal).