Infectious mononucleosis is caused by the Epstein-Barr virus, which in teenagers and young adults may result in acute symptoms that last for several weeks. Fatigue and low energy can linger for several months.
Description
Infectious mononucleosis (IM), also called mono or glandular fever, is commonly transmitted among teenagers and young adults by kissing or sexual activity; hence it is sometimes called the "kissing disease."
By age 35–40, approximately 95% of the population has been infected with the Epstein-Barr virus (EBV) that causes IM. Although anyone can develop mononucleosis, primary (first) infections commonly occur in young adults between the ages of 15 and 35. Symptoms of IM are particularly common in teenagers. In the developed world, 15–20% of people are infected during adolescence and about half of these teens become ill. Among adults, 30—50% of those contracting IM become ill. Although males and females are equally susceptible, in the United States whites are 30-fold more likely than blacks to contract IM.
Typically IM runs its course in 10–30 days. However people with weakened or suppressed immune systems, such as AIDS or organ-transplant patients, are especially vulnerable to potentially serious complications from mononucleosis.
Following IM, the EBV remains dormant (latent) in a few cells in the throat and blood for the remainder of one's life. Periodically the virus may reactivate and be transmitted through saliva; however IM symptoms rarely reoccur.
Causes
Infectious mononucleosis is caused by the first infection with the Epstein-Barr virus, also called herpes virus 4. It is one of the most common human viruses and is endemic throughout the world. EBV is a member of the herpes family of DNA viruses. This family of viruses includes those that cause cold sores, chickenpox, and shingles. Most people are infected with multiple strains of EBV. The different EBV strains are found in separate parts of the body: the circulating lymphocytes (white blood cells), cell-free blood plasma, or the oral cavity.
EBV is spread by contact with viral-infected saliva through coughing, sneezing, kissing, or the sharing of items such as drinking glasses, eating utensils, straws, toothbrushes, or lip gloss. Some evidence indicates that in teens and young adults IM is primarily transmitted by sexual intercourse. However EBV is not highly contagious and household members have only a very small risk of infection unless there is direct contact with infected saliva.
Symptoms
Less than 10% of children under age 10 develop symptoms with EBV infection. The incubation period after exposure to EBV is generally about 7–14 days in children and teens and 30–60 days in adults. An infected person can transmit EBV during this period and for as long as five months after symptoms disappear.
The first symptoms of IM are usually general weakness and extreme fatigue. An infected person may require 12–16 hours of sleep daily prior the development of other symptoms. IM symptoms are similar to cold or flu symptoms:
Fever and chills occurs in about 90% of IM cases. EBV is most contagious during this stage of the illness.
An enlarged spleen, causing pain in the upper left of the abdomen, occurs in about 50–60% of infections.
Sore throat and/or swollen tonsils occurs in less than 50% of mononucleosis infections.
Swollen lymph glands (nodes) in the neck, armpits, and/or groin develop in less than 50% of infections.
These acute symptoms usually last one to two weeks.
Splenic enlargement generally peaks during the fourth week after symptoms appear and then subsides. However an enlarged spleen may rupture in 0.1–0.2% of cases, causing sharp pain on the left side of the abdomen. Additional symptoms of a ruptured spleen include light-headedness, a fast heart rate, and difficulty breathing. Splenic rupture most often occurs within the first three weeks and is the most common cause of death from mononucleosis. It requires immediate medical attention and may require emergency surgery to stop the bleeding.
There are other rare—but potentially life-threatening—complications of mononucleosis:
Neurological complications affecting the central nervous system may develop in 1–2% of infections. Bell's palsy is a temporary condition caused by weakened or paralyzed facial muscles on one side of the face.
The heart muscle may become inflamed.
A significant number of the body's red blood cells or platelets may be destroyed and there may be reduced number of circulating red and white blood cells.
Diagnosis
A variety of conditions can produce symptoms similar to those of IM; however if cold or flu-like symptoms persist for longer than two weeks, mononucleosis may be suspected. Mononucleosis usually is diagnosed by a blood test—called a mono spot test—that measures anti-bodies to EBV. Antibodies may not be detectable until the second or third week after the onset of symptoms. The antibodies peak between weeks two and five and can persist at low levels for up to a year.
About 90% of IM cases show a positive mono spot. Infants and young children do not make the type of anti-bodies that are measured by the mono test. If the mono spot is inconclusive, additional blood tests may be performed that measure an increase in the overall number of white blood cells or an increase in abnormal-appearing lymphocytes that make antibodies against EBV. Other tests can identify at least six specific types of EBV anti-bodies that may be present in the blood.
Treatment
The most effective treatment for infectious mononucleosis is rest, followed by a gradual return to normal activities. If the spleen is enlarged, all contact sports, heavy lifting, and jarring activity such as cheerleading, should be avoided until the enlargement has subsided completely. However exercise such as swimming, running, and other non-contact sports may be resumed. Since mononucleosis can involve the liver, it is important not to consume alcohol.
Although there is no cure for mononucleosis, alternative remedies may help the body to fight the infection and relieve symptoms. Medical practitioners recommend eating four to six small daily meals of unprocessed foods, fresh fruits, and vegetables. It is important to drink plenty of water. Meat, sugar, saturated fats, and caffeinated and decaffeinated drinks should be avoided. Gargling with salt water (one half teaspoon in one cup of warm water) or lozenges may relieve a sore throat.
Vitamins A, B-complex, and C, and magnesium, calcium, and potassium supplements can boost the immune system and increase energy levels.
Herbals
Herbal remedies may help treat mononucleosis, although they are unproven:
astragalus (Astragalus membranaceus) for physical weakness
cleavers (Galium species) to cleanse the lymphatic system
echinacea (Echinacea augustifolia) to boost the immune system
Acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) may relieve symptoms of IM. Aspirin should be avoided because mononucleosis has been associated with Reye's syndrome—a serious illness in children and teens—that is aggravated by aspirin.
Although antibiotics are ineffective for treating EBV, a sore throat from mononucleosis can be complicated by a streptococcal infection, sinus infection, or an abscess or pocket of infection on the tonsils. Such bacterial infections can be treated with antibiotics. A five—day course of corticosteroid anti-inflammatory medications (Prednisone) occasionally is prescribed for breathing difficulties caused by swollen tonsils or lymph nodes in the neck or throat.
Prognosis
Most people with IM return to their normal daily routines within two to three weeks, although it may take up to six months for normal energy levels to return.
A large study suggested that EBV infection increases the risk for Hodgkin lymphoma, a highly treatable cancer of the lymphatic system. About one-third of Hodgkin tumors contain EBV and about one in 1,000 young adults with mononucleosis will develop the cancer, typically about four years after IM.
The development of two other rare types of cancer—Burkitt's lymphoma and nasopharyngeal carcinoma—appears to be associated with EBV. There also is some evidence that people with high levels of antibodies against EBV are at a higher risk of developing multiple sclerosis.
Prevention
Even though IM is not highly contagious, there is no way to completely avoid infection with EBV. In the majority of cases, IM is without symptoms. Furthermore EBV can be transmitted long after the symptoms of infection are gone and, indeed, periodically throughout the remainder of life. Good hygiene, particularly hand washing and the habit of not sharing toothbrushes or eating utensils may help prevent EBV infection.
BOOKS
Decker, Janet M., et al. Mononucleosis. New York: Chelsea House, 2004.
Mononucleosis—A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. Icon Health Publications, 2004.
PERIODICALS
Ambinder, Richard. "Infection and Lymphoma." New England Journal of Medicine 349 (October 2, 2003): 1309–11.
Bates, Betsy. "Mononucleosis Means Delaying Contact Sports. (1-3 Months After Symptom Onset.)" Pediatric News 36 (October 2002): 10–11.
Cherian, Benny. "Latest Thinking on Glandular Fever." Pulse September 15, 2003: 54.
Sitki-Green, Diane L., et al. "Biology of Epstein-Barr Virus During Infectious Mononucleosis>" Journal of Infectious Diseases 189 (February 1, 2004): 483–92.
ORGANIZATIONS
National Institute of Allergy and Infectious Diseases. National Institutes of Health. 6610 Rockledge Drive, MSC 6612, Bethesda, MD 20892-6612. <http://www.niaid.nih.gov>.
OTHER
Epstein-Barr Virus and Infectious Mononucleosis. National Center for Infectious Diseases. Centers for Disease Control and Prevention. October 26, 2002 [cited May 9, 2004]. <http://www.cdc.gov/ncidod/diseases/ebv.htm>.
