Mono (Infectious Mononucleosis)

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What is mono?

Mono (infectious mononucleosis) is a contagious viral illness most commonly caused by the Epstein-Barr virus (EBV). It affects the respiratory tract, liver, and spleen. Mono most commonly occurs in persons15-35 year old. The virus may be in the body for 4-10 weeks before symptoms develop. Initially the person may feel rundown, have a slight headache, and experience a loss of appetite. After 3-5 days, acute symptoms may appear, including sore throat; fatigue; swollen glands in the neck, armpits, and groin; fever; muscle aches; and occasionally a rash. The spleen in the upper left abdomen may be enlarged and tender and liver enzyme levels may increase. There may be difficulty breathing due to enlarged tonsils and other tissue. Not everyone with mono experiences every symptom and the level of severity will vary from person to person.

How do I know if it's mono?

The same symptoms can be caused by other illnesses so it is advisable to visit your health care provider to have them evaluated and possibly have a mono test done. It may be 5 to 7 days into the illness before mono antibodies develop to a detectable level in the blood. If you test negative initially but your symptoms persist, you may want to have the test repeated. Other more specific tests can also be ordered.

How is mono spread?

Infectious mononucleosis is known as the "kissing disease" because it is spread through saliva by intimate contact (coughing, kissing, sharing of food). Do not share drinking glasses, eating utensils, or cigarettes. The illness is most contagious when there is fever. It may be impossible to know who passed the infection to you because not everyone who is infected with EBV will develop classic mono. However, the infected person is still able to unknowingly spread the illness to others. Quarantine of people who have mono is not necessary because it is not highly contagious. People with mono rarely spread the disease to roommates or friends with whom they have only casual contact. The risk of contracting mono does increase with stress, fatigue or exhaustion, or recent illness. If you have mono, you should also avoid contact with persons with immune deficiencies (anyone with AIDS, cancer, on chemotherapy, or anti-rejection drugs) because they are more susceptible to catching the illness. Washing your hands thoroughly and often with soap and water or an alcohol-based hand rub remains one of the best ways to prevent the spread of infection.

How long does mono last?

The length of the illness will differ from person to person. About a third of those with mono never even need to stay in bed because their illness is so mild. Most people who have mono are up and around again within two weeks or less. Occasionally, however, more bed rest is required and complications may develop. Contact sports and strenuous exercise may be discouraged for one to two months after getting mono but other activities can be resumed earlier. People who are infected with EBV virus are usually immune from ever getting the virus again.

What is the treatment for mono?

Treatment usually includes rest. It is not always necessary to stay in bed, but adequate rest is essential. A pain reliever such as acetaminophen (e.g., Tylenol) may be taken for sore throat discomfort, fever, and muscle aching. Aspirin should be avoided because there is a slight risk of a rare complication (Reye's Syndrome) associated with inflammation of the brain and liver when aspirin is used to treat symptoms of a viral illness. Aspirin and ibuprofen (e.g., Advil) both could potentially aggravate a gastrointestinal bleeding problem.

Gargling with warm salt water (1/2 tsp. salt to an 8 ounce glass of water), an antacid solution, or sucking on hard candy may help soothe a sore throat. Avoid scratchy or hard, crunchy foods.

The EBV virus may cause some mild liver abnormalities but your liver function should return to normal as you recover. However, you are advised not to drink alcohol while you are ill and to avoid it for a month or so after you recover. People who become jaundiced (yellow skin, eyes, dark urine) need to avoid alcohol for as long as a year after having mono because of the possible damage to the liver cells.

If your spleen is enlarged, your health care provider may recommend a stool softener to prevent constipation. This lessens the chance of the spleen rupturing as a result of straining to have a bowel movement. Eating a balanced diet, high in fruits and vegetables is also advised. Increasing your fluid intake is important to help prevent dehydration.

If you develop excessive swelling of the throat or rupture of the spleen is impending, steroids may be prescribed. Steroids are not a routine treatment for infectious mononucleosis.

Antibiotics are not effective in treating viral illnesses, including infectious mononucleosis. Your own immune system should be able to fight the infection if you take good care of yourself while you are ill. The antibiotics ampicillin and amoxicillin should especially be avoided due to a high incidence of rash with mono.

What complications can occur with mono?

Mono hepatitis (inflammation of the liver and jaundice) occasionally develops. Persons with mono hepatitis are often sicker and may require hospitalization, especially if nausea, vomiting, and dehydration occur. Women who are taking oral contraceptives may be taken off the birth control pills until the mono hepatitis resolves.

Rupture of the spleen is a rare but serious complication of mono. Indications of a ruptured spleen include pain that starts in the left upper abdomen, radiates to the top of the left shoulder, is worse with inhaling, and then spreads across the whole abdomen. Immediate medical attention is required. Half of the ruptured spleens that occur in mono patients are the result of direct blows to the spleen or physical exertion.

Strep infections (Group A streptococcal) of the throat and tonsils occur in about eight percent of mono patients. Antibiotics can treat the strep infection, but they are not effective against EBV.

What should I expect in recovering from mono?

You will need to protect your immune system's functioning by getting adequate rest, eating well, and taking good care of yourself in general. Even though the acute phase of the illness is over in two weeks or so, it can take longer to get back to your normal energy level. In fact, fatigue may last three to six weeks or longer beyond the acute phase of the illness.

Because there does not seem to be a link between the severity of the mono and the rupturing of the spleen, contact sports and rigorous exercise should be avoided for at least 4 weeks or until your health care provider advises that it is safe to resume normal activities.

Contact your health care provider if you have difficulty swallowing or sleeping, if your symptoms are getting worse, if your fever is still present after 10 days, if you are not well enough to return to classes after 14 days, or if you still have symptoms after 4 weeks.

Seek medical care immediately if you have difficulty breathing, severe abdominal pain, left shoulder pain, pale or clammy skin, bleeding into the skin or elsewhere, fast or pounding heartbeat or if you feel lightheaded or weak.

Disclaimer: This material is provided for informational purposes only. It does not constitute medical advice and is not intended to replace professional care. Please consult your health care provider with any questions or concerns you may have regarding your condition.

For additional information, contact CMU Health Services, 989-774-3944 or e-mail:



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