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INFECTIOUS MONONUCLEOSIS OVERVIEW — Infectious mononucleosis, also known as "mono" or the "kissing disease," is an infection that may cause fever, sore throat, fatigue, and/or enlarged lymph nodes in the neck. It most commonly occurs in adolescents and young adults. In general, mononucleosis is not considered a serious illness. However, mononucleosis can lead to significant loss of time from school or work due to profound fatigue and, on rare occasion, can cause severe or even life-threatening illness.
This topic will discuss the symptoms, diagnosis, and treatment of mononucleosis in adolescents and adults.
HOW DID I GET MONO? — Infectious mononucleosis is caused by the Epstein-Barr virus (EBV). EBV can spread through contact with saliva from an infected person; for example, you can get it through kissing, sharing eating utensils with, or drinking from the same glass as someone who is infected with the virus.
Many people are exposed to EBV at some point during childhood, although they may not realize it at the time. For adolescents and young adults who were not infected as a child, exposure often results from contact with an infected person's saliva. After a person has been exposed, it's possible for the virus to remain in their body for months or even years, meaning they could spread the infection to others during this time without realizing they are contagious. In addition, it may also be possible to spread the virus through other bodily fluids, such as semen or vaginal secretions.
MONO SYMPTOMS — Most young children who become infected with Epstein-Barr virus (EBV) do not develop symptoms. In contrast, people who are first exposed to EBV as adolescents or adults are more likely to develop symptomatic infection due to the way their immune systems respond to the virus at older ages.
Common symptoms — It may take four to eight weeks after initially acquiring the virus for the first symptoms (body aches, headache, low-grade fever) to appear. The most common mono symptoms include:
●Fever (temperature greater than 100.4°F or 38°C)
●Sore throat
●Enlarged lymph nodes (glands) in the neck
●Fatigue, which may be severe and can occasionally last for more than a month
Some people have all of these symptoms, while others have only one or two symptoms, such as sore throat or fever and enlarged lymph nodes. Young children and older adults may have only a fever and muscle aches.
Enlargement of the spleen — The spleen is an organ in the left upper abdomen, just under the diaphragm (figure 1). It becomes enlarged in about half of people with mono. If the spleen becomes enlarged, doctors recommend avoiding contact sports or heavy lifting for a few weeks. This advice is given to prevent the rare complication of splenic rupture that can occur after trauma but can also happen spontaneously. Symptoms of rupture include sudden, sharp pain in the abdomen. This is a potentially life-threatening complication that requires immediate medical treatment. (See 'When can I go back to work or school?' below.)
HOW IS MONO DIAGNOSED? — Mono may be suspected based upon a person's symptoms and physical examination. Blood tests are done to confirm the diagnosis. However, the most commonly used blood test for diagnosis in North America, known as the Monospot, can be falsely negative during the first weeks of symptoms. Your doctor might also order tests for other infections that can have similar symptoms, especially when initial testing with the Monospot is negative.
MONO TREATMENT — The goal of mono treatment is to ease the symptoms while the immune system contains the virus. Antibiotics (which are used to treat bacterial infections) are not helpful because a virus causes mono. There are no antiviral medications that are known to treat or cure Epstein-Barr virus effectively.
Pain and fever — Sore throat, muscle aches, and fever can be treated with nonprescription medications, such as acetaminophen (sample brand name: Tylenol) or ibuprofen (sample brand names: Motrin, Advil). Acetaminophen is broken down by the liver. Thus, it is important to closely follow the dosing instructions or your health care provider's instructions to take this medication safely. Acetaminophen and ibuprofen are also recommended for use in children. Aspirin should not be given to young children with mono because of possible liver complications.
Rest — Mono can cause severe fatigue, although most people recover within two to four weeks. For some, significant tiredness lasts for weeks to months. Early in the infection, it is important to get adequate rest, although complete bed rest is unnecessary.
Diet — Feeling ill often causes a loss of appetite. This is normal and usually improves as the infection resolves. It is essential, even if you have no appetite, to drink an adequate amount of fluids. This is especially true if you take ibuprofen for pain or fever because ibuprofen can affect kidney function if you become dehydrated. You are drinking adequate fluids if your urine is a pale yellow color.
WHEN CAN I GO BACK TO WORK OR SCHOOL? — Many people with mono develop an enlarged spleen, which can last for a few weeks or longer. Although you can return to school or work when you are feeling better, it's important to avoid activities that can cause injury to the spleen.
Experts generally recommend that athletes not participate in contact or vigorous sport activities for at least the first three to four weeks of the illness. Your health care provider should determine when it is safe for you to participate in strenuous activities or contact sports.
When you do begin participating in sports activities again, we recommend starting slowly, increasing activity gradually. Even highly trained athletes may not feel as fit after having mono as they did before the illness.
WHEN WILL I FEEL BETTER? — Most people who suffer from infectious mono recover completely without any long-term complications. Symptoms usually begin to improve within one to two weeks.
WHERE TO GET MORE INFORMATION — Your health care provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient education: Mononucleosis (The Basics)
Patient education: Swollen neck nodes in children (The Basics)
Patient education: Cytomegalovirus (The Basics)
Patient education: When to worry about a fever in adults (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
This topic currently has no corresponding Basic content.
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Clinical manifestations and treatment of Epstein-Barr virus infection
Overview of diagnostic tests for cytomegalovirus infection
Epidemiology, clinical manifestations, and treatment of cytomegalovirus infection in immunocompetent adults
Evaluation of acute pharyngitis in adults
Infectious mononucleosis
