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Patient information: Infectious mononucleosis (mono) in adults and adolescents (Beyond the Basics)

INFECTIOUS MONONUCLEOSIS OVERVIEW

Infectious mononucleosis, also known as mono or "the kissing disease," is an infection that causes fever, sore throat, fatigue, and enlarged lymph nodes in the neck. It most commonly occurs in adolescents and young adults. Although not generally considered a serious illness, mononucleosis can lead to significant loss of time from school or work due to profound fatigue.

This topic will discuss the symptoms, diagnosis, and treatment of mononucleosis in adolescents and adults.

HOW DID I GET MONO?

Mono is caused by acquiring Epstein-Barr virus (EBV), which can spread from person to person through contact with saliva. Kissing or sharing of eating utensils or drinking glasses with a person who is sick with mono should be avoided.

Most people are exposed to EBV during childhood, although most infected young children do not develop symptoms. Symptomatic infection is much more common in teenagers and young adults, and can lead to illness in the 5 to 10 percent of adolescents and adults who have not been exposed to the virus. That is why symptomatic disease is more common in teenagers and young adults. (See "Clinical manifestations and treatment of Epstein-Barr virus infection".)

MONO SYMPTOMS

Common symptoms — It may take four to eight weeks after exposure to the virus for the first symptoms (body aches, headache, low-grade fever) to appear. The most common mono symptoms include:

  • Fever (temperature greater than 100.4ºF or 38ºC)
  • Sore throat
  • Enlarged lymph nodes (glands) in the neck
  • Fatigue, which may be severe and can occasionally last for months

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. (See "Infectious mononucleosis in adults and adolescents".)

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 sports activities or heavy lifting for a few weeks. This advice is given to avoid 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, blood tests can be falsely negative during the first weeks of symptoms.

MONO TREATMENT

The goal of mono treatment is to ease the symptoms while the immune system contains the initial viral infection. Antibiotics are not helpful because mono is caused by a virus and there are no antiviral medications that can treat or cure EBV.

Pain and fever — Sore throat, muscle aches, and fever can be treated with non-prescription medications, such as acetaminophen (Tylenol® and others) or ibuprofen (Motrin®, Advil®). Acetaminophen is broken down by the liver. Thus, it is important to closely follow the dosing instructions or your healthcare provider's instructions to safely take this medication. 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 not necessary.

Diet — Feeling ill often causes a loss of appetite. This is normal, and usually improves as the infection improves. It is important, even if you have no appetite, to drink an adequate amount of fluids. This is especially true if you are taking 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 sports activities for at least the first three to four weeks of the illness [1]. Your healthcare 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 with mono recover completely without any long-term complications. Symptoms usually begin to improve within one to two weeks.

WHERE TO GET MORE INFORMATION

Your healthcare 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 web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare 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 information: Mono, the “kissing disease” (The Basics)
Patient information: Swollen neck nodes in children (The Basics)
Patient information: Cytomegalovirus (The Basics)
Patient information: 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 in adults and adolescents

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Literature review current through: Nov 2014. | This topic last updated: Jul 31, 2013.
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