Mononucleosis

(Infectious Mononucleosis; Mono)

Definition

Mononucleosis (mono) is an infection caused by a virus. It is marked by fever, lack of energy, and swollen glands.

Swollen Glands

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Causes    TOP

Mono is caused by the Epstein-Barr virus (EBV). Found mainly in saliva and mucus, it is passed from person to person by intimate behavior, such as kissing.

Risk Factors    TOP

Many people get EBV during their lifetime. Here are factors that raise the chance that EBV will turn into mono:

  • Getting EBV after age 10
  • Lowered immune system due to other illness, stress, or lack of energy
  • Living in close quarters with many people, such as in a college dormitory

Getting mono once means you will be immune to it in the future.

Symptoms    TOP

Signs of mono start 4 to 7 weeks after you were exposed to the virus. The first symptoms may be a sense of weakness that lasts about 1 week. Next, you may have:

  • High fever
  • Severe sore throat/swollen tonsils
  • Swollen glands
  • Lack of energy
  • Loss of hunger
  • Muscle aches
  • Belly swelling
  • Yellowing of the skin and whites of the eyes— jaundice

Diagnosis    TOP

You will be asked about your symptoms and health history. A physical exam will be done.

Your bodily fluids may be tested. This can be done with blood tests.

Treatment    TOP

There is no way to cure mono or to shorten the length of the illness. It lasts 4-6 weeks, but the lack of energy may last longer.

During the first few weeks, you should not play contact sports or lift anything heavy. A swollen spleen puts you at high risk of splenic rupture. This needs surgery. In rare cases, it can be fatal.

Get plenty of rest. Other steps may be to:

  • Take pain relievers, such as ibuprofen
  • Gargle with warm, salty water
  • Drink plenty of fluids
  • Take steroids to reduce swelling in the throat, if advised by your doctor

Prevention    TOP

You can prevent mono by:

  • Avoiding intimate contact, especially kissing, with anyone who has active mono
  • Do not share drinks or food with anyone who has mono

RESOURCES:

Centers for Disease Control and Prevention
http://www.cdc.gov
National Institute of Allergy and Infectious Diseases
http://www.niaid.nih.gov

CANADIAN RESOURCES:

About Kids Health—The Hospital for Sick Children
http://www.aboutkidshealth.ca
The College of Family Physicians of Canada
http://www.cfpc.ca

References:

Balfour HH Jr, Hokanson KM, et al. A virologic pilot study of valacyclovir in infectious mononucleosis. J Clin Virol. 2007;39:16-21.
Ebell MH, Call M, et al. Does this patient have infectious mononucleosis?: The rational clinical examination systematic review. JAMA. 2016 Apr 12;315(14):1502-1509.
Epstein-Barr virus infection. EBSCO DynaMed Plus website. Available at: https://www.dyname.... Updated January 5, 2018. Accessed July 17, 2018.
Luzuriaga K, Sullivan JL. Infectious mononucleosis. N Engl J Med. 2010 May 27;362(21):1993-2000.
Mononucleosis. Academy of Family Physicians Family Doctor website. Available at:
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Updated October 24, 2017. Accessed July 17, 2018.
Last reviewed June 2018 by James Cornell, MD
Last Updated: 7/18/18

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