Infectious Mononucleosis Definition

An illness that results from infection with the Epstein-barr virus. Infectious mononucleosis is most prevalent among adolescents and young adults though may occur at any age.

The infection spreads through contact with saliva; among young people and within families, sharing drinks and food are common means of contracting the illness.

The Epstein-Barr virus infects B-cell lymphocytes, also called mononuclear (single nucleus) lymphocytes, which is what gives the illness its name.

Symptoms of Mononucleosis and Diagnostic Path

The symptoms of infectious mononucleosis are flulike and generally mild to moderate in severity. Many people do not realize they have the illness. Symptoms include

  • Low-grade fever
  • Headache
  • Sore throat (pharyngitis)
  • Fatigue
  • Cervical and axillary lymphadenopathy (swollen lymph nodes in the neck and underarms)
  • Abdominal tenderness
  • Slight jaundice (yellow discoloration of the skin)

The diagnostic path includes blood tests; the presence of abnormal lymphocytes and antibodies for Epstein-Barr virus confirms the diagnosis. Some people have mild hepatitis (inflammation of the liver), which blood tests also confirm, and mild to moderate splenomegaly (enlarged spleen), which the doctor can detect with palpation (by feeling the abdomen).

Treatment Options and Outlook

Treatment is supportive, with rest and plenty of fluids. The course of illness may run three to six weeks, during which time the person is contagious and can spread the infection to other people. Most people recover fully, though it may take several months to feel back to normal.

Though infectious mononucleosis is generally a benign, self-limiting viral infection, the Epstein-Barr virus remains in the body for life and is linked to certain kinds of cancer (notably Burkitt’s lymphoma). A person can have infectious mononucleosis only once; the body develops immunity with infection.

Risk Factors and Preventive Measures against Mononucleosis

The Epstein-Barr virus is ubiquitous in the world; avoiding infection is nearly impossible. Measures such as frequent hand washing and appropriate sneeze/cough etiquette reduce the risk for passing the infection to others. Adequate rest during the active illness reduces the risk for complications.

See also ANTIBODYANTIBODY-MEDIATED IMMUNITYB-CELL LYMPHOCYTE; LYMPHOCYTE.

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