Department: COMBATING INFECTION
USUALLY CAUSED BY the Epstein-Barr virus (EBV), a member of the herpesvirus family, mononucleosis is a viral infection transmitted by intimate contact with body secretions.1 It's often called the "kissing disease" because the virus infects the oral mucosa and salivary glands and is commonly transmitted in saliva.2
Infectious mononucleosis is most prevalent in adolescents and young adults in upper socioeconomic classes of developed countries.3 Most people become infected with EBV sometime in their lives; as many as 95% of adults between ages 35 and 40 in the United States have been infected with EBV.4 Once a person is infected, the virus remains dormant for the rest of the person's life. Asymptomatic viral reactivation can occur periodically, with the virus commonly found in saliva.4
Another virus, cytomegalovirus (CMV), can cause infectious mononucleosis, although it's far less common. This virus may be transmitted in urine and genital secretions.5
Signs and symptoms
Usually beginning 4 to 8 weeks after infection, common signs and symptoms of infectious mononucleosis include malaise, anorexia, fever, pharyngitis, periorbital edema, and lymphadenopathy (which often involves the posterior cervical chain).2 It may also be associated with hepatomegaly and splenomegaly. Patients may be infectious before experiencing signs and symptoms and remain infectious for 6 to 18 months.2
Rare complications include Guillain-Barré syndrome, meningitis, encephalitis, and splenic rupture.2 Airway obstruction may occur with extreme tonsillar enlargement.
Testing and treatment
Diagnosis is based on patient history and physical assessment findings, and a Monospot test. The healthcare provider may make a diagnosis based on the classic triad of clinical signs—fever, pharyngitis, and lymphadenopathy—lasting for 1 to 4 weeks.4
The Monospot test is sensitive to heterophile antibodies, which will often confirm the diagnosis for infections caused by EBV. However, signs and symptoms may be present for up to 4 weeks before the test is positive. If the Monospot test is negative, a normal to moderately elevated white blood cell count and lymphocytosis with greater than 10% atypical lymphocytes support the diagnosis.4
Treatment includes rest and analgesia to relieve fever, headache, and pharyngitis. Encourage patients to drink plenty of water to prevent dehydration. Isolation isn't necessary, but advise them to avoid intimate contact with others. They should also refrain from strenuous physical activity during the first month to reduce the risk of splenic rupture.5 Advise patients that they may feel some lethargy for about 2 to 3 months following infection.3
1. Cunha BA. Infectious mononucleosis
2. King J. Infectious mononucleosis: update and considerations. Nurse Pract
3. Porth CM. Essentials of Pathophysiology: Concepts of Altered Health States
. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2008.
4. Centers for Disease Control and Prevention. Epstein-Barr virus and infectious mononucleosis
5. Fauci A, Braunwald E, Kasper D, et al. Harrison's Principles of Internal Medicine
. 17th ed. New York, NY: McGraw-Hill Medical; 2008.