Infectious Mononucleosis (Mono)

Infectious mononucleosis is caused by the Epstein-Barr virus (EBV). It is a double stranded DNA virus indistinguishable from other members of the herpes virus group. It get its’ name from the mononuclear (single nucleus) cells. It is also known as the “kissing disease”, because the most frequent mode of transmission is intimate salivary contact. It can also be transmitted from shared drinking and eating utensils, toothbrushes, etc. Mono is not likely to spread by aerosol (ex. sneezing) or fomites (ex. doorknobs).

About half the population is not exposed to this virus until late adolescence. The peak incidence for girls is 14-16 and boys 16-18. After initial contact with the virus, there is an incubation period of 4-6 weeks and then the symptoms start appearing. Symptoms include fever, sore throat and lymph adenopathy (swollen and tender lymph nodes). Mono may be called glandular fever as well because of the swelling in the lymph nodes. Fevers can get as high as 102 degrees Fahrenheit and may remain high for 3-4 weeks. Other symptoms include enlargement of the spleen and liver, fatigue, loss of appetite, periorbital edema (swelling of the tissue around the eyes), petechiae (tiny bruising like spots on the roof of mouth), and a fine rash. The white blood cell and liver enzyme counts are elevated, and anemia can occur with low platelet counts.

Diagnosis is made based on the clinical picture and the hematological features. A sample of the patients’ blood is mixed with sheep’s blood and if the patient has mono, the sheep’s blood cells will stick together. Antibodies to sheep or horse red blood cells are positive in 90% of cases.

Mono is not a fatal disease, but there is no specific antiviral therapy. Doctors will most likely prescribe much rest. Acetaminophen and ibuprofen are sometimes used to relieve aches and manage the fevers, but the use of aspirin is not recommended due to the link to Reye’s syndrome. Corticosteroids are used to reduce the amount of tonsillar swelling and intravenous rehydration is necessary. Patients are cautioned to avoid contact sports for 6 weeks after recovery to avoid the risk of spleen rupture.

Most cases of mono resolve without complication, but some rarely occur. Complications are tonsillar enlargement, which can cause respiratory obstruction; rupture of spleen; encephalitis, an infection of the brain tissue; Galen-Barer syndrome, a progressive and sequential worsening syndrome of weakness and paralysis; hemolytic anemia, the red blood cells are destroyed; uvetis, an eye involvement; myocarditis, an inflammation of heart muscle; pneumonia; hephritis, a kidney infection; and Reye’s syndrome; a severe neurological syndrome.