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PATIENT INFORMATION

CLA: INFECTIOUS MONONUCLEOSIS

INFECTIOUS MONONUCLEOSIS

Though the clinical entity called Infectious Mononucleosis (IM), “Mono”, Glandular Fever, or “Kissing Disease” was first described in 1920, it was not until 1968 that it’s cause was determined to be the Ebstein-Barr virus (EBV).  This virus causes a multitude of clinical symptoms, from mild flu-like symptoms in children, the classic triad of fever, sore throat, and swollen neck lymph nodes in adolescents and adults, to complications such as hepatitis, ruptured spleen, anemia and neurological abnormalities. A profound sense of tiredness is common. Approximately one-half of our population will have been exposed to EBV and have developed antibodies to it by age 5. The most common age range for what we see clinically as “mono” is between the ages of 7 and 35.  In general, the older the patient when the initial infection with EBV occurs, the worse the symptoms and potential complications.

The EBV virus is spread through the saliva after first infecting the lining of the throat. It is transmitted by sharing drinking cups, silverware, kissing, etc. As viral infections go, it is not highly contagious, so those who live in the household of the patient may not necessarily acquire the virus if precautions are taken to avoid the spread of saliva. In the adolescent/young adult group, the symptoms will usually be gone in two to three weeks, though the patient’s energy level will not usually be back to normal for three months or more. If normal activity is resumed too quickly, relapses are frequent. Once the patient has made antibodies to EBV, he/she is immune for life. The virus also remains for life.

LABORATORY TESTS

The EBV virus infects many organs of the body, but predominately the lymphoid system, blood, liver and spleen. A mild form of hepatitis is common which is diagnosed by slight swelling and abnormal chemistry tests. The spleen is also commonly swollen. In the blood, the number of lymphocytes is commonly increased, giving rise to the term “mononucleosis,” which means “increase in cells with one nucleus”. Some of the nuclei of these lymphocytes are characteristically swollen in appearance. The white blood cell count (WBC), of which the lymphocytes are a part, is typically increased above normal.

The test that is most commonly used to confirm the presence of IM  looks to identify the presence of  unusual antibodies that EBV stimulates lymphoid cells to produce, called “heterophile” antibodies. Heterophile (meaning “different loving”) antibodies are unusual in that they are not programmed to attack the stimulating agent (EBV in this circumstance), but rather some other foreign material. In this case, these antibodies attack red blood cells of certain animals. This forms the basis for the “monospot” test, in which the patient’s blood serum is mixed with animal red blood cells and the mix is observed for clumping, which indicates the presence of these unusual antibodies. The laboratory has a more specific way of doing this test, such that the result will indicate relatively how much of the antibody is present. This is important because, occasionally, it is important to look for a rise in quantity of these antibodies over time (for example, 2- 3 weeks). Occasionally, there are clinical circumstances where further blood testing is needed, and the laboratory also performs tests for antibodies made specifically against various parts of the EBV structure.

YOUR TEST RESULTS

If the test result for IM is abnormal, you will certainly want to discuss it with your physician, because there are a number of important complications of which you should be aware and also because, though IM is not highly contagious, it is communicable to those near you.

TREATMENT

There is no specific medication for the treatment of IM. Rest, liquids and supportive care are usually all that are required. However, there are a number of potentially severe complications of which you should be aware, one of the most significant being rupture of the spleen, which is a surgical emergency. Great care must be taken to avoid any activity that could predispose to injury to the spleen.  In some circumstances, especially if you are debilitated, have a lymphoid system which is not functioning properly, or are taking certain medications, there are some general antiviral and other medicines from which you may benefit. It is important that you discuss this with a physician.