Infectious Mononucleosis -
Mono

Mononucleosis, often called "Mono", is a usually mild self-limiting acute viral infection and, in most cases, does not deserve its bad reputation.  While mono is not usually considered a serious illness, it may have serious complications.  Usually (85% of the time) caused by the Epstein-Barr virus (EBV), it usually runs its course quickly and rarely produces any serious complications.  There are, however, other viruses that may produce a mono-like illness.  A less common form of mononucleosis is caused by cytomegalovirus (CMV).

Incidence

Mononucleosis is an illness that affects teenagers and young adults, mainly ages 14 to 30, but can occur in children and older adults.  It has been estimated that approximately 50% of students have had mono by the time they enroll in college.

Signs and Symptoms

Many times the symptoms are so mild that it is not recognized for what it is: The symptoms of mononucleosis may be the same as many other illnesses, such as "colds" or strep throat.  For this reason, it is particularly difficult to diagnose in the early stages of the illness, although the diagnosis is usually based on symptoms and a physical exam.  Symptoms usually disappear within 2-4 weeks, with fatigue sometimes lingering longer.

Diagnosis and Tests

Confirmation, if necessary, can be accomplished by either of two blood tests:

1. EBV causes an increase in a specific type of white blood cell, the atypical lymphocyte.  A white blood cell count, WBC, will reflect this change commonly seen in people who have mononucleosis.  Diagnostic problems can result because enlarged lymphocytes are common with mono, but can also be a symptom of leukemia.  Blood tests can distinguish between the type of white cell seen in leukemia and that with mono.
2. The mono spot test identifies an antibody which is present in mononucleosis and is the test most commonly used to tell whether someone has mono or some other ailment.  This test may not become positive until one has had symptoms for 5-14 days and may remain positive for months to years.  It is important to remember the mono test merely helps to make the diagnosis; it does not indicate the severity of the disease and does not predict how long symptoms will last.  This blood test detects the antibodies (proteins) that the body makes to fight EBV or CMV.  Because it takes a while for antibodies to develop after infection, your doctor may need to order or repeat the test one to two weeks after you develop symptoms.  At that time the test is about 85% accurate.

Other tests your doctor might order include a complete blood count (CBC) to see if your blood platelet count is lower than normal and if lymphocytes are abnormal, and a chemistry panel to see if liver enzymes are abnormal.

Treatment and Prevention

There are no conventional medical treatments to cure mononucleosis, only those that help manage the symptoms.  In approximately 20-30% of people with mononucleosis there is a concurrent bacterial throat infection.  Any antibiotics prescribed may help with the sore throat, but not the EBV infection.

Relieve pain and fever with analgesics.  Contact sports should be avoided while the spleen is enlarged.  Cold drinks and frozen desserts are both ways to relieve sore throat symptoms.  Doctors also recommend gargling with saltwater (about half a teaspoon salt to 8 ounces of warm water) and sucking on throat lozenges available over-the-counter in pharmacies and other stores.  If throat or tonsils are infected, a throat culture should be taken so the doctor can prescribe an appropriate antibiotic.  Ampicillin is usually not recommended because it sometimes causes a rash that can be confused with the pink, measles-like rash that 1 out of 5 mono patients develops.

Acetaminophen is preferable to aspirin for pain and fever relief because of the association of the EBV and Reye's syndrome in children.  In most cases of mononucleosis, hospitalization is not indicated.  It has been shown that those who remain active to the limit of personal comfort get well more rapidly than those who remain in bed.

Prevention
EBV is found in moist, exhaled air, and in nose or mouth secretions.  It is not as contagious as many other viruses but may be transmitted through direct contact.  This explains its nickname of the "kissing disease".  There is a long incubation period of 30 to 50 days from the time one is exposed to the virus to the time one gets sick.  In addition, the virus can be transmitted in other ways, such as sipping from the same straw or glass as an infected person – or even being close when the person coughs or sneezes.

Isolation of the patient is not indicated; one can not catch mononucleosis by sitting in the same room with someone who has it, although persons who have had mononucleosis can shed the virus periodically in their saliva for the rest of their lives.  Some people can have the virus in their systems without ever having symptoms, and still be infectious.

Prognosis; Complications

Fever usually abates in about 10 days, and swollen lymph glands and spleen heal in 4 weeks.  Fatigue usually resolves within a few weeks, but may linger for 2 to 3 months.

Possible complications include:

• Secondary throat infection
• Rupture of spleen (rare) – avoid pressure on the spleen
• Neurological complications (rare) – seizures, ataxia, Guillain-Barre syndrome, Bell's palsy
• Hepatitis with jaundice (more common in patients older than 35)
• Hemolytic anemia
• Death in immunocompromised individuals.