There are a number of possible complications of mono that can occur within the nervous system. The most common are cranial nerve palsies (including Bell's palsy) and encephalitis (inflammation of the brain).

 

Other nervous system complications of mono can include:

 

In 85 percent of cases, these complications improve on their own, without treatment.

 

It is normal for the liver to be mildly affected when a person has mononucleosis. Hepatitis, which is inflammation of the liver, is common. In most cases, this complication of mono improves without treatment. It is extremely rare for mono to cause any permanent damage to the liver.

 

Complications of mono that affect the hear are uncommon but can include:

 

Difficulty breathing can occur in someone with mono, because swollen tonsils can block the airway. This complication of mono usually responds well to steroid medicine.

 

Possible Long-Term Complications of Mono

The Epstein-Barr virus (EBV), which causes most cases of mononucleosis, establishes a lifelong, dormant (inactive) infection in some cells of the body's immune system. A late event in a very few carriers of this virus is the emergence of Burkitt's lymphoma (a type of tumor in the tissue of the lymph nodes) and nasopharyngeal carcinoma (a cancerous tumor of the nose and the canal between the cavity of the mouth and the esophagus), two rare cancers that are not normally found in the United States. EBV appears to play an important role in these cancers, but is probably not the sole cause of disease.