Epstein-Barr Virus (EBV) is a common virus: According to Dr. John Sullivan, writing in the medical database UpToDate, it is estimated that 90 to 95 percent of adults have evidence of being infected by the virus at some time. It commonly causes mononucleosis--infamously known as the "kissing disease" because of its method of being spread by intimate contact. However, mononucleosis is not the only potential complication of infection with EBV--neurological complications may occur as well.
A study reported in the May 2006 "Journal of Child Neurology" found that out of over 200 cases of encephalitis that were documented, about 10 percent of them were caused by EBV. Encephalitis is a term that means inflammation of the brain tissue, and is accompanied by typical signs of this inflammation. A change in level of consciousness, behavioral changes, difficulty walking or talking, and even strange sensations of tingling and numbness--called paresthesias--may be seen. In addition, a person with encephalitis may experience hemiparesis, which is a weakness along an entire side of the body.
When the optic nerve becomes inflamed and/or infected, the general name for this condition is optic neuritis. Infection with EBV may result in this neurological symptom, especially if the eye is infected with the virus. In this case, eye pain and gradual loss of vision may occur. According to Drs. Osborne and Balcer, writing in UpToDate, vision usually diminishes over a course of hours to days; the peak of vision loss occurs within one to two weeks. Flashes of light, light flickers and loss of color vision are also potential indicators of optic neuritis.
Cranial Nerve Palsies
A cranial nerve palsy is a disorder of one of the nerves of the head. In patients infected with EBV, the most common nerve to be affected is the facial nerve; this is another neurological symptom of EBV. Indications of a facial nerve palsy include an abrupt onset of paralysis of one side of the face--the side in which the nerve is affected. A sagging eyebrow and inability to close one eye are other clues that a facial nerve is being affected by EBV.
A mononeuropathy is a disease or disorder of a single nerve. It is often caused by compression, entrapment or trauma to a specific nerve; for instance, carpal tunnel syndrome occurs when the median nerve of the wrist becomes entrapped. Symptoms of a mononeuropathy include pain, tingling, burning sensation or numbness. Infection with EBV may lead to mononeuropathies as well: a study reported in the May 1994 edition of the journal "Pediatric Neurology" documented the case of a young man who had axillary nerve damage from EBV infection. This resulted in shoulder pain and weakness that took several months to improve.