INFECTIOUS mononucleosis has become a well known entity. The literature contains several articles describing in detail the classic clinical pictures. However, in cases which do not conform to the usual description the diagnosis is often confused or missed. In particular, this may be true when the symptoms are predominantly neurologic.
The involvement of the central nervous system may manifest itself by severe headaches, cranial nerve palsies, cerebellar signs and peripheral neuropathies. Thus there arises confusion with other diseases wherein neurologic symptoms are found. Infectious mononucleosis must be considered in the differential diagnosis of various types of lymphocytic meningitis, encephalitis, poliomyelitis, polyneuritis and the Guillain-Barré syndrome.
The Guillain-Barré syndrome was originally described as a peripheral radiculoneuritis, with findings of an increased protein level in the spinal fluid, associated with a normal or only slightly elevated white blood cell count. Symptoms of meningitis or meningoencephalitis with involvement of the cranial nerves are