To the Editor: Guillain-Barré syndrome, or acute inflammatory demyelinating polyneuropathy, is generally regarded as predominantly a motor neuropathy. However, sensory disturbances such as paresthesias occur frequently, and outright pain occurs in up to 72% of the cases. Less widely appreciated is the occurrence of more pronounced perceptual disturbances and even outright hallucinatory experiences in this disorder. A review of the more recent medical literature uncovered only two descriptions of hallucinatory phenomena in Guillain-Barré syndrome (i.e., reference 1), and none in the English-language literature. We report a case of bizarre hallucinatory experiences in a man with severe Guillain-Barré syndrome.
Mr. A, a 76-year-old man, was admitted to the hospital with rapidly decreasing motor strength and was subsequently diagnosed with Guillain-Barré syndrome. During the first few days of hospitalization, he reported seeing cats in a large cage and people coming into his room to give lumber to his doctor. His weakness rapidly progressed, necessitating intubation and a 6-week stay in the intensive care unit. At extubation, he reported having been raped by a staff member. His description of the act of sodomy was highly implausible and did not stand up to investigation.
Over the next 6 months, the lack of return of his motor strength was disappointing. He regained only slight movement in his proximal upper and lower extremities. He continued to describe unusual experiences. These included seeing pictures floating in his room and the recurrent sensation that "plastic worms" were writhing in his hands. A particularly disturbing and recurrent sensation that occurred on awakening was that of being suspended over an open chasm. This would abruptly disappear when nursing staff spoke to him. The sensation bore a striking resemblance to sleep paralysis, differing primarily in its length (lasting many minutes). Mr. A, in retrospect, admitted that these unusual experiences must have been "fantasies." He displayed no evidence of ongoing delusions, delirium, or any psychotic symptoms other than the experiences described. The addition of a low dose of trazodone (50 mg/day) and haloperidol (0.5 mg at bedtime) had no significant effect on his symptoms. Over time his physical sensations lessened only slightly, but the fantasies associated with them faded to a greater extent.
The perceptions described by this otherwise lucid man are strikingly similar to those seen in normal dreaming and hypnagogic or hypnopompic hallucinations. It has been postulated (2) that dreamlike and other hallucinatory experiences may occur when there is a disruption in the "corollary discharge" system that allows us to discriminate between self-generated and externally generated neural activity. Sleep, particularly REM sleep, is a state of greatly reduced responsiveness to external stimuli and partial flaccid paralysis largely caused by the postsynaptic inhibition of motor neurons. The sensory and motor denervation that occurs in Guillain-Barré syndrome might allow the same confusion between internally and externally generated thoughts and sensations that occur in sleep, resulting in thoughts having a dreamlike or hallucinatory quality.
Increased awareness of hallucinatory experiences in denervation syndromes will allow us to better allay the anxiety generated in patients by these profoundly disturbing experiences. Exploration of this phenomenon might also help increase our understanding of the pathophysiology of hallucinations in the "functional" psychoses.