Trigeminal neuralgia and multiple sclerosis

1-2 per cent of the patients suffering from multiple sclerosis (MS) are afflicted with trigeminal neuralgia and 2 - 8 per cent vice-versa. Thus, comorbidity of MS and TN is obvious. Commonly a patch with demyelination or later on a glial plaque located in the pontine entry zone of the trigeminal root is responsible for the manifestation of TN. Therefore, Jannetta's operation with microvascular decompression of the trigeminal root is ineffective in these cases. Using carbamacepine as first choice and phenytoine as second choice in the treatment of MS-depending TN caution is necessary because higher daily dosage might aggravate nystagmus and other cerebellar MS-symptoms.