We report the case of a middle-aged woman who developed trigeminal neuralgia as a sequela of multiple sclerosis (MS). pain and affects the Expanded Disability Status Level (EDSS) scores and health-related quality of life. When it occurs in patients with MS, it is generally refractory to drugs and requires multiple surgical procedures [5]. Here, we describe the successful treatment of debilitating drug-refractory trigeminal neuralgia by a single mandibular nerve block followed by natalizumab administration in a middle-aged woman with MS. Case presentation A 48-year-old woman was admitted to our hospital due to drug-refractory trigeminal neuralgia. At 31 years of age, she Evocalcet experienced experienced double vision and tetraparesis after giving birth to her second child. Since then, she experienced experienced relapses twice a 12 months and had been Evocalcet diagnosed with relapsing-remitting MS. She had been prescribed interferon b-1b; however, she could not continue the treatment because of the onset of depression. Since interferon b-1b had been the only disease-modifying drug sold at that time, her treatment had been switched to prednisolone (15 mg/day) and azathioprine (50 mg/day). This treatment had been ineffective, and she experienced continued to experience relapses twice a 12 months. At 43 years of age, she was confined to a wheelchair. At 46 years of age, she had developed drug-refractory trigeminal neuralgia with demyelinating brainstem lesions that caused sustained, strong right-sided pain at the back of the tongue and consequently affected her oral intake and daily life activities. An MRI showing the extent of her brainstem lesions is usually shown in Physique ?Figure1A1A and Figure ?Figure1B.1B. Because she experienced paroxysmal pain more than a dozen occasions a day in addition to prolonged pain, she had decreased her food intake and lost excess weight. Open in a separate window Physique 1 Brain MRI findings – lesions in the brainstemA, B: brain T2-weighted imaging shows multiple high-intensity lesions in the brainstem, including the intramedullary running path of the trigeminal nerve (white arrows); C: the lesions exhibit no gadolinium enhancement MRI:?magnetic resonance imaging At 48 years of age, the patient was admitted to our hospital. Neurological examination revealed drug-refractory trigeminal neuralgia with strong right-sided pain at the back of PCK1 the tongue, lower lip, and chin; right-sided hypoesthesia in the lower lip; diplopia; bilateral medial longitudinal fasciculus (MLF) syndrome; moderate spastic tetraparesis; moderate ataxia; and paresthesia and hypoesthesia in the right upper and both lower extremities. Her blood assessments were unfavorable for inflammatory markers and autoantibodies, including anti-aquaporin 4, anti-nuclear, and anti-dsDNA antibodies. The cerebrospinal fluid analysis revealed a normal white blood cell count (0/L), protein level (29 mg/dL), and myelin basic protein level ( 31.2 pg/mL), even though immunoglobulin G index was elevated (0.87) and oligoclonal IgG bands were present. Brain T2-weighted imaging demonstrated multiple high-intensity lesions in the brainstem, including the intramedullary running path of the trigeminal nerve. The lesions exhibited no gadolinium enhancement (Figure ?(Figure1A1A-?-1C1C). The lesions involved the right trigeminal nerve tract, but vascular compression at the entry of the trigeminal nerve root was not recognized on fast imaging employing steady-state acquisition (FIESTA). In addition, brain T2-weighted imaging showed high-intensity lesions in the periventricular and subcortical white matter. T1-weighted imaging showed that many of these lesions were hypointense (Figure ?(Figure2A2A-?-2C2C). Open in a separate window Figure 2 Brain MRI findings – lesions in the periventricular and subcortical white matterA, B: brain T2-weighted imaging shows high-intensity lesions in the periventricular and subcortical white matter (white arrows); C: T1-weighted imaging shows that many of these lesions are hypointense (white arrows) MRI: magnetic resonance imaging Spinal Evocalcet cord T2-weighted imaging showed 11 high-intensity white matter lesions with a length equivalent to less than 1.5 vertebral bodies (Figure ?(Figure3A,3A, ?,3B3B). Open in a separate window Figure 3 Spinal cord MRI findingsA, B: spinal cord T2-weighted imaging shows 11 high-intensity white matter lesions with a length equivalent to less than 1.5 vertebral bodies (white arrows) MRI:?magnetic resonance imaging The patient was diagnosed with trigeminal neuralgia due to relapse of MS. The trigeminal neuralgia was refractory to medications such as carbamazepine, levetiracetam, acetaminophen, tramadol, and morphine. Therefore, an anesthesiologist administered a mandibular nerve block with radiofrequency thermocoagulation. The needle was inserted at an extraoral point 4 cm from the corner of the mouth and advanced to the.