Central pain after thalamic stroke: clinical and radiological characteristics

ABSTRACT

BACKGROUND AND OBJECTIVES: Although pain resulting from thalamic stroke was described by D jerine & Roussy in 1906, its pathomechanism & anatomical substrate have not been defined yet. Several clinical & experimental studies suggest that laterality of lesion for generation of central pain is as important as location of lesion. We performed this study to evaluate clinical features of thalamic pain syndrome, including incidence, onset interval from stroke, nature, distribution, accompaniments, and to assess the relationships between laterality & location of lesion and occurrence of pain. METHODS: We reviewed the medical records and brain imaging of all patients with thalamic stroke from 1990 to 1997. Patients with thalamic pain syndrome due to a single well-demarcated thalamic stroke were included, and excluded tumoral, non-vascular etilogy, and patients with sensory deficit without pain and excluded patients who had multiple cerebral lesions even they have thalamic pain syndrome. RESULTS: One-hundred one cases were selected under the inclusion criteria, and twenty-four patients(24%) with thalamic pain syndrome were identified from 101 thalamic stroke. Pain onset within the first week poststroke was 17(71%). The patients with allodynia were 8(33%), increased by movement, stress, and thermal contact. The painful area distributed mainly limbs(50%), especially arm(35%), face plus hemibody(34%), and hemibody below face(8%). Thalamic pain syndrome accompanied with the pain and temperature loss was 17(71%). Thirteen patients had a right-sided lesion, 11 left-sided lesion. The lesion causing thalamic pain syndrome mainly located in the posterolateral areas(75%). CONCLUSIONS: We conclude that the thalamic pain syndrome resulting from mainly posterolateral thalamic lesion cause the spontaneous pain on the contralateral body, especially upper extrimity, and accompanied with pain & tempterature loss. The laterality of lesion is not represent for generation of thalamic pain syndrome. Key word thalamic stroke, central pain.