Central pain and thalamic hyperactivity: a single photon emission computerized tomographic study.
Five patients with central post-stroke pain (CPSP) accepted to be studied according to the following paradigm: a single photon emission computerized tomography (SPECT) using [123I]N-isopropyl-iodoamphetamine (IMP) was made in each patient 20 min following i.v. injection of IMP; during this time, the patients were stimulated in order to reproduce their spontaneous pain. Of the five patients, two had CPSP with hyperpathia following a stroke (with a lesion on CT scan involving the thalamo-cortical pathway in one and involving the thalamus in the other); two had CPSP following a stroke in the middle cerebral artery area, without hyperpathia; and the last patient suffered pain from algodystrophia following a fracture of the wrist. In the two cases with hyperpathia, SPECT demonstrated a contralateral relative hyperactivity in a central region corresponding to the thalamic area. This was not observed in the three other patients. In the two patients with hyperpathia, a second SPECT scan with stimulation of the contralateral pain-free arm did not demonstrate any hyperactivity in the thalamic area. These results suggest that a thalamic neuronal hyperactivity may characterize some hyperpathic syndromes and, in accordance with our previous results obtained in the rat, that the loss of inhibition on medial thalamic neurons may be a main feature of hyperpathia following certain cerebral stroke syndromes.
Pierre
Cesaro
C
Département de Neurosciences Médicales, C.H.U. Henri Mondor, 94000 Creteil France Service de Médecine Nucléaire, CHU Avicenne, 93000 Bobigny France.
Mann
Michael W
MW
Moretti
Jean Luc
JL
Defer
Gilles
G
Roualdès
Brigitte
B
Nguyen
Jean Paul
JP
Degos
Jean Denis
JD
D000368:Aged; D002561:Cerebrovascular Disorders / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*; D013788:Thalamus / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed