[Relationship between cutaneous temperature and hand edema and allodynia after stroke--the etiology of shoulder-hand syndrome].

The etiology of shoulder-hand syndrome is as yet unknown. We hypothesized that it may be due to damaged unmyelinated fibers in front of the subscapular muscle. We examined the existence of edema and hypersensitivity to pain in the hands of stroke patients during the subacute stage and their relationships to cutaneous temperatures of the index fingertips in 75 hemiplegic patients (23 without edema, 32 with only edema, and 20 with edema plus allodynia). Patients were placed into two groups (comfortable and warm) depending on room temperature (22.2-25.6°C and 25.7-30°C, respectively). Of the patients with hand edema plus allodynia, 75% had a large lesion in the capsula, cortical white matter, and putamen. It was previously reported that the cutaneous temperature of the arm on the paralysis side of patients with lesions of the capsula or putamen was lower than that on the non-paralysis side. In the edema plus allodynia group, the temperature of the index fingertip on the affected side was higher than that of their contralateral fingers; the differences were smaller under warm conditions possibly due to blockade of the sympathetic nerves in the peripheral nerve. By contrast, in patients in the edema group, there were no differences in cutaneous temperatures of their two index fingers. Thus, it appears that patients with mild cases of shoulder-hand syndrome have conduction blocks in the posterior cord of the brachial plexus, while those with severe cases have both conduction blocks and neurogenic inflammation in both the lateral and posterior cords.