In two cases of poststroke shoulder-hand syndrome, the patients complained of hemi-paretic shoulder pain. Both cases showed characteristic findings on magnetic resonance imaging (MRI) of the paretic shoulder. Case 1 underwent MRI before the syndrome occurred, while Case 2 underwent MRI after the syndrome occurred. In both cases, chemical saturation T2-weighted images revealed high intensity signals mainly anterior to the scapula, but also surrounding the articular capsule of the shoulder joint. Also, the subscapular muscle and subscapular bursa appeared damaged, and bloody fluid extended into the connective tissue. In Case 2, chemical saturation T2-weighted images revealed high intensity signals in the axillary fat. The paretic hands of both patients showed conscious and objective allodynia, edema, and decreased range of finger flexion and carpal extension. Observed symptoms were consistent with a diagnosis of complex regional pain syndrome (CRPS). Adherence of the posterior brachial plexus to the subscapular muscle may result in positional relationship changes and tears to the cords when the paretic shoulder is moved. The resultant small fiber neuropathy may result in edema by conduction block. Furthermore, aseptic synovitis from neurogenic inflammation may also occur. In Case 1, the arthritis of the shoulder appeared before the neuropathy. This indicates that damage to the subscapular bursa rather than neuropathy may be the underlying cause of the arthritis.
