Complex regional pain syndrome is characterized by
pain,
allodynia,
hyperalgesia,
edema, signs of vasomotor instability,
movement disorders, joint stiffness, and regional
osteopenia. It is recognized to be difficult to treat, despite various methods of treatment, including physiotherapy,
calcitonin,
corticosteroids, sympathetic blockade, and nonsteroidal anti-inflammatory drugs. Pathophysiologically,
complex regional pain syndrome reveals enhanced regional
bone resorption and high bone turnover, and so
bisphosphonates, which have a potent inhibitory effect on
bone resorption, were proposed for the treatment of
complex regional pain syndrome.
CASE PRESENTATION: A 48-year-old Japanese man with
complex regional pain syndrome type I had severe right ankle
pain with a visual analog scale score of 59 out of 100 regardless of treatment with physiotherapy and nonsteroidal anti-inflammatory drugs for five months. Radiographs showed marked regional osteoporotic changes and bone scintigraphy revealed a marked increase in radioactivity in his ankle. One month after the start of
oral administration of
risedronate (2.5 mg per day), his bone
pain had fallen from a VAS score of 59 out of 100 to 18 out of 100. Bone scintigraphy at 12 months showed a marked reduction in radioactivity to a level comparable to that in his normal, left ankle. On the basis of these results, the treatment was discontinued at 15 months. At 32 months, our patient had almost no
pain and radiographic findings revealed that the regional osteoporotic change had returned to normal.A second 48-year-old Japanese man with
complex regional pain syndrome type I had severe right foot
pain with a visual analog scale score of 83 out of 100 regardless of treatment with physiotherapy and nonsteroidal anti-inflammatory drugs for nine months. Radiographs showed regional osteoporotic change in his phalanges, metatarsals, and tarsals, and bone scintigraphy revealed a marked increase in radioactivity in his foot. One month after the start of
oral administration of
alendronate (35 mg per week), his bone
pain had fallen from a visual analog scale score of 83 out of 100 to 30 out of 100 and, at nine months, was further reduced to 3 out of 100. The treatment was discontinued at 15 months because of successful
pain reduction. At 30 months, our patient had no
pain and the radiographic findings revealed marked improvement in regional osteoporotic changes.
CONCLUSIONS: