Radiation-induced camptocormia and dropped head syndrome Review and case report of radiation-induced movement disorders

Background In recent years, camptocormia and dropped head syndrome (DHS) have gained attention as particular forms of movement disorders. Camptocormia presents with involuntary forward flexion of the thoracolumbar spine that typically increases during walking or standing and may severely impede walking ability. DHS is characterized by weakness of the neck extensors and a consecutive inability to extend the neck; in severe cases the head is fixed in a "chin to chest position." Many diseases may underlie these conditions, and there have been some reports about radiation-induced camptocormia and DHS. Methods A PubMed search with the keywords "camptocormia," "dropped head syndrome," "radiation-induced myopathy," "radiation-induced neuropathy," and "radiation-induced movement disorder" was carried out to better characterize radiation-induced movement disorders and the radiation techniques involved. In addition, the case of a patient developing camptocormia 23 years after radiation therapy of a non-Hodgkin's lymphoma of the abdomen is described. Results In total, nine case series of radiation-induced DHS (n = 45 patients) and-including our case-three case reports (n = 3 patients) about radiogenic camptocormia were retrieved. Most cases (40/45 patients) occurred less than 15 years after radiotherapy involving extended fields for Hodgkin's disease. Conclusion The use of wide radiation fields including many spinal segments with paraspinal muscles may lead to radiation-induced movement disorders. If paraspinal muscles and the thoracolumbar spine are involved, the clinical presentation can be that of camptocormia. DHS may result if there is involvement of the cervical spine. To prevent these disorders, sparing of the spine and paraspinal muscles is desirable.