The treatment for superficial siderosis

Abstract

Superficial siderosis (SS) has distinctive clinical features, including chronic progressive sensorineural hearing disturbance, cerebellar ataxia, and myelopathy, which are associated with hemosiderin deposition on the surface of the brain and spinal cord. The treatment strategy for SS consists of two kinds of procedures : elimination of chronic minor bleeding, and reduction of neurodegenerative processes caused by oxidative stress due to the deposited hemosiderin. First, to eliminate hemorrhage in the subarachnoid space―which causes the hemosiderin deposition in the central nervous system (CNS)―an early appropriate inspection of bleeding sources and subsequent surgical treatments, including fistula closure, are required. Recent imaging technologies, including constructive interference into steady state (CISS)/fast imaging employing steady–state acquisition (FIESTA) and dynamic CT myelography, have improved the ability to search for bleeding sources, such as dural defects, enabling early surgical treatment. Unfortunately, most patients require additional treatment to reduce hemosiderin neurotoxicity as neurological symptoms of patients undergoing such surgical treatments continue to deteriorate. To date, no effective treatment methods against hemosiderin neurotoxicity have been reported. Therapeutic efficacy for clinical and radiological features and safety in administration of deferiprone, a lipid–soluble iron chelator that can penetrate through the blood–brain barrier and chelate free iron in the CNS, have been reported. The clinical trial of the administration of deferiprone revealed quantitative clinical and radiological recovery in several postoperative patients with SS, where an early and long–term administration of deferiprone led to better outcomes, indicating a potential promising treatment. An earlier cochlear implantation was also reported to be beneficial for sensorineural hearing loss, which might depend on the site of the lesion and the degree of cochlear nerve functionality. In conclusion, the combination therapy of surgical elimination of a chronic bleeding source and administration of the iron chelator is probably the best treatment strategy for SS, and optionally, a cochlear implantation for patients manifesting hearing loss should be considered as well.