Superficial siderosis of the central nervous system: An unusual cause for headache and hearing loss

Superficial siderosis of the central nervous system (SSCN) is a very rare disorder caused by deposition of haemosiderin in the superficial and subpial layers of the central nervous system due to repeated chronic subarachnoid or intraventricular haemorrhage. The clinical syndrome of SSCN consists of sensorineural hearing loss, progressive ataxia and spasticity. A 52 year-old woman who has a history of chronic progressive hearing loss, severe headache and gait instability for one year is presented. The neurological examination revealed bilateral sensorineural hearing loss, cerebellar ataxia and mild spasticity of the lower extremities. Brain MRI showed classical superficial siderosis in the form of hyposignal intensity along the leptomeninges. The prominent sites of hemosiderin deposition in this case were cerebellar vermis, around the brain stem and whole spinal cord surface. Cerebrospinal fluid findings confirmed chronic subarachnoid hemorrhage but bleeding site could not be demonstrated by cerebral angiography. This case report draws attention to this rare complication of chronic subarachnoid hemorrhage, which can be recognized early by its clinical triad and MRI findings. Neurology Asia 2006; 11 : 145 – 149 Address correspondence to: Sevki Sahin MD, Baglarbasi mah. Gumus sok. No: 5/6, 3483 Maltepe / Istanbul-TURKEY. �hone:���-��6-3����5�, �a�: ���-��6-3������, e-mail: �rsahin�gmail.�om INTRODUCTION Superficial siderosis of the central nervous system (SSCN) is a rare condition characterized by deposition of hemosiderin on the cerebellum (especially the vermis), basal frontal lobe and olfactory bulbs, temporal cortex, brainstem and cranial nerves (especially VIII), spinal cord and nerve roots.1 Deposition of free iron and hemosiderin in pial and subpial structures leads to intoxication of the central nervous system (CNS) and represents the pathophysiological mechanism of superficial siderosis. Hypointensity of the marginal zones of the central nervous system on T2 weighted MR images indicates an iron-induced susceptibility effect and seems pathognomonic for superficial siderosis.2 This deposition eventually results in destruction and demyelination within the central nervous system, leading to the cardinal clinical findings of superficial siderosis: hearing loss, ataxia, and myelopathy.3,4 The deposition of hemosiderin is due to repeated chronic subarachnoid or intraventricular bleeding most commonly secondary to repeated hemorrhages from tumors (especially ependymomas) and vascular malformations.5 In most cases, no source of bleeding is found.6 Treatment of superficial siderosis is focused around treating the source of bleeding.7 This is the report of a patient with SSCN where no cause was found, presenting with headache, deafness and gait ataxia. CASE REPORT A 52-year-old previously healthly woman presented with a one year history of mild progressive bilateral deafness, throbbing headache predominantly in frontotemporal regions and gait ataxia. She experienced headache accompanied by nausea, photophobia and phonophobia and were not relieved by analgesics and ergotamines. There was no history of systemic hypertension and craniospinal injury or operation of the brain and spinal cord. She had never experienced any episode of severe headache, nausea and vomiting which would indicate acute subarachnoid hemorrhage. No history of diseases or medications which would cause bleeding tendency was noted. Family history was unremarkable for neurodegenerative diseases. General physical examination was unremarkable. Neurological examination revealed a healthy, alert and cooperative patient with no stiff neck. Mental status examination showed no evidence of cognitive impairment. The Mini-Mental State Exam score was 28/30. The muscle power was normal. Both lower limbs were spastic with brisk deep tendon reflexes and bilateral extensor plantar responses. There was mild dysmetry and dysdiadokokinesia both sides. She could not perform tandem gait due to instability. Audiogram revealed sensorineural hearing loss of both ears, which was more on the left and high tone frequency loss was more prominent Neurology Asia December 2006 146 than lower tone frequency loss. CT brain scan with contrast was unremarkable. Brain MRI particularly with fluid attenuated inversion recovery (FLAIR) images showed high signal intensity in the cerebellar fissures, basal cisterns, Sylvian fissures and brainstem (Figure 1). MRI of the spine showed diffuse hypointensity at the surface of the whole cord, with no intra or extramedullary lesion (Figure 2). Lumbar puncture revealed a normal open pressure of 130 mm H2O and the cerebrospinal fluid (CSF) was xanthochromic. CSF analysis revealed 4,200 red blood cells/ml and protein of 60 mg/dl. No organisms were detected by gram stain, Indian ink preparation and culture. VDRL was negative. No malignant cell or siderophage were detected from cytologic examination. CSF iron and ferritin were 4 ug/dl and 89.6 ng/ml respectively. Other CSF and plasma biochemistry results are listed in Table 1. Cerebral digital subtraction angiography (DSA) was normal. The patient was diagnosed as idiopathic SSCN. She was given supportive treatment including 500 mg/day paracetamol in severe headache attacks, and 2,400 mg/per day piracetam for gait disturbance. The headache gradually improved over the subsequent year, and the neurological status remained stable.