superficial siderosis of the central nervous system due to chronic , recurrent subarachnoid hemorrhage is a rare and potentially debilitating disorder .
the classic manifestation is progressive bilateral sensorineural hearing loss , although ataxia and pyramidal signs also are common . in the largest review of literature to date ,
though the age of presentation ranges from 15 to 78 years , it is seen more commonly in patients above 40 years .
. we hereby present a young boy with this disorder to emphasize its occurrence in children .
a twelve - year - old boy presented to the neurology outpatient clinic with a history of intermittent holocranial headaches since two years and recent - onset blanking spells .
the headaches were moderately severe , with no diurnal variation , occurring once in two weeks with no particular aggravating factor and subsiding with analgesic medication .
however , at two years of age , he had developed sudden - onset vomiting , irritability , and imbalance which was progressive , not associated with fever , trauma , or varicella infection . over the subsequent month , he developed a divergent squint .
a computed tomography of the brain revealed a mass lesion in the cerebellar vermis with supratentorial hydrocephalus .
he underwent near - total excision of the tumor , with a thin rim of the tumor left behind .
for the residual rim of tumor margin , he was subjected to external radiotherapy to the posterior fossa with 6 mv photons ( total dose being 5040cgy/28fr/54 days ) and was declared free of the disease subsequently .
a magnetic resonance imaging ( mri ) of the brain was done which was normal except for postoperative changes ; hence , the headaches were treated with plain analgesics . over the next two years
, he developed intermittent brief episodes of blanking spells , when he was referred to our center .
a thorough neurological assessment revealed nystagmus , ataxia , and dysarthria with a normal tone .
an electroencephalogram done for the blanking spells showed mild epileptiform abnormality and he was put on oxcarbamazepine .
a repeat mri revealed cystic space in the posterior fossa ( as a result of the previous surgery ) and hypointensities around the cerebellar folia [ figure 1a ] .
assessment of brainstem auditory evoked potentials confirmed bilateral mild sensorineural hearing loss . a repeat clinical assessment after six months showed significant deterioration in dysarthria and ataxia . a repeat mri after six months showed progression in the deposition of hemosiderin in the cerebellar folia from the previous one [ figure 1b ] .
the clinical picture of a progressive worsening ataxia with sensorineural hearing loss along with the neuroimaging findings of the deposition of hemosiderin in the cerebellum clinches a diagnosis of superficial siderosis in this child , secondary to the surgery of the posterior fossa done in early childhood .
( a ) susceptibility weighted images showing hypointensities around the cerebellar folia , representing deposition of hemosiderin ( b ) imaging done after six months showed progressively increased deposition of hemosiderin
nevertheless , the origin of superficial siderosis of the central nervous system remains undetermined in most cases .
highly vascular spinal tumors , vascular abnormalities of the central nervous system , and surgical procedures of the posterior fossa are the most commonly identified sources of chronic bleeding
. a past history of trauma and prior intradural surgery may be further risk factors .
it is a distinct clinical syndrome characterized by sensorineural deafness ( 95% ) , cerebellar ataxia ( 88% ) , and pyramidal signs ( 76% ) .
other features include dementia ( 24% ) , bladder disturbance ( 24% ) , anosmia ( at least 17% ) , anisocoria ( at least 10% ) , and sensory signs ( 13% ) .
less frequent features are extraocular motor palsies , pain in the neck or back , bilateral sciatica , and lower motor neuron signs ( 5 - 10% each ) . in a case report by sevki et al .
, headache was also quoted to be a presenting symptom . in our patient , headache was the main presenting complaint followed later by progressive ataxia and hearing loss .
the pathogenesis of superficial siderosis involves recurrent subarachnoid hemorrhage resulting in the prolonged contact of these tissues with iron . within the cerebellum ,
the microglia as well as bergmann glia are uniquely sensitive to iron - mediated cell damage .
the terminal processes of bergmann glia that interface with the subarachnoid space mediate iron uptake from the cerebrospinal fluid ( csf ) , inducing the synthesis of ferritin within these cells . because ferritin sequesters iron and is thus thought to play a role in iron detoxification , intracellular iron may not cause toxicity until ferritin biosynthesis is overwhelmed by a large iron load .
excess free iron may then stimulate lipid peroxidation , leading to localized tissue necrosis . in the past
, superficial siderosis was diagnosed almost exclusively at autopsy . with the advent of mr imaging
mri has identified siderosis in reportedly asymptomatic patients . in one series , which examined 8,843 consecutive mri studies ,
however , he had clear signs of a progressive deficit on serial assessments . in most cases ,
the use of various therapies has been reported without a clearly discernible benefit , namely , steroids , iron chelators , selegiline , vitamin c , and other antioxidants . in cases where a source of chronic subarachnoid bleeding is identified ,
however , in about 25 - 40% of the patients , a source of siderosis is not identified , as in our patient , and treatment remains essentially symptomatic . to conclude , our case is unusual as the classical syndrome of superficial siderosis
is seen at a young age , secondary to an early surgery of the posterior fossa .
 superficial siderosis of the central nervous system results from deposition of hemosiderin in the subpial layers of the brain and spinal cord . 
 patients usually present after 40 years of age with progressive ataxia and sensorineural hearing impairment . 
 we present the case of a twelve - year - old boy who had a surgery of the posterior fossa at the age of two years and then developed recurrent headaches , instability of gait , and hearing deficit at around ten years of age . 
 clinical examination revealed progressive ataxia and mild sensorineural hearing loss . 
 he also had infrequent seizures with mild electroencephalographic abnormality . 
 his serial magnetic resonance imaging ( mris ) showed a progressive deposition of hemosiderin in the cerebellar folia and around the brainstem , confirming a diagnosis of superficial siderosis . 
 this case report draws attention to this rare condition , usually seen in adults , even though rarely it can be seen in children as a chronic sequela of surgery of the posterior fossa . 
Introduction
Case Report
Discussion