General Neurology
Ulnar neuropathies
May. 22, 2023
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The author explains the clinical presentation, pathophysiology, prevention, diagnostic workup, and management of superficial siderosis of the central nervous system. Superficial siderosis is a potentially devastating syndrome usually caused by recurrent subarachnoid hemorrhage with accumulation of hemosiderin and other iron-containing pigments in the leptomeninges, brain surface, brainstem, cerebellum, cranial nerves, and spinal cord. Superficial siderosis can mimic many other central nervous system degenerative or multifocal disorders, including amyotrophic lateral sclerosis and multiple sclerosis.
• Superficial siderosis is a rare and potentially devastating syndrome caused by recurrent subarachnoid hemorrhage with accumulation of hemosiderin and other iron-containing pigments in the leptomeninges, brain surface, brainstem, cerebellum, cranial nerves, and spinal cord. | |
• Common features include progressive sensorineural hearing loss, cerebellar ataxia, pyramidal signs (eg, spastic paraparesis, quadriparesis, etc.), ataxia, and headache. | |
• Superficial siderosis is caused by recurrent subarachnoid hemorrhage with dissemination of heme by circulating cerebrospinal fluid and subsequent accumulation of hemosiderin and other iron-containing pigments in the leptomeninges, brain surface, brainstem, cerebellum, cranial nerves, and spinal cord. | |
• The condition may be progressively disabling or fatal. Even with successful surgical resection of the causative lesion (when that is identified), significant functional recovery cannot be anticipated. However, progression generally is lessened or averted, at least in the short periods of follow-up reported. | |
• A wide variety of conditions may cause superficial siderosis, including various cerebral or spinal vascular abnormalities, neoplasms or other mass lesions of the brain and spinal cord or surrounding structures, trauma, and rarely some neurosurgical procedures, congenital abnormalities, and other sources of vascular damage. | |
• Management is directed at resection of the source of bleeding. |
Superficial siderosis is a rare and potentially devastating syndrome caused by recurrent subarachnoid hemorrhage with accumulation of hemosiderin and other iron-containing pigments in the leptomeninges, brain surface, brainstem, cerebellum, cranial nerves, and spinal cord (56). Although superficial siderosis had been produced experimentally in dogs as early as 1960 (40), superficial siderosis had been considered a rare condition, usually diagnosed postmortem, until the advent of CT and MRI in the mid-1980s (81). It is now increasingly recognized.
• Common clinical features of superficial siderosis include progressive sensorineural hearing loss, cerebellar ataxia, pyramidal signs (eg, spastic paraparesis, quadriparesis, etc.), ataxia, and headache. | |
• The progressive sensorineural hearing loss of superficial siderosis may be the presenting or predominant symptom, may be slowly progressive over many years, and may be caused by a combination of retrocochlear and cochlear damage. | |
• Other clinical features of superficial siderosis seen in a minority of patients include seizures, corticobasal syndrome, cranial nerve abnormalities, spinal myoclonus, polyradiculopathy and sciatica, neck or back ache, urinary incontinence, somatosensory deficits, acute intracranial pressure crisis superimposed on chronic intracranial hypertension, and episodic encephalopathy with associated headache and vomiting. |
Common clinical features of superficial siderosis include progressive sensorineural hearing loss, cerebellar ataxia, pyramidal signs (eg, spastic paraparesis, quadriparesis, etc.), ataxia, and headache (62; 90; 33; 41; 65; 71; 53; 119; 50; 131; 63; 75; 102; 56; 109).
The progressive sensorineural hearing loss may be the presenting or predominant symptom (50; 75; 102), may be slowly progressive over many years (75; 102), and may be caused by a combination of retrocochlear and cochlear damage (106). Hearing loss is typically sloping and asymmetric, exceeds hearing loss expected for age and gender, and may be associated with decreased word recognition (102). Superficial siderosis should be considered in all patients presenting with progressive sensorineural hearing loss and ataxia (112). Sudden sensorineural hearing loss has also been attributed anecdotally to superficial siderosis, but whether the superficial siderosis was causal or incidental is not clear (59). Some patients develop peripheral vestibular disorders in conjunction with hearing loss with associated caloric weakness, disequilibrium, dizziness, and vertigo (118; 114; 131).
Neuropsychological disturbances are common in classical superficial siderosis (07). Neuropsychological testing has demonstrated impairments in speech production, visual recall memory, executive functions, and ability to represent other people’s mental states (113).
Other clinical features seen in a minority of patients include seizures, corticobasal syndrome, cranial nerve abnormalities, spinal myoclonus, polyradiculopathy and sciatica, neck or back ache, urinary incontinence, somatosensory deficits, acute intracranial pressure crisis superimposed on chronic intracranial hypertension, and episodic encephalopathy with associated headache and vomiting (37; 50; 131; 63; 35; 116; 56; 89; 20; 42; 05; 31; 115). Cranial nerve abnormalities can include anosmia or hyposmia, anisocoria, optic neuropathy, visual field deficits, fourth nerve palsy, diplopia, nystagmus, trigeminal neuropathy, hemifacial spasm, sensorineural hearing loss, intermittent vertigo, bilateral vestibulopathy, and dysarthria (50; 58; 107).
A significant number of cases may be asymptomatic, possibly reflecting a milder form of disease or a presymptomatic state (37; 62; 42; 109; 31).
The prognosis is often poor. The condition may be progressively disabling or fatal. Even with successful surgical resection of the causative lesion (when that is identified), significant functional recovery cannot be anticipated. However, generally progression is lessened or averted, at least in the short periods of follow-up reported (95).
In survivors of spontaneous symptomatic intracerebral hemorrhage related to probable or possible cerebral amyloid angiopathy, disseminated cortical superficial siderosis predicts early recurrent lobar hemorrhage (86; 13; 11). The evolution of cortical superficial siderosis over time may be a useful biomarker for assessing disease progression and risk of intracerebral hemorrhage in cerebral amyloid angiopathy (14).
Cortical superficial siderosis results from fairly advanced cerebral amyloid angiopathy of the leptomeningeal vessels and may trigger secondary ischemic injury in affected areas (18). Patients with cortical superficial siderosis and suspected cerebral amyloid angiopathy are at high risk for cerebral amyloid angiopathy-related incident intracranial hemorrhage and poor functional outcome (124).
In patients with acute intracerebral hemorrhage, cortical superficial siderosis severity is an independent predictor of diffusion-weighted imaging lesions (85). In a memory clinic population, cortical superficial siderosis was related to cerebrovascular disease and may be a manifestation of severe cerebral amyloid angiopathy, even in patients without intracerebral hemorrhage (94).
A 62-year-old man presented with difficulty walking, diffuse weakness, falls, and syncope (98). He had a 1-week history of rapidly progressive hand weakness and weakness of the limbs. There was no history of recent or remote trauma, but he had a history of subarachnoid hemorrhage 6 months prior to evaluation that had been managed conservatively. MRI of the brain showed mild effacement of the sulcal spaces on T1- and T2-weighted images, and there was a positive phase shift and blooming along the sulcal spaces on phase-contrast and maximum-intensity projection susceptibility-weighted images suggestive of superficial siderosis, but evident source of bleeding.
Cervical spinal MRI revealed an intradural extramedullary mass occupying the anterior intradural space, compressing and displacing the spinal cord posteriorly, with hyperintense signal on T1-weighted images and hypointense signal on T2-weighted images.
There was no clear contrast enhancement of the mass on postcontrast, fat-saturated, T1-weighted images because of strong T1 hyperintensity on the unenhanced images, but mild heterogeneous peripheral enhancement of the mass was seen on the subtracted images.
Sagittal PET-CT images showed a moderately fluorodeoxyglucose-avid, extramedullary, intradural mass with no other foci of fluorodeoxyglucose avidity elsewhere.
The patient underwent C3–C5 laminectomy with excision of a firm, smooth-surfaced, and blackish-colored intradural extramedullary mass lesion. Histopathological examination showed a diffusely pigmented tumor with a peritheliomatous arrangement of cells (ie, tumor cells around blood vessels with necrosis of tumor cells further away from vessels), which obscured the cytological details.
After bleaching, the tumor cells had pleomorphic, round-to-oval nuclei with inconspicuous nucleoli and a moderate amount of cytoplasm.
On higher magnification, the tumor cells had mild nuclear pleomorphism and moderate-to-abundant cytoplasm, with occasional cells containing a blackish-brown pigment. No significant increase in mitosis was evident.
On immunostaining with Ki-67 (the Ki-67 protein, also known as MKI67, which is a cellular marker for proliferation), the tumor had a low proliferation index (< 1%), which is characteristic of melanocytomas. Subsequent careful examination of the skin and the fundus of the eye did not reveal any melanotic lesions. Therefore, the tumor was considered a primary melanocytoma of the cervical spine. The patient improved symptomatically in the postoperative period.
• Superficial siderosis is caused by recurrent subarachnoid hemorrhage with dissemination of heme by circulating cerebrospinal fluid and subsequent accumulation of hemosiderin and other iron-containing pigments in the leptomeninges, brain surface, brainstem, cerebellum, cranial nerves, and spinal cord. | |
• Cerebral amyloid angiopathy patients, who are prone to develop superficial siderosis, may prove to be a useful subgroup in whom to explore pathogenetic mechanisms for superficial siderosis. |
Superficial siderosis is caused by recurrent subarachnoid hemorrhage with dissemination of heme by circulating cerebrospinal fluid and subsequent accumulation of hemosiderin and other iron-containing pigments in the leptomeninges, brain surface, brainstem, cerebellum, cranial nerves, and spinal cord (48). Hemosiderin may be intracellular or extracellular. Large mononuclear phagocytes containing granules of hemosiderin (ie, siderophages) can be demonstrated pathologically. Histologic sections demonstrate severe damage to the eighth cranial nerve and cerebellum (47; 80; 48), presumably as a result of preferential deposition from glial catabolism of ferritin within these structures (28). In the cerebellum, Bergmann glia and abundant microglia synthesize heme-oxygenase-1 and ferritin in response to heme (48). Hearing loss can be caused by degeneration of spiral ganglion cells (75). Localized deposition of hemosiderin in the cortex may produce specific cognitive impairments and hallucinations, depending on the location and severity of deposition (108).
Cerebral amyloid angiopathy patients, who are prone to develop superficial siderosis, may prove to be a useful subgroup in whom to explore pathogenetic mechanisms for superficial siderosis (16; 08; 97; 04; 51; 66; 74; 08; 22; 86; 12). In cerebral amyloid angiopathy, the multifocality of cortical superficial siderosis correlates with disease severity, suggesting that cortical superficial siderosis is caused by discrete hemorrhagic foci (12). In addition, MRI-visible centrum semiovale perivascular spaces are highly prevalent and are associated with cortical superficial siderosis, although the basis of this association has not been established (16); MRI-visible centrum semiovale perivascular spaces are a potential biomarker of impaired interstitial fluid drainage in sporadic cerebral amyloid angiopathy, and it is possible that severe leptomeningeal and cortical vascular amyloid is related to impaired interstitial fluid drainage from cerebral white matter, and the subsequent development of superficial siderosis (16). In addition, superficial siderosis is inversely associated with counts of cerebral microbleeds and with the APOE ε2 genotype (whereas cerebral microbleeds are associated with the APOE ε4 genotypes) (97); these results suggest that cerebral amyloid angiopathy-related superficial siderosis and cerebral microbleeds may arise from distinct vasculopathic mechanisms (97).
Bleeding from the epidural venous plexus may cause superficial siderosis associated with ventral dural defects (105).
• Almost all reported cases of superficial siderosis have been single case reports or small case series. | |
• Little is known about the epidemiology of the condition although it is being increasingly recognized by MRI. | |
• The prevalence of superficial siderosis is higher in a memory disorders clinic population than reported in the general population. | |
• The presence of superficial siderosis has been associated with lower cognitive scores, microbleeds, white matter hyperintensities, and APOE ε4, independent of diagnosis. |
Almost all reported cases of superficial siderosis have been as single case reports or small case series. Little is known about the epidemiology of the condition although it is being increasingly recognized by magnetic resonance imaging. The prevalence of superficial siderosis is higher in a memory disorders clinic population than reported in the general population (132). There is an increased prevalence of dementia in patients with preexisting cortical superficial siderosis (130). Down syndrome patients also have a significantly higher mean microbleed count and greater likelihood of superficial siderosis than age-matched controls (93). It has been reported as occurring in approximately 6% to 40% of those with cerebral amyloid angiopathy (15; 123), compared with nearly 5% of those with Alzheimer disease, 2.5% of those with other types of dementia, 2% of those with mild cognitive impairment, and in less than 1% of those with subjective memory complaints or other disorders (132). In a clinical series of 41 patients with bilateral vestibulopathy, superficial siderosis was identified as the cause in 3 (7%) (44). The presence of superficial siderosis has been associated with lower cognitive scores, microbleeds, white matter hyperintensities, and APOE ε4, independent of diagnosis (123; 132), although not all studies agree (19).
A synthetic study that combined Framingham (n=1724; 2000 to 2009) and Rotterdam (n=4325; 2005 to 2013) study participants who underwent brain MRI, a total of 6049 participants were identified, of whom 401 (7%) had deep/mixed microbleeds, 776 (13%) had lobar microbleeds without cortical superficial siderosis, and 26 (0.4%) had cortical superficial siderosis with/without microbleeds (96). Participants with cortical superficial siderosis were older, had overrepresentation of the APOE ɛ4 allele, and greater prevalence of intracerebral hemorrhage. During a mean follow-up of 5.6 years, 42% of those with cortical superficial siderosis had a stroke, 19% had transient neurologic deficits, and 4% developed incident dementia.
There are often long delays between symptom onset and definitive diagnosis of superficial siderosis (35). Superficial siderosis can mimic many other central nervous system degenerative or multifocal disorders. For example, cases have been reported that have been confused with amyotrophic lateral sclerosis (with slowly progressive weakness, fasciculations, and hyperreflexia) (29) and multiple sclerosis (with oligoclonal bands in some cases) (79).
There are often long delays between symptom onset and definitive diagnosis of superficial siderosis (35). Superficial siderosis can mimic many other central nervous system degenerative or multifocal disorders. For example, cases have been reported that have been confused with amyotrophic lateral sclerosis (with slowly progressive weakness, fasciculations, and hyperreflexia) (29) and multiple sclerosis (with oligoclonal bands in some cases) (79).
A wide variety of conditions may cause superficial siderosis, including the following (02; 16; 43; 56; 89; 97; 127; 04; 51; 66; 74; 117; 03; 08; 25; 26; 68; 76; 126; 104; 06; 69; 01; 129; 78; 32; 64; 87):
Cerebral or spinal vascular abnormalities | |
• Cerebral or spinal arteriovenous malformation | |
• Cerebral or spinal dural arteriovenous fistula | |
• Cavernous malformation | |
• Intracranial aneurysm | |
• Neonatal intraventricular hemorrhage | |
• Cerebral amyloid angiopathy | |
• Subarachnoid hemorrhage associated with bilateral internal jugular thromboses | |
• Central nervous system vasculitis associated with hemochromatosis | |
Neoplasms or other mass lesions | |
• Spinal pilocytic astrocytoma | |
• Ependymoma (or subependymoma) of the fourth ventricle, conus medullaris, filum terminale, cauda equina | |
• Spinal teratoma | |
• Filum terminale paraganglioma | |
• Meningeal melanocytoma | |
• Metastatic melanoma | |
• Cerebral papillary glioneuronal tumor | |
• Germ cell tumor of the basal ganglia | |
• Prolactinoma | |
• Childhood cerebellar tumors or pontine hematoma | |
• Spinal extradural cyst | |
• Craniopharyngioma | |
Trauma | |
• Chronic subdural hematoma | |
• Traumatic fluid-filled cavities in the spinal cord | |
• Cervical root avulsion or brachial plexopathy with chronic intrathecal bleeding from dural sleeve pseudomeningoceles | |
Postsurgical | |
• Ventriculoperitoneal shunt placement | |
• Postsurgical pseudomeningoceles | |
• Incomplete dural closure following posterior fossa surgery | |
• Following surgery for pontine hematoma that established a pathway for extravasated blood into the fourth ventricle | |
• Cervical laminoplasty with fractured hardware puncturing the adjacent dura | |
• Cervical laminectomy and autograft fusion for the removal of a spinal schwannoma | |
Other sources of vascular damage | |
• Hereditary transthyretin-related amyloidosis | |
• Occipital encephalocele | |
• Clival meningocele | |
• Dural defects, possibly associated with CSF hypovolemia | |
• Sacral polycystic meningocele | |
• Dural ectasia | |
• Chronic cerebellar hemorrhage in spontaneous intracranial hypotension | |
• Neonatal alloimmune thrombocytopenia | |
• Germinal matrix hemorrhage | |
• Intradural thoracic disc herniation |
According to Lee and colleagues, superficial siderosis should also be considered in cases of rapidly progressive hearing loss occurring over weeks (57); the following table was modified by Dr. Douglas Lanska using information from Lee’s study.
• Intracranial (noninfectious) | ||
- superficial siderosis | ||
- lymphoma | ||
- metastatic deposit | ||
- meningioma | ||
- cavernous angioma | ||
• Paraneoplastic syndrome | ||
- small cell lung carcinoma | ||
- thymoma | ||
• Inflammatory or autoimmune disorders | ||
- autoimmune inner-ear disease | ||
- sarcoidosis | ||
- vasculitis | ||
- Sjögren syndrome | ||
• Infectious disorders | ||
- meningitis | ||
- syphilis | ||
- human immunodeficiency virus | ||
• Medication-induced causes | ||
|
Despite thorough evaluation (eg, with MRI, CT, angiography, and myelography), no cause is identified in a significant fraction of cases (50; 21).
• Superficial siderosis should be suspected in patients with progressive sensorineural hearing loss, ataxia, and pyramidal dysfunction. | |
• A thorough evaluation is needed when superficial siderosis is suspected in order to localize the source of bleeding. MRI is the most important diagnostic study, in conjunction with lumbar puncture and selective use of angiography. | |
• MRI studies demonstrate hemosiderin deposition along the superficial surfaces of the brain, brainstem, cerebellum, and spinal cord. Hypointense rims around the brain, brainstem, cerebellum, cranial nerves, or spinal cord are commonly seen on T2-weighted images, and hyperintense rims may be demonstrated on T1-weighted images. | |
• CT may show widespread meningeal enhancement or cerebellar atrophy. | |
• Although CT may suggest the diagnosis of superficial siderosis, MRI is more sensitive and specific. | |
• Cortical superficial siderosis in combination with other small vessel disease imaging markers is highly indicative of cerebral amyloid angiopathy. | |
• When superficial siderosis is diagnosed on brain imaging and no source is identified, spinal imaging is essential. Dural diverticula, pseudomeningoceles, and other dural defects (including transdural leaks) are usually best shown on myelography or CT myelography. The location of a dural defect associated with longitudinally extensive intraspinal collections may be best localized by dynamic CT myelography. | |
• Lumbar puncture may demonstrate recurrent or persistent xanthochromia, red cells, a slightly elevated white cell count, increased protein, increased iron and ferritin levels in the cerebrospinal fluid, and siderophages. |
Superficial siderosis should be suspected in patients with progressive sensorineural hearing loss, ataxia, and pyramidal dysfunction (21). A long asymptomatic phase and the lack of a predictive relationship between the duration and severity of hearing loss impede use of audiometry to diagnose superficial siderosis (103). However, asymmetric hearing loss exceeding expectations, particularly with a history of head trauma or a previous neurosurgical procedure, should raise suspicion for the disorder. Nevertheless, superficial siderosis may be misdiagnosed as idiopathic or age-associated bilateral sensorineural deafness (36).
A thorough evaluation is needed when superficial siderosis is suspected to localize the source of bleeding. MRI is the most important diagnostic study, in conjunction with lumbar puncture and selective use of angiography. Although used in the past (120), there is little role for brain biopsy any longer to diagnose this condition. Nevertheless, even with thorough diagnostic evaluation, the source of bleeding remains unidentified in many cases (72; 50).
MRI studies demonstrate hemosiderin deposition along the superficial surfaces of the brain, brainstem, cerebellum, and spinal cord (50; 30). Hypointense rims around the brain, brainstem, cerebellum, cranial nerves, or spinal cord are commonly seen on T2-weighted images, and hyperintense rims may be demonstrated on T1-weighted images (99; 83; 111; 55; 33; 65; 50). A temporal bone MRI protocol including 3D-constructive interference in steady state (3D-CISS) and susceptibility-weighted imaging (SWI) may be helpful in patients with sensorineural deafness or vestibular deficits and ataxia due to superficial siderosis (115). In cerebral amyloid angiopathy, cortical superficial siderosis on MRI corresponds to accumulated iron-positive deposits in the superficial cortical layers, representing the chronic manifestation of prior bleeding episodes from leptomeningeal vessels (18).
CT may show widespread meningeal enhancement or cerebellar atrophy (81; 99). Although CT may suggest the diagnosis of superficial siderosis, MRI is more sensitive and specific (99; 50).
Cortical superficial siderosis in combination with other small vessel disease imaging markers is highly indicative of cerebral amyloid angiopathy; in contrast, cortical superficial siderosis is absent in CADASIL, whereas other small vessel disease imaging features are similar to those of cerebral amyloid angiopathy patients with cortical superficial siderosis (122). In a meta-analysis, the most frequently reported CT features of cerebral amyloid angiopathy-associated intracerebral hemorrhage were subarachnoid extension and an irregular intracerebral hemorrhage border (91). Acute convexity subarachnoid hemorrhage in association with radiologic evidence of cortical superficial siderosis is likely due to cerebral amyloid angiopathy without lobar hemorrhage (09; 84). Cerebral amyloid angiopathy-associated intracerebral hemorrhage was more likely to be multiple on CT than noncerebral amyloid angiopathy-associated intracerebral hemorrhage (91). Superficial siderosis on MRI was present in about half (52%) of cerebral amyloid angiopathy-associated intracerebral hemorrhage (91). In patients with cerebral amyloid angiopathy, the presence and extent of cortical superficial siderosis are the most important MRI prognostic risk factors for future intracerebral hemorrhage (10). Cortical superficial siderosis evolution on MRI is common in patients with symptomatic cerebral amyloid angiopathy (82).
Cerebellar superficial siderosis is also common in cerebral amyloid angiopathy and is present in approximately 10% of cases (46).
In a prospective observational cohort study of spontaneous intracerebral hemorrhage, clinical and radiologic markers associated with cortical superficial siderosis were predictive of underlying cerebral amyloid angiopathy (73). Clinical factors independently associated with the presence of cortical superficial siderosis included increasing age, preexisting dementia, and history of intracerebral hemorrhage. Among radiologic biomarkers, factors independently associated with the presence of cortical superficial siderosis were lobar location of intracerebral hemorrhage, severe white matter hyperintensities, and absence of lacunes. During a median follow-up of 6 years, only the presence of disseminated cortical superficial siderosis was associated with recurrent symptomatic intracerebral hemorrhage.
When superficial siderosis is diagnosed on brain imaging and no source is identified, spinal imaging is essential (60; 35). Dural diverticula, pseudomeningoceles, and other dural defects (including transdural leaks) are usually best shown on myelography or CT myelography (50; 121). The location of a dural defect associated with longitudinally extensive intraspinal collections may be best localized by dynamic CT myelography (50).
Persisting spinal dural CSF leaks can frequently be identified in patients with a symmetric infratentorial siderosis pattern. Evaluation of such cases should include MRI of the whole spine. A retrospective analysis of 93 adult cases of superficial siderosis at a tertiary medical center from 2007 to 2018 included 42 patients with isolated supratentorial siderosis, 30 with symmetric infratentorial siderosis, and 21 with limited (asymmetric) infratentorial siderosis (34). Amyloid angiopathy and subarachnoid hemorrhage were identified causes for isolated supratentorial siderosis. Spinal dural abnormalities were detected in all 4 cases with a symmetric infratentorial siderosis pattern without a history of a causative intracranial bleeding event sufficient to explain the siderosis. When the evaluation algorithm was modified to search for spinal dural leaks in cases of symmetric infratentorial siderosis either (1) without an intracranial bleeding event sufficient to explain the siderosis or additional (2) with a history of intracranial bleeding event without known bleeding etiology (spinal dural CSF leaks may also cause intracranial hemorrhage), one additional spinal dural leak was detected among the 8 cases in this combined group.
Lumbar puncture may demonstrate recurrent or persistent xanthochromia, red cells, a slightly elevated white cell count, increased protein, increased iron and ferritin levels in the cerebrospinal fluid, and siderophages (99; 120; 67; 50; 50). Again, because of the intermittent bleeding in small amounts, CSF may be normal (50).
Angiography may reveal various vascular malformations (37). In some cases, vascular malformations identified on angiography were not identified with MRI or myelography. In many cases, angiography also does not identify the source of bleeding, probably because of the small volume of ongoing, intermittent blood leakage (52; 50; 50; 121).
• Management is directed at resection of the source of bleeding. | |
• Despite the retrocochlear nature of the disorder, bilateral profound hearing loss from superficial siderosis is not an absolute contraindication for cochlear implants. | |
• Pharmacotherapy with iron-chelation therapy is not of demonstrated effectiveness, nor is shunting of cerebrospinal fluid or corticosteroid therapy. |
Management is directed at resection of the source of bleeding (99; 61; 50; 49; 95; 35; 56). Symptomatic treatment is directed as well at various features of the condition, including headache, seizures, etc.
Despite the retrocochlear nature of the disorder, bilateral profound hearing loss from superficial siderosis is not an absolute contraindication for cochlear implants (27; 38; 45; 125; 101; 128; 75; 102; 100; 110; 88; 77). The reported success of cochlear implantation in such cases is variable (101; 128; 110), with some anecdotal reports of benefit (38; 45; 100) and others of lack of benefit or only marginal benefit (125; 88). Furthermore, apparent initial benefit from cochlear implants in patients with superficial siderosis may not be long-standing, particularly in those with progressive underlying disease (128; 110). Long-term outcomes depend on the site of lesion, the degree of cochlear nerve function, and the ongoing neural deterioration (110).
Pharmacotherapy with iron-chelation therapy is not of demonstrated effectiveness (99), nor is shunting of cerebrospinal fluid (70) or corticosteroid therapy (92). Improvement in hearing and mobility has been anecdotally reported following treatment with deferiprone, a new iron chelation therapy that can penetrate the blood-brain barrier (24; 23), but this therapy has also been associated with agranulocytosis (39), therefore, controlled studies will be necessary to establish the efficacy and overall utility of this therapy.
All contributors' financial relationships have been reviewed and mitigated to ensure that this and every other article is free from commercial bias.
Douglas J Lanska MD FAAN MS MSPH
Dr. Lanska of the University of Wisconsin School of Medicine and Public Health and the Medical College of Wisconsin has no relevant financial relationships to disclose.
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