Superficial siderosis and csf hypovolemia: the defect (dural) in the link

Progressive superficial siderosis despite complete remission of intracranial hypotension symptoms following epidural patching: Case report

Spontaneous intracranial hypotension (SIH) commonly results from ventral spinal cerebrospinal fluid (CSF) leaks and epidural patches are advocated as first-line treatment. Complications such as superficial siderosis can arise but have previously been reported only in the context of long-term persistent, ongoing, CSF leak and SIH. We report a case of a patient with SIH from a ventral spinal CSF leak that was treated with epidural patching and experienced complete resolution of SIH. Four years later SIH symptoms recurred, and brain magnetic resonance imaging unexpectedly showed the interval accumulation of hemosiderin pigmentation on the cerebellum and brainstem during the period when the patient was without symptoms of SIH. This case uniquely demonstrates the progression of superficial siderosis despite the apparent resolution of SIH. Our findings suggest two divergent pathophysiological outcomes from spinal ventral dural tear: (1) CSF loss causing SIH; and (2) persistent low-level bleeding arising from the spinal dural tear leading to superficial siderosis. These divergent pathophysiologies had a discordant response to epidural patching. Epidural patching successfully treated the SIH but did not prevent the progression of superficial siderosis, indicating that some patients may require more than epidural patching despite symptom resolution. This case highlights the need for post-treatment monitoring protocols in patients with ventral spinal CSF leaks and SIH and raises important questions about the adequacy of epidural patching in certain SIH cases arising from ventral spinal CSF leak.

Lumbar Subarachnoid-Peritoneal Shunting Deteriorates Superficial Siderosis Associated with a Dural Defect

Superficial siderosis is a disease in which hemosiderin is deposited under the leptomeninges and subpial layers of hindbrain structures, e.g., the cerebellum, brainstem, and eighth cranial nerve. The main symptoms of superficial siderosis are cerebellar ataxia, hearing loss, cognitive decline, and myelopathy. The activities of daily living of patients with superficial siderosis are severely impaired due to the progressive symptoms. Here, we report a patient with superficial siderosis whose symptoms deteriorated after lumbar subarachnoid-peritoneal (L-P) shunt surgery. She received L-P shunt surgery based on the diagnosis of idiopathic normal pressure hydrocephalus at another hospital. The patient had a history of cervical surgery, and a dural defect was identified at the C4-5 level by a detailed magnetic resonance imaging study. We hypothesized that the L-P shunt reduced cerebrospinal pressure and increased bleeding from the fragile vessels in the dural defect, which might have increased hemosiderin deposition.

Progressive loss of hearing and balance in superficial siderosis due to occult spinal dural defects

PURPOSE

Superficial siderosis, a progressive, debilitating, neurological disease, often presents with bilateral impairment of auditory and vestibular function. We highlight that superficial siderosis is often due to a repairable spinal dural defect of the type that can also cause spontaneous intracranial hypotension.

METHODS

Retrospective chart review of five patients presenting with moderate to severe, progressive bilateral sensorineural hearing loss as well as vestibular loss. All patients had developed superficial siderosis from spinal dural defects: three after trauma, one after spinal surgery and one from a thoracic discogenic microspur.

RESULTS

The diagnosis was made late in all five patients; despite surgical repair in four, hearing and vestibular loss failed to improve.

CONCLUSIONS

In patients presenting with progressive bilateral sensorineural hearing loss, superficial siderosis should be considered as a possible cause. If these patients also have bilateral vestibular loss, cerebellar impairment and anosmia, then the diagnosis is likely and the inevitable disease progress might be halted by finding and repairing the spinal dural defect.

Cerebrospinal fluid biomarkers of superficial siderosis in patients with spontaneous intracranial hypotension

BACKGROUND AND PURPOSE

Spontaneous intracranial hypotension (SIH) is an important etiology of infratentorial superficial siderosis (iSS) of the central nervous system. However, the prevalence of iSS amongst patients with SIH is unknown and the imaging findings of iSS might represent a late stage of disease. The aim was to identify cerebrospinal fluid (CSF) biomarkers of iSS in patients with SIH.

METHODS

Consecutive patients evaluated for SIH at our institution between May 2017 and January 2019 were included. Lumbar CSF samples were analyzed for the presence of ferritin and bilirubin. Magnetic resonance imaging was assessed for the presence of iSS.

RESULTS

Twenty-four patients with SIH were included. CSF samples were positive for bilirubin in 2/19 (10.5%). CSF ferritin was elevated in 7/23 (30.4%). Signs of iSS on imaging were present in four patients (16.7%). All patients with imaging signs of iSS demonstrated elevated CSF ferritin. Ferritin level was significantly higher amongst patients demonstrating iSS compared to those without (median 45.0 vs. 11.0 μg/l; p = 0.003). Symptom duration was longer in patients with iSS than in patients without iSS (median 40 months vs. 9 months, p = 0.018).

CONCLUSION

Cerebrospinal fluid alterations indicative of iSS are prevalent amongst patients with SIH. It is speculated that a preclinical phase without symptoms or imaging signs but during which elevated biomarkers of the disease are apparent from CSF analysis might exist. It is suggested that measurement of CSF ferritin is incorporated in the work-up of patients with SIH to identify those at risk of developing iSS.

Asymptomatic superficial siderosis after posterior fossa tumor resection: illustrative case

BACKGROUND

Superficial siderosis of the central nervous system is a rare syndrome notable for the presence of hemosiderin deposition due to chronic, repetitive hemorrhages into the subarachnoid space.

OBSERVATIONS

The authors presented a case of superficial siderosis in a 14-year-old girl. It arose as a late postoperative complication after resection of a medulloblastoma. Despite the patient being asymptomatic, surveillance imaging demonstrated diffuse hemosiderin deposition within the cerebellar folia and cisternal segments of cranial nerves VII and VIII on gradient echo (GRE) sequences. Formal audiometric testing demonstrated bilateral loss of high-frequency tone recognition consistent with early sensorineural hearing loss. A pseudomeningocele due to multiple dural defects was identified as the likely cause, and definitive surgical repair was performed. Intraoperatively, the presence of blood-tinged cerebrospinal fluid confirmed a diagnosis of superficial siderosis.

LESSONS

This case highlighted the potential need to routinely include GRE or susceptibility-weighted sequences in postoperative surveillance imaging after resection of pediatric posterior fossa tumors.

Superficial Siderosis: A Clinical Review

Superficial siderosis of the central nervous system results from subpial hemosiderin deposition due to chronic low-grade bleeding into the subarachnoid space. The confluent and marginal subpial hemosiderin is best appreciated on iron-sensitive magnetic resonance imaging sequences. With widespread use of magnetic resonance imaging, the disorder is increasingly being recognized, including in asymptomatic individuals. Gait ataxia, often with hearing impairment is a common clinical presentation. A clinical history of subarachnoid hemorrhage is generally not present. A macrovascular pathology is generally not causative. The most common etiology is dural disease, often dural tears. Prior or less commonly ongoing symptoms of craniospinal hypovolemia may be present. Common etiologies for dural tears include disc disease and trauma, including surgical trauma. Patients with dural tears due to herniated and calcified discs often have a ventral intraspinal fluid collection due to cerebrospinal fluid leak. A precise identification of the dural tear relies on multimodality imaging. It has been speculated that chronic bleeding from fragile blood vessels around the dural tear may be the likely underlying mechanism. Surgical correction of the bleeding source is a logical therapeutic strategy. Clinical outcomes are variable, although neuroimaging evidence of successful dural tear repair is noted. The currently available data regarding use of deferiprone in patients with superficial siderosis is insufficient to recommend its routine use in patients. ANN NEUROL 2021;89:1068-1079.

Diskogenic Dural Defect Is the Reason for the Ventral Location of the Epidural Spinal Fluid Collection Seen in Superficial Siderosis

Purpose of Review

Superficial siderosis (SS) of the nervous system is often due to a dural pathology. This review focuses on recent developments related to the management of this subgroup of patients with SS.

Recent Findings

The presence of an epidural ventral spinal fluid collection in patients with SS is a clue to the presence of a diskogenic dural defect. The location of the defect is ascertained by a dynamic CT myelogram, which involves placing the patient in a prone position with hips elevated. This permits gravity-assisted preferential ventral localization of the contrast and active scanning during contrast injection facilitates a precise delineation of the initial point of contrast extravasation which localizes the defect.

Summary

Diskogenic dural defects are commonly the underlying etiology for SS in patients with a ventral spinal fluid collection. A dynamic CT myelogram facilitates detection and subsequent repair of these defects, which arrests the continued low-grade subarachnoid bleeding.

Spontaneous Intracranial Hypotension: Atypical Radiologic Appearances, Imaging Mimickers, and Clinical Look-Alikes

Spontaneous intracranial hypotension is a condition characterized by low CSF volume secondary to leakage through a dural defect with no identifiable cause. Patients classically present with orthostatic headaches, but this symptom is not specific to spontaneous intracranial hypotension, and initial misdiagnosis is common. The most prominent features of spontaneous intracranial hypotension on intracranial MR imaging include "brain sag" and diffuse pachymeningeal enhancement, but these characteristics can be seen in several other conditions. Understanding the clinical and imaging features of spontaneous intracranial hypotension and its mimickers will lead to more prompt and accurate diagnoses. Here we discuss conditions that mimic the radiologic and clinical presentation of spontaneous intracranial hypotension as well as other disorders that CSF leaks can imitate.

Ventral Longitudinal Intraspinal Fluid Collection in Patients with Cervical Disc Herniation: A Report of Two Cases

We encountered two cases of cervical disc herniation, wherein cerebrospinal fluid collection in the ventral epidural space between the cervical spine and the thoracic spine was noted. The patients, two women aged 71 and 43 years, were diagnosed with cervical disc herniation and underwent anterior cervical discectomy and fusion. Unexpected cerebrospinal fluid leakage was observed prior to exposure of the dura mater. Notably, the dura mater was intact following the removal of the herniated disc in both cases. No cerebrospinal fluid leakage symptoms were observed, and relief from the neurological symptoms related to the cervical disc herniation was observed in both cases following the surgery. Findings of preoperative magnetic resonance imaging and computed tomography myelography were carefully reviewed, retrospectively. Both patients presented with similar features including expansion of cerebrospinal fluid collection in the ventral epidural space between the cervical spine and the thoracic spine. These observed features were similar to those of superficial siderosis, which is a form of duropathy—a disease caused by dural defects. Therefore, the patients in this case study might have a subclinical duropathy with associated cervical disc herniation.

Successful endoscopic identification of the bleeding source in the ventral dura of the cervical spine in a case of superficial siderosis

The authors report on the case of a 65-year-old man suffering progressive gait disturbance and hearing impairment due to superficial siderosis (SS). According to the literature, repeated hemorrhage into the subarachnoid space causes SS; however, the bleeding source remains unknown in half of SS patients. In the presented case, preoperative MRI revealed a fluid-filled intraspinal cavity extending from C2 to T8 with a dural defect at the ventral C7 level. During surgery, the dural defect was seen to connect to the intraspinal cavity filled with xanthochromic fluid. Importantly, endoscopic observation verified that the rupture of fragile bridging veins in the cavity was the definite bleeding source. Postoperative MRI confirmed disappearance of the intraspinal cavity, and the patient's symptoms gradually improved. The use of endoscopy helped to establish the diagnosis and led to definite treatment. Fragile bridging veins in the fluid-filled interdural layers were novelly verified as a bleeding source in SS. Recognizing this phenomenon is important since it can establish closure of the dural defect as a definite treatment in SS with an intraspinal cavity.

Spontaneous intracranial hypotension and its complications

Spontaneous intracranial hypotension (SIH) is a syndrome that was unknown until the advent of magnetic resonance imaging (MRI). It is a cause of orthostatic headache, which remains underdiagnosed and, rarely, can result in several complications including dural venous sinus thrombosis, subdural hematoma and subarachnoid hemorrhage. Some of these complications are potentially life-threatening and should be recognized promptly, mainly by imaging studies. We reviewed the MRI of nine patients with SIH and describe the complications observed in three of these patients. Two of them had subdural hematoma and one had a dural venous sinus thrombosis detected by computed tomography and MRI. We concluded that MRI findings are of great importance in the diagnosis of SIH and its complications, which often influence the clinical-surgical treatment of the patient.

Clival meningocele causing bilateral hearing loss in a child due to superficial siderosis of the central nervous system: case report

Superficial siderosis (SS) of the CNS is a rare and often unrecognized condition. Caused by hemosiderin deposition from chronic, repetitive hemorrhage in the subarachnoid space, it results in parenchymal damage in the subpial layers of the brain and spinal cord. T2-weighted MRI shows the characteristic hypointensity of hemosiderin deposition, classically occurring around the cerebellum, brainstem, and spinal cord. Patients present with progressive gait ataxia and sensorineural hearing impairment. Although there have been several studies, case reports, and review articles over the years, the clear pathophysiology of subarachnoid space hemorrhage remains to be elucidated. The proposed causes include prior intradural surgery, prior trauma, tumors, vascular abnormalities, nerve root avulsion, and dural abnormalities. Surgical repair of a dural defect associated with SS has been shown to be efficacious at preventing symptomatic progression. There have been several reports of dural defects within the spinal canal treated with surgery. Here, the authors present the first known case of a dural defect of the ventral skull base, namely a clival meningocele, presumed to be causing SS. In this case report, a 10-year-old girl with a history of head trauma at the age of 3 years was found to have a clival meningocele 3 years after her original trauma. On follow-up imaging, the patient was found to have radiographic growth of the meningocele along with evidence of SS of the CNS. The patient was treated conservatively until she began to have progressive hearing loss. It was presumed that the growing meningocele was the source of her SS. An endoscopic endonasal transclival approach with a multilayer dural reconstruction was performed to fix the dural defect and repair the meningocele in hopes of mitigating the progression of her symptoms. At her 12-month postoperative follow-up, she was doing well, with audiometry showing a slightly decreased hearing threshold in the left ear but improved speech discrimination bilaterally. Postoperative MRI showed a stable level of hemosiderin deposition and meningocele repair. Long-term follow-up will be necessary to evaluate for continued clinical stabilization or possible improvement.

Spinal endoscopy combined with selective CT myelography for dural closure of the spinal dural defect with superficial siderosis: technical note

The authors describe a new procedure to detect the tiny dural hole in patients with superficial siderosis (SS) and CSF leakage using a coronary angioscope system for spinal endoscopy and selective CT myelography using a spinal drainage tube. Under fluoroscopy, surgeons inserted the coronary angioscope into the spinal subarachnoid space, similar to the procedure of spinal drainage, and slowly advanced it to the cervical spine. The angioscope clearly showed the small dural hole and injured arachnoid membrane. One week later, the spinal drainage tube was inserted, and the tip of the drainage tube was located just below the level of the dural defect found by the spinal endoscopic examination. This selective CT myelography clarifies the location of the dural defect. During surgery, the small dural hole could be easily located, and it was securely sutured. It is sometimes difficult to detect the actual location of the small dural hole even with thin-slice MRI or dynamic CT myelography in patients with SS. The use of a coronary angioscope for the spinal endoscopy combined with selective CT myelography may provide an effective examination to assess dural closure of the spinal dural defect with SS in cases without obvious dural defects on conventional imaging.

Superficial siderosis of the central nervous system associated with incomplete dural closure following posterior fossa surgery: report of 3 cases

This report reviews a series of 3 patients who developed superficial siderosis following posterior fossa operations in which dural closure was incomplete. In all 3 patients, revision surgery and complete duraplasty was performed to halt the progression of superficial siderosis. Following surgery, 2 patients experienced resolution of their CSF xanthochromia while 1 patient had reduced CSF xanthochromia. In this paper the authors also review the etiology, pathophysiology, diagnosis, and treatment of this condition. The authors suggest that posterior fossa dural patency and pseudomeningocele are risk factors for the latent development of superficial siderosis and recommend that revision duraplasty be performed in patients with posterior fossa pseudomeningoceles and superficial siderosis to prevent progression of the disease.

Low-pressure/spinal fluid leak headache

Low cerebrospinal fluid (CSF) pressure results in neurologic deficits, of which the most common manifestation is headache. Typically, the headache is postural - and specifically, orthostatic - in presentation. There are three hypotheses to explain the occurrence of headache associated with low CSF fluid. The first is traction on pain-sensitive intracranial and meningeal structures; the second is CSF hypovolemia; and the third is spinal loss of CSF resulting in increased compliance at the caudal end of the CSF space. Spontaneous intracranial hypotension (SIH), once believed to be rare, is now more commonly recognized. It is typically associated with orthostatic headache (although initially it may not be) and one or more other symptoms such as alterations in hearing, nausea, vomiting, neck stiffness, diplopia, and visual field cuts. Magnetic resonance imaging (MRI) of the brain with gadolinium is the first study of choice, which typically reveals diffuse pachymeningeal enhancement and, frequently, cerebellar tonsillar descent and posterior fossa crowding. Epidural blood patch (EBP) is the treatment of choice. Surgery and epidural fibrin glue injection are options for those who fail conservative therapy and/or EBP.

Dural closure for the treatment of superficial siderosis

Superficial siderosis (SS) of the CNS is a rare disease caused by repeated hemorrhages in the subarachnoid space. The subsequent deposition of hemosiderin in the brain and spinal cord leads to the progression of neurological deficits. The causes of bleeding include prior intradural surgery, carcinoma, arteriovenous malformation, nerve root avulsion, and dural abnormality. Recently, surgical treatment of SS associated with dural defect has been reported. The authors of the present report describe 2 surgically treated SS cases and review the literature on surgically treated SS. The patients had dural defects with fluid-filled collections in the spinal canal. In both cases, the dural defects were successfully closed, and the fluid collection was resolved postoperatively. In one case, the neurological symptoms did not progress postoperatively. In the other case, the patient had long history of SS, and the clinical manifestations partially deteriorated after surgery, despite the successful dural closure.

In previously reported surgically treated cases, the dural defects were closed by sutures, patches, fibrin glue, or muscle/fat grafting. Regardless of the closing method, dural defect closure has been shown to stop CSF leakage and subarachnoid hemorrhaging. Successfully repairing the defect can halt the disease progression in most cases and may improve the symptoms that are associated with CSF hypovolemia. However, the effect of the dural closure may be limited in patients with long histories of SS because of the irreversibility of the neural tissue damage caused by hemosiderin deposition. In patients with SS, it is important to diagnose and repair the dural defect early to minimize the neurological impairments that are associated with dural defects.

Chronic cerebellar hemorrhage in spontaneous intracranial hypotension: association with ventral spinal cerebrospinal fluid leaks

Object

Spontaneous intracranial hypotension is an important cause of new-onset daily persistent headache. Cerebellar hemorrhage has been identified as a possible feature of spontaneous intracranial hypotension. The authors reviewed the MR imaging studies from a group of patients with spontaneous intracranial hypotension to assess the presence of cerebellar hemorrhage.

Methods

Medical records and radiological images were reviewed in 262 cases involving patients with spontaneous intracranial hypotension who had undergone MR imaging of the brain as well as spinal imaging.

Results

Chronic cerebellar hemorrhages were found in 7 (2.7%) of the 262 patients with spontaneous intracranial hypotension. These hemorrhages were found in 7 (19.4%) of the 36 patients with a ventral spinal CSF leak and in none of the 226 patients who did not have such a CSF leak (p < 0.0001). The degree of hemosiderin deposits was variable, ranging from mild involvement of the cerebellar folia to widespread superficial siderosis. Only the 1 patient with superficial siderosis had symptoms due to the hemorrhages. The time period between the onset of symptoms due to spontaneous intracranial hypotension and MR imaging examination was significantly longer in those patients with cerebellar hemorrhage than in those with a ventral spinal CSF leak and no evidence for cerebellar hemorrhage (mean 19.6 years vs 2.3 months, p < 0.0001).

Conclusions

Chronic cerebellar hemorrhage should be included among the manifestations of spontaneous intracranial hypotension. The severity is variable, but the hemorrhage generally is asymptomatic. The underlying spinal CSF leak is ventral and mostly of long duration.

A unifying hypothesis for a patient with superficial siderosis, low-pressure headache, intraspinal cyst, back pain, and prominent vascularity

A source of bleeding is often not evident during the evaluation of patients with superficial siderosis of the CNS despite extensive imaging. An intraspinal fluid-filled collection of variable dimensions is frequently observed on spine MR imaging in patients with idiopathic superficial siderosis. A similar finding has also been reported in patients with idiopathic intracranial hypotension. The authors report on a patient with superficial siderosis and a longitudinally extensive intraspinal fluid-filled collection secondary to a dural tear. The patient had a history of low-pressure headaches. His spine MR imaging and spine CT suggested the possibility of an underlying vascular malformation, but none was found on angiography. Repair of the dural tear resulted in resolution of the intraspinal fluid collection and CSF abnormalities. The significance of the association between superficial siderosis and idiopathic intracranial hypotension, and potential therapeutic and pathophysiological implications, are the subject of this report.

Neuroimaging in superficial siderosis: an in-depth look

Despite extensive imaging, a source of bleeding is often not evident during the evaluation of patients with superficial siderosis (SS) of the central nervous system. An intraspinal fluid-filled collection of variable dimensions is frequently seen on spine MR imaging in patients with idiopathic SS. A similar finding has also been reported in patients with craniospinal hypotension. This review discusses the role of multitechnique imaging in the work-up of patients with SS and focuses on recent developments.