Spontaneous intracranial hypotension with deep brain swelling

Venous infarction mimicking a neoplasm in spontaneous intracranial hypotension: an unusual cause of Parinaud's syndrome

We present a case of longstanding, undiagnosed spontaneous intracranial hypotension (SIH) with an acute presentation of Parinaud's syndrome, in whom serial imaging demonstrated development of a midbrain mass. The patient was ultimately diagnosed with tumefactive venous infarction secondary to SIH. However, this patient underwent a brainstem biopsy, which in retrospect may have been avoidable. This case demonstrates the imaging features of tumefactive venous infarction in SIH and highlights the risk of misinterpretation as a neoplasm with potentially catastrophic consequences.

Intracranial hypotension: clinical presentation, imaging findings, and imaging-guided therapy

PURPOSE OF REVIEW

To illustrate clinical presentations, imaging findings, and diagnostic and therapeutic approaches associated with various conditions of intracranial hypotension.

RECENT FINDINGS

Intracranial hypotension occurs spontaneously, following (lumbar) dural puncture, accidental dural opening, or excessive surgical cerebrospinal fluid drainage. The typical clinical manifestation - orthostatic headache - may be masqueraded by atypical clinical findings, including coma, frontotemporal dementia, leptomeningeal hemosiderosis-associated symptoms, and others. MRI signs are highly specific, but the imaging strategy to search for spinal cerebrospinal fluid leaks (none, computed tomography myelography, magnetic resonance myelography with gadolinium, digital subtraction myelography) is a matter of debate. The same is true for the mode of treatment (bed rest, blind, fluoroscopy or computed tomography-guided epidural blood patching, fibrin patching, surgery).

SUMMARY

Clinical presentation as well as diagnostic and therapeutic approaches in intracranial hypotension are very heterogenous.

[Intracranial hypotension]

In this review article the clinical manifestations, imaging findings, diagnostic and therapeutic approaches for intracranial hypotension are described. The typical manifestation, orthostatic headache, may sometimes be masked by atypical manifestations including coma, frontotemporal dementia and symptoms associated with leptomeningeal hemosiderosis. Spinal and cranial magnetic resonance imaging (MRI) findings are not always unequivocal and the diagnostic and therapeutic approaches are controversially discussed: Searching for the underlying spinal leak(s) of cerebral spinal fluid (CSF) is considered to be unnecessary or done with different modalities, such as computed tomography (CT) myelography, gadolinium-enhanced myelography and digital subtraction myelography. Various treatment approaches including conservative therapy, blind, fluoroscopy-guided and CT-guided epidural blood patches, CT-guided fibrin injection and surgery exist.

Apparent diffusion coefficient measurements to support a diagnosis of intracranial hypotension

OBJECTIVE

Intracranial hypotension (ICH) can be a challenging diagnosis, as cerebrospinal fluid leaks may be difficult to confirm, patients may have other causes for clinical symptoms and imaging findings can be non-specific, particularly in the setting of comorbidities. We investigate the use of brain diffusion measurements [apparent diffusion coefficient (ADC) values] in the assessment of ICH.

METHODS

13 cases of ICH were identified retrospectively based on imaging findings and their clinical histories were compared with 13 control subjects. Regional ADC values and average diffusion constant (Dav) from brain slice ADC histograms were measured.

RESULTS

ADC values trended higher in all brain regions in patients with ICH than those in control subjects, with statistically significant differences in frontal white matter, mid-brain and deep grey structures. Dav determined by a single-slice ADC histogram was significantly higher in patients with ICH than in the control group (p = 0.008). In two cases followed longitudinally, Dav correlated with the patient's symptoms and decreased towards normal value with blood patch. In one case, decreased Dav correlated with the formation of subdural collections.

CONCLUSION

Cerebral oedema as assessed by increased ADC is strongly correlated with ICH (10 of 13 cases). Histographic analysis of ADC values may offer increased accuracy of ADC measurement. ADC value assessment in the determination of ICH may be particularly useful in complex clinical cases, where treatment is followed over time or where gadolinium is not used and meningeal enhancement cannot be assessed.

ADVANCES IN KNOWLEDGE

This article investigates the use of brain diffusion measurements in the assessment of ICH in the clinical setting.

Management of patients with spontaneous intracranial hypotension causing altered level of consciousness: report of two cases and review of literature

BACKGROUND

Decreased level of consciousness is a rare neurological manifestation of spontaneous intracranial hypotension (SIH), which typically presents with orthostatic headache. The optimal management of this uncommon presentation remains uncertain.

METHODS

We analyzed the presentation, management and outcome of two patients in our institution and reviewed 22 patients reported in the literature with SIH and decreased level of consciousness, defined as any decrease in the patient's Glasgow Coma Scale score.

RESULTS

There were 20 male and four female patients (M:F ratio of 5:1) with an average age of 52 years (range 37 to 68 years). There was a variable time interval of up to many months between the initial presentation of SIH and changes in the level of consciousness. An epidural autologous blood patch was eventually successful in 79% of the patients, although up to three trials were necessary in seven of these patients. Intrathecal saline infusion used as a temporizing measure resulted in excellent response within hours in five out of six patients who received this treatment. Drainage of the subdural collection either did not result in any sustained improvement or resulted in clinical deterioration in 12 out of 12 patients who received this treatment.

CONCLUSIONS

In the absence of a clinical trial because of the rarity of this entity, the treatment of SIH complicated by decreased level of consciousness remained controversial in the past. However, current collective experience supports early treatment of patients with SIH and decreased level of consciousness with one or more epidural blood patches. Fibrin glue and surgical duroplasty are the next steps in the management of patients in whom epidural blood patches fail. Drainage of the subdural collections may be detrimental.

Spontaneous intracranial hypotension syndrome may mimic aseptic meningitis

BACKGROUND

Spontaneous intracranial hypotension (SIH) is recognized with increasing frequency. A throbbing headache occurring or worsening in the upright position and improving after lying down, a so-called 'orthostatic headache', low cerebrospinal fluid (CSF) pressure, and diffuse pachymeningeal enhancement on brain magnetic resonance imaging (MRI) are the major features of the classic syndrome. These patients, who are admitted with fever, headache, and CSF findings revealing lymphocytic pleocytosis, elevated protein concentration, normal glucose levels, and negative culture results, are prone to be misdiagnosed with aseptic meningitis. The aims of this single-centre retrospective study were to determine the epidemiological, clinical, laboratory, and radiological features of patients initially evaluated as having aseptic meningitis but subsequently diagnosed with SIH, and to touch upon the key points of the differential diagnosis in daily infectious diseases practice.

METHODS

Patients referred to Cerrahpasa Medical School with a presumed diagnosis of aseptic meningitis or viral meningitis between 1 January 2006 and 1 January 2011 were reviewed. Epidemiological, clinical, laboratory, radiological, and follow-up data obtained from the hospital database were processed. Patients confirmed to have SIH syndrome were included for evaluation.

RESULTS

Eleven cases of SIH syndrome were diagnosed during the study period (8 male and 3 female, median age 30 y, range 21-44 y). All had headache, hearing changes, and nausea. Vomiting (10/11) and posterior neck pain (9/11) were also frequent. Seven had fever and 5 had a stiff neck. Four cases had lymphocytic pleocytosis, 4 cases had elevated CSF protein concentrations (> 1.5 times the upper limit of normal), and 2 cases had slightly lower CSF glucose levels. Polymerase chain reaction (PCR) analyses of the CSF for Mycobacterium tuberculosis complex, herpes simplex viruses 1 and 2, and enteroviruses were negative in all cases. MRI of the 11 cases revealed signs of spontaneous CSF leaks with diffuse pachymeningeal gadolinium enhancement (11/11), sagging of the brain (9/11), enlargement of the pituitary (6/11), engorgement of the venous structures (5/11), and subdural fluid collections (2/11). CSF leaks were demonstrated by intrathecal magnetic resonance or computed tomography myelography at different levels along the thoracic spine (7/11), cervico-thoracic junction (2/11), and thoraco-lumbar junction (2/11). Autologous blood injection into the spinal epidural space ('blood patch') was performed for treatment. Strict bed rest followed, and all patients recovered fully within a week; no recurrence or complication was observed during the follow-up periods, which ranged from 6 months to 5 y.

CONCLUSIONS

Findings of fever, headache, and meningeal irritation are generally accepted as the clinical features of meningitis. When CSF findings are not characteristically compatible with bacterial meningitis and particularly when the headache is orthostatic in nature, SIH should also be included in the differential diagnosis. MRI findings are characteristic and clearly contribute to the differential diagnosis between viral meningitis and SIH.

What differences exist in the appropriate treatment of congenital versus acquired adult Chiari type I malformation?

Chiari type I malformation is found in 1 out of 20 magnetic resonance imaging (MRI) studies. Isolated tonsillar herniation is of limited utility and should be considered within the clinical context because these patients can be asymptomatic. Cine MRI showing compression of the cerebrospinal fluid (CSF) spaces in the foramen magnum area is a crucial technique for making treatment decisions. Congenital malformation is thought to be due to a volumetric small posterior fossa. The most common symptom in these patients is cough headache. Posterior fossa reconstruction is mandatory in patients with progressive symptoms/signs, hydrocephalus, or syringomyelia, but not in patients who are asymptomatic or those with stable and tolerable symptoms. Acquired tonsillar descent can be secondary to a variety of disorders conditioning disproportion between the volume of the cranial cavity and that of the intracranial contents, or to CSF hypovolemia, which is the most common cause for acquired herniation. CSF hypovolemia can be spontaneous or secondary to CSF removal. Treatment of acquired tonsillar herniation depends on the responsible etiology.

Frontotemporal brain sagging syndrome: an SIH-like presentation mimicking FTD

BACKGROUND

Behavioral variant frontotemporal dementia (bvFTD) is a relatively well-defined clinical syndrome. It is associated with frontal and temporal lobe structural/metabolic changes and pathologic findings of a neurodegenerative disease. We have been evaluating patients with clinical and imaging features partially consistent with bvFTD but with evidence also suggestive of brain sagging, which we refer to as frontotemporal brain sagging syndrome (FBSS).

METHODS

Retrospective medical chart review to identify all patients seen at our institution between 1996 and 2010, who had a clinical diagnosis of FTD and imaging evidence of brain sag.

RESULTS

Eight patients, 7 male and 1 female, were diagnosed with FBSS. The median age at symptom onset was 53 years. All patients had insidious onset and slow progression of behavioral and cognitive dysfunction accompanied by daytime somnolence and headache. Of the 5 patients with functional imaging, all showed evidence of hypometabolism of the frontotemporal regions. On brain MRI, all patients had evidence of brain sagging with distortion of the brainstem; 3 patients had diffuse pachymeningeal enhancement. CSF opening pressure was varied and CSF protein was mildly elevated. A definite site of CSF leak was not identified by myelogram or cisternography, except in one patient with a site highly suggestive of leak who subsequently underwent surgery confirming a CSF leak. In 2 patients with a neuropathologic examination, there was no evidence of a neurodegenerative disease.

CONCLUSIONS

This case series demonstrates that FBSS may mimic typical bvFTD but should be recognized as an unusual presentation that is potentially treatable.

A transient third cranial nerve palsy as presenting sign of spontaneous intracranial hypotension

Spontaneous intracranial hypotension is an uncommon cause of sudden and persistent headache: associated symptoms are common, among which there are cranial nerve palsies, especially of the abducens nerve. We report a case of a 21-year-old man with a transient and isolated third nerve palsy due to spontaneous intracranial hypotension. To our knowledge, there are only few reports in the literature of such association.

Pseudohypoxic Brain Swelling (Postoperative Intracranial Hypotension-Associated Venous Congestion) After Spinal Surgery: Report of 2 Cases

BACKGROUND AND IMPORTANCE:

Pseudohypoxic brain swelling is a rare event that may occur after uneventful brain surgery when subgaleal vacuum drainage is used. To date, such cases of unexpected postoperative disturbances of consciousness associated with radiological signs of basal ganglia, thalamic, brainstem, and cerebellum damage without any signs of vessel occlusion have not been known to occur after spinal surgery.

CLINICAL PRESENTATION:

We report for the first time on 2 patients presenting with a clinical and radiological picture of pseudohypoxic brain swelling after spinal surgery. In the first patient, bilateral basal ganglia damage occurred after thoracic spondylodiscitis surgery, manifested by epileptic seizures and coma lasting 1 week postoperatively with subsequent recovery. The second patient suffered basal ganglia and cerebellar and brainstem infarction after lumbar spondylodiscitis surgery, resulting in death. Because intraoperative cerebrospinal fluid leakage and use of postoperative epidural suction drainage with cerebrospinal fluid loss occurred in both cases, they are highly suspected to have potentially caused the complications.

CONCLUSION:

Pseudohypoxic brain swelling should be considered in patients with unexpected neurological deterioration after spinal surgery. It might be a form of postoperative intracranial hypotension-associated venous congestion, which should be distinguished from common postoperative cerebral ischemic events caused by arterial or venous occlusions.

Intracranial hypotension and PRES: case report

We report a case of a woman presenting, 7 days after epidural analgesia for a caesarean section, to the emergency room for a worsening of the headache and tonico-clonic seizures. MRI showed alterations suggestive of the presence of intracranial hypotension (IH) as well as evidence of posterior reversible encephalopathy syndrome (PRES). She was treated with a blood patch which leads to the prompt regression of the clinical symptoms and follow-up MRI, after 15 days, showed complete resolution of radiological alterations. The possible pathogenetic relationship between IH, secondary to the inadvertent dural puncture, and PRES is discussed. We suggest that venous stagnation and hydrostatic edema, secondary to intracranial hypotension, probably played a crucial role in the pathogenesis of PRES.

Spontaneous intracranial hypotension syndrome: a novel speculative physiopathological hypothesis and a novel patch method in a series of 28 consecutive patients

Object

Spontaneous intracranial hypotension (SIH) is a potentially serious pathological syndrome consisting of specific symptoms and neuroradiological signs that can sometimes be used to assess the efficacy of the treatment. In this paper the authors report a series of 28 patients with this syndrome who were all treated with an epidural blood patch at the authors' institution. The authors propose a novel physiopathological theory of SIH based on some anatomical considerations about the spinal venous drainage system.

Methods

Between January 1993 and January 2007, the authors treated 28 patients in whom SIH had been diagnosed. Twenty-seven of the 28 patients presented with the typical findings of SIH on brain MR imaging (dural enhancement and thickening subdural collections, caudal displacement of cerebellar tonsils, and reduction in height of suprachiasmatic cisterns). The sites of the patients' neuroradiologically suspected CSF leakage were different, but the blood patch procedure was performed at the lumbar level in all patients. The patients were then assessed at 3-month and 1- and 3-year follow-up visits. At the last visit (although only available for 11 patients) 83.3% of patients were completely free from clinical symptoms and 8.3% complained of sporadic orthostatic headache.

Results

The authors think that in the so-called SIH syndrome, the dural leak, even in those cases in which it can be clearly identified on neuroradiological examinations, is not the cause of the disease but the effect of the epidural hypotension maintained by the inferior cava vein outflow to the heart. The goal of their blood patch procedure (a sort of epidural block obtained using autologous blood and fibrin glue at the L1–2 level) is not to seal CSF leaks, but instead to help in reversing the CSF-blood gradient within the epidural space along the entire cord.

Conclusions

The authors' procedure seems to lead to good and long-lasting clinical results.

Supratentorial craniotomy complicated by an homolateral remote cerebellar hemorrhage and a controlateral perisylvian infarction: case report

The authors present the case of a 49-year-old male patient with a right remote cerebellar hemorrhage and left perisylvian venous infarction complicating a right supratentorial craniotomy for temporal meningomia resection. These two events may result from a functional stenosis (due to perioperative brainstem sag) of the junction between the vein of Galen and the straight sinus. Remote cerebellar hemorrhage could then be explained by infarction in the territory of cerebellar veins emptying in the vein of Galen, and the left perisylvian infarction could be caused by venous infarction in the territory of a dominant superficial sylvian vein emptying in the basal vein. This hypothesis could shed light on the pathophysiology of remote cerebellar hemorrhage.

Postsurgical intracranial hypotension: diagnostic and prognostic imaging findings

BACKGROUND AND PURPOSE

CSF loss with consecutive intracranial hypotension has been discussed as a possible pathogenetic mechanism in poor clinical outcome after uneventful neurosurgery and appears to be correlated to specific imaging findings. The purpose of this study was to describe the clinical and imaging findings of symptomatic intracranial hypotension likely induced by wound suction drainage.

MATERIALS AND METHODS

This is a review of previously published cases of patients in whom this condition developed after uneventful intracranial surgery. We performed an analysis of 3 more cases, of which 2 occurred after spinal surgery with accidental dural opening.

RESULTS

Sixteen patients who remained unconscious or did not become fully responsive after surgery showed symmetric bilateral thalamic/basal ganglia signal intensity changes on CT and MR imaging studies. Of these 16 patients, 4 died and 2 also had brain stem signal intensity changes. All patients had rapid and distinct intraoperative and postoperative CSF loss documented on CT and/or MR imaging studies by a transient increase of the sag ratio, defined as maximal anteroposterior midbrain diameter by maximal bipeduncular diameter.

CONCLUSIONS

The clinical course and typical MR imaging findings characterize the disease entity postsurgical intracranial hypotension. These findings also underline the potential danger of wound suction drainage in the case of possible CSF loss.

Relative decrease in signal intensity of subcortical white matter in spontaneous intracranial hypotension on fluid-attenuated inversion recovery images

BACKGROUND AND PURPOSE

In reviewing MR images of patients with spontaneous intracranial hypotension (SIH), we found an accentuated decrease in the subcortical white matter on fluid-attenuated inversion recovery (FLAIR) images. Our aim was to determine whether the signal intensity of the subcortical white matter decreases on FLAIR and T2-weighted images in SIH.

MATERIALS AND METHODS

We retrospectively examined pretreatment MR images including 7 FLAIR and 10 T2-weighted images obtained from 10 patients with SIH and follow-up images (5 FLAIR and 7 T2-weighted images). Two observers measured the signal intensities in the subcortical white matter on MR images at the level of the centrum semiovale and, to calculate the signal intensity ratios, measured those of the adjacent cortex and corpus callosum. Furthermore, 4 observers performed visual evaluation for accentuated signal intensity decreases for receiver operating characteristic (ROC) analysis.

RESULTS

The intensity ratios of the subcortical white matter, both to the adjacent cortex and corpus callosum, were significantly different between the control and pretreatment images in SIH and between pretreatment and follow-up images in SIH on FLAIR images, whereas these showed no significant differences between the control and follow-up images in SIH. On visual inspection, an accentuated decrease in signal intensity in the subcortical white matter was shown on pretreatment FLAIR images, which returned to the control level on follow-up images. However, on the T2-weighted images we could hardly recognize the decrease in the signal intensity.

CONCLUSIONS

Awareness of the decreased signal intensity of the subcortical white matter on FLAIR images could help in the diagnosis of SIH.

Application of IHS Criteria to Headache Attributed to Spontaneous Intracranial Hypotension in a Large Population

We applied the recent International Headache Society (IHS) criteria for headache related to spontaneous intracranial hypotension (SIH) to 90 consecutive patients with a final diagnosis of SIH confirmed by cerebral magnetic resonance imaging with contrast. Orthostatic headache (developing within 2 h of standing or sitting up) was present in 67 patients (75%) but appeared within 15 min after standing or sitting—as required by point A of the criteria—in only 53 (59%). Forty-four (49%) patients did not satisfy point A, including 22 (24%) with non-orthostatic headache and 14 (16%) with headache developing ≥ 15 min after standing or sitting up; 80 (89%) did not satisfy point D. Only three (3%) patients had headache fully satisfying the IHS criteria. These findings indicate that the current IHS criteria do not capture most patients with SIH-associated headache. Excluding the requirement for response to epidural blood patch (criterion D) and considering headaches appearing within 2 h of sitting or standing up would capture more patients.

The venous hinge--an objective sign for the diagnosis and follow-up of treatment in patients with intracranial hypotension syndrome

INTRODUCTION

In patients with Intracranial Hypotension Syndrome (IHS), we observed reduction of the angle between vein of the Galen (VOG) and internal cerebral vein (ICV), which returns to the baseline after treatment. We coin the term "venous hinge" to describe this dynamic process and discuss its importance in IHS.

METHODS

A midsagittal T1W image showing both VOG and ICV in the same plane was retrospectively analyzed by three different neuroradiologists in 17 patients with IHS. The angle between the lines drawn along the main axis of VOG and ICV (venous hinge angle (VHA)) was measured and documented. This angle measured from the magnetic resonance imaging (MRI) of the 50 normal controls was also recorded. Paired t tests were used to compare the VHA between male and female controls and between patients of IHS and normal controls. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were calculated. The VHA was also calculated after treatment of these patients and paired t test was done to look for significant change in the VHA after treatment.

RESULTS

The mean VHA formed by the veins in the IHS and control groups were 65 degrees (35-98 degrees) and 91 degrees (76-124 degrees) respectively (P < 0.0001). At a VHA of 79 degrees, the sensitivity, specificity, PPV, and NPV for diagnosis of IHS were 88.24%, 92%, 78.95%, and 95.83% respectively. In ten patients, follow-up MRI demonstrated normalization of the collapsing angle following appropriate treatment (p = 0.003).

CONCLUSION

We report a previously undescribed imaging finding in patients with IHS. Recognition of this sign may aid in the diagnosis of IHS.

Anatomy and development of the meninges: implications for subdural collections and CSF circulation

The dura is traditionally viewed as a supportive fibrous covering of the brain containing the dural venous sinuses but otherwise devoid of vessels and lacking any specific function. However, review of the embryology and anatomy reveals the dura to be a complex, vascularized and innervated structure, not a simple fibrous covering. The dura contains an inner vascular plexus that is larger in the infant than in the adult, and this plexus likely plays a role in CSF absorption. This role could be particularly important in the infant whose arachnoid granulations are not completely developed. Although subdural hemorrhage is frequently traumatic, there are nontraumatic conditions associated with subdural hemorrhage, and the inner dural plexus is a likely source of bleeding in these nontraumatic circumstances. This review outlines the development and age-specific vascularity of the dura and offers an alternative perspective on the role of the dura in homeostasis of the central nervous system.