Gary M. Miller

Meningeal biopsy in intracranial hypotension Meningeal enhancement on MRI

Intracranial hypotension is a cause of diffuse enhancement of the pachymeninx with gadolinium, which often is associated with subdural fluid collections.We reviewed the results of meningeal biopsy in six patients with intracranial hypotension and diffuse pachymeningeal enhancement to correlate the MRI findings with histopathologic observations and to explain the abnormalities seen on MRI. Grossly, the dura mater was unremarkable in all patients, as were the leptomeninges, except for one patient with prolonged (18 months) intracranial hypotension in whom the arachnoid was thickened and opaque. Microscopically, the dura mater was entirely normal on its epidural aspect; however, a fairly thin zone of fibroblasts and thin-walled small blood vessels in an amorphous matrix was noted on the subdural aspect. In the patient with longstanding symptoms, diffuse benign arachnoidal cell proliferation was also noted, probably a reaction triggered by longstanding changes in the subdural area, as noted in the five other patients. There was no evidence of inflammation, infection, or metastatic neoplasia. These findings suggest that in intracranial hypotension, the dural-meningeal abnormalities probably represent reactive secondary phenomena, likely related to hydrostatic changes in the CSF, and not a primary meningeal process. NEUROLOGY 1995;45: 1801-1807

Intractable vomiting as the initial presentation of neuromyelitis optica

We report 12 aquaporin‐4 antibody‐positive patients (12% of seropositive Mayo Clinic patients identified since 2005) whose initial presenting symptom of neuromyelitis optica was intractable vomiting. The initial evaluation in 75% was gastroenterologic. Vomiting lasted a median of 4 weeks (range, 2 days–80 weeks). Optic neuritis or transverse myelitis developed after vomiting onset in 11 patients (median interval, 11 weeks; range, 1–156). At last evaluation (median, 48 months after vomiting onset), 7 patients fulfilled neuromyelitis optica diagnostic criteria. Our clinical, pathologic and neuroimaging observations suggest the aquaporin‐4–rich area postrema may be a first point of attack in neuromyelitis optica. Ann Neurol 2010;68:757–761

Absent pachymeningeal gadolinium enhancement on cranial MRI despite symptomatic CSF leak

Article abstract CSF leak is recognized to cause orthostatic headaches and diffuse pachymeningeal gadolinium enhancement (DPMGE) on MRI. We report six patients with typical symptoms and documented CSF leaks without DPMGE. Two had normal meninges from the onset; one initially had normal meninges, but subsequently DPMGE developed. In three, the initially noted DPMGE resolved while they were still symptomatic with documented continued CSF leaks. Absent DPMGE does not rule out CSF leak. When clinical manifestations suggest this disorder, additional diagnostic studies should be pursued.

Right Aortic Arch With Isolation of the Left Subclavian Artery: Case Report and Review of the Literature

Of the right aortic arch anomalies, a right arch with isolation of the left subclavian artery is the least common. Herein we describe a 52-year-old woman in whom this anomaly was discovered during cerebral angiography for evaluation of a giant symptomatic intracavernous carotid aneurysm. Isolation of the left subclavian artery may be suggested in a patient with a right arch in whom the blood pressure or pulse in the left upper extremity is diminished. Although the isolated left subclavian artery produces the hemodynamic alterations of a subclavian steal, review of the 39 cases reported in the literature revealed only 5 patients with symptoms suggestive of vertebrobasilar insufficiency and 5 patients with weakness of the left upper extremity. Although the patient we describe had no known heart disease, congenital heart disease was present in 23 of the 39 reported cases (59%), tetralogy of Fallot occurring most frequently.

Meningeal Gadolinium Enhancement in Low-pressure Headaches

Three patients with headaches in erect but not recumbent positions had barely measurable cerebrospinal fluid (CSF) pressures and aseptic but abnormal CSF findings with variable pleocytosis and elevated protein content. The CSF glucose level was normal and there were no blasts or malignant cells. Gadolinium‐enhanced magnetic resonance imaging (MRI) in all 3 showed diffuse meningeal enhancement. In 2, headaches and MRI abnormalities completely resolved spontaneously. The third patient, who had a prior ventriculoperitoneal shunt, improved after shunt revision.

Multiple sclerosis of the spinal cord: magnetic resonance appearance.

OBJECTIVE To determine the MR appearance of spinal cord multiple sclerosis (MS) plaques in patients presenting with myelopathy by using a high-field (1.5 T) imager. MATERIALS AND METHODS We studied 119 patients who underwent high-field (1.5 T) MR studies of the spinal cord for evaluation of myelopathy. All 119 patients were thought to have possible findings of spinal cord MS at the time of the MRI interpretation. RESULTS Sixty-four plaques were studied in 47 patients with clinically definite MS and adequate quality MRI. Of these patients 68% had a single spinal cord plaque, 19% had two plaques, and 13% had three or more plaques. Sixty-two percent of the plaques occurred in the cervical spinal cord and most frequently involved the posterior (41%) and lateral (25%) aspects of the spinal cord. None of the 64 lesions involved the entire thickness of the spinal cord. The lesion length varied from 2 to 60 mm, with 84% of the lesions < 15 mm in length. The spinal cord diameter was unchanged in 84% of plaques, enlarged at the level of the lesion in 14%, and atrophic in 2%. Just over half (55%) of the plaques enhanced with intravenously administered gadolinium. Of the patients who received synchronous head and spinal cord examinations on the same day, 24% had normal findings on the MR study of the head. Follow-up spinal cord studies were available in nine patients. New lesions developed in two patients, while previously described lesions resolved. In three patients only new lesions developed. In four patients no change occurred in the existing number of cord plaques. CONCLUSION Spinal cord demyelinating plaques present as well-circumscribed foci of increased T2 signal that asymmetrically involve the spinal cord parenchyma. Knowledge of their usual appearance may prevent unnecessary biopsy. An MR examination of the head may confirm the imaging suggestion of spinal cord demyelinating disease, because up to 76% of patients have abnormal intracranial findings. In the remaining 24% of cases in which the clinical diagnosis is not certain and MR findings in the head are negative, a follow-up spinal cord study is recommended, because these lesions evolve and change over time.

Evidence of posterior fossa hypoplasia in the familial variant of adult Chiari I malformation: case report.

OBJECTIVE AND IMPORTANCE A case of familial Chiari I malformation and a review of the literature are presented. Recent posterior fossa morphological studies suggest that the sporadic variant of adult Chiari I malformation may be caused by occipital dysplasia and overcrowding of posterior fossa contents. This analysis was applied retrospectively for two of the three members of this familial variant. CLINICAL PRESENTATION A family is described in which symptomatic Chiari I malformation occurred in two generations: monozygotic twin sisters and the daughter of one sister. The monozygotic twins developed symptoms within 1 year of each other, and both had associated syringomyelia. The daughter of one of the twins presented with symptomatic tonsillar herniation alone at a young age. INTERVENTION All three family members underwent surgical decompression of the craniovertebral junction, with or without syringosubarachnoid shunting, with good results. CONCLUSION Cases of familial Chiari I malformation are rare, although they are probably under-reported. An evaluation of posterior fossa morphology in these patients suggests that occipital dysplasia and overcrowding of posterior fossa contents may be the substrate for both familial and sporadic cases of Chiari I malformation and suggests a unifying concept of origin.

Hemangioblastoma of the optic nerve: case report.

An optic nerve hemangioblastoma arising in the optic nerve of a patient with von Hippel-Lindau syndrome is reported. This represents the 10th published example of a hemangioblastoma arising at this site, the second description of the magnetic resonance imaging features of a hemangioblastoma at this location, and the second patient from whom an optic nerve hemangioblastoma has been removed with the goal of preserving the optic nerve as well as vision. A majority of these optic nerve hemangioblastomas have arisen in patients with von Hippel-Lindau syndrome. All patients experienced progressive loss of vision either to blindness or surgical intervention, although a vast majority of the lesions were sharply demarcated from the adjacent nerve and, thus, potentially resectable. Optic nerve hemangioblastomas are a rare cause of blindness but potentially preventable when treated with a conservative surgical approach aided by neuroimaging guidance. The recognition of discordance between the degree of vision loss and the extent or progression of a retinal hemangioblastoma may be an important clue to diagnosis in the patient with von Hippel-Lindau syndrome.

Pretruncal Nonaneurysmal Subarachnoid Hemorrhage

OBJECTIVE To review the diagnostic evaluation and the clinical course of patients with pretruncal nonaneurysmal subarachnoid hemorrhage. MATERIAL AND METHODS The study population consisted of a consecutive series of patients with a pretruncal nonaneurysmal subarachnoid hemorrhage encountered at Mayo Clinic Rochester during a 6-year interval. We reviewed the clinical manifestations, the neuroimaging characteristics, and the appropriate management. RESULTS The 15 male and 9 female patients with a pretruncal nonaneurysmal subarachnoid hemorrhage ranged from 3 to 72 years of age (median, 45). Of the 24 patients, 18 had a sudden explosive headache at the time of initial assessment. Ventricular shunting for acute hydrocephalus was indicated in one patient. Neuroimaging studies demonstrated that the center of the hemorrhage was prepontine, and it extended into the interpeduncular or premedullary cisterns. In two patients, a small focal hemorrhage was not noted on an admission computed tomographic scan but was identified on repeated study. A second four-vessel cerebral angiogram, obtained in most patients, showed normal findings in four patients who had had cerebral vasospasm on the first study. In one patient, moderate cerebral vasospasm was found on the second angiogram. No patient had rebleeding. One patient had transient dysphasia associated with cerebral vasospasm after cerebral angiography. Two patients had a family history of aneurysmal subarachnoid hemorrhage. CONCLUSION The excellent outcome in patients with pretruncal nonaneurysmal subarachnoid hemorrhage is in distinct contrast to the overall somber outcome associated with aneurysmal subarachnoid hemorrhage. A ruptured aneurysm of the posterior circulation may mimic a pretruncal nonaneurysmal subarachnoid hemorrhage and should be excluded on the basis of a technically satisfactory cerebral angiogram.

Spinal cord biopsy: a review of 38 cases.

OBJECTIVENeurosurgeons are frequently asked to evaluate patients for spinal cord biopsies when preoperative magnetic resonance imaging studies demonstrate nonspecific features. These lesions often appear unresectable, but surgeons must decide whether a biopsy is warranted. To determine the best approach to these cases, we evaluated the clinicopathological findings for patients with unknown spinal cord lesions who underwent spinal cord biopsies. METHODSThirty-eight consecutive patients who underwent spinal cord biopsies at the Mayo Clinic (Rochester, MN) between August 1988 and July 1998 were studied. A detailed review of the case histories, radiological results, surgical notes, histological findings, and outcomes was performed. RESULTSSpinal cord biopsies were performed for 21 male and 17 female patients (mean age, 42.1 yr) with progressive neurological deficits related to spinal cord lesions. All patients underwent preoperative magnetic resonance imaging evaluations. High T2-weighted signal intensity and spinal cord expansion were identified in 92 and 87% of cases, respectively. After gadolinium infusion, the majority (94%) of the inflammatory lesions demonstrated patchy and often peripherally situated enhancement. This neuroradiological pattern was less common for neoplasms (50%) and benign lesions (40%). The most common pathological findings were inflammatory changes of demyelination or sarcoidosis, which together accounted for 13 cases (34%). Nonspecific changes or benign lesions were observed in 10 cases (26%). Neoplasms were identified in eight cases (21%). One case of tuberculosis and one of schistosomiasis were found. Overall, 47% of the preoperative diagnoses made by the attending surgeon were correct. For 26% of the patients, specific treatment was based on the biopsy results. The average follow-up period was 12 months (standard deviation, 14 mo; range, 0–50 mo). CONCLUSIONPreoperative laboratory and imaging studies are often diagnostically inconclusive in cases of spinal cord lesions with nonspecific features. Biopsies should be considered for patients with progressive symptomatic lesions.