Transient locked-in syndrome after uncal herniation.
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Brain↗
Biomedical subjects
G M Miller
Publications and source records attributed to G M Miller.
Suspected non-small cell lung cancer: incidence of occult brain and skeletal metastases and effectiveness of imaging for detection--pilot study.
PURPOSE: To estimate the incidence of occult metastases to the brain and skeleton in patients suspected of having non-small cell lung cancer (NSCLC) (stage higher than T1Nomo) with surgically resectable disease, to assess the accuracy of screening magnetic resonance (MR) imaging and radionuclide bone scanning for help in identifying occult metastases, and to determine the effectiveness of a high dose of MR contrast material. MATERIALS AND METHODS: Twenty-nine patients suspected of having NSCLC localized to the lung or to the lung and regional nodes underwent preoperative MR imaging with contrast material enhancement and radionuclide bone scanning for detection of brain or skeletal metastases. Patients were followed up for 12 months to determine the incidence of clinical metastatic disease. RESULTS: Eight (28%) patients had occult metastatic disease to the brain or skeleton. Brain metastases were identified on MR images in five of six patients. Bone metastases were identified on MR images in four of five patients and on bone scans in three of five patients. MR imaging was no more accurate than bone scanning for skeletal evaluation. A high dose of MR contrast material allowed detection of more metastases and of small lesions. CONCLUSION: Contrast-enhanced MR imaging of the brain is indicated for the exclusion of brain metastases in patients with clinically operable known or possible NSCLC and a large (> 3-cm) lung mass. Skeletal imaging may be indicated if an isolated brain metastasis is detected.
Aged↗
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.
Adolescent↗
Juxtafacet cysts of the cervical spine.
OBJECTIVE: We report a retrospective series of 13 patients who presented with symptoms and signs caused by cervical juxtafacet cysts. Clinical findings, radiographic features, surgical management strategies, and possible causes are reported and discussed. METHODS: We reviewed clinical histories, radiographic studies, surgical notes, and pathological records of all 13 patients who underwent surgery for subaxial cervical juxtafacet cysts from 1984 to 1997 at the Mayo Clinic in Rochester, MN. During the summer of 1997, surgical outcomes were assessed by direct or telephone interview. RESULTS: Nine patients were men and four were women. The average age at the time of presentation was 66 years. One patient had undergone a previous anterior cervical fusion below the level of the cyst. Ten patients presented with radiculopathies. Two patients presented with myeloradiculopathies. One patient presented with a cervical myelopathy. Computed tomographic myelography and magnetic resonance imaging were essential in establishing a preoperative diagnosis. The cysts were located at C7-T1 in nine patients, at C4-C5 in two patients, at C6-C7 in one patient, and at C3-C4 in one patient. All patients underwent posterior laminectomy or hemilaminectomy, excision of the cyst, and decompression of the thecal sac and/or nerve root. Two patients underwent concurrent posterior fusion procedures for instability. All patients experienced good to excellent relief of their radicular pain. All three myelopathies stabilized after surgery. There were no major complications or recurrences. CONCLUSION: Juxtafacet cysts seem to be a degenerative change of the cervical spine rather than a traumatic event. Similar to their counterparts in the lumbar spine, they tend to arise in segments with increased mobility. Surgical treatment is effective.
Aged↗
MR imaging in pretruncal nonaneurysmal subarachnoid hemorrhage: is it worthwhile?
BACKGROUND AND PURPOSE: The cause of pretruncal (perimesencephalic) nonaneurysmal subarachnoid hemorrhage is not known. MRI of the brain or spine is often performed to exclude any other vascular abnormalities. Its diagnostic value is not known. METHODS: We used MR imaging of the brain with routine sequences, gadolinium enhancement, and additional thin T1-weighted axial sections following a triple dose of contrast. RESULTS: We performed MR imaging of the brain in 18 patients with a pretruncal nonaneurysmal subarachnoid hemorrhage. The focal nature of the subarachnoid hemorrhage exclusively in front of the brain stem was confirmed in 14 patients studied within 7 days of the ictus. No vascular abnormalities were found in 17 cases, including 14 patients with gadolinium enhancement. An incidental capillary telangiectasia was found in 1 patient. Fluid-attenuated inverse recovery MR additionally documented blood in the sulci due to cerebrospinal fluid recirculation of blood. Five patients underwent MR imaging of the spine, and no arteriovenous malformations were found. CONCLUSIONS: MR imaging did not reveal a source of pretruncal subarachnoid hemorrhage. The cost of MR imaging probably outweighs the benefit in the evaluation of this variant of subarachnoid hemorrhage.
Brain↗
Acquired Chiari I malformation secondary to spontaneous spinal cerebrospinal fluid leakage and chronic intracranial hypotension syndrome in seven cases.
OBJECT: Spontaneous spinal cerebrospinal fluid (CSF) leakage with development of the intracranial hypotension syndrome and acquired Chiari I malformation due to lumbar spinal CSF diversion procedures have both been well described. However, concomitant presentation of both syndromes has rarely been reported. The object of this paper is to present data in seven cases in which both syndromes were present. Three illustrative cases are reported in detail. METHODS: The authors describe seven symptomatic cases of spontaneous spinal CSF leakage with chronic intracranial hypotension syndrome in which magnetic resonance (MR) images depicted dural enhancement, brain sagging, loss of CSF cisterns, and acquired Chiari I malformation. CONCLUSIONS: This subtype of intracranial hypotension syndrome probably results from chronic spinal drainage of CSF or high-flow CSF shunting and subsequent loss of brain buoyancy that results in brain settling and herniation of hindbrain structures through the foramen magnum. Of 35 cases of spontaneous spinal CSF leakage identified in the authors' practice over the last decade, MR imaging evidence of acquired Chiari I malformation has been shown in seven. Not to be confused with idiopathic Chiari I malformation, ideal therapy requires recognition of the syndrome and treatment directed to the site of the spinal CSF leak.
Adult↗
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.
Adolescent↗
What nature's knockout teaches us about GnRH activity: hypogonadal mice and neuronal grafts.
The hypogonadal mouse is one of "nature's knockouts," bearing a specific deletion in the gene for gonadotropin-releasing hormone (GnRH), with the result that no GnRH peptide is detectable in the brain. The lack of reproductive development after birth provides an animal model that has proved fruitful in clarifying the role of GnRH in reproductive behavior and physiology. Behavioral studies with hypogonadal mice convincingly demonstrate that although GnRH may facilitate the appearance of sexual behavior, this peptide is not essential for either male or female sexual behavior in the mouse. Administration of GnRH to hypogonadal mice with regimens mimicking GnRH pulsatility initiates reproductive development. Surprisingly, continuous exposure to GnRH stimulates remarkable ovarian and uterine growth and increased FSH release, although pituitary content of LH and FSH remains unchanged. In contrast, when brain grafts of normal fetal preoptic area (POA), containing GnRH cells, are implanted in the third ventricle of adult hypogonadal mice, both pituitary and plasma gonadotropin levels increase. Grafted GnRH neurons innervate the median eminence of the host and support pulsatile LH secretion in the majority of animals with graft-associated gonadal development. Studies of hypogonadal mice with POA grafts demonstrate that distinct components of reproductive function are dissociable: hosts may demonstrate reflex but not spontaneous ovulation; others may show positive but not negative feedback. Activation of grafted GnRH cells in response to sensory input to the host, as revealed in Fos expression studies, is an example of the integration of the graft with the host brain that underlies such capabilities. A goal of these studies is to elucidate the specific connectivity underlying discrete aspects of reproductive function.
Animals↗
Sectional anatomy using the personal computer.
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Anatomy, Cross-Sectional↗
Airway fire during elective tracheostomy.
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Adult↗
MR imaging of progressive downward herniation of the diencephalon.
Some clinicians have challenged the clinicopathologic correlation in patients with brain herniation from acute mass lesions. Earlier studies have questioned the significance of downward displacement of the brainstem in supratentorial herniation. Using recent generation MRI, we studied a patient with an acute hemorrhagic infarction. MRI demonstrated significant compression of the diencephalon with downward displacement of the midbrain and hyperintensity on T2-weighted sequences in the lateral mesencephalon during progression from early diencephalic stage to midbrain upper pons stage of herniation. This is the first intra vitam documentation of diencephalic herniation by MR imaging and confirms rostrocaudal deterioration usually found at autopsy.
Aged↗
Syndrome of orthostatic headaches and diffuse pachymeningeal gadolinium enhancement.
OBJECTIVE: To characterize clinical and imaging features, biopsy findings, etiologic factors, and outcome in the syndrome of intracranial hypotension, headaches, and diffuse pachymeningeal gadolinium enhancement on magnetic resonance imaging (MRI). MATERIAL AND METHODS: We describe our experience with 26 consecutive patients with orthostatic headaches and diffuse pachymeningeal gadolinium enhancement, for all of whom clinical, imaging, and follow-up data were available. For 10 patients who had undergone meningeal biopsy, slide material was also reviewed. RESULTS: The 15 men and 11 women ranged from 24 to 76 years of age. All 26 patients had postural headaches; in 22 patients, the headaches were completely alleviated by recumbency. Nausea or emesis, neck pain, horizontal diplopia, changes in hearing, photophobia, upper limb pains or paresthesias, visual blurring, or dysgeusia was noted in some of the patients. Cardinal MRI features were diffuse pachymeningeal gadolinium enhancement (100%), subdural collections of fluid (69%), and evidence of descent of the brain (62%) that sometimes resembled type I Chiari malformation. Cerebrospinal fluid (CSF) opening pressures were 40 mm or less in only 46%. In three patients, CSF pressures were consistently no less than 90 and as high as 130 mm of water. A variable pleocytosis of 5 or more cells/mm3 was noted in 15 patients (more than 40 cells/mm3 in 4 patients). A variable increase in CSF protein was noted in at least one spinal tap in 23 patients. Six patients had overdraining CSF shunts; CSF leak was documented in another 11 patients. Shunt revision or ligation and surgical correction of the leak led to a resolution of the clinical and MRI abnormalities in all cases thus treated. Improvement occurred with epidural blood patch in four patients. Three of the 12 patients treated supportively have remained symptomatic. Histologically, a thin subdural zone of fibroblasts and thin-walled vessels was noted in an amorphous matrix. Two patients with prolonged symptoms had a more pronounced proliferative reaction. CONCLUSION: The syndrome of low-pressure headaches and pachymeningeal gadolinium enhancement is being recognized with increasing frequency. The source of the CSF leak can be demonstrated in many patients. Meningeal abnormalities are likely attributable to decreased CSF volume and hydrostatic CSF pressure changes. The prognosis is typically good.
Adult↗
Posterior vertebral body erosion by arachnoid diverticula in cauda equina syndrome: an unusual manifestation of ankylosing spondylitis.
Cauda equina syndrome is an uncommon complication of longstanding ankylosing spondylitis. It is associated with dorsal arachnoid diverticula, which may erode the lamina and spinous processes of the bony lumbosacral spine. We describe a patient who developed cauda equina syndrome associated with the unusual finding of erosion of the posterior aspect of 2 vertebral bodies by arachnoid diverticula. This was clearly revealed by magnetic resonance imaging of the spine.
Aged↗
Butterfly vertebra.
A 41-year-old man with low back pain and lumbar disc disease was found to have L-3 butterfly vertebra on imaging studies as an incidental finding. This uncommon congenital anomaly of the vertebral column is usually asymptomatic and of no clinical significance. Awareness of this deformity and its imaging features is important diagnostically.
Abnormalities, Multiple↗
Gonadotropin-releasing hormone messenger RNA expression in gonadotroph tumors and normal human pituitary.
Gonadotroph tumors predominantly secrete FSH or free gonadotropin hormone subunits and rarely LH. In contrast to normal gonadotrophs, a subset of tumors synthesize FSH beta-subunit (SU) in excess of alpha-SU, and the cause of gonadotropin hormone-SU biosynthetic defects in these tumors is unknown. Gonadotropin-releasing hormone (GnRH) is known to modify gonadotropin hormone-SU biosynthesis and secretion and may be an important determinant of gonadotroph tumor hormone regulation. Data in experimental animals have demonstrated that endogenous expression of GnRH may occur in the pituitary. We therefore determined whether 1) the GnRH gene is expressed in gonadotroph tumors and normal pituitaries using reverse transcriptase (RT)-PCR; 2) the GnRH receptor gene is co-expressed in gonadotroph tumors; 3) an alternative upstream transcriptional start site on the GnRH gene is utilized; and 4) media from primary cultures of gonadotroph tumors have detectable GnRH immunoreactivity by RIA. GnRH messenger RNA (mRNA) was detected in 10/10 gonadotroph tumors, eight of which expressed GnRH-Receptor mRNA. Both mRNAs were detected in all normal pituitaries studied (n = 6). Six of 10 gonadotroph tumors and 3/6 normal pituitaries had GnRH transcripts derived from the upstream transcriptional start site (5'GnRH). GnRH immunoreactivity was detected in overnight media from 3/3 primary gonadotroph tumor cultures (range: 1.89-5.86pg/mL; limit of detection (LD) = < 1.58pg/mL) but was not detectable in control media. This is the first study to demonstrate endogenous GnRH gene expression in human pituitary adenomas and normal human pituitary tissue. The presence of both GnRH and GnRH-Rc suggest that GnRH may be a paracrine/autocrine regulator of cell function in the pituitary and may affect gonadotroph tumor hormone phenotype.
Adenoma↗
Neuromodulation of transplanted gonadotropin-releasing hormone neurons in male and female hypogonadal mice with preoptic area brain grafts.
Implantation of normal preoptic area (POA) tissue into the third ventricle of adult hypogonadal (HPG) mice provides a source of GnRH neurons that innervate the host median eminence and stimulate reproductive development in the sterile mutants. To further evaluate graft-host integration, the effects of N-methyl-D,L-aspartic acid (NMA) and opiate antagonists on LH secretion in HPG mice with POA transplants (HPG/POA) were tested. NMA challenges significantly stimulated LH secretion in 10 of 11 HPG/POA females. Only 5 of 12 HPG/POA males responded to the same treatment. Administration of the opiate antagonists naloxone or naloxone methiodide was ineffective in stimulating LH release in any mice, but opiate antagonist pretreatment significantly potentiated the LH secretory response to NMA in female, but not male, HPG/POA mice. A potential anatomical substrate for this facilitation may be the beta-endorphin-immunoreactive innervation of the POA grafts in all HPG/POA brains examined. beta-Endorphin fibers were also present in the median eminence in the vicinity of GnRH outgrowth from the grafts. However, similar innervation patterns in HPG/POA males that did not respond to opioid antagonism suggests that this is not sufficient. We tested whether the sex difference in HPG/POA responsivity to neuromodulation is related to the steroid milieu in the hosts. 17 beta-Estradiol (E2) treatment facilitated the LH secretory response of male HPG/POA to NMA challenges whether animals were castrated and given an E2 capsule prior to graft implantation or one week before testing two months after graft surgery. Intact or vehicle (sesame oil)-treated, castrated HPG/POA males rarely responded to NMA challenges, yet graft-derived GnRH innervation of the hosts' median eminence was comparable in all treatment groups. GnRH challenge testing indicated that pituitary sensitivity of the HPG/POA males was not significantly altered by E2 treatment, suggesting that estrogen acted centrally. These results indicate that the activity of grafted GnRH neurons may be modulated by endogenous opioids of host origin as well as by the hormonal milieu.
Animals↗
A pseudoepidemic of tuberculin skin test conversions caused by a particular lot of purified protein derivative of tuberculin test solution.
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Adult↗
Somatostatin receptor subtype gene expression in pituitary adenomas.
Somatostatin (SRIF) exerts its diverse biological effects through a family of membrane receptors. In addition to inhibiting GH secretion, SRIF has antiproliferative effects and has been used clinically in the treatment of pituitary tumors. SRIF receptor (SSTR) expression has recently been identified in pituitary adenomas, and it is unknown whether differential expression of SSTR subtypes predicts clinical responses to SRIF analogs. We therefore determined which SSTR subtype messenger RNAs (mRNAs) are expressed in pituitary adenoma phenotypes and in normal human pituitary tissue using reverse transcriptase-polymerase chain reaction and tested whether expression of specific SSTR subtype mRNA is necessary for SRIF inhibition of GH secretion in human somatotroph adenomas in vitro. Expression of SSTR subtypes 1, 2, and 5 mRNA was identified in all pituitary adenoma types and normal pituitary tissue. In contrast, SSTR3 mRNA was detected in only one somatotroph adenoma as well as in control insulinoma tissue, a tissue known to express SSTR3 mRNA, and was not detected in normal pituitary tissue. SSTR4 mRNA was not detected in any human pituitary tissue. To determine whether specific SSTR subtype mRNA expression is required for SRIF inhibition of GH secretion, five somatotroph adenomas were treated with 10(-7) mol/L SRIF in vitro, and significant inhibition of GH release occurred in all adenomas. All five tumors expressed SSTR2 mRNA and SSTR5 mRNA, and three expressed SSTR1 mRNA. The absence of SSTR1 mRNA expression did not affect the ability of SRIF to suppress GH secretion. We conclude that: 1) human pituitary adenomas and normal pituitary express multiple SSTR gene transcripts; 2) SSTR5 mRNA, which has not been reported in other human endocrine tumor types, is expressed in neoplastic and normal pituitary tissue; and 3) SSTR2 mRNA, SSTR5 mRNA, and variable SSTR1 mRNA are expressed in GH-secreting tumors, which are responsive to SRIF in vitro. Further understanding of SSTR gene expression in pituitary adenomas will facilitate our understanding of the pathogenetic mechanisms of tumorigenesis and may provide a rationale for the use of specific SRIF analogs for clinical application.
Adenoma↗