1/89. Brainstem dysfunction in chiari malformation presenting as profound hypoglycemia: presentation of four cases, review of the literature, and conjecture as to mechanism.OBJECTIVE: We report four patients whose cases resulted in our observation that profound hypoglycemia resulting from intermittent hyperinsulinism plays a significant role in patients with brainstem dysfunction from Chiari I or II malformations who have intermittent autonomic dysfunction ("blue spells"). methods: The records of four children with severe brainstem dysfunction associated with hindbrain herniation (Chiari I or II malformation) were reviewed retrospectively. Each patient had severe lower cranial nerve dysfunction that required tracheotomy and feeding tube placement. After we found that profound hypoglycemia had occurred during a spell of autonomic dysfunction in one patient, the charts of the other three patients were reviewed for evidence of hypoglycemia. Now, whenever one of them has evidence of autonomic dysfunction, prospective studies of glucose and insulin levels are performed. Three of the patients had Chiari II malformation in association with myelomeningocele, and one patient had a Chiari I malformation resulting from Pfeiffer's syndrome. RESULTS: hypoglycemia occurred in these patients episodically, and usually when their shunts were functioning. The hypoglycemia was associated with hyperinsulinemia in each patient. The brainstem structures of these children (presumably the dorsal motor nuclei of the vagus) were extremely sensitive to changes in local or regional intracranial pressure. These changes were triggered by intermittent shunt failure, agitation from pain, abdominal distention from constipation, and retention of CO2. In patients with Chiari malformations, even mild increases in intracranial pressure lead to brainstem dysfunction. One possible explanation is that pressure on the deformed Xth cranial nerve nuclei may lead to insulin release and life-threatening hypoglycemia. Continuous-drip feeds are necessary to prevent this complication. CONCLUSION: patients with severe intermittent brainstem dysfunction after decompression of Chiari I or Chiari II malformations should have laboratory studies of glucose levels performed at the time of the episodes to rule out hypoglycemia.- - - - - - - - - - ranking = 1keywords = herniation, meningocele (Clic here for more details about this article) |
2/89. arnold-chiari malformation with syringomyelia in an elderly woman.PRESENTATION: A 76-year-old woman, complaining of leg pain and unsteady gait for 3 years, presented with a spastic paraparetic gait, severe spasticity and touch, thermal and pain sensory loss limited to arms, lower thorax and upper abdomen. Brain and spinal cord magnetic resonance imaging showed a large loculated syrinx. Cerebellar tonsillar herniation into the foramen magnum was also seen (arnold-chiari malformation, type I). OUTCOME: The patient had successful cervico-spinal surgical decompression which resulted in marked reduction in hypertonia and weakness, normal gait and normal joint movement at 6 months. CONCLUSION: This unusual, late clinical presentation of a congenital disease underlines the importance of a comprehensive diagnostic work-up in the elderly patients with complex neurological signs.- - - - - - - - - - ranking = 0.88261784811788keywords = herniation (Clic here for more details about this article) |
3/89. Chiari malformation and sleep-disordered breathing: a review of diagnostic and management issues.Chiari Malformation (CM) encompasses several patterns of congenital or acquired cerebellar herniation through the foramen magnum. This may result in brain-stem compression that impacts control of breathing and is associated with obstructive and central apneas. A high clinical suspicion for sleep-disordered breathing is needed in the care of such patients after as well as before corrective surgery. To introduce a review of CM with a focus on the relevance to sleep medicine, we present a case of a 13-year-old female who was diagnosed with CM Type 1 in the course of an evaluation of symptomatic central sleep apnea. After initial improvement following surgery there was recurrence of brain-stem compression. The only clinical expression of which was polysomnographically evident recurrence of sleep apnea.- - - - - - - - - - ranking = 0.88261784811788keywords = herniation (Clic here for more details about this article) |
4/89. Expansion of Chiari I-associated syringomyelia after posterior-fossa decompression.Chiari I malformation (CMI) is an abnormality that involves caudal herniation of the cerebellar tonsils into the foramen magnum. CMI has been shown to be closely associated with the development of syringomyelia (SM). OBJECTS: Several theories have emerged to explain the apparent correlation between the existence of CMI with subsequent development of SM. However, the exact mechanism of the evolution of SM is still subject to controversy. We report here the case of a 12-year-old girl admitted to hospital with headache, vomiting, ataxia, and moderate pyramidal signs. methods: Radiological evaluation revealed the presence of CMI, accompanied by a small SM. The patient underwent posterior fossa decompression and improved significantly. She was re-admitted 6 months later with clinical evidence of progressive spinal cord dysfunction. MR revealed gross expansion of the syrinx. CONCLUSIONS: This case raises questions regarding the pathophysiology of CMI and its association with SM. The case indicates the need for neurological and radiological follow-up for patients undergoing posterior fossa decompression due to CMI, even for those without an initial syrinx. This is the first report known to us of expansion of a syrinx following decompression of an associated CMI.- - - - - - - - - - ranking = 0.88261784811788keywords = herniation (Clic here for more details about this article) |
5/89. Prepontine lesions with chiari II malformation. Report of two cases.In 2 cases of infants with the Chiari II malformation, a prepontine cyst presented in association with the hindbrain abnormalities characteristic of the Chiari II syndrome. Both infants presented with bulbar dysfunction and had poor outcome despite decompression of the cerebellar tonsillar herniation and drainage of the prepontine cysts. No such association between prepontine lesions and Chiari II has been described previously.- - - - - - - - - - ranking = 0.88261784811788keywords = herniation (Clic here for more details about this article) |
6/89. Chiari type I malformation in children and adolescents with cystic fibrosis.Chiari type I malformation is characterized by herniation of the cerebellar tonsils through the foramen magnum. An association between Chiari type I malformation and cystic fibrosis (CF) has not previously been established. We report on five children and adolescents with CF in whom Chiari type I malformations were diagnosed. Three patients were 17-18 years old at time of diagnosis, one was 3 years old, and one was 10 months of age. All patients were followed at the cystic fibrosis Center at St. Christopher's Hospital for Children and were diagnosed with the malformations between June 1988 and June 1997. Over this same period, 400 CF patients 18 years or younger were followed routinely. All patients had the diagnosis of Chiari type I confirmed by brain-stem MRI. Neurologic findings included swallowing dysfunction, syncopal episodes, numbness of extremities, recurrent vomiting, and headaches. No two patients had the same presenting neurologic findings. Our data suggest that Chiari type I malformation is more common in CF than in the general population. The possibility of Chiari type I malformation should be included in the differential diagnosis of unexplained neurologic complaints in patients with CF.- - - - - - - - - - ranking = 0.88261784811788keywords = herniation (Clic here for more details about this article) |
7/89. Chiari I malformation: clinical presentation and management.Chiari malformations are cerebellar anomalies. The four types of Chiari malformations, as described more than 100 years ago by Dr. Hans Chiari, have neither anatomic nor embryologic correlation. Their only commonality is that they all involve the cerebellum. Chiari I malformation consists of herniation of the cerebellar tonsils into the foramen magnum, thus crowding the craniocervical junction. Chiari II malformation is almost exclusively associated with myelomeningocele and hydrocephalus. It consists of herniation of not only the tonsils but also all the contents of the posterior fossa into the foramen magnum. This herniation involves the brainstem, fourth ventricle, and cerebellar vermis. Chiari III and IV malformations are rare. Chiari III represents an encephalocele (external sac containing brainstem and posterior fossa contents); thus, the cerebellum and brainstem are descending not only into the spine, but also into an external sac. Chiari IV consists of cerebellar hypoplasia. The Chiari I malformation has the latest mean age of clinical presentation. A Chiari type I anomaly presenting in adulthood is the focus of this article. Surgery is indicated with neurological dysfunction, symptomatic syrinx, or hydrocephalus. Of all Chiari I patients, 15%-20% will have hydrocephalus. For some of them, the hydrocephalus will resolve with ventriculoperitoneal shunting, alleviating the need for a Chiari decompression. Long-term prognosis for patients with symptomatic Chiari type I malformations who undergo surgical treatment is variable, based on the patients' presenting symptoms and spinal cord cyst response.- - - - - - - - - - ranking = 2.7652356962358keywords = herniation, meningocele (Clic here for more details about this article) |
8/89. When does low mean high? Isolated cerebral ventricular increased intracranial pressure in a patient with a Chiari I malformation.OBJECTIVE: To present an unusual case of pseudotumor cerebri with increased intracranial pressure isolated to the cerebral ventricles resulting from a Chiari I malformation. MATERIALS AND methods: The patient received a complete ophthalmologic examination on initial presentation and subsequent visits, including visual acuity, pupillary examination, intraocular pressures, dilated fundus examination with assessment of degree of papilledema, and visual field testing. intracranial pressure was measured by lumbar puncture and subsequently by intracranial pressure bolt monitoring. magnetic resonance imaging (MRI) was used to diagnose the Chiari I malformation. RESULTS: The patient initially presented with bitemporal headaches, elevated opening pressure on lumbar puncture, and mild papilledema with a normal MRI. After lumboperitoneal shunt placement and several revisions, the patient presented with decreased vision OD secondary to Terson syndrome and worsening papilledema. Subsequent evaluation revealed normal lumbar opening pressures and a Chiari I malformation. She underwent ventriculoperitoneal shunt placement with resolution of her symptoms. CONCLUSIONS: Tonsillar herniation is a well-documented complication of lumboperitoneal shunt revision. Obstruction of cerebrospinal flow through the foramina of Magendie and Luschka can result in increased intracranial pressure isolated to the cerebral ventricles. In a patient with signs and symptoms of increased intracranial pressure but normal lumbar opening pressure, a Chiari I malformation should be suspected, particularly with a history of multiple lumboperitoneal shunt revisions.- - - - - - - - - - ranking = 0.88261784811788keywords = herniation (Clic here for more details about this article) |
9/89. A craniocervical injury-induced syringomyelia caused by central canal dilation secondary to acquired tonsillar herniation. Case report.The authors report on a 19-year-old man with an acquired tonsillar herniation caused by a craniocervical junction injury in which serial magnetic resonance (MR) images demonstrated patent and isolated segments of the central canal participating in the dilation and then formation of a cervical syrinx. The patient was involved in a motor vehicle accident; he developed tonsillar herniation as a complication of subarachnoid and epidural hemorrhage, predominantly observed around the cisterna magna and upper cervical canal. Repeated MR images obtained over an 11-month period indicated the for mation and acute enlargement of the syrinx. Ten months after the accident, the patient presented with sensory disturbance in both upper extremities and spasticity due to syringomyelia. He underwent craniocervical decompressive surgery and doraplasty, which reduced the size of syringomyelia. The authors postulate that the patent central canal may play a role in determining the location of a syrinx remote from a focus of cerebrospinal fluid obstruction.- - - - - - - - - - ranking = 5.2957070887073keywords = herniation (Clic here for more details about this article) |
10/89. Sudden unexpected death in young adults with chronic hydrocephalus.We present four cases of sudden unexpected death in young adults with chronic hydrocephalus. The patients were between 20 and 28 years of age and had suffered from aqueduct stenosis (two patients), spina bifida in combination with arnold-chiari malformation (type II) and fragile X-syndrome. The patients suddenly collapsed with cardiorespiratory failure and could not be resuscitated and none had a history of headache or seizures. The post-mortem examinations revealed no unusual findings and a definite cause of death could not be established. Neuropathological examination revealed chronically hydrocephalic brains without any signs of uncal or tonsillar herniation. We hypothesise that a sudden pressure-induced decompensation of cerebral neuronal pathways involving insular and limbic cortex, hypothalamus and brain stem nuclei, may have caused disturbances of the cardiopulmonary control centres in the reticular formation of the brain stem, which in turn may have led to instantaneous cardiorespiratory arrest resulting in sudden "neurogenic" cardiac death.- - - - - - - - - - ranking = 0.88261784811788keywords = herniation (Clic here for more details about this article) |
| | Next -> |