1/28. 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 = myelomeningocele (Clic here for more details about this article) |
2/28. 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 = 1keywords = myelomeningocele (Clic here for more details about this article) |
3/28. Occipital encephalocele, lipomeningomyelocele, and Chiari I malformation: case report and review of the literature.CASE REPORT. We report a pediatric patient with encephalocele, lipomeningomyelocele, and Chiari I malformation. DISCUSSION. We also review the extant medical literature regarding associations between these three entities. We propose that the combination of these three pathologies, which is reported here for the first time, is not serendipitous but rather a low-frequency association. CONCLUSIONS. After a literature review, we speculate that encephalocele and lipomeningomyelocele most probably occur by mechanisms similar to those that produce encephalocele and meningomyelocele and that the tonsillar ectopia in our patient is due to an abnormally small posterior cranial fossa resulting from the lack of neural tissue within the cranium at critical times during development or has its genesis, as some encephaloceles may, in inappropriate paraxial mesoderm formation.- - - - - - - - - - ranking = 1.1471047728852keywords = meningomyelocele (Clic here for more details about this article) |
4/28. Rhombencephalosynapsis and a Chiari II malformation.Rhombencephalosynapsis is an anomaly of the hindbrain characteristically presenting with cerebellar fusion and absence of cerebellar vermis on magnetic resonance imaging. Its association with spinal anomalies has not been reported previously. We report a unique case, a 22-year-old man with cerebellar fusion associated with a cervicothoracic meningomyelocele, diastematomyelia, tethering of the spinal cord, and dorsal dermal sinuses. In addition, cerebellar tonsillar herniation and tectal beaking similar to that seen in Chiari II malformations were present. These findings suggest that rhombencephalosynapsis can be associated with spinal malformations and, furthermore, that cases with the common features of rhombencephalosynapsis and a Chiari II malformation can exist. Such an association likely represents a new anomaly of the hindbrain and spine.- - - - - - - - - - ranking = 0.16387211041217keywords = meningomyelocele (Clic here for more details about this article) |
5/28. Chiari II malformation and occult spinal dysraphism. case reports and a review of the literature.We report two cases of children with occult spinal dysraphism who were also found to have many associated brain anomalies seen in the Chiari II malformation. No previous report has commented on the possible association between the Chiari II malformation and the 'closed' form of neural tube defect. One child had symptoms referable to pathology at the craniocervical junction. Neither child had cutaneous stigmata associated with occult spinal dysraphism over the caudal midline spine. These cases, although seemingly rare, lend support to the theories that the association between the Chiari II malformation and patients with myelomeningoceles is due to dysgenesis of the rostral and caudal neural tube. These cases are also important as refutation of earlier theories that link these two entities by proposing that the Chiari II malformation is due to overdrainage of cerebrospinal fluid at the site of myelomeningocele.- - - - - - - - - - ranking = 2keywords = myelomeningocele (Clic here for more details about this article) |
6/28. Frontal foramina, Chiari II malformation, and hydrocephalus in a female.Reported is a 4-year-old female with Chiari II malformation and congenital hydrocephalus associated with lumbosacral myelomeningocele who also presented with frontal calvarial foramina depicted by head computed tomographic scans with three-dimensional reconstructions. Magnetic resonance demonstrated bilateral and symmetric frontal lobe malformation-separated-lip clefts schizencephaly-adjacent to the bilateral frontal calvarial foramina. Because the different types of malformations evident in this patient do not share the same developmental origin, the association of findings is unusual and suggests the occurrence of an unknown prenatal factor acting along different stages of central nervous system development.- - - - - - - - - - ranking = 1keywords = myelomeningocele (Clic here for more details about this article) |
7/28. Thoracic meningocele, meningomyelocele or myelocystocele? Diagnostic difficulties, consequent implications and treatment.spina bifida cystica is a closing disorder of the neural tube which infrequently occurs in the thoracic region. A rare lesion called myelocystocele is a variant of spina bifida cystica and is associated with syringomyelia, Chiari type 2 malformation and hydrocephalus. Usually the patient has no neurological deficit, but future deterioration can occur due to posterior tethering of the spinal cord by adhesions. The prenatal diagnosis by ultrasound study can be misleading and in order to attain the correct diagnosis, especially if abortion is considered, a prenatal MRI scan should be done before the parents are counselled, and should be repeated prior to operative treatment. Surgical correction of myelocystocele is not only for cosmetic reasons, but also to untether the spinal cord prophylactically to prevent future neurological deterioration. In this case report, we present a child born with a thoracic myelocystocele, the diagnostic difficulties, consequent implications and surgical treatment.- - - - - - - - - - ranking = 0.65548844164866keywords = meningomyelocele (Clic here for more details about this article) |
8/28. Precocious, early and fast puberty in males with Chiari I malformation.Type I Chiari malformation is a disorder characterized by a displacement of the cerebellar tonsils through the foramen magnum into the upper cervical spinal canal and, contrary to type II arnold-chiari malformation, without the presence of myelomeningocele. As described in the literature, patients suffering from arnold-chiari malformation with myelomeningocele can frequently present with precocious puberty, whereas only one report shows an association between Chiari I malformation and early puberty. We describe three young males--8.8, 9.4 and 10.4 years old--who were diagnosed with precocious, early and fast puberty associated with type I Chiari malformation. In patients 2 and 3, the reason for diagnostic management recommendation was a rapid progression of pubertal development over one year. None of the patients manifested hypophyseal-hypothalamic axis dysfunction other than sexual precocity. Neurological and ophthalmological examinations were normal in all patients. Our data show that type I Chiari malformation can be considered one of the possible causes for precocious, early and accelerated puberty in male patients, suggesting the need to carry out brain nuclear magnetic resonance imaging in order to investigate the presence of this malformation.- - - - - - - - - - ranking = 2keywords = myelomeningocele (Clic here for more details about this article) |
9/28. Spontaneous pneumocephalus presenting with apnea attacks in a newborn with open myelomeningocele.We report a case who had an open myelomeningocele and developed respiratory arrest associated with spontaneous pneumocephalus. Spontaneous respiration resumed after closing of the defect and ventriculoperitoneal shunting. We conclude that repair of the defect in the early period is very useful both to minimize the infection risk and to prevent the complication of pneumocephalus in these cases.- - - - - - - - - - ranking = 5keywords = myelomeningocele (Clic here for more details about this article) |
10/28. Myelomeningocele in an infant with intrauterine exposure to efavirenz.We report a case of myelomeningocele in an infant whose mother was exposed to efavirenz during the first 16 weeks of pregnancy. Although the true risk for myelomeningocele with the use of efavirenz early in pregnancy is still unknown, the findings in humans are consistent with those observed in primates and suggest that efavirenz is a potent teratogen. Thus, we suggest that efavirenz only be prescribed for women of childbearing potential when no other comparable antiretroviral options are available.- - - - - - - - - - ranking = 2keywords = myelomeningocele (Clic here for more details about this article) |
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