Continuous bedside cerebral blood flow monitoring.

Continuous cerebral blood flow monitors are being used in critically ill neuroscience patients to assess blood flow in vulnerable regions of the brain and to evaluate the effects of treatments on these areas. Neuroscience nurses need to interpret cerebral blood flow values in relation to the many other physiologic parameters which are monitored in this population. Case studies are used to illustrate various patterns of regional blood flow in response to brain insults and therapeutics. Research implications of continuous cerebral blood flow monitoring are explored.

Epidural abscess of the cervical spine: MR findings in five cases.

Cervical epidural abscess is an uncommon infectious process of the spinal epidural space. Although this disorder is often unsuspected clinically, the patient's signs and symptoms may suggest other diagnoses that frequently lead to an MR examination. We retrospectively reviewed the MR examinations of five patients with surgically proved cervical epidural abscess in order to assist in the diagnosis of this clinically elusive disorder. Each epidural abscess was evaluated for MR signal intensity, location, extent, delineation, and enhancement pattern. We assessed the spinal cord for compression and signal intensity and analyzed the vertebrae, intervertebral disks, and paraspinal soft tissue. Compared with the spinal cord, the abscess was isointense or hypointense on T1-weighted spin-echo images and hyperintense on T2-weighted images. The abscess was hyperintense or isointense relative to the cord on T2* gradient-echo images. Enhancement of the abscess occurred in the two patients given an IV injection of gadopentetate dimeglumine. The epidural abscess was located anteriorly in three patients, posteriorly in one, and was circumferential in one. The abscess extended from two to nine vertebral bodies in length. In each case, the abscess caused some degree of spinal cord compression, and one patient had bright signal intensity within the cord on T2-weighted images. Three patients had MR changes of accompanying osteomyelitis and paravertebral abscess. MR imaging is useful in diagnosing cervical epidural abscess and in evaluating associated abnormality of the spinal cord, vertebral bodies, intervertebral disks, and paraspinal soft tissue.

CT and MR appearance of cervical acrylic struts.

A patient sustained trauma to the cervical spine and underwent surgical fusion that included the use of methyl methacrylate struts. The CT and MR appearances of these acrylic struts are described.

Monoamine alterations during experimental hydrocephalus in neonatal rats.

The present study was designed to determine the selected monoamine changes that occur during infantile hydrocephalus. Obstructive hydrocephalus was induced in newborn rats by injection of a suspension of kaolin into the 4th ventricle and cisterna magna. Eleven days later, experimental animals and their sham-operated littermate controls were killed and pieces of frontoparietal cortex, neostriatum, cerebellar vermis, and brain stem were processed for high performance liquid chromatography. Grossly, the lateral ventricles were extremely enlarged, the cerebral cortex was thinned, the neostriatum was compressed, and portions of the tectum and cerebellum were vacuolated. Decreases in norepinephrine (71%), dopamine (73%), and serotonin (50%) were observed in the cerebral cortex, neostriatum, and cerebellum, respectively. Brain stem norepinephrine and serotonin were increased 70% and 50%, respectively. These increases may indicate impairment of axonal transport or damage to projections from the locus ceruleus and raphe region. These preliminary results suggest that infantile hydrocephalus causes perturbations in the levels of different monoamines in several brain regions. Such changes may critically influence neuronal function and development, as well as the therapeutic management of hydrocephalus.

Association of a ganglioneuroma with an arteriovenous malformation: case report.

The unusual concurrence of a brain tumor and an arteriovenous malformation (AVM) is discussed in this case report. A 12-year-old child presented with a severe headache, and an intracerebral mass was found on neuroradiological study. At operation, we encountered a superficial AVM, not shown on the computed tomogram or arteriogram. At a second procedure, a ganglioneuroma was removed. The literature on the concurrence of these two entities is reviewed; comments are made on the pathology of ganglion cell tumors.

Hemoglobinemia and renal failure from an intracerebral hematoma simulating a vein of Galen aneurysm.

A case of an intracranial hematoma in a neonate causing the release of free hemoglobin into the plasma is presented. No previous such case has been described. The relationship between hemoglobinemia and the occurrence of acute renal failure in this neonate is discussed, with comments on the possible etiological role of the hemoglobinemia.

Identification of acetylcholinesterase-reactive neurons and neuropil in neostriatal transplants.

To identify and describe neurons in neostriatal transplants that synthesize acetylcholinesterase (AChE), the present study has utilized the irreversible AChE inhibitor diisopropylfluorophosphate (DFP) combined with AChE histochemistry. Dissociated suspensions of tissue taken from the striatal ridge of embryos at 14 days of gestation were transplanted into the neostriatum of adult rats 5 days after intrastriatal kainic acid lesions. Two types of AChE neurons have been identified in transplants treated with DFP. One type resembled the large intensely reactive AChE neuron that is thought to be a cholinergic interneuron of the normal neostriatum. The other type resembled smaller, less reactive AChE neurons of the neostriatum, as well as medium-sized, lightly reactive AChE neurons of the globus pallidus. Qualitative observations suggest that these less reactive AChE neurons were more numerous in transplants compared to the normal neostriatum. Both AChE neuronal types were found in segregated clusters throughout the grafts. Transplants processed for AChE histochemistry without DFP treatment contained two types of AChE neuropil. Dark areas of AChE neuropil similar in intensity to the normal neostriatum were found between larger areas of lighter AChE neuropil. These results demonstrate that neostriatal transplants contain AChE neurons and suggest that these neurons contribute to the AChE reactivity within the graft.

Bilateral hearing loss after unilateral removal of an acoustic neuroma by the suboccipital approach: case report.

Contralateral hearing loss is a very rare complication of acoustic neuroma surgery. A case of immediate postoperative contralateral hearing loss is reported. Possible causes and the pertinent literature are reviewed.