A review of ancillary tests in evaluating brain death.

The neurological determination of death (NDD) is primarily considered to be clinical. However, situations may arise where confounding factors make this clinical assessment difficult or impossible. As a result, ancillary tests have been developed in order to aid in the confirmation of brain death. As assessment of neuronal electrical activity; electroencephalography (EEG) is no longer recommended in this determination, tools assessing cerebral perfusion, as reflected by the presence or absence of cerebral blood flow (CBF), are the mainstay of NDD. The preferred ancillary test currently is Hexamethylpropylene amine oxime-single photon emission computed tomography (HMPAO SPECT) radionuclide angiography. When this is not available, or is equivocal, 4-vessel cerebral angiography can be used to determine the presence or absence of intracranial blood flow. However, as cerebral angiography has its own limitations, other techniques are sought by physicians in the Intensive Care and Neuro-intensive Care settings to replace cerebral angiography. In this article, we briefly review the history of diagnosis of brain death, pathophysiologic issues in making this determination, and currently available CBF imaging techniques, discussing each in turn with respect to their utility in the diagnosis of brain death.

Large ophthalmic segment aneurysms with anterior optic pathway compression: assessment of anatomical and visual outcomes after endosaccular coil therapy.

OBJECT: The optimal therapy for ophthalmic segment aneurysms with anterior optic pathway compression (AOPC) is undecided. Surgical results have been described, but the results of endovascular coil therapy have not been well documented. METHODS: The authors retrospectively reviewed data obtained in all patients who harbored unruptured ophthalmic segment aneurysms with AOPC who underwent endovascular coil therapy at their institution. They analyzed baseline and outcome visual function, aneurysm features, extent of aneurysm closure, internal carotid artery (ICA) occlusion, additional interventions, and neurological outcome. In 17 patients (16 women), age 38 to 83 years, there were 28 affected eyes. All aneurysms were greater than 10 mm in diameter. In the initial procedures 16 of 17 patients received endosaccular coils and the ICA was preserved; in one patient the aneurysm was trapped and the ICA occluded. Patients then underwent follow up for a mean of 2.90 years (range 1 month-1 1.2 years) after the last procedure. One patient died of subarachnoid hemorrhage (SAH) 1 month postoperatively and thus no follow-up data were available for this case. Vision worsened in six patients, stabilized in four, and improved in six. Twelve patients underwent 13 subsequent procedures, including endovascular ICA occlusion in seven, repeated coil therapy in five, and optic nerve decompression in one; vision improved in 83% of these cases after ICA occlusion. A second patient died of SAH 5 months after repeated coil treatment. At the final follow up, vision had improved in eight patients (50%), stabilized in four (25%), and worsened in four (25%). In 16 patients with follow-up studies, aneurysm closure was complete in eight (50%) and incomplete in eight (50%). CONCLUSIONS: The authors found that in patients with ophthalmic segment aneurysms causing chronic AOPC, endosaccular platinum coil therapy, with ICA preservation, may not benefit vision and that additional procedures may be needed. Evaluation of their results suggests that endovascular trapping of the aneurysm and sacrifice of the ICA appear to result in good visual, clinical, and anatomical outcomes.

Primary intradural extraarachnoid hodgkin lymphoma of the cervical spine. Case report.

This 42-year-old man presented with an intradural extramedullary mass in his lower cervical spine. On imaging studies the lesion mimicked the appearance of a meningioma. At surgery, the mass was found to be an intradural extra-arachnoid tumor. An intraoperative pathological examination determined the lesion to be a Hodgkin lymphoma. The procedure was limited to biopsy sampling and the patient was treated further with adriamycin, bleomycin, vincristine, and dacarbazine chemotherapy, after which remission was demonstrated both clinically and on images. Analysis of a frozen section obtained during the procedure aided in the diagnosis of the tumor, thus preventing further resection and the potential neurological complications associated with more radical resection. To the authors' knowledge this is the first reported case of a presumed primary intradural extraarachnoid Hodgkin lymphoma.

Jugular bulb oximetry for prediction of vasospasm following subarachnoid hemorrhage.

BACKGROUND: Cerebral vasospasm adversely impacts the outcome of those suffering aneurysmal subarachnoid hemorrhage (SAH). Prediction of vasospasm could improve outcomes. We hypothesized that preclinical vasospasm would be heralded by an increase in cerebral oxygen extractions (AVDO2) which could be detected by jugular bulb oximetry. A pilot study was conducted to address this hypothesis. METHODS: Fourteen consenting patients with aneurysmal SAH, undergoing early surgery, were entered into the study. Four patients were withdrawn from the study secondary to failure of catheters or religious belief. At the time of craniotomy, a jugular bulb catheter was placed. Post-operatively, arterial and jugular bulb blood samples were taken every 12 hours to calculate AVDO2. As this was an observational study, no change in management occurred based on measurements. RESULTS: Four of 10 patients had clinical vasospasm. These patients had a significant rise in AVDO2 approximately one day prior to the onset of neurologic deficits (P<0.001). Symptoms resolved along with a significant improvement in AVDO2 on instituting hypertensive, hemo-dilutional, and hypervolemic therapy in these patients. The six patients who did not exhibit clinical vasospasm did not demonstrate significant rise in AVDO2. CONCLUSIONS: Jugular bulb oximetry is simple and cost effective. Increases in AVDO2 using this technique were predictive of clinically evident vasospasm in the subsequent hours to days. This investigation supports a larger study to assess the utility of jugular bulb oximetry in predicting vasospasm in aneurysmal SAH.

Neuroepithelial cysts presenting with movement disorders: two cases.

BACKGROUND: The authors present two cases of movement disorders caused by neuroepithelial cysts and highlight their management. Neuroepithelial cysts are ependymal or epithelial lined fluid collections of unknown etiology within the central nervous system parenchyma with no obvious ventricular or subarachnoid connection. Most cysts are asymptomatic, however, some present with seizures, mass effect, or rarely with movement disorders. CASE REPORTS: The first patient, a 27-year-old female, presented with progressive weakness, dystonic posturing, tremor, ballismus and choreoathetotic movements of her right upper extremity. Her symptoms improved after stereotactic drainage of a neuroepithelial cyst in her basal ganglia but recurred within a year. The second case, a 56-year-old female, presented with diplopia, nystagmus, gait imbalance and hemiparesis. Her symptoms improved after stereotactic drainage of a midbrain neuroepithelial cyst. The cyst reaccumulated over the next few years and she became symptomatic with left arm tremor and facial weakness. Aspiration was again performed with symptomatic improvement for nine months. Her tremor recurred and a cyst access device was placed stereotactically. She improved and has remained stable for over a year. CONCLUSION: Simple stereotactic drainage of neuroepithelial cysts has a high recurrence rate. The authors recommend considering placement of a drainage device to facilitate aspiration of the cyst fluid during follow-up, if needed.