Transient Neurological Events Research Articles

Mild Traumatic Brain Injury in U.S. Soldiers Returning from Iraq

To the Editor: We wish to express a number of concerns about the methods used in the study of mild traumatic brain injury by Hoge et al. (Jan. 31 issue).1 We learned through firsthand experi­ ence in the combat zone that immediately after a concussion, the soldier’s reported account is most accurate during the initial 24 hours after the blast incident.2 We therefore would be con­ cerned about recall bias introduced 3 to 4 months after a return from deployment. In addition, unlike perforation of the tympan­ ic membrane, a transient neurologic event (e.g., a “split­second” loss of consciousness) after a blast incident is not a sentinel finding of direct­ blast overpressure.2 Rather, it is a combination of at least three biodynamic variables: bodily displacement, direct­blast overpressure (involving intrinsic neural­tissue strains), and cardiopulmo­ nary insufficiency.3-5 The adverse effects of cardiopulmonary­ induced transient neurologic events (e.g., vasode­ pressor presyncope) are neither necessarily per­ manent nor cumulative, as a result of biologic restorative processes. Thus, we are concerned that the assessment methods used do not properly reflect the dimen­ sions of mild traumatic brain injury. Further­ more, we believe that the diagnosis of mild trau­ matic brain injury can be made only over time.

Prognosis of Nonfocal Transient Neurologic Attacks

Transient neurologic events with focal signs (i.e., hemiparesis, dysarthria, or amaurosis fugax) are traditionally called transient ischemic attacks

Complications of cerebral angiography: a prospective analysis of 2,924 consecutive procedures

Cerebral angiography is an invasive procedure associated with a small, but definite risk of neurological morbidity. In this study we sought to establish the nature and rate of complications at our institution among a large prospective cohort of consecutive patients. Also, the data were analysed in an attempt to identify risk factors for complications associated with catheter angiography. Data were prospectively collected for a consecutive cohort of patients undergoing diagnostic cerebral angiography between January 2001 and May 2006. A total of 2,924 diagnostic cerebral angiography procedures were performed during this period. The following data were recorded for each procedure: date of procedure, patient age and sex, clinical indication, referring specialty, referral status (routine/emergency), operator, angiographic findings, and the nature of any clinical complication or asymptomatic adverse event (arterial dissection). Clinical complications occurred in 23 (0.79%) of the angiographic procedures: 12 (0.41%) significant puncture-site haematomas, 10 (0.34%) transient neurological events, and 1 nonfatal reaction to contrast agent. There were no permanent neurological complications. Asymptomatic technical complications occurred in 13 (0.44%) of the angiographic procedures: 3 groin dissections and 10 dissections of the cervical vessels. No patient with a neck dissection suffered an immediate or delayed stroke. Emergency procedures (P = 0.0004) and angiography procedures performed for intracerebral haemorrhage (P = 0.02) and subarachnoid haemorrhage (P = 0.04) were associated with an increased risk of complications. Neurological complications following cerebral angiography are rare (0.34%), but must be minimized by careful case selection and the prudent use of alternative noninvasive angiographic techniques, particularly in the acute setting. The low complication rate in this series was largely due to the favourable case mix.

Images in Neurology: Cerebral Microbleeds Due To Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA) refers to the deposition of beta amyloid in the small and medium sized arteries of the brain and predisposes the individual to primary intracranial hemorrhage (PICH), dementia and transient neurological events. A-75-year-old non-diabetic, normotensive male presented to us with history of sudden onset of abnormal behavior characterized by irrelevant talking and straying on the road for about 20 minutes followed by spontaneous recovery. At the time of presentation to the emergency room his neurological examination was non-focal with no deficits. Gradient echo brain magnetic resonance imaging (MRI) as a part of stroke work up revealed multiple small chronic hemorrhagic lesions (microbleeds) suggestive of CAA (Fig 1 and 2). CAA is an important cause of PICH in the elderly accounting for up to 10% of all PICH in this age group. Patients with CAA may remain asymptomatic or may present with transient ischemic attacks or a devastating PICH. A definitive diagnosis of CAA rests on pathological examination of the affected blood vessel however gradient echo magnetic resonance imaging is a sensitive and noninvasive technique and the presence, number and distribution of microbleeds has a strong correlation with future PICH and cognitive decline 1. It is important to request gradient echo sequences if a diagnosis of CAA is been considered as convention MRI sequences like diffusion weighted imaging may miss these microbleeds. Currently there is no effective treatment for CAA though research continues to find an effective anti-amyloid therapy. There are no clear guidelines regarding anti-thrombotic therapy in patients with CAA. It makes sense to treat cardiovascular risk factors like hypertensive, dyslipidemia and diabetes aggressively in these patients. The decision regarding anti-platelet therapy needs to be individualized taking into consideration the patient's cardiovascular profile. Our patient currently remains asymptomatic on daily aspirin therapy. Figure 1 Figure 1&2: Gradient echo magnetic resonance imaging showing multiple cerebral microbleeds suggestive of chronic hemorrhagic lesions.

Toxic metabolic encephalopathy after parathyroidectomy with methylene blue localization

To determine the correlation between methylene blue use and toxic metabolic encephalopathy in patients undergoing surgery for primary hyperparathyroidism. A retrospective study of 193 patients was performed to collect demographic, perioperative, and postoperative data. Patients were divided into two groups: Group A (postoperative neurological sequelae) and Group B (no neurological sequelae). All data points were compared between the groups. Twelve of 193 patients were placed in Group A; 181 patients were placed in Group B. Ten patients in Group A were female, and 10 patients were older than 60 years. Of the patients in Group A, 100% were taking a serotonin reuptake inhibitor (SRI). In Group B, 8.8% of patients were taking an SRI. All the patients who experienced transient neurological events were taking an SRI. A correlation can be made between methylene blue infusion and SRI usage. Patients taking SRIs may represent a high-risk group for postoperative neurological events when methylene blue is utilized.

Cerebral Amyloid Angiopathy: CT and MR Imaging Findings

Cerebral amyloid angiopathy (CAA) is an important but underrecognized cause of cerebrovascular disorders that predominantly affect elderly patients. CAA results from deposition of beta-amyloid protein in cortical, subcortical, and leptomeningeal vessels. This deposition is responsible for the wide spectrum of clinical symptoms and neuroimaging findings. Many cases of CAA are asymptomatic. However, when cases are symptomatic, patients can present with transient neurologic events, progressive cognitive decline, or potentially devastating intracranial hemorrhage. Computed tomography is the imaging study of choice for evaluation of suspected acute cortical hemorrhage, which may be accompanied by subarachnoid, subdural, or intraventricular hemorrhage. Magnetic resonance imaging is best suited for identification of small or chronic cortical hemorrhages and ischemic sequelae of this disease, exclusion of other causes of acute cortical-subcortical hemorrhage, and assessment of disease progression. Accurate recognition of imaging findings is important in guiding clinical decision making in patients with CAA.

Regional versus general anaesthesia for carotid endarterectomy: Impact of change in practice

Local anaesthesia (LA) for carotid endarterectomy (CEA) may offer advantages over general anaesthesia (GA). Our aim was to compare outcome from CEA before and after changing our anaesthetic technique from GA to LA. Sequential patients who underwent CEA between January 1997 and December 2001 were identified from a prospectively collected database. GA was used during the first two years of this period and LA was used exclusively over the last three years. Differences in the incidence of intraoperative shunting, perioperative stroke and transient ischaemic attack (TIA), cranial nerve injury, neck haematoma, perioperative death and duration of hospital stay were assessed. Three hundred and seventy one CEAs were carried out in 363 patients, 179 under GA and 192 under LA. Indications were TIAs (140), stroke with recovery (134), amaurosis fugax (85) and asymptomatic high-grade stenosis (12). Intraoperative shunting was used in 66 (37%) GA operations and 36 (18.8%) LA operations (p<0.01). There were nine strokes and four transient neurological events; 10 (5.5%) patients developed such problems with GA and three (1.6%) with LA (p<0.05). There were four deaths, three (1.7%) after GA and one (0.5%) after LA (p=NS). Duration of hospital stay was less in the LA group at a median (range) of three days (2-10) compared with 4.5 (3-14) days in the GA group (p<0.001). Employing LA rather than GA for CEA has been associated with a reduction in intraoperative shunting and perioperative stroke, and the duration of hospital stay. LA appears to offer clinical and possible cost advantages over GA.

A Tailored Approach to Catheter Ablation of Paroxysmal Atrial Fibrillation

Because the genesis of atrial fibrillation (AF) is multifactorial and variable, an ablation strategy that involves pulmonary vein isolation and/or a particular set of ablation lines may not be equally effective or efficient in all patients with AF. A tailored strategy that targets initiators and drivers of AF is a possible alternative to a standardized lesion set. Catheter ablation was performed in 153 consecutive patients (mean age, 56+/-11 years) with symptomatic paroxysmal AF with the use of an 8-mm tip radiofrequency ablation catheter. The esophagus was visualized with barium. The pulmonary veins and left atrium were mapped during spontaneous or induced AF. Arrhythmogenic pulmonary veins were isolated or encircled. If AF was still present or inducible, complex electrograms in the left atrium, coronary sinus, and superior vena cava were targeted for ablation. The end point of ablation was absence of frequent atrial ectopy and spontaneous AF during isoproterenol infusion and noninducibility of AF. Routine energy applications near the esophagus were avoided. During follow-up, left atrial flutter developed in 19% of patients and was still present in 10% at >12 weeks of follow-up. A repeat ablation procedure was performed in 18% of patients. During a mean follow-up of 11+/-4 months, 77% of patients were free from AF and/or atrial flutter without antiarrhythmic drug therapy. Pericardial tamponade or transient neurological events occurred in 2% of procedures. A tailored ablation strategy that only targets triggers and drivers of AF is feasible and eliminates paroxysmal AF in approximately 80% of patients.

Neurological examination identified 61% of patients with focal cerebral hemisphere lesions but without obvious focal signs

Anderson NE, Mason DF, Fink JN, et al . Detection of focal cerebral hemisphere lesions using the neurological examination. J Neurol Neurosurg Psychiatry 2005;76:545–9. [OpenUrl][1][Abstract/FREE Full Text][2] Q In patients...

Cerebral Protection During Carotid Stenting Using Flow Reversal

Background Carotid angioplasty and stenting can be used in stroke prevention in high-risk patients. As embolic complications can occur during carotid angioplasty and stenting, a device was developed to protect from cerebral embolization. Methods Between September 1999 and May 2002, carotid angioplasty and stenting was performed in 100 patients (84 men; mean age, 69.2 years) with symptomatic (26%) or asymptomatic (74%) severe carotid artery stenosis. Wallstents were used in all cases with selective pre-dilatation. Cerebral protection devices (Parodi Anti-Emboli System [PAES], ArteriA, San Francisco, Calif) were used in all patients. All patients were evaluated by a neurologist, both before and after the procedure. According to the criteria set forth by the large trials, the occurrence of minor, major or fatal stroke and myocardial infarction (end points) within 30 days and follow-up were determined as end points. Data were collected prospectively. Results The overall perioperative stroke and death rate was 3% (1 noncorresponding minor stroke, 1 hemorrhagic stroke, and 1 cardiac event). Four patients developed postoperative transient neurologic events (three related to hemodynamic instability and the fourth due to postoperative embolization). The overall technical success rate for carotid angioplasty (protection device placed in position percutaneously) was 99%. Conclusion The efficacy and safety of carotid angioplasty and stenting with PAES are confirmed. This innovative protection device may prevent the debris released by angioplasty from entering the cerebral circulation. Further investigation is warranted.

Cerebral protection during carotid stenting using flow reversal

Carotid angioplasty and stenting can be used in stroke prevention in high-risk patients. As embolic complications can occur during carotid angioplasty and stenting, a device was developed to protect from cerebral embolization. Between September 1999 and May 2002, carotid angioplasty and stenting was performed in 100 patients (84 men; mean age, 69.2 years) with symptomatic (26%) or asymptomatic (74%) severe carotid artery stenosis. Wallstents were used in all cases with selective pre-dilatation. Cerebral protection devices (Parodi Anti-Emboli System [PAES], ArteriA, San Francisco, Calif) were used in all patients. All patients were evaluated by a neurologist, both before and after the procedure. According to the criteria set forth by the large trials, the occurrence of minor, major or fatal stroke and myocardial infarction (end points) within 30 days and follow-up were determined as end points. Data were collected prospectively. The overall perioperative stroke and death rate was 3% (1 noncorresponding minor stroke, 1 hemorrhagic stroke, and 1 cardiac event). Four patients developed postoperative transient neurologic events (three related to hemodynamic instability and the fourth due to postoperative embolization). The overall technical success rate for carotid angioplasty (protection device placed in position percutaneously) was 99%. The efficacy and safety of carotid angioplasty and stenting with PAES are confirmed. This innovative protection device may prevent the debris released by angioplasty from entering the cerebral circulation. Further investigation is warranted.

Near-infrared spectroscopy for monitoring cerebral ischemia during selective cerebral perfusion

To minimize the neurological complications following cardiovascular surgery, it is essential to prevent an occurrence of cerebrovascular embolism and to detect and solve cerebral malperfusion without delay in the operating theater. Although we have introduced near-infrared spectroscopy (NIRS) monitoring for the purpose of detecting cerebral malperfusion, no criterion has been available. We searched for this criterion by examining the relationship of sustained drop in the regional oxygen saturation (rSO2) of the frontal lobes to the occurrence of neurological events. The 59 consecutive patients undergoing aortic surgery with selective cerebral perfusion (SCP) were examined. The rSO2 was monitored throughout the surgery and the durations of drops in rSO2 to below 55% and those below 60% were determined for each patient. The durations of rSO2 drop and other surgery-related parameters were compared between the patients in whom neurological events occurred and those without such events. A total of 16 cases (27.1%) presented with neurological events. Newly developed cerebral infarction was documented in 6 of these 16 cases. Operation time and the durations for which rSO2 dropped were significantly longer for the 16 patients with neurological events than for the 43 patients without events (Op time: 546.8 versus 448.1 min, P=0.0064; rSO2 below 60%: 141.2 versus 49.8 min, P=0.0032; rSO2 below 55%: 66.6 versus 10.6 min, P=0.0011), while there was no significant difference in age, bypass time, aortic clamping time, SCP time, and circulatory arrest time between the two groups. In the 3 patients with infarcts suggestive to hypoperfusion, sustained decrease in rSO2 was observed, while it was not significant in the remaining 3 patients with infarcts suggestive to embolism. Among the 53 patients without infarction, transient neurological events occurred more frequently in patients with sustained drop in rSO2 below 55% for over 5 min (44.4% versus 5.7%, P=0.0014). A sustained drop in rSO2 during aortic surgery is closely related to the occurrence of neurological events following surgery. We recommend that recovery of drop in rSO2 below 55% should be addressed without delay. However, use of NIRS is limited for detecting embolic events or hypoperfusion in the basilar region.

Transient ischemic attack (TIA) in a child with severe transient erythroblastopenia of childhood (TEC) – causal relation or coincidence?

Introduction: Transient erythroblastopenia of childhood (TEC) is a generally harmless, rare bone marrow disorder of unknown etiology, probably triggered by viral infections. The disorder occurs in children aged 3 months to 4 years and is characterized by progressive normocytic-normo-chromic anemia, reticulocytopenia and elevated serum iron levels. Apart from anemia, leading to palor and fatigue, severe symptoms are rare. Sporadic cases of transient neurologic events have been reported in association with TEC, however, hardly any data is found when reviewing the literature.

Reoperation for neurological complications following carotid endarterectomy.

There remains a dilemma whether or not to re-explore the carotid artery when a neurological complication occurs after carotid endarterectomy. This study reviewed the indications for, findings and clinical outcomes following re-exploration. Patients who experienced transient or permanent neurological events following carotid endarterectomy were identified from a prospectively compiled computerized database. Case notes were retrieved to determine time to onset of symptoms, use of carotid artery imaging and details about patients who had surgical re-exploration, and outcomes. Some 780 consecutive carotid endarterectomies were performed over 16 years, with an incidence of major stroke or death of 2.3 per cent (18 patients). Fifty-one patients experienced transient or permanent neurological events following surgery, 25 of whom underwent re-exploration. The findings included carotid thrombosis (ten patients), flap or other technical cause (three), haematoma (two) and no abnormality (ten). The neurological outcome after 30 days was similar, whether or not the carotid artery was re-explored. Carotid artery re-exploration was undertaken in approximately half of the patients who developed neurological complications following carotid endarterectomy. Although the cause was identified and a secondary procedure was undertaken in 14 of 25 patients, there was no improvement in clinical outcome at 30 days compared with that of patients managed non-operatively.

Complications Associated with Selective High-dose Intraarterial Cisplatin and Concomitant Radiation Therapy for Advanced Head and Neck Cancer

To describe the incidence and severity of complications associated with intraarterial cisplatin and concomitant radiation therapy for advanced head and neck cancer. One hundred five patients treated between June 1993 and March 1998 were studied. Forty-seven (44%) had T4 lesions and 40 (37%) had bulky (N2/3) nodal disease. Three hundred eighty-five procedures were performed. All patients were treated with selective intraarterial tumor-directed cisplatin (150 mg/m(2) weekly x 4), simultaneous intravenous thiosulfate (9 g/m(2)) for systemic neutralization of cisplatin, and conventional external-beam radiation to the primary tumor and nodal disease (total dose of 66-74 Gy). One hundred five patients were evaluated for complications. Twenty-two (5.7%) groin hematomas occurred, none of which needed therapy. Two asymptomatic common carotid artery dissections were reported. Two patients experienced acute occlusion of the external iliac artery requiring a femorofemoral bypass. Overall, there were 41 grade III/IV chemotoxic events related to treatment. Chemotoxic events included 29 mucosal events, nine hematologic events, two otologic events, and one gastrointestinal event. No renal events occurred. There were three permanent and three transient neurologic events. Selective high-dose intraarterial cisplatin and concomitant radiation therapy for advanced head and neck cancer can be performed safely with a relatively low complication rate compared to standard intravenous chemotherapy treatment protocols.

Carotid artery stenting: analysis of data for 105 patients at high risk.

Carotid artery stenting (CAS) has been recommended as an alternative to carotid endarterectomy (CEA) by some clinicians. However, recently published clinical trials have reported 30-day stroke and death rates of 10% to 12%. This prompted review of our experience with CAS in patients at high risk, to document our results and guide further use of CAS. From September 1996 to the present, we performed 114 consecutive CAS procedures in 105 patients. Sixty-three patients were men (60%) and 42 patients were women (40%), with mean age of 70 years (range, 45-93 years). Indications for CAS included recurrent stenosis after previous CEA in 74 patients (65%), primary lesions in 32 patients at high risk (28%), and carotid stenosis with previous ipsilateral radiation therapy in 8 patients (7%). Asymptomatic stenosis (>80%) was managed in 70 patients (61%), and symptomatic lesions (>50%) were treated in 44 patients (39%). CAS was technically successful in all patients. Mean severity of stenosis before CAS was 87% +/- 6%, compared with 9% +/- 4% after CAS. Two patients (1.9%) died, 1 of reperfusion-intracerebral hemorrhage and 1 of myocardial infarction 10 days after discharge; and 1 patient (0.95%) had a stroke (retinal infarction), for a 30-day stroke and death rate of 2.85%. Two patients (1.9%) had transient neurologic events. No cranial nerve deficits were noted. No neurologic complications have been noted in the last 27 patients (26%). A 30-day stroke and death rate of 2.85% in our experience demonstrates acceptability of CAS as an alternative to repeat operation or primary CEA in patients at high risk or in patients with radiation-induced stenosis. We recommend further clinical investigation of CAS and participation in clinical trials by vascular surgeons.

Carotid Angioplasty and Stenting

The relative indications for CAS versus CEA have not been determined. Whereas endarterectomy remains the gold standard for the treatment of significant carotid artery stenosis, early results suggest that angioplasty and stenting may be indicated in selected patients with risk factors for complications from endarterectomy. Despite involving vastly different mechanisms for treatment of atherosclerotic lesions, permanent neurologic morbidity and mortality rates for both techniques are similar. The transient or minor neurologic events seen more often with CAS may be amenable to prevention with distal protection techniques currently undergoing clinical testing. With careful preprocedural evaluation of medical comorbidities, appropriate treatment with antiplatelet agents, and careful evaluation of the target lesion, most potential complications of angioplasty and stenting may be avoided or at least anticipated. Further technical advancements in endovascular therapy and patient-driven preferences for less-invasive procedures are likely to expand the indications and applications of CAS.

Effects of deep hypothermic circulatory arrest on outcome after resection of ascending aortic aneurysm

Background. Aneurysm of the ascending aorta is a common finding especially in patients with aortic valve diseases. The aim of this study was to analyze early and midterm outcome in patients operated on for aneurysm of the ascending aorta with or without the use of deep hypothermic circulatory arrest (DHCA). Methods. Between January 1996 and December 2000, 133 of 410 patients with thoracic aortic pathology were operated on for an aortic aneurysm limited mainly to the ascending aorta. Early and midterm outcomes were assessed and quality of life (QOL) evaluated using the Short-Form 36 Health Survey Questionnaire (SF-36). Results. Sixty patients (group 1) were operated on with DHCA and 73 patients (group 2) without DHCA. In-hospital mortality was identical in both groups (9.6% versus 6.7%; p = not significant) whereas postoperative transient neurologic events were significantly more frequent in group 1 (6.7% versus 0%; p < 0.05). Midterm clinical outcome was not different between groups but QOL showed significant impairment in daily functional physical and emotional activity in group 1 patients compared with group 2 and an age-matched standard population. Conclusions. The risk of transient neurologic complications is significantly increased with the use of DHCA and QOL is impaired without benefits in the long-term outcome especially among older patients.

Hysterical Conversion Disorder in a Young Girl at Moderate Altitude

Case report A 10-year-old girl hiked with other members of her group to a summit at a height of 2400 m in Switzerland. They left in the morning from their residence altitude of 600 m, were dropped off with a 4-wheel-drive car at a shelter at 1400 m, and started to hike from this point. During the ascent and after 2 hours of walking, the young girl complained of a headache and a sensation of oppression, but she reached the top together with the rest of the group. The group spent 1 hour having lunch on the summit. After lunch, her headache and her sensation of being unable to take a deep breath were exacerbated, and she became ataxic and unable to stand up; yet she did not lose consciousness. She was carried by several adults and brought down to a shelter at 1400 m after a lapse of 3 hours without improvement of her symptoms. The accompanying adults were in a hurry, and a call for help was sent out. The medical team arrived within 20 minutes by helicopter due to the inaccessibility of the shelter. The helicopter’s physician noticed that the patient was conscious, with no sensory or motor deficiency; the pupils and osteotendinous reflexes were normal. She presented dyskinetic movement of both arms and slight dysarthria, and she spoke in a hushed voice; she was completely unable to stand up (falling backward with exaggerated movements) and also had a tendency to somnolence. Arterial pressure, heart rate, respiratory rate, temperature, and oxygen saturation were all normal, yet her intense headache and her sensation of being unable to get enough air were persistent symptoms. Quite strikingly, she appeared to be completely indifferent and did not ask for any explanations about her clinical condition. She did not report any medical history. At the shelter, oxygen was administered, and an intravenous line was inserted. She was thereafter transported to the

Low rate of complications of cerebral angiography in routine clinical practice.

The use of cerebral angiography (ANGIO) to select patients for carotid endarterectomy (CEA) has been limited by concern about the risk of complications of the procedure. The authors sought to determine the rate of neurologic complications at both an academic medical center (AMC) and a community hospital (CH). The authors reviewed the records of 569 patients undergoing ANGIO. Any documentation of stroke, transient neurologic event, myocardial infarction, or death occurring in the 24 hours after the procedure was recorded. The rate of neurologic complications at the AMC and CH were compared to published studies. The overall complication rate was 0.5% for stroke and 0.4% for TIA. There was no difference between the AMC and CH. One of the strokes was of moderate severity and four of the five patients with complications subsequently underwent endarterectomy. The rate of major neurologic complications due to ANGIO may be lower than expected, even when performed in a non-academic setting. Awareness of local ANGIO complication rates is important when selecting patients for CEA.