Alejandro Forteza

Mechanisms of ischemic stroke in HIV-infected patients.

Objective: To evaluate the types and mechanisms of stroke in a large population of HIV-infected patients. Methods: We reviewed records of consecutive HIV-infected patients with acute stroke admitted to a large metropolitan hospital between 1996 and 2004. Stroke mechanism was defined by consensus between two cerebrovascular neurologists using TOAST classification. Results: A total of 82 patients were included, 77 with ischemic stroke and 5 with intracerebral hemorrhage. Mean age was 42 years and 89% were African American. Previous diagnosis of HIV infection was documented in 91% and AIDS diagnosis in 80%. Mean CD4 count was 113 cells/mm3 and 85% had CD4 count <200 cells/mm3. A total of 61% of patients had received combination antiretroviral treatment (CART). The mechanism of ischemic stroke was large artery atherosclerosis in 12%, cardiac embolism in 18%, small vessel occlusion in 18%, other determined etiology in 23%, and undetermined in 29% (including 19% with incomplete evaluation). Vasculitis was deemed responsible for the stroke in 10 patients (13%) and hypercoagulability in 7 (9%). Protein S deficiency was noted in 10/22 (45%) and anticardiolipin antibodies in 9/31 (29%) tested patients. When comparing patients with large or small vessel disease (atherothrombotic strokes) vs the rest of the population, there were no differences in exposure to CART or CD4 count, but patients with non-atherothrombotic strokes were younger (p = 0.04). Recent cocaine exposure was less common among patients with atherothrombotic strokes (p = 0.02). Strokes were fatal or severely disabling in 35% of cases. Conclusions: Stroke mechanisms are variable in HIV-infected patients, with a relatively high incidence of vasculitis and hypercoagulability. In our population of severely immunodepressed patients, exposure to combination antiretroviral treatment did not significantly influence the mechanism of stroke.

Detection of microemboli by transcranial Doppler ultrasonography in aneurysmal subarachnoid hemorrhage

OBJECTIVE To determine the frequency and characteristics of microembolic signals (MES) in subarachnoid hemorrhage (SAH). METHODS Twenty-three patients with aneurysmal SAH were monitored with transcranial Doppler ultrasonography for the presence of MES and vasospasm. Each middle cerebral artery was monitored for 30 minutes three times each week. Patients were excluded if they had traumatic SAH or cardiac or arterial sources of emboli. Monitoring was initiated 6.3 days (1–16 d) after SAH and lasted 6.6 days (1–13 d). Eleven individuals without SAH or other cerebrovascular diseases who were treated in the same unit served as control subjects. Each patient underwent monitoring of both middle cerebral arteries a mean of three times; therefore, 46 vessels were studied (a total of 138 observations). Control subjects underwent assessment of each middle cerebral artery once, for a total of 22 control vessels. RESULTS MES were detected for 16 of 23 patients (70%) and 44 of 138 patient vessels (32%) monitored, compared with 2 of 11 control subjects (18%) and 2 of 22 control vessels (9%) (P < 0.05). MES were observed for 83% of patients with clinical vasospasm and 54% of those without clinical vasospasm. Ultrasonographic vasospasm was observed for 71 of 138 vessels monitored; MES were observed for 28% of vessels with vasospasm and 36% of those without vasospasm. Aneurysms proximal to the monitored artery were identified in 38 of 138 vessels, of which 34% exhibited MES, which is similar to the frequency for vessels without proximal aneurysms (31%). Coiled, clipped, and unsecured aneurysms exhibited similar frequencies of MES. CONCLUSION MES were common in SAH, occurring in 70% of cases of SAH and one-third of all vessels monitored. Although MES were more frequent among patients with clinical vasospasm, this difference did not reach statistical significance. We were unable to demonstrate a relationship between ultrasonographic vasospasm and MES, and the presence of a proximal secured or unsecured aneurysm did not alter the chance of detection of MES. Further studies are required to determine the origin and clinical relevance of MES in SAH.

Acetazolamide for the treatment of migraine with aura in CADASIL.

making it impossible to perform the intended task. She expressed anxiety and frustration with regard to these involuntary actions. She had left motor neglect, presenting with slowing and underutilizing the left hand voluntarily for tasks on intention and verbal command. Automatic gestures of the left hand were normal. She also presented left hand apraxia on imitation (she failed 10 items out of 24 with her left hand) and tactile anomia of the left hand (she failed 8 items out of 10 with the left hand; the right hand performed well on all items). There was no visuospatial neglect or extinction of the sensory modalities. Discussion. I propose the term “compulsive grasping hand syndrome” in my patient to refer to spontaneous, stereotyped, involuntary left hand grasp reaction to her right hand as a consequence of her right hand movements. This abnormal behavior fits partially with the definition of anarchic hand, but the behavioral type could be distinguished by the presence of compulsive contralateral hand grasping without groping, mirror movements, and utilization behavior.3,5 In patients with intermanual conflict alien hand,5,6 or diagonistic dyspraxia,7 there is a dissociative phenomenon in which one hand is acting at cross-purpose to the other following voluntary activities. In our patients, the involuntary left hand grasping related to all type of movements of the right hand suggests a motor grasp response phenomenon to the contralateral hand movements. Paradoxical motor behavior in my patient could be related to the involvement of pathways projecting to supplementary motor area via corpus callosum that drive intentional and volitional movements. Compulsive grasping hand movement could be interpreted as a release phenomenon of the learned praxis of the left hand due to damage to genu and body of the corpus callosum. Compulsive grasping hand and other anarchic hand movements are clinical signs of a defective internal response inhibition, and more generally, fragments of the spectrum of frontal hand syndromes.

Transcranial Doppler Detection of Fat Emboli

BACKGROUND AND PURPOSE The fat embolism syndrome (FES) is characterized by the simultaneous occurrence of pulmonary and neurological symptoms as well as skin and mucosal petechiae in the setting of long-bone fractures or their surgical repair. Its pathophysiology is poorly understood, and effective treatments are lacking. We present 5 patients with long-bone fractures in whom in vivo microembolism was detected by transcranial Doppler. METHODS Five patients with long-bone fractures were monitored with transcranial Doppler for microembolic signals (MESs) after trauma. Two patients also had intraoperative monitoring. A TC-2020 instrument equipped with MES detection software was used. Detected signals were saved for subsequent review. Selected signals satisfied criteria defined previously and were categorized as large or small. RESULTS Cerebral microembolism was detected in all 5 patients and was transient, resolving within 4 days of injury. Intraoperative monitoring revealed an increase in MESs during intramedullary nail insertion. The characteristics of MESs after injury varied among patients, with large signals being more frequent in the only patient with a patent foramen ovale. CONCLUSIONS Cerebral microembolism after long-bone fractures can be detected in vivo and monitored over time. These findings may have potential diagnostic and therapeutic implications.

Cerebral Fat Microembolism and Cognitive Decline After Hip and Knee Replacement

Background and Purpose— Intra-operative cerebral microembolism may be a factor in the etiology of cognitive decline after orthopedic surgery. We here examine the impact of intra-operative microembolism on cognitive dysfunction after hip and knee replacement surgery. Methods— We enrolled 24 patients, at least 65 years old, requiring elective knee or hip replacement surgery. A transcranial Doppler shunt study was done to determine study eligibility so that the final study population consisted of 12 consecutive patients with and 12 consecutive patients without a venous-arterial shunt. A standard neuropsychological test battery was administered before surgery, at hospital discharge and 3 months after surgery. All patients were monitored intra-operatively for microemboli. Quality of life data were assessed at 1 year. Results— The mean age of patients was 74 years. All patients had intra-operative microemboli. The mean number of emboli was 9.9±18. Cognitive decline was present in 18/22 (75%) at discharge and in 10/22 (45%) at 3 months, despite improved quality of life measures. There was no correlation between cognitive decline and intra-operative microembolism. Conclusion— Cognitive decline was seen frequently after hip and knee surgery. Intra-operative microembolism occurred universally but did not significantly influence postoperative cognition. Quality of life and functional outcome demonstrated improvement in all cases in spite of cognitive dysfunction.

Microemboli in Aneurysmal Subarachnoid Hemorrhage

The determinants of ischemic complications in subarachnoid hemorrhage (SAH) are not well defined. The objective of this study is to evaluate the role of microemboli in SAH‐related cerebral ischemia.

Surgical treatment of nonbacterial thrombotic endocarditis presenting with stroke

AbstractBackgroundNecropsy studies have shown that nonbacterial thrombotic endocarditis (NBTE) may be associated with cerebral infarctions and antemortem diagnosis is now possible. However, the best treatment for patients with NBTE presenting with stroke is not known.Summary of reportWe describe three patients presenting with an acute embolic stroke secondary to large,mobile vegetations detected by transthoracic (one case) or transesophageal echocardiography (two cases). All patients underwent surgery for removal of the vegetations to prevent recurrent embolic events; valve replacement was necessary in two cases. The sterile nature of the vegetations was confirmed by pathological examination and negative stains and cultures of the surgical samples. A previously unrecognized hypercoagulable condition was diagnosed in all patients (antiphospholipid antibody syndrome in two cases and disseminated adenocarcinoma in one case).ConclusionNBTE should be considered among the possible causes of embolic stroke even in the absence of history of cancer, hypercoagulability, or previous embolic manifestations. If NBTE is diagnosed, the possibility of underlying thrombophilia should be thoroughly investigated. Valvular surgery represents a valuable therapeutic alternative in patients with large mobile vegetations, valvular dysfunction or recurrent embolic events despite anticoagulation.

In-hospital delays to stroke thrombolysis: paradoxical effect of early arrival

Abstract Objective: To determine the causes of in-hospital delays for thrombolysis. Methods: We performed a 4 year retrospective chart analysis of i.v. tPA-treated patients at an academic medical center. Data collected included age, stroke severity by the National Institutes of Health Stroke Scale (NIHSS) and the following time points: symptom onset, hospital arrival, computed tomography (CT), i.v. tPA order and i.v. tPA initiation of infusion. Results: Thirty-one cases with sufficient information for analysis were identified. Mean time from onset to arrival was 58 minutes, from arrival to brain CT was 32 minutes, and from onset to i.v. rtPA infusion was 169 minutes. The mean delay between i.v. tPA order and infusion was 32 minutes. Delay between order and administration of i.v. tPA resulted in treatment after 3 hours in 9/31 cases. An inverse relationship between early hospital arrival and delayed thrombolysis was noted. Age and stroke severity did not impact treatment times. Conclusion: An unexpected delay between order and actual initiation of i.v. tPA infusion resulted in almost one-third of patients receiving thrombolytics after 3 hours from symptom onset. The cause of this delay could not be discerned by this study. The paradoxical effect between early arrival to hospital and delayed treatment may be related to a sense of urgency in those arriving close to 3 hours after onset. Critical reviews such as this permit identification of hospital delays in stroke treatment, thus allowing institution of appropriate strategies to ensure prompt treatment.

Internal Carotid Artery Dissection Causing a Branch Retinal Artery Occlusion in a Young Adult

PURPOSE To report a 34-year-old healthy man with an internal carotid artery dissection who presented with an ipsilateral branch retinal artery occlusion. METHOD Case report. RESULTS Ophthalmic examination of a young adult presenting with transient monocular visual loss and a superior nasal field defect disclosed a left inferior branch retinal artery occlusion. After fluorescein angiography, the patient had a vasovagal response, and his condition worsened to a left central retinal artery occlusion. Neurologic evaluation followed by carotid angiography disclosed a left internal carotid artery dissection with total occlusion of the internal carotid artery. CONCLUSION The differential diagnosis of retinal arterial occlusion in a young healthy adult without any notable ocular or medical history, including trauma, should include spontaneous internal carotid artery dissection.

Ultrasound velocity criteria for vertebral origin stenosis.

Despite remaining an important cause of posterior circulation stroke, the non‐invasive diagnosis of vertebral artery origin (VAo) stenosis is problematic. We here examine peak systolic velocity (PSV) criteria for the diagnosis of VAo stenosis and assess if the PSV ratio at the origin to the distal segments improves diagnostic accuracy.