Deepak Nair

Small strokes causing severe vertigo Frequency of false-negative MRIs and nonlacunar mechanisms

Objective: Describe characteristics of small strokes causing acute vestibular syndrome (AVS). Methods: Ambispective cross-sectional study of patients with AVS (acute vertigo or dizziness, nystagmus, nausea/vomiting, head-motion intolerance, unsteady gait) with at least one stroke risk factor from 1999 to 2011 at a single stroke referral center. Patients underwent nonquantitative HINTS “plus” examination (head impulse, nystagmus, test-of-skew plus hearing), neuroimaging to confirm diagnoses (97% by MRI), and repeat MRI in those with initially normal imaging but clinical signs of a central lesion. We identified patients with diffusion-weighted imaging (DWI) strokes ≤10 mm in axial diameter. Results: Of 190 high-risk AVS presentations (105 strokes), we found small strokes in 15 patients (median age 64 years, range 41–85). The most common vestibular structure infarcted was the inferior cerebellar peduncle (73%); the most common stroke location was the lateral medulla (60%). Focal neurologic signs were present in only 27%. The HINTS “plus” battery identified small strokes with greater sensitivity than early MRI-DWI (100% vs 47%, p < 0.001). False-negative initial MRIs (6–48 hours) were more common with small strokes than large strokes (53% [n = 8/15] vs 7.8% [n = 7/90], p < 0.001). Nonlacunar stroke mechanisms were responsible in 47%, including 6 vertebral artery occlusions or dissections. Conclusions: Small strokes affecting central vestibular projections can present with isolated AVS. The HINTS “plus” hearing battery identifies these patients with greater accuracy than early MRI-DWI, which is falsely negative in half, up to 48 hours after onset. We found nonlacunar mechanisms in half, suggesting greater risk than might otherwise be assumed for patients with such small infarctions.

Acute Decompressive Hemicraniectomy to Control High Intracranial Pressure in Patients with Malignant MCA Ischemic Strokes

Opinion statementMalignant middle cerebral artery (MCA) infarction occurs in about 10% of all patients with supratentorial ischemic strokes. The infarction involves the entire MCA territory. Due to the consequences of severe brain edema, brain herniation, elevated intracranial pressure (ICP), and midline shift, these events carry a mortality rate of up to 80%. No clinical trials have been conducted to study the efficacy of the osmotic agents such as mannitol or hypertonic saline. Furthermore, aggressive use of such treatments may be detrimental. Surgical decompression has previously been proposed as a way to relieve the vicious cycle of malignant cerebral edema and reduced cerebral perfusion. Its use in relieving ICP is also controversial. Recently, a pooled analysis of three independent European trials has shown that decompressive hemicraniectomy is clearly beneficial in reducing mortality from large hemispheric infarctions. Although controversies still exist on its indications, surgical decompression can effectively reduce ICP, reduce mortality, and improve neurologic outcomes in selected patients with a malignant MCA stroke syndrome.

Intravenous Tissue Plasminogen Activator Can Be Safely Given without Complete Blood Count Results Back

Introduction It is well known that the efficacy of intravenous (IV) tissue plasminogen activator (tPA) is time-dependent when used to treat patients with acute ischemic strokes. Aim Our study examines the safety issue of giving IV tPA without complete blood count (CBC) resulted. Materials and Methods This is a retrospective observational study by examining the database from Huashan Hospital in China and OSF/INI Comprehensive Stroke Center in United States. Patient data collected included demographics, occurrence of symptomatic intracranial hemorrhage, door to needle intervals, National Institute of Health Stroke Scale scores on admission, CBC results on admission and follow-up modified Rankin Scale scores. Linear regression and multivariable logistic regression analysis were used to identify factors that would have an impact on door-to-needle intervals. Results Our study included120 patients from Huashan Hospital and 123 patients from INI. Among them, 36 in Huashan Hospital and 51in INI received IV tPA prior to their CBC resulted. Normal platelet count was found in 98.8% patients after tPA was given. One patient had thrombocytopenia but no hemorrhagic event. A significantly shorter door to needle interval (DTN) was found in the group without CBC resulted. There was also a difference in treatment interval between the two hospitals. Door to needle intervals had a strong correlation to onset to treatment intervals and NIHSS scores on admission. Conclusion In patients presented with acute ischemic stroke, the risk of developing hemorrhagic event is low if IV tPA is given before CBC has resulted. The door to needle intervals can be significantly reduced.

A case of vestibular and oculomotor pathology from bilateral AICA watershed infarcts treated with basilar artery stenting

Bilateral AICA infarcts may be the result of impaired arterial flow in watershed territories that overlap with PICA and SCA brainstem/cerebellar circulation among patients with critical basilar artery stenosis (1-3). We report one such patient with watershed bilateral AICA infarcts. She had a two-week history of progressive truncal ataxia, frequent falls, dysarthria and episodic vomiting. Examination suggested brainstem/cerebellar localization. She had bilateral symmetric infarcts of the cerebellar flocculus and middle cerebellar peduncles (MCP) due to tandem proximal and mid-basilar artery (BA) stenosis. Failure to improve on maximal medical therapy led to BA angioplasty/ stenting, with improved brainstem/cerebellum circulation and neurologic deficits.