Spontaneous subarachnoid hemorrhage: a best-practice approach to identification and management in the ED.

Emergency clinicians must have a high index of suspicion and a judicious approach to evaluating the chief complaint (ie, headache) of patients with suspected subarachnoid hemorrhage, as accurate initial diagnosis and management are critical to optimizing outcomes. Aneurysmal subarachnoid hemorrhage accounts for a small percentage of strokes, but contributes significantly to the morbidity rate in stroke. The diagnosis is challenging and has devastating consequences if missed. This review evaluates the literature and current evidence, including controversies and recent guidelines, to support a best-practice approach to the diagnosis and treatment of patients with spontaneous subarachnoid hemorrhage.

Low risk for subsequent subarachnoid hemorrhage for emergency department patients with headache, bloody cerebrospinal fluid, and negative findings on cerebrovascular imaging.

UNLABELLED: OBJECT.: When patients present to the emergency department (ED) with acute headache concerning for subarachnoid hemorrhage (SAH) and a lumbar puncture (LP) shows blood in the CSF, it is difficult to distinguish the results of a traumatic LP from those of SAH. CT angiography (CTA) is often performed, but the long-term outcome for patients with a positive LP and normal neurovascular imaging remains uncertain. The primary objective of this study was to determine whether patients who presented to the ED with acute headache and had red blood cells (RBCs) in their CSF on LP but negative cerebrovascular imaging suffered subsequent SAH. METHODS: A case series study of consecutive adult ED patients who incurred charges for LP between 2001 and 2009 was performed from 2010 through 2011. Inclusion criteria were: headache, > 5 RBCs/mm(3) in CSF, noncontrast head CT with no evidence of hemorrhage, and cerebrovascular CTA or MRA without aneurysm or vascular lesion within 2 weeks of the ED visit. Patients with less than 6 months of available follow-up were excluded. The primary outcomes were 1) subsequent nontraumatic SAH and 2) new vascular lesion. Secondary outcomes were complications related to SAH, or LP or angiography. RESULTS: Of 4641 ED patients billed for an LP, 181 patients (mean age 42 years) were included in this study. Over a median follow-up of 53 months, 0 (0%) of 181 patients (95% CI 0%-2.0%) had a subsequent SAH or new vascular lesion identified. Although not the primary outcome, there was 1 patient who was ultimately diagnosed with vasculitis. Eighteen (9.9%) of 181 patients (95% CI 6.0%-15.3%) had an LP-related complication and 0 (0%) of 181 patients (95% CI 0%-2.0%) had an angiography-related complication. CONCLUSIONS: Patients who present to the ED with acute headache concerning for SAH and have a finding of bloody CSF on LP but negative findings on cerebrovascular imaging are at low risk for subsequent SAH and thus are likely to be safe for discharge. Replacement of the CT/LP with a CT/CTA diagnostic algorithm merits further investigation.

An Evidence-Based Approach To Diagnosis And Management Of Subarachnoid Hemorrhage In The Emergency Department.

Aneurysmal subarachnoid hemorrhage accounts for a small percentage of strokes, but it is a significant contributor to the morbidity rate. The diagnosis is challenging and has devastating consequences if it is missed. Accurate initial diagnosis and management are critical to the outcome of the disease. The emergency clinician must have a high index of suspicion and a judicious approach to evaluating the chief complaint of patients with spontaneous subarachnoid hemorrhage (ie, headache). This review evaluates the literature and current evidence, including controversies and recent American Heart Association guidelines, to support a best-practice approach to the diagnosis and treatment of patients with spontaneous subarachnoid hemorrhage.

Interpreting red blood cells in lumbar puncture: distinguishing true subarachnoid hemorrhage from traumatic tap.

OBJECTIVES: The study purpose was to determine the optimal use of lumbar puncture (LP) red blood cell (RBC) counts to identify subarachnoid hemorrhage (SAH) when some blood remains in the final tube. METHODS: A case series was performed at a tertiary emergency department (ED). Records of 4,496 consecutive adult patients billed for LPs between 2001 and 2009 were reviewed. Inclusion criteria were headache (HA), final tube RBCs ≥ 5, and neurovascular imaging within 2 weeks of the visit. Demographics, relevant history and physical examination components, LP results, and neuroimaging findings were recorded for 280 patients. True-positive (TP) and true-negative (TN) SAH were strictly defined. Primary outcomes were the areas under the receiver operating characteristic curves (AUC) for final tube RBC count, differential RBC count between the final and initial tubes, and absolute differential RBC count between the final and initial tubes divided by the mean RBC count of the two tubes (also called the percent change in RBC count). RESULTS: There were 26 TP and 196 TN results; 58 patients were neither. The TP group consisted of 19 patients with visible or possible SAH on imaging (17 on noncontrast head computed tomography [CT; 12 definite and five possible] and two on magnetic resonance imaging), six with xanthochromia and a vascular lesion (aneurysm or arteriovenous malformation [AVM] > 2 mm), and one with xanthochromia and polymerase chain reaction (PCR)-positive meningitis. As a test for SAH, final tube RBC AUC was 0.85 (95% confidence interval [CI] = 0.80 to 0.91). Interval likelihood ratios (LRs) for final tube RBC count were LR 0 (95% CI = 0 to 0.3) for RBCs < 100, LR 1.6 (95% CI = 1.1 to 2.3) for 100 < RBCs < 10,000, and LR 6.3 (95% CI = 4.8 to 23.4) for RBCs > 10,000. Differential RBC count was not associated with SAH, with AUC 0.45 (95% CI = 0.31 to 0.60). However, the percent change in RBC count between the final and initial tubes had an AUC 0.84 (95% CI = 0.78 to 0.90), and the optimal test threshold for SAH was 0.63, with positive LR 3.6 (95% CI = 2.7 to 4.7) and negative LR 0.10 (95% CI = 0.03 to 0.4) for percent change <63% and >63%, respectively. This test added additional independent information to the final tube RBC count based on improved logistic regression model fit and discriminatory ability as measured by the LR test and c statistic, respectively. CONCLUSIONS: Final LP tube RBC count and the percent change in RBC count, but not the simple differential count between the final and initial tubes, were associated with SAH. In this sample, there were no patients with SAH who had RBCs < 100 in the final tube, and RBCs > 10,000 increased the odds of SAH by a factor of 6.

Capacity-speed relationships in prefrontal cortex.

Working memory (WM) capacity and WM processing speed are simple cognitive measures that underlie human performance in complex processes such as reasoning and language comprehension. These cognitive measures have shown to be interrelated in behavioral studies, yet the neural mechanism behind this interdependence has not been elucidated. We have carried out two functional MRI studies to separately identify brain regions involved in capacity and speed. Experiment 1, using a block-design WM verbal task, identified increased WM capacity with increased activity in right prefrontal regions, and Experiment 2, using a single-trial WM verbal task, identified increased WM processing speed with increased activity in similar regions. Our results suggest that right prefrontal areas may be a common region interlinking these two cognitive measures. Moreover, an overlap analysis with regions associated with binding or chunking suggest that this strategic memory consolidation process may be the mechanism interlinking WM capacity and WM speed.

CT angiography predicts use of tertiary interventional services in acute ischemic stroke patients.

BACKGROUND: Patients with acute stroke are often transferred to tertiary care centers for advanced interventional services. We hypothesized that the presence of a proximal cerebral artery occlusion on CT angiography (CTA) is an independent predictor of the use of these services. METHODS: We performed a historical cohort study of consecutive ischemic stroke patients presenting within 24 h of symptom onset to an academic emergency department who underwent emergent CTA. Use of tertiary care interventions including intra-arterial (IA) thrombolysis, mechanical clot retrieval, and neurosurgery were captured. RESULTS: During the study period, 207/290 (71%) of patients with acute ischemic stroke underwent emergent CTA. Of the patients, 74/207 (36%) showed evidence of a proximal cerebral artery occlusion, and 22/207 (11%) underwent an interventional procedure. Those with proximal occlusions were more likely to receive a neurointervention (26% vs. 2%, p < 0.001). They were more likely to undergo IA thrombolysis (9% vs. 0%, p = 0.001) or a mechanical intervention (19% vs. 0%, p < 0.0001), but not more likely to undergo neurosurgery (5% vs. 2%, p = 0.2). After controlling for the initial NIH stroke scale (NIHSS) score, proximal occlusion remained an independent predictor of the use of neurointerventional services (OR 8.5, 95% CI 2.2-33). Evidence of proximal occlusion on CTA predicted use of neurointervention with sensitivity of 82% (95% CI 59-94%), specificity of 71% (95% CI 64%-77%), positive predictive value (PPV) of 25% (95% CI 16%-37%), and negative predictive value (NPV) of 97% (95% CI 92%-99%). CONCLUSION: Proximal cerebral artery occlusion on CTA predicts the need for advanced neurointerventional services.

Validating age-related functional imaging changes in verbal working memory with acute stroke.

Functional imaging studies consistently find that older adults recruit bilateral brain regions in cognitive tasks that are strongly lateralized in younger adults, a characterization known as the Hemispheric Asymmetry Reduction in Older Adults model. While functional imaging displays what brain areas are active during tasks, it cannot demonstrate what brain regions are necessary for task performance. We used behavioral data from acute stroke patients to test the hypothesis that older adults need both hemispheres for a verbal working memory task that is predominantly left-lateralized in younger adults. Right-handed younger (age ⩽ 50, n = 7) and older adults (age > 50, n =21) with acute unilateral stroke, as well as younger (n =6) and older (n =13) transient ischemic attack (TIA) patients, performed a self-paced verbal item-recognition task. Older patients with stroke to either hemisphere had a higher frequency of deficits in the verbal working memory task compared to older TIA patients. Additionally, the deficits in older stroke patients were mainly in retrieval time while the deficits in younger stroke patients were mainly in accuracy. These data suggest that bihemispheric activity is necessary for older adults to successfully perform a verbal working memory task.