UMEM Educational Pearls - By WanTsu Wendy Chang

Zhang H, Yang X, Lin Y, Chen L, Ye H. The efficacy of greater occipital nerve block for the treatment of migraine: a systematic review and meta-analysis. Clin Neurol Neurosurg. 2018;165:129-133.

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Arrigan MT, Heran MKS, Shewchuk JR. Reversible cerebral vasoconstriction syndrome: an important and common cause of thunderclap and recurrent headaches. Clin Radiol. 2017 Dec 21 [Epub ahead of print]

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• Endovascular thrombectomy is recommended for patients with large vessel occlusion within 6 hours of stroke symptom onset.
• Eligibility has been based on the time that patient was last known to be well.
• Prior studies suggest that patients who have evidence of ischemic brain tissue that has not yet infarcted could benefit from reperfusion even when performed more than 6 hours after patient was last known to be well.
• The DAWN (DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention with Trevo) trial enrolled 206 patients from 26 sites over 29 months.  
• It is unclear how many patients were screened for enrollment.
• This study was sponsored by Stryker Neurovascular and only allowed the use of their Trevo endovascular stent retriever device for the thrombectomy group.

Nogueira RG, Jadhav AP, Haussen DC, et al. Thrombectomy 6 to 24 hours after stroke with a mismatch between deficit and infarct. N Engl J Med. 2017 Nov 11. [Epub ahead of print]

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• Aphasia can be caused by ischemia of the left middle cerebral artery (MCA) territory.
• However, a stroke of the left MCA territory is usually accompanied by some component of contralateral motor and sensory deficits, gaze deviation, or visual field cut.
• Aphasia can also be caused by stroke mimics such as infection, toxic/metabolic abnormalities, dementia, migraine, or seizure.

Casella G, Llinas RH, Marsh EB. Isolated aphasia in the emergency department: The likelihood of ischemia is low. Clin Neurol Neurosurg 2017:163:24-26.

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Hawley C, Sakr M, Scapinello S, et al. Traumatic brain injuries in older adults - 6 years of data for one UK trauma centre: retrospective analysis of prospectively collected data. Emerg Med J 2017;0:1-8.

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• Benzodiazepine is first-line therapy for treatment of status epilepticus.
• The RAMPART study in 2012 by Silbergleit et al. demonstrated that prehospital treatment of status epilepticus with IM midazolam was more effective than IV lorazepam, even though the time from drug administration to seizure cessation was shorter for IV lorazepam.
• It is important to note that there is a 30% treatment failure rate for a single appropriately dosed benzodiazepine in treatment of status epilepticus.

• Alshehri A, Abulaban A, Bokhari R, et al. Intravenous vs. nonintravenous benzodiazepines for the cessation of seizures: a systematic review and meta-analysis of randomized controlled trials. Acad Emerg Med 2017;24(7):875-83.
• Silbergleit R, Durkalski V, Lowenstein D, et al. Intramuscular versus intravenous therapy for prehospital status epilepticus. N Engl J Med 2012;366(7):591-600.

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• There is a vitreous hemorrhage of the left globe associated with subarachnoid hemorrhage (SAH), intraventricular hemorrhage, and diffuse cerebral edema on this non-contrast head CT.
• This is also known as Terson syndrome, reported to occur in 15-30% of patients with SAH.
• The mechanism by which this intraocular hemorrhage occurred is thought to be from a sudden increase in intracranial pressure causing obstruction of the central retinal vein.

Image courtesy of Dr. Nasir Siddiqui, Radiopaedia.org. From the case rID: 36469

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Background:

• Seizures account for 1.2% of all ED visits with 24% representing first-time seizures.
• The 2014 ACEP Clinical Policy on the evaluation and management of patients presenting to the ED with seizures recommend that antiepileptic medication not be initiated for uncomplicated first-time seizure.
• Literature suggests that epileptiform activity on EEG predicts seizure recurrence while earlier EEG performance has a higher rate of finding epilepsy than delayed EEG performance.

• Wyman AJ, Mayes BN, Hernandez-Nino J, Rozario N, Beverly SK, Asimos AW. The first-time seizure emergency department electroencephalogram study. Ann Emerg Med 2017;69(2):184-191.
• Huff JS, Melnick ER, Tomaszewski CA, et al. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with seizures. Ann Emerg Med 2014;63(4):437-447.
• Krumholz A, Wiebe S, Gronseth G, et al. Practice parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology 2007;69(21):1996-2007.

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• Vasogenic cerebral edema is most commonly seen with brain tumors and cerebral abscesses.
• It mainly involves the white matter.
• Gray-white differentiation is maintained, so the edema has a finger-like pattern on CT (see Figure).
• It is caused by disruption of the blood-brain-barrier, thus responds to treatment with steroids.

Case image courtesy of Dr David Cuete, Radiopaedia.org, rID: 23178

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Chou R, Totten AM, Carney N, et al. Predictive Utility of the Total Glasgow Coma Scale Versus the Motor Component of the Glasgow Coma Scale for Identification of Patients with Serious Traumatic Injuries. Ann Emerg Med. 2017 Jan 11. [Epub ahead of print].

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• Headache is the 4th most common ED visit in the US.
• Clinical experience suggests that IV fluids (IVF) are commonly used as adjunctive treatment for headaches, however, the efficacy is unknown.
• A retrospective study using the National Hospital Ambulatory Medical Care Survey (NHAMCS) found that ED length of stay was significantly greater in patients who received IVF than in those who did not (202 min vs. 131 min, p<0.001) even after adjusting for initial pain score, sex, age, and mode of arrival. 
• A post-hoc analysis of data collected from 4 ED-based migraine trials found that IVF was not associated with improvement of pain score or sustained headache freedom.
• There is no current evidence to suggest a direct analgesic effect of IVF in the treatment of headaches.

• Jones CW, et al. Epidemiology of intravenous fluid use for headache treatment: Findings from the National Hospital Ambulatory Medical Care Survey. Am J Emerg Med. 2017. [Epub ahead of print]
• Balbin JEB, et al. Intravenous fluids for migraine: a post hoc analysis of clinical trial data. Am J Emerg Med. 2016;34:713-6.

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• Aphasia is an impairment of language
• 3 important assessments in an aphasic patient are fluency, comprehension, and repetition (see attached figure)
• Patients with fluent speech are able to generate speech spontaneously, though the content of their speech may have errors
• Patients with non-fluent speech have difficulty initiating speech
• Patients who have fluent speech but are unable to repeat have a problem with comprehension or a disconnect between the sensory and motor components of language
  • In Wernicke’s aphasia, patients cannot comprehend what they read and hear 
  • In conduction aphasia, patients can comprehend what they read and hear

Types of aphasia [Online image]. Retrieved February 8, 2017 from https://www.aphasia.org/

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• Limited data is available to guide when individuals should return to driving after a concussion.
• Cognitive impairments in reaction time, executive function, and attention can persist even after symptoms of a concussion resolve.
• Schmidt et al. compared driving performance between individuals within 48 hours following symptom resolution after a concussion with matched controls using simulated driving.
• They found that concussed individuals had poorer driving performance despite being asymptomatic.
• This study is limited by a small sample size (n=28), however, it raises interesting questions regarding whether driving should be restricted following concussions and how should readiness to return to driving be determined.

Schmidt JD, Hoffman NL, Ranchet M, et al. Driving after concussion: Is it safe to drive after symptoms resolve? J Neurotrauma. 2016 Dec 13. [Epub ahead of print]

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• This retrospective study compared the number of patients meeting goal door-to-needle (DTN) time of 60 minutes with and without an ED pharmacist participating on the stroke alert team.
• A higher proportion of patients with an ED pharmacist met goal DTN time of 60 minutes (71% vs. 39%, p=0.002, 95% CI 0.10-0.50).
• Patients with an ED pharmacist had an average 20-minute decrease in door-to-needle time (p=0.004, 95% CI 6.6-33.4).

Montgomery K, Hall AB, Keriazes G. Impact of an emergency medicine pharmacist on time to thrombolysis in acute ischemic stroke. Am J Emerg Med 2016;34:1997-9.

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• There is increased attenuation of the basal cisterns and subarachnoid space as well as diffuse cerebral edema.
• At first glance, it appears to be a subarachnoid hemorrhage.
• However, the Hounsfield unit of the density is lower than blood.
• This is a pseudosubarachnoid hemorrhage sign.  
• This can be seen in anoxic injury with cerebral edema, pyogenic meningitis, venous sinus thrombosis, bilateral large subdural hemorrhages.

Kim JM, Eom TH. The pseudosubarachnoid hemorrhage: clinical implications of subarachnoid hemorrhage misdiagnosis. Pediatr Emerg Care. 2016 May 12. [Epub ahead of print]

• The patient has a right subdural hematoma (SDH) with midline shift and right uncal herniation. 
• The classic presentation of a cerebral lesion with uncal herniation is ipsilateral mydriasis, contralateral hemiparesis, and abnormal extensor posturing.
• In this patient’s case, there is compression of the contralateral cerebral peduncle of the midbrain by the edge of the tentorium cerebelli producing an ipsilateral hemiplegia (see attachment for Figure 2).
• This false localizing sign is named Kernohan’s notch syndrome, Kernohan’s notch phenomenon, or Kernohan’s sign.

Diagram modified from "Localised Neurological Disease and Its Management A Intracranial". clinicalgate.com/localised-neurological-disease-and-its-management-a-intracranial/. Accessed 10 Aug 2016.

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1. Powers WJ, Derdeyn CP, Biller J, et al. 2015 American Heart Association/American Stroke Association Focused Update of the 2013 Guidelines for the Early Management of Patients with Acute Ischemic Stroke Regarding Endovascular Treatment: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2015;46(10):3020-35.
2. Lima FO, Silva GS, Furie KL, et al. Field Assessment Stroke Triage for Emergency Destination: A Simple and Accurate Prehospital Scale to Detect Large Vessel Occlusion Strokes. Stroke. 2016 Jun 30. [Epub ahead of print]

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