Arun Talkad

HINTS to Diagnose Stroke in the Acute Vestibular Syndrome Three-Step Bedside Oculomotor Examination More Sensitive Than Early MRI Diffusion-Weighted Imaging

Background and Purpose— Acute vestibular syndrome (AVS) is often due to vestibular neuritis but can result from vertebrobasilar strokes. Misdiagnosis of posterior fossa infarcts in emergency care settings is frequent. Bedside oculomotor findings may reliably identify stroke in AVS, but prospective studies have been lacking. Methods— The authors conducted a prospective, cross-sectional study at an academic hospital. Consecutive patients with AVS (vertigo, nystagmus, nausea/vomiting, head-motion intolerance, unsteady gait) with ≥1 stroke risk factor underwent structured examination, including horizontal head impulse test of vestibulo-ocular reflex function, observation of nystagmus in different gaze positions, and prism cross-cover test of ocular alignment. All underwent neuroimaging and admission (generally <72 hours after symptom onset). Strokes were diagnosed by MRI or CT. Peripheral lesions were diagnosed by normal MRI and clinical follow-up. Results— One hundred one high-risk patients with AVS included 25 peripheral and 76 central lesions (69 ischemic strokes, 4 hemorrhages, 3 other). The presence of normal horizontal head impulse test, direction-changing nystagmus in eccentric gaze, or skew deviation (vertical ocular misalignment) was 100% sensitive and 96% specific for stroke. Skew was present in 17% and associated with brainstem lesions (4% peripheral, 4% pure cerebellar, 30% brainstem involvement; &khgr;2, P=0.003). Skew correctly predicted lateral pontine stroke in 2 of 3 cases in which an abnormal horizontal head impulse test erroneously suggested peripheral localization. Initial MRI diffusion-weighted imaging was falsely negative in 12% (all <48 hours after symptom onset). Conclusions— Skew predicts brainstem involvement in AVS and can identify stroke when an abnormal horizontal head impulse test falsely suggests a peripheral lesion. A 3-step bedside oculomotor examination (HINTS: Head-Impulse—Nystagmus—Test-of-Skew) appears more sensitive for stroke than early MRI in AVS.

Intravenous Recombinant Tissue Plasminogen Activator in a Pregnant Woman With Cardioembolic Stroke

Background and Purpose— Historically, the use of tissue plasminogen activator (tPA) thrombolysis in pregnancy has been regarded as relatively contraindicated. Underlying this stance has been the concern over the risk of bleeding complications in both mother and child. Summary of Case— We report the successful use of intravenous recombinant tPA (rtPA) thrombolysis in a pregnant woman with acute cardioembolic stroke. Conclusions— The patient improved clinically, did not develop complications after receiving rtPA, and at 37 weeks’ gestation, delivered a healthy infant, demonstrating that rtPA thrombolysis may be used safely in pregnant women.

HINTS to Diagnose Stroke in the Acute Vestibular Syndrome

Background and Purpose— Acute vestibular syndrome (AVS) is often due to vestibular neuritis but can result from vertebrobasilar strokes. Misdiagnosis of posterior fossa infarcts in emergency care settings is frequent. Bedside oculomotor findings may reliably identify stroke in AVS, but prospective studies have been lacking. Methods— The authors conducted a prospective, cross-sectional study at an academic hospital. Consecutive patients with AVS (vertigo, nystagmus, nausea/vomiting, head-motion intolerance, unsteady gait) with ≥1 stroke risk factor underwent structured examination, including horizontal head impulse test of vestibulo-ocular reflex function, observation of nystagmus in different gaze positions, and prism cross-cover test of ocular alignment. All underwent neuroimaging and admission (generally <72 hours after symptom onset). Strokes were diagnosed by MRI or CT. Peripheral lesions were diagnosed by normal MRI and clinical follow-up. Results— One hundred one high-risk patients with AVS included 25 peripheral and 76 central lesions (69 ischemic strokes, 4 hemorrhages, 3 other). The presence of normal horizontal head impulse test, direction-changing nystagmus in eccentric gaze, or skew deviation (vertical ocular misalignment) was 100% sensitive and 96% specific for stroke. Skew was present in 17% and associated with brainstem lesions (4% peripheral, 4% pure cerebellar, 30% brainstem involvement; &khgr;2, P=0.003). Skew correctly predicted lateral pontine stroke in 2 of 3 cases in which an abnormal horizontal head impulse test erroneously suggested peripheral localization. Initial MRI diffusion-weighted imaging was falsely negative in 12% (all <48 hours after symptom onset). Conclusions— Skew predicts brainstem involvement in AVS and can identify stroke when an abnormal horizontal head impulse test falsely suggests a peripheral lesion. A 3-step bedside oculomotor examination (HINTS: Head-Impulse—Nystagmus—Test-of-Skew) appears more sensitive for stroke than early MRI in AVS.

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.

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.

H.I.N.T.S. to Diagnose Stroke in the Acute Vestibular Syndrome—Three-Step Bedside Oculomotor Exam More Sensitive than Early MRI DWI

Background and Purpose— Acute vestibular syndrome (AVS) is often due to vestibular neuritis but can result from vertebrobasilar strokes. Misdiagnosis of posterior fossa infarcts in emergency care settings is frequent. Bedside oculomotor findings may reliably identify stroke in AVS, but prospective studies have been lacking. Methods— The authors conducted a prospective, cross-sectional study at an academic hospital. Consecutive patients with AVS (vertigo, nystagmus, nausea/vomiting, head-motion intolerance, unsteady gait) with ≥1 stroke risk factor underwent structured examination, including horizontal head impulse test of vestibulo-ocular reflex function, observation of nystagmus in different gaze positions, and prism cross-cover test of ocular alignment. All underwent neuroimaging and admission (generally <72 hours after symptom onset). Strokes were diagnosed by MRI or CT. Peripheral lesions were diagnosed by normal MRI and clinical follow-up. Results— One hundred one high-risk patients with AVS included 25 peripheral and 76 central lesions (69 ischemic strokes, 4 hemorrhages, 3 other). The presence of normal horizontal head impulse test, direction-changing nystagmus in eccentric gaze, or skew deviation (vertical ocular misalignment) was 100% sensitive and 96% specific for stroke. Skew was present in 17% and associated with brainstem lesions (4% peripheral, 4% pure cerebellar, 30% brainstem involvement; &khgr;2, P=0.003). Skew correctly predicted lateral pontine stroke in 2 of 3 cases in which an abnormal horizontal head impulse test erroneously suggested peripheral localization. Initial MRI diffusion-weighted imaging was falsely negative in 12% (all <48 hours after symptom onset). Conclusions— Skew predicts brainstem involvement in AVS and can identify stroke when an abnormal horizontal head impulse test falsely suggests a peripheral lesion. A 3-step bedside oculomotor examination (HINTS: Head-Impulse—Nystagmus—Test-of-Skew) appears more sensitive for stroke than early MRI in AVS.