neur 7510 neurology clerkship

NEUR 7510Neurology Clerkship

Session 2:Spells

Definitions

• Stroke: sudden loss of brain function due to blockage or rupture of a blood vessel; alternatively an acute brain related event (focal/generalized)

• Embolic stroke: blockage of a vessel from a proximal source

• Thrombotic stroke: in situ obstruction of blood flow resulting in ischemia

• Lacunar infarction: small vessel related ischemic stroke

• Hemorrhagic infarction: bleeding into the brain and damaging brain tissue

Or

Carotid artery disease• Atherosclerosis is common at the bifurcation of the common carotid artery • Stenosis of the internal carotid artery is a potentially treatable cause of:

– Ischaemic stroke – Transient ischaemic attack – Retinal infarction

• A patient with an asymptomatic 50% carotid stenosis has 1-2% per year risk of a stroke

• The risk of stroke increases with the degree of stenosis • Once a stenosis has become symptomatic the risk of a stroke is further

increased • Once an ischaemic stroke has occurred the risk of further stroke is ~10% in

the first year and ~5% in subsequent years

Assessment of stenosis• Carotid bruits are an unreliable guide to severity of stenosis • May be absent in patients with severe stenosis

Intra-arterial angiography is the traditional method of assessing degree of stenosis 4% risk of inducing further neurological event 1% risk of permanent stroke

Duplex ultrasoundDoppler recordings allow assessment of flow at stenosis Also allows imaging of arterial anatomy

Lacunar infarct: This 52-year-old man with a history of poorly controlled hypertension presented with right body numbness. Examination was significant for a blood pressure of 182/96 mm Hg, retinal arterio-venous nicking and right-sided hemibody hypesthesia to pinprick and temperature sensation. The T2-weighted axial image on the left shows an area of high signal intensity within the left thalamus. The corresponding diffusion-weighted MR image on the right shows an isolated area of high signal intensity within the left thalamus.

What nonvascular processes mimic stroke?

Gilden, D. H. N Engl J Med 2004;351:1323-1331

Brain MRIs Contrasting Bell's Palsy with a Central Pontine Infarct

100 patients with cerebrovascular disease

• Subarachnoid hemorrhage (5%)?

• Intraparenchymal hemorrhage (20%)?

• Ischemia (75%)?

100 patients with cerebral ischemia

• 25% Large vessel atherothromboembolism• 25% Small vessel disease• 25% Cardioembolism• 5% Other conditions• 20% Unknown

Types of brain hemorrhage• Intraparenchymal

– Often hypertensive– Amyloid angiopathy– Into a tumor– Trauma related– Underlying vascular

abnormality• Subarachnoid

– Trauma– Related to an aneurysm

• Subdural– Chronic versus acute; often

related to trauma or bleeding propensity

• Epidural– Acute often related to

trauma and injury to middle meningeal artery

Coup and contre-coup Epidural hematoma Subdural hematomaInjury

Intraparenchymal hematoma Diffuse axonal injury

TRAUMA ANDTHE

BRAIN

In what four locations do spontaneous (hypertensive) intracerebral hemorrhages most commonly occur?

– Basal Ganglia • Putamen - Contralateral hemiparesis, contralateral sensory loss,

contralateral conjugate gaze paresis, homonymous hemianopia, aphasia, neglect, or apraxia

• Caudate nucleus - Contralateral hemiparesis, contralateral conjugate gaze paresis, or confusion

– Thalamus - Contralateral sensory loss, contralateral hemiparesis, gaze paresis, homonymous hemianopia, miosis, aphasia, or confusion

– Brain stem (typically pons) - Quadriparesis, facial weakness, decreased level of consciousness, gaze paresis, ocular bobbing, miosis, or autonomic instability

– Cerebellum - Ataxia, usually beginning in the trunk, ipsilateral facial weakness, ipsilateral sensory loss, gaze paresis, skew deviation, miosis, or decreased level of consciousness

– Lobar - Contralateral hemiparesis or sensory loss, contralateral conjugate gaze paresis, homonymous hemianopia, abulia, aphasia, neglect, or apraxia

Putamen (50%); thalamus (25%); pons/brainstem (10%); cerebellum (10%), and cerebral hemispheres (5%)

64 yo RH Woman

• 5 min right arm weakness

• 2nd episode involved the leg

• What is the most likely anatomic localization?

Exam:AV nickingRt cervical bruitRight facial weaknessRt pronator drift w/ slow ffm & 4/5 wrist extRt leg weaknessRt toe: upgoing

Account for the forehead symmetryabsence of sensory findingsgood grip strength in the face of very slow finger tappingsymmetric reflexes

History reveals long-standing hypertension, MI 3 yrs prior, long Tobacco use and rx for a diuretic

Pathological processMechanisms of injury

What is the patient was 30 yo?

Tests

Diagnostic studies: which are needed– Coagulation studies– Drug/tox screen– Genetic studies/cholesterol/glucose/other– ECG/Rhythm monitoring– ECHO (TTE/TEE)– Arch study– Arteries: carotid ultrasound/CTA/MRA– 4 vessel angiography– Brain CT/MRI/MRA/MRV/CTV

Management• Preventive therapy?

– Blood pressure– Smoking– Blood sugar– Cholesterol– Exercise– Medications

• Prevent complications?• Aid in recovery?• Risk factors?• Preventable?• Present management

– TPA– Coumadin– Antiplatelet

Medical management• Stop smoking • Pharmacological treatment of hypertension and diabetes • Prophylactic aspirin

– Asprin prevents around 40 ‘vascular events’ per 1000 patients treated for 3 years

– It should be started at 175-150 mg daily once ischaemic stroke confirmed by CT

– It should also be given to those with asymptomatic stenoses – The combination of aspirin and dipyridamole is no more effective

than aspirin alone.

Surgery for symptomatic stenosisNorth American Symptomatic Carotid Endarterectomy Trial (NASCET)• Compared endarterectomy plus medical treatment in those patients with • Non-disabling stroke in 4-6 months prior to surgery • Severe (70-99%) ipsilateral stenosis • The risk of stroke or death over 2 years was reduced (9% vs. 26%) in surgery group • 5.8% randomised to surgery had stroke within 30 days • Benefit also seen in those with more than 50% stenosis but not to same degree

European Carotid Surgery Trial (ECST)• ECST risk of stroke or death over 3 years was reduced (12% vs. 22%) in surgery group • 7.5% randomised to surgery had stroke or died within 30 days of operation • In those with mild (0-30%) and moderate (30-60%) symptomatic stenoses there was benefit from surgery • Overall, In those with symptomatic stenoses • Best results are seen in those with more severe stenosis • Benefit only seen in institutions with low perioperative stroke and death rate • Surgery indicated in those with severe stenosis (more than 70%) that have recently become symptomatic • Operation should be performed by experienced surgeon • Centres should audit their results and have a perioperative stroke rate of less than 7% • Angina and hypertension should be well controlled pre-operatively • If patient selection is poor or complication rate high then there will be no benefit from surgery. 

Carotid angioplasty• Angioplasty (± stent placement) is being used to dilate stenoses • No published randomised trials • In uncontrolled studies severe stenoses (more than 70%) have been dilated to less than 50% • Re-stenosis often occurs and a significant risk of stroke during the procedure

Surgery for asymptomatic stenosis

Asymptomatic Carotid Atherosclerosis Study• 1662 patients with more than 60% reduction in luminal diameter • Randomised to either:

– Endarterectomy + medical treatment (aspirin 300 mg) – Medical treatment alone

• Risk of ipsilateral stroke over 5 year period was reduced (5% vs. 11%) in surgery group

• 2.3% in surgery group had stroke within 30 days of surgery • 0.4% in medical group had stroke in same time period • Overall, benefit for those with asymptomatic stenosis but only the presence of a low

perioperative complication rate.

Asymptomatic Carotid Surgery Trial• 3120 patients with more than 60% reduction in luminal diameter • Randomised to either immediate or deferred carotid surgery • Risk of stroke within 30 days of surgery was 3.1% • Risk of stroke over 5 year period was reduced (3.8% vs. 11%) in surgery group • Results were similar to ACAS study

58 yo LH Man

• 10 minute episode– LUE tingling– Within a minute spread to face & leg– LUE & LLE would not work

• Anatomical localization? • Exam

– Bruits: femoral, subclavian arteries

• Does the normal examination help or hurt the presumed localization?

Questions

• Differential of transient focal neurologic dysfunction and distinguishing features

• Long-term prognosis of a transient ischemic attack (TIA)?

• Admission required?

81 yo M

• Acute onset of vertigo and nausea• Rt leg unsteady & Rt facial numbness• Anatomical localization?

HoarseEyes move rapidly to Lt then slowly to RtRt pupil 2 mm with ptosis; Lt pupil 4 mmRt face: reduced pp & tempPalate pulls to LtRUE & RLE dysmetriaLUE & LLE decreased pp & temp

• Eye movements: Nystagmus• Defining central and peripheral vertigo• Differentiating central vs. peripheral vertigo• Diagnosis of this patient• Mechanism?• Treatment?• What are the cause & treatment of isolated

vertigo attacks?• What if there was left hearing loss and facial

weakness?• What it evolved slowly?

.

Axial T2-weighted image shows a high-intensity signal (white) in the right inferior cerebellum, with displacement of the medulla. Neurosurgical intervention was required because of brain-stem compression with noncommunicating hydrocephalus and progressive deterioration in mental status. On the day after surgery, the patient's mental status rapidly improved. Over the next week, his nystagmus resolved and he began walking. The inset illustrates the vascular supply to the inferior cerebellum. The inferior cerebellum is perfused by the medial and lateral branches of the posterior inferior cerebellar artery (PICA) and the anterior inferior cerebellar artery (AICA).7,8

MRI Right Inferior Cerebellar Infarction in a Man with Acute Vertigo, Vomiting, Nystagmus Elicited by Right, Left, or Upward Gaze, and

Severe Gait Instability.

Hotson, J. R. et al. N Engl J Med 1998;339:680-685

Dix-Halpike Test in BPV

Treatment of BPV

Hotson, J. R. et al. N Engl J Med 1998;339:680-685

Schematic Drawing of Peripheral and Central Vestibular Nystagmus with and without Visual Fixation.

A 53-year-old man awoke in the morning with acute dizziness. He staggered to the bathroom, where he vomited repeatedly. When he was seen at a local emergency room 12 hours later, he had left-beating nystagmus in all positions of gaze but otherwise no focal neurologic findings.

How should he be evaluated and treated?

The first task of the examining physician is to determine whether the vertigo is of central or peripheral origin, since some central causes of acute vertigo, such as cerebellar hemorrhage or infarction, can be life-threatening and may require immediate intervention.1

This differentiation can usually be made at the bedside on the basis of the type of the spontaneous nystagmus, the results of the head-thrust test (described below), the severity of the imbalance, and the presence or absence of associated neurologic signs.

Spontaneous nystagmus of peripheral origin is typically horizontal with a torsional (rotational) component; it does not change direction with a change in gaze.

By contrast, spontaneous nystagmus of central origin is often purely horizontal, vertical, or torsional and usually changes direction with changes in the position of the gaze.

The head-thrust test is a simple bedside test of the horizontal vestibulo-ocular reflex.2 It is performed by grasping the patient's head and applying a brief, small-amplitude, high-acceleration head turn, first to one side and then to the other. To start, the eyes should be about 10 degrees away from the primary position in the orbit so that after a 10-degree head turn, the eyes will be near the primary position. The patient fixates on the examiner's nose and the examiner watches for corrective rapid eye movements (saccades), which are a sign of decreased vestibular response (i.e., the eyes move with the head rather than staying fixed on the nose). If "catch-up" saccades occur after head thrusts in one direction but not after those in the other direction, this indicates the presence of a peripheral vestibular lesion on that side (in the labyrinth or the 8th nerve including the root's entry zone in the brain stem). Patients with an acute peripheral vestibular lesion typically can stand, although they will veer toward the side of the lesion. By contrast, patients with vertigo of central origin are often unable to stand without support. Associated neurologic signs such as dysarthria, incoordination, numbness, or weakness suggest a central origin.

The syndrome of acute, prolonged vertigo of peripheral origin is commonly called vestibular neuritis, although other terms such as "vestibular neuronitis," "labyrinthitis," "neurolabyrinthitis," and "unilateral vestibulopathy of unknown cause" have also been used.3 The vertigo typically develops over a period of hours, is severe for a few days, and then subsides over the course of a few weeks. Some patients can have residual nonspecific dizziness and imbalance that lasts for months. The condition is thought to result from a selective inflammation of the vestibular nerve, presumably of viral origin. The facts that the disorder often has a viral prodrome, that it occurs in epidemics, that it may affect several members of the same family, and that it occurs more commonly in spring and early summer all support a viral cause.3 Postmortem studies have found atrophy of the vestibular nerve and the vestibular sensory epithelium that is similar to the pathological findings with known viral disorders of the inner ear, such as measles and mumps.4,5 Several viruses selectively infect the labyrinth, the 8th nerve, or both in animal models.6,7

A common feature of vestibular neuritis is selective damage to the superior part of the vestibular labyrinth (horizontal and anterior semicircular canals and utricle) supplied by the superior division of the vestibular nerve, with sparing of the inferior part (posterior semicircular canal and saccule) supplied by the inferior division.8

Benign paroxysmal positional vertigo (originating from the posterior semicircular canal) often develops as a sequela even if the patient has no remaining function in the horizontal or anterior semicircular canal.3,9

Selective inflammation of the superior division of the vestibular nerve10 or anatomical differences in the bony canals of the two divisions11 might explain this relative vulnerability.

T1-weighted gadolinium-enhanced axial image through the posterior fossa at the level of the cerebellopontine angle shows the typical appearance of an acoustic neuroma (vestibular schwannoma). The larger, rounded portion (black arrow) represents the cisternal component of the mass, and the smaller, conical portion (white arrow) represents the intracanalicular component.

The tumor was resected through a left suboccipital craniotomy. It involved both the superior and inferior vestibular nerves. The histologic diagnosis was acoustic neuroma.

The patient's postoperative course was complicated by a pulmonary embolism, which required placement of an inferior vena caval filter. When the patient was last seen four months postoperatively, he was deaf in the left ear and had intermittent left-sided tinnitus.

A 27-year-old man presented with a two-week history of left sensorineural hearing loss and tinnitus.

19 yo student

5 minutes of strange behavior:– Abrupt blinking and picking at clothes– Unresponsive to questioning– Pushed roommated– Walked aimlessly– Cleared gradually– Amnestic to event

Questions

• Type of event

• DDx: seizure, TIA, syncope

• Episodes– Prodrome– Spell– Recovery

• Predisposing factors

• Define seizure and epilepsy

Questions II• Prevalence• Lifetime risk of seizures• Is violence part of seizures• Tests?

– MRI vs. CT

• EEG• Chances of a 2nd seizure after an unprovoked

single seizure• Rx? Life long?• Define status epilepticus

Thalamacortical Circuitry and EEG

Genetic Epilepsy

Hippocampal Sclerosis:Mesial Temporal Lobe Epilepsy

Mesial Temporal Sclerosis

At the age of 23 years, he reported seizures had begun at 15 years old, after he had been struck on the right side of the head by his father and had lost consciousness. The seizures were preceded by an aura of warmth on the right side of the head; occasionally, he had brief myoclonic jerks before losing awareness. His brother added that the patient would look to the right and then fall, stiffen, and shake for several minutes. Tongue biting and incontinence accompanied the seizures, which were followed by confusion and sometimes combativeness for as long as 30 minutes.

• An 11-year-old right-handed boy was admitted to the hospital because of a seizure.

• The child had been well until the day of admission, when he stood up and fell, striking his head on a desk. He became unconscious, with arms extended and pronated, and had a right focal motor seizure that became generalized and lasted 20 minutes. There was no contusion, rash, or lymphadenopathy. Emergency medical technicians found him confused, combative, and unresponsive to verbal stimuli. He was brought to this hospital.

• The boy's mother stated that he had developed normally without any serious illnesses. An adult brother had died of complications of the acquired immunodeficiency syndrome (AIDS) several years earlier. The patient resided with his mother, his stepfather, and two healthy kittens. There was no history of fever, headache, rash, visual problems, previous seizures, travel, exposure to ill persons, or use of tobacco, alcohol, or illicit drugs.

Cat scratch encephalitis due to B. quinta

Questions III

• What are the systemic dangers of continued convulsions?

• The dangers of ongoing seizures to the brain?• The risks of intravenous phenytoin,

fosphenytoin, and valproic acid?• Outline the treatment of convulsive status

epilepticus• What are the Minnesota rules on driving and

epilepsy? http://www.dps.state.mn.us/dvs/index.html

Name Half-life Side effects Serious S/Es

Phenytoin 12-24 ataxia liver failure

Carbamazepine 8-12 above Stevens-Johnson

Aplastic anemia

Valproate 8-12 Neural tube defects

Liver

Gapapentin ? Confusion ?none

Anticonvulsants: need to check

Questions

• Define therapeutic antiepileptic level

• Discuss teratogenecity of anticonvulsants

• Discuss dose adjustment during pregnancy and postpartum

Vignette

• 24 yo man with atypical seizures– Dropping objects at work– Collapse w/o LOC during a joke– Falling asleep at meetings– Vivid dreams

• Diagnosis

• Test(s)

Treatments

• 49 yo with obstructive sleep apnea• 63 yo with restless legs syndrome• 17 yo student bus ride @ 6:25 AM• 47 yo with depression, anxiety & frequent AM

awakenings• 67 yo woman whose spouse has requent

nocturnal myoclonus• 41 yo man with multiple sclerosis and frequent

nocturnal extensor spasms• 56 yo factory worker with frequent shift changes