Best Dx/Best Rx: Stroke

From: Subject: Best Dx/Best Rx: Stroke Date: Wed, 3 Jun 2009 21:35:11 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_01D2_01C9E493.2CB93330" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_01D2_01C9E493.2CB93330 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.acpmedicine.com/acp/newrxdx/rxdx/dxrx1104.htm Best Dx/Best Rx: Stroke

Stroke

Scott E. Kasner, M.D.
University of = Pennsylvania=20 School of Medicine

Lewis B. Morgenstern, M.D.
University of = Michigan=20 Medical School

Defin= ition/Key=20 Clinical Features
Diffe= rential=20 Diagnosis
Best = Tests
Best = Therapy
Best = References

Definition/Key Clinical=20 Features

A sudden neurologic deficit caused by either = ischemia=20 (80%) or hemorrhage (20%)=20
Acute ischemic stroke produces varied signs = and=20 symptoms, depending on the location of the occlusion
- Anterior cerebral artery (ACA): = contralateral leg=20 weakness
- Middle cerebral artery (MCA): contralateral=20 hemiparesis and hemisensory deficit (face + arm > leg); aphasia = (dominant=20 hemisphere) or neglect (nondominant hemisphere); contralateral = visual-field=20 defect; deviation of gaze; dysarthria; and other cortical symptoms =
- Posterior cerebral artery (PCA): occipital = infarction=20 and contralateral visual-field loss; contralateral hemiparesis; = behavioral=20 changes=20
- Vertebral arteries or basilar artery: = crossed facial=20 sensory and body motor signs; diplopia; facial numbness and = weakness;=20 vertigo; nausea and vomiting; tinnitus; hearing loss; ataxia; gait=20 abnormality; hemiparesis; dysphagia; and dysarthria
- Penetrating vessels: pure motor hemiparesis, = pure=20 sensory stroke, clumsy hand=96dysarthria syndrome, or ataxic = hemiparesis=20
Hemorrhagic stroke=20
- Subarachnoid (5%)
  - Severe headache=20
  - Rapid onset=20
  - Photophobia=20
  - Stiff neck=20
  - Decreased level of consciousness=20
  - Focal neurologic signs
- Intracerebral (intraparenchymal) = (15%)=20
  - Severe headache
  - Focal neurologic signs (resembles ischemic = stroke)
Transient ischemic attack (TIA): sudden = vascular-related=20 focal neurologic deficit that resolves completely and lasts < 24 = hr,=20 generally < 1 hr; a herald of ischemic stroke and an opportunity to = intervene

Differential = Diagnosis

Drugs or other toxins=20
Seizure=20
Metabolic derangements
Migraine
Brain tumor
Intracranial hemorrhage
Psychiatric disease

Best=20 Tests

Noncontrast CT to distinguish ischemic stroke = from=20 hemorrhagic stroke=20
To localize lesion and evaluate blood vessels = in=20 ischemic stroke
- Brain MRI=20
- Angiography=20
- CT-angiography (CT-A)=20
- Magnetic resonance angiography (MRA)=20
- Carotid duplex ultrasound=20
- Transcranial Doppler ultrasound =
Cardiac evaluation of ischemic strokes=20
- Cardiac history and examination
- Electrocardiogram=20
- Transthoracic echocardiogram (TTE) or = transesophageal=20 echocardiogram (TEE)
Laboratory tests=20
- Fasting lipids within 48 hours of symptom = onset=20
- Homocysteine level=20
- Complete blood count=20
- Prothrombin time=20
- Partial thromboplastin time=20
- Chemistry panel

Best=20 Therapy

Acute Ischemic=20 Stroke=20

Aspirin (160 to 325 mg daily) administered = within 48 hr=20 of stroke onset; aspirin should be withheld for at least 24 hr after=20 administration of thrombolytics=20
Intravenous recombinant tissue plasminogen = activator=20 (rt-PA) as soon as possible after onset of symptoms
- Indications
  - Firm clinical diagnosis of potentially = disabling=20 stroke=20
  - Onset of symptoms or last time seen normal = < 3 hr=20 ago
- Absolute contraindications
  - Onset > 3 hr ago or patient not seen = normal=20 within previous 3 hr=20
  - Intracranial mass lesion or hemorrhage on=20 noncontrast head CT
  - Previous stroke or serious head trauma = within=20 previous 3 mo
  - Any history of intracranial hemorrhage =
  - Current use of anticoagulants with PT > = 15 sec or=20 use of heparin within the past 48 hr=20
  - Platelets < 100,000/mm^{3 =}
  - Presenting symptoms suggestive of = subarachnoid=20 hemorrhage (worst headache of patient's life)
  - Blood pressure > 185/110 mm Hg unless = minimal=20 doses of a smooth-acting I.V. agent such as labetalol were = sufficient to=20 lower below this range
  - Previously known cerebral aneurysm or = arteriovenous=20 malformation
- Relative contraindications
  - Glucose < 50 or > 400 mg/dl
  - Seizure at stroke onset
  - Major surgery within 14 days
  - Arterial puncture at a noncompressible = site or=20 lumbar puncture within 1 wk=20
  - Rapidly improving symptoms suggestive of = TIA
  - GI or GU hemorrhage within 21 days =
- Dose: 0.9 mg/kg (maximum dose, 90 mg) = infused over 1=20 hour, with 10% of the total dose infused over the first minute; if = treatment=20 with rt-PA is suspected of inducing intracranial hemorrhage, the = infusion=20 should be suspended

Supportive medical management
- Maintain respiratory function, using = intubation and=20 mechanical ventilation if necessary; maintain oxygen saturation = above 95%=20
- Maintain adequate blood pressure; avoid = rapid lowering=20 of blood pressure; antihypertensive therapy is indicated before and = during=20 thrombolysis with rt-PA, when infarction converts to hemorrhage, and = in=20 patients with myocardial ischemia, aortic dissection, or = hypertensive=20 encephalopathy=20
- Maintain normal fluid volume
- Maintain normal body temperature with = antipyretics or=20 cooling blankets
- Maintain normal blood glucose levels=20
- Surgical decompression to relieve = intracranial=20 pressure in acute cerebellar stroke
- Begin early prophylaxis for deep vein = thrombosis with=20 heparin (5,000 units S.C. q. 12 hr); if heparin is contraindicated = (e.g.,=20 patients with acute hemorrhage), use pneumatic compression = stockings=20
- Prevent aspiration pneumonia=20
- Early physical therapy, occupational = therapy, and=20 speech therapy
Reduce risk factors for ischemic stroke = prevention:=20 control hypertension, tobacco use, hyperlipidemia, diabetes, excessive = alcohol=20 consumption, elevated homocysteine levels, infection, and = inflammation;=20 encourage exercise
Management of risk of cardioembolism
- Oral anticoagulation for patients at high = risk for=20 cardioembolism, including those with atrial fibrillation, mechanical = prosthetic valves, severe dilated cardiomyopathy, intracardiac = thrombus,=20 and/or akinetic ventricular segments
  - Warfarin: contraindicated in pregnancy, = poor=20 compliance, alcohol abuse, and risk of falling; dose: adjusted to=20 international normalized ratio (INR) between 2.0 and 3.0 for most=20 patients=20
  - Ximelagatran: efficacy similar to that of = warfarin=20 in patients with atrial fibrillation and deep vein thromboembolism =
- Aspirin or other antiplatelet agents for = patients at=20 lower risk of cardioembolism or with contraindication to warfarin =
- Antibiotics for treatment of endocarditis=20
Manage carotid artery disease by carotid = endarterectomy=20 or carotid angioplasty and stenting
Antiplatelet treatment to prevent ischemic = stroke=20
- Aspirin (50=96325 mg/day): can cause = gastritis, peptic=20 ulcer disease=20
- Ticlopidine: reduces risk of stroke by 21%, = compared=20 with aspirin; may cause significant neutropenia and thrombocytopenia = and=20 requires complete blood count monitoring every 2 wk for the first 3 = mo; can=20 cause diarrhea and rash=20
  - Dose: 250 mg b.i.d.
  - Cost/mo: $86
- Clopidogrel: reduces risk of major vascular = events by=20 7.3%, compared with aspirin, though not specifically stroke; causes = a lower=20 frequency of neutropenia than ticlopidine; can cause rash, diarrhea, = and,=20 rarely, thrombotic thrombocytopenic purpura=20
  - Dose: 75 mg daily
  - Cost/mo: $115
- Dipyridamole (extended-release) + aspirin: = reduces=20 risk of stroke by 23%, compared with aspirin alone; side effect: = headache=20
  - Dose: 25 mg aspirin + 200 mg = extended-release=20 dipyridamole b.i.d.
  - Cost/mo: $115 =

Intracerebral Hemorrhage=20

Surgical evacuation of hematoma
Ventricular drainage for = hydrocephalus=20
Sedation with propofol to control = intracranial=20 pressure (ICP), with ICP monitor; with or without neuromuscular = blockade=20
Osmotic diuretics before hematoma evacuation =
- Mannitol load, 0.5=961.0 g/kg I.V.; = maintenance dose,=20 0.25=961.0 g q. 6 hr; titrate to keep serum osmolality 300=96310 = mOsm/kg=20 H₂O
Hyperventilation: titrate to keep = Pco₂ at=20 30=9635 mm Hg; wean slowly
Further supportive care as for ischemic = stroke=20

Subarachnoid = Hemorrhage=20

Surgical clipping or endovascular coiling = within 72 hr=20 of onset; before clipping or coiling, patients are kept mildly = sedated in a=20 quiet room and given stool softeners to reduce the risk of = rebleeding=20
After clipping, daily transcranial Doppler=20 examinations to monitor vasospasm=20
At first sign of vasospasm, begin = hypertensive,=20 hypervolemic, and hemodilution therapy to maximize cerebral blood = flow, but=20 only in patients with secured (clipped or coiled) aneurysms
Anticonvulsants at first sign of seizure =
Blood pressure should be gently, not = drastically,=20 controlled
Emergency CT scan in case of change in = mental status=20 to look for hydrocephalus, which can be treated with ventricular = drainage=20
Begin nimodipine on the first day and = continue for 21=20 days=20
Patients should be well hydrated, and blood = pressure=20 should be slightly high

Uncommon=20 Causes of Ischemic Stroke=20

Dissection of the internal carotid artery and = vertebral=20 artery: may follow head and neck trauma or occur spontaneously=20
- Clinical features: neck pain, headache, = Horner=20 syndrome, TIA or ischemic stroke, and tinnitus or audible = bruits=20
- Diagnosis: conventional angiography (gold = standard)=20 shows string sign, tapered stenosis or occlusion, dissecting = aneurysm,=20 intimal flap, distal pouch formation, and an underlying = arteriopathy; CT-A,=20 MRI, or MRA may be used
- Treatment: early antithrombotic therapy with = heparin=20 or, if contraindicated, aspirin; continue until serial imaging = demonstrates=20 recanalization or stabilization of the dissected = vessel
Vasculitis: may be primary or secondary to = infections=20 (syphilis, tuberculosis, or varicella-zoster virus), toxins (cocaine,=20 amphetamines, or LSD), neoplasms, or systemic inflammatory disorders=20 (polyarteritis nodosa, Churg-Strauss angiitis, Wegener granulomatosis, = giant=20 cell arteritis, systemic lupus erythematosus, or rheumatoid = arthritis)=20
- Clinical features: headache, seizures, focal = neurologic deficits, and multifocal encephalopathy=20
- Diagnosis: angiography shows segmental = narrowing and=20 dilatation ("beading")=20
- Treatment: appropriate for any underlying = systemic=20 disorder; immunosuppressive regimens with corticosteroids and other = agents=20 are often used empirically
Prothrombotic states: may be hereditary or = acquired,=20 including abnormalities of red cell or platelet function, coagulation = factors,=20 or endogenous fibrinolysis; uncommon but should be considered when no=20 alternative etiology is identified=20
Cerebral venous thrombosis: a rare cause of = stroke; most=20 commonly caused by infection in children and by pregnancy in adults; = most=20 cases are associated with pregnancy
- Clinical features: severe headache, nausea, = vomiting,=20 papilledema, fluctuating focal neurologic deficits such as = unilateral=20 weakness, numbness, or seizures
- Diagnosis: cerebral angiography (gold = standard), MRI,=20 or MR venogram (MRV); lumbar puncture may show elevated protein = levels, red=20 blood cells, or xanthochromia; noncontrast CT reveals acute = hemorrhage or=20 mass effect; contrast CT may show empty delta sign in the sagittal=20 sinus=20
- Treatment: I.V. heparin during acute period, = then oral=20 anticoagulation for several months until MRI or MRV shows sinus=20 patency

Best = References

Adams HP, et al: Stroke 34:1056, 2003

Albers GW, et al: Stroke 30:2502, 1999

Broderick JP, et al: Stroke 30:905, = 1999

Coull BM, et al: Stroke 33:1934, 2002

November=20 2004