Basics
Description
- TIA " an episode of reversible neurologic deficit caused by a temporary decrease in blood flow to an area of the central nervous system (CNS)
- Classically described as symptoms lasting <24 hr, but most TIA symptoms resolve in <1 hr
- A warning for stroke, as 12 " 30% of strokes will be preceded by TIA
Etiology
- Transient decrease in perfusion to an area of the CNS, which can be caused by:
- Thrombosis in medium to large arteries with atherosclerosis (25%)
- Intracranial small vessel disease (25%)
- Embolic cause from the heart (20%)
- Miscellaneous, including arterial dissection, vasculitis, and hypercoagulable states (5%)
- No clear predisposing vascular cause found (25%)
Diagnosis
Signs and Symptoms
- Symptoms are determined by the vascular territories which are affected
- Large vessel TIA syndromes:
- Anterior cerebral artery (ACA) " unilateral motor/sensory loss to leg > arm, disinhibition
- Middle cerebral artery (MCA) " unilateral motor/sensory loss to face/arm > leg, aphasia if dominant hemisphere, neglect if nondominant hemisphere, homonymous hemianopsia
- Posterior cerebral artery (PCA) " homonymous hemianopsia, may have alexia, prosopagnosia (cant recognize faces)
- Anterior inferior cerebellar artery (AICA) " unilateral deafness, vertigo, tinnitus, vomiting, ipsilateral facial weakness and limb ataxia, contralateral decrease in pain and temperature sensation
- Posterior inferior cerebellar artery (PICA) " unilateral palatal weakness, unilateral limb ataxia, unilateral Horner's syndrome, decreased pain/temperature sensation on contralateral body:
- Vertebrobasilar artery " ataxia, oculomotor palsies, facial paresis, loss of consciousness, quadriplegia
- Carotid artery " unilateral motor/sensory loss to face/leg/arm, aphasia if dominant hemisphere, neglect if nondominant hemisphere, homonymous hemianopsia
- Small vessel TIA syndromes:
- Amaurosis fugax " transient monocular blindness from occlusion of ophthalmic branch of internal carotid
- Lacunar infarcts " occlusion of a deep penetrating artery of the brain. Usually produce pure motor or pure sensory deficits
- Internal capsule " hemiparesis or dysarthria with clumsy hand
- Corona radiata " hemiparesis
- Pons " dysarthria with clumsy hand
- Thalamus " sensory loss to 1 side of the body
History
- Historical features suggestive of TIA:
- Sudden onset
- Short duration (as >60% of events last <1 hr)
- Negative symptoms " CNS is underperfused and therefore, not functioning, so TIA syndromes generally produce loss of neurologic function " i.e., weakness or aphasia
- Symptoms are focal, related to specific vascular territory
- Historical features not suggestive of TIA:
- Gradual onset
- Positive symptoms " increased neurologic function in a particular area, such as convulsion, tingling, or twitching, suggests increased CNS activity as with migraine or seizure
Physical Exam
- Detailed neurologic exam: Strength, sensation, coordination, gait, naming/speech, and visual fields
- Persistent neurologic deficits suggest acute stroke rather than TIA
- The National Institute of Health Stroke Scale (NIHSS) is a reliable and easily repeatable neurologic exam (http://www.ninds.nih.gov/doctors/NIH_Stroke_Scale.pdf)
Essential Workup
- Rapid history and physical exam including detailed neurologic exam
- Fingerstick glucose " hypoglycemia can produce focal neurologic deficits
- Noncontrast CT head " rule out hemorrhage
- If patients present with persistent deficits, obtain STAT neurologic consultation with concern for acute stroke rather than TIA
Diagnosis Tests & Interpretation
Lab
- Glucose
- Chemistry panel " check Na, renal function
- CBC " exclude anemia, polycytosis
- Troponin " rule out concomitant ACS or demand ischemia
- Hemoglobin A1C and fasting lipid panel for patients being admitted/observed
Imaging
- CT:
- Upon arrival to ED, STAT noncontrast head CT to rule out CNS hemorrhage
- MRI:
- Up to 50% of patients that clinically have a TIA will have evidence of infarction on MRI:
- Goal is to have MRI in <24 hr
- Diffusion-weighted imaging (DWI) is the most sensitive protocol for detection of tissue infarction
- Vascular imaging:
- Either with initial imaging or inpatient workup, perform vascular imaging of the head and neck:
- Almost 50% of patients with TIA have stenosis or occlusion of large arteries
- Carotid duplex ultrasound can be used to detect internal carotid stenosis
- CT angiography:
- Can be performed at the time of initial noncontrast head CT
- Can be used to detect stenosis in intracranial and extracranial vessels
- Requires contrast
- MR angiography:
- Can be used to detect stenosis in intracranial and extracranial vessels
- Time of flight (TOF) sequences can provide angiographic images without contrast
Diagnostic Procedures/Surgery
- ECG " evaluate for thrombogenic rhythms such as atrial fibrillation
- Echocardiography in patients with no other cause for TIA " exclude existing thrombus and abnormal wall motion or aneurysms that cause thrombus
Differential Diagnosis
- Hypoglycemia
- Seizure
- Paralysis after seizure (Todds paralysis)
- Atypical migraine
- Psychiatric disease
- Stroke
- CNS tumors or metastases
- Subdural hemorrhage
- Subarachnoid hemorrhage
- Multiple sclerosis
- Intracerebral hemorrhage
- Air embolism
- Vasculitis
- Arterial dissection
- Congenital heart disease
- Vasculitis
- Arterial dissection
- Sickle cell disease
- Neurocutaneous syndromes
- Vascular malformations
- Meningitis
Treatment
Pre-Hospital
- Rapid assessment of neurologic deficits
- Consider transport to a stroke center, when available, if deficits persist
Initial Stabilization/Therapy
- IV access
- Cardiac monitoring
- Supplemental oxygen if hypoxic
Ed Treatment/Procedures
- Main goals in the management of TIA:
- Improve perfusion to ischemic tissue
- Prevent a subsequent stroke
- BP management:
- BP should not be lowered acutely unless over 220/120 mm Hg
- Hypertensive patients with TIA should have their BP lowered if stable at 24 hr after TIA
- Key in patients upon discharge
- 1st line " HCTZ or ACE inhibitor
- Antiplatelet therapy:
- All patients, in the absence of contraindications, need antiplatelet therapy for stroke prevention
- 1st line " aspirin (ASA):
- ASA allergy " clopidogrel, ticlopidine
- ASA/dipyridamole may be more effective than ASA alone
- Anticoagulation:
- Indicated for new onset atrial fibrillation or existing atrial fibrillation not on anticoagulants
- Options include heparin/low-molecular-weight heparin with a transition to warfarin or dabigatran
- The decision to anticoagulate is not emergent; discuss with admitting physician
- Carotid endarterectomy (CEA):
- CEA within 2 wk after TIA in patients with >70% carotid stenosis reduces stroke risk by 10 " 15%
- Lipid therapy:
- AHA guidelines recommend statin therapy for patients with TIA with a goal LDL of under 70 mg/dL
- Key in patients upon discharge
Medication
- Antiplatelet agents:
- Aspirin 160 " 325 mg daily
- Aspirin/dipyridamole 25 mg/200 mg daily
- Clopidogrel 300 mg initially then 75 mg daily
- Anticoagulation:
- Heparin 5,000 " 7,500 U IV bolus, followed by 1,000 U/h infusion OR 80 U/kg IV bolus then 18 U/kg/h
- Warfarin dose is dependent on age and weight, but goal INR for atrial fibrillation is 2 " 3
- Dabigatran 150 mg daily (normal renal function)
- Acute BP management:
- Labetalol 20 mg IV bolus, followed by 20 " 80 mg IV every 10 min; max. cumulative dose of 300 mg
- Nicardipine 5 mg/h infection, increase by 2.5 mg/h every 5 " 15 min; max. dose of 15 mg/h
Follow-Up
Disposition
Admission Criteria
- There are no clear indications for admission or discharge
- Patients with TIA have variable short-term risk of stroke
- Goal of admission is to prevent subsequent stroke in high-risk patients
- Scoring systems have been developed to predict short-term risk of stroke and therefore can guide disposition
- Most common = ABCD2 score:
- Age >60 = 1 point
- BP >140/90 = 1 point
- Clinical features:
- Unilateral weakness = 2 points
- Speech difficulty alone = 1 point
- Duration:
- >60 min = 2 points
- 10 " 59 min = 1 point
- <10 min = 0 points
- Diabetes = 1 point
- ABCD2 score 0 " 3 = low risk of stroke ( ¢ ¼1% at 7 days)
- ABCD2 score 4 " 5 = moderate risk for stroke ( ¢ ¼6% at 7 days)
- ABCD2 score 6 " 7 = high risk for stroke ( ¢ ¼12% at 7 days)
- Patients with moderate to high risk for short-term stroke = admission
- Patients with low risk for short-term stroke, but poor follow-up = observation unit
All children with TIA should be admitted for close neurologic observation, with strong consideration of ICU level care
Discharge Criteria
- No clear discharge criteria exist:
- Low risk for short-term stroke, with good follow-up
Issues for Referral
- The risk of stroke after TIA is highest within 2 days of symptoms
- Discharged patients need to see neurology/primary care within 24 " 48 hr
Follow-Up Recommendations
- Primary Care/Neurology " management of risk factors for cerebrovascular disease (hypertension, diabetes, etc.)
- Vascular surgery " for carotid stenosis. Follow-up within 1 wk, plan for possible CEA within 2 wk
- Cardiology " for those patients with cardiac cause of stroke, such as atrial fibrillation or cardiomyopathy
Pearls and Pitfalls
- Pearls:
- Risk stratification scores (such as ABCD2) can help guide disposition
- Patients with carotid stenosis need rapid vascular surgery follow-up
- Pitfalls:
- Failure to recognize the subtle lacunar TIA syndromes, such as sensory loss
- Failure to rapidly check a glucose in a patient with a focal neurologic deficit
- Discharging patients with TIA without close outpatient follow-up
Additional Reading
- Davis SM, Donnan GA. Clinical practice. Secondary prevention after ischemic stroke or transient ischemic attack. New Engl J Med. 2012;366:1914 " 1922.
- Panagos PD. Transient ischemic attack (TIA): The initial diagnostic and therapeutic dilemma. Am J Emerg Med. 2012;30:794 " 799.
- Pare JR, Kahn JH. Basic neuroanatomy and stroke syndromes. Emerg Med Clin North Am. 2012;30:601 " 615.
- Siket MS, Edlow JA. Transient ischemic attack: Reviewing the evolution of the definition, diagnosis, risk stratification, and management for the emergency physician. Emerg Med Clin North Am. 2012;30:745 " 770.
- Sorensen AG, Ay H. Transient ischemic attack: Definition, diagnosis, and risk stratification. Neuroimaging Clin N Am. 2011;21:303 " 313.
Codes
ICD9
- 435.3 Vertebrobasilar artery syndrome
- 435.8 Other specified transient cerebral ischemias
- 435.9 Unspecified transient cerebral ischemia
ICD10
- G45.8 Oth transient cerebral ischemic attacks and related synd
- G45.9 Transient cerebral ischemic attack, unspecified
- G46.1 Anterior cerebral artery syndrome
- G46.0 Middle cerebral artery syndrome
- G46.2 Posterior cerebral artery syndrome
SNOMED
- 266257000 Transient ischemic attack (disorder)
- 195210002 Anterior cerebral artery syndrome (disorder)
- 195209007 Middle cerebral artery syndrome (disorder)
- 195211003 Posterior cerebral artery syndrome (disorder)
- 230716006 Carotid territory transient ischemic attack