transient ischemic attacks

TRANSIENT ISCHEMIC ATTACK (TIA)

By: DR. WALID REDA ASHOUR

TRANSIENT

ISCHEMIC

ATTACK

Definition: Acute, focal neurological deficit with

clinical resolution over a period of minutes or

up to an hour and which is thought to be due to

inadequate cerebral or ocular blood supply as

a result of arterial thrombosis , low flow or

embolism.

OR

brief episode of neurological dysfunction caused

by focal disturbance of brain or retinal ischemia,

with clinical symptoms typically lasting less than

1 hour and without evidence of infarction.

** Symptoms resolve following rapid

fragmentation and dissolution of the

microemboli / thrombus.

TIA

* Onset sudden & rapid, with complete resolution.

* Most TIAs last approximately 2 to 20 minutes.

* Initially should involve all affected areas relatively

simultaneously.

* Should involve focal loss of neurologic function,

with symptoms reflecting dysfunction of cerebrum,

brainstem, or cerebellum.

Probably NOT TIA * Ill-defined onset, waxes & wanes, or slowly worsens.

* Leaves persistent neurologic deficits, however mild.

* Neurologic dysfunction of few seconds duration

* Episode lasting for more than 1 hour.

* Marching of symptoms from one body part to another.

* Positive phenomena: involuntary movements, jerking, scintillating scotoma.

* Global brain symptoms: giddiness, LOC.

The symptoms start more or less abruptly, and they are ‘focal’, indicating a disturbance in a particular area of brain, or in one eye.

Motor symptoms (the most common): * Weakness,* Clumsiness or * Heaviness. in the upper limb or lower limb or face alone, or in various combinations, usually on just one side of the body.sensory symptoms:* Numbness or

* Tingling.

Transient monocular blindness (amaurosis fugax): Affects the upper or lower half of vision, or all the vision of one eye, and is often described like a blind or shutter coming down from above, or up from below.

Indeed, if a patient still has symptoms more than an hour after the onset, the chances are that they will persist for more than 24 hours and so the patient will

actually have had a stroke

N.B. Vertigo, diplopia, dysphagia, unsteadiness,

tinnitus, amnesia, drop attacks, and possibly

dysarthria are so often due to global cerebral

ischaemia, or non-vascular causes, that if one

occurs as an single symptom the diagnosis of TIA

is very uncertain

** In the clinical analysis of TIAs, it is important to

separate a single transient episode from repeated

ones that are all of uniform type. The latter are

more a warning of impending vascular occlusion,

particularly of the internal carotid artery, whereas

the former, especially when prolonged, are again

often caused by an embolus that leaves no lasting

clinical effect.

TIAs can reflect the involvement of virtually any

cerebral artery: common or internal carotid; middle,

posterior, or anterior cerebral; ophthalmic; vertebral,

basilar, or cerebellar; or a penetrating branch. The

carotid (80 %) or vertebrobasilar vascular territories

(20 %).

TIAs may precede, accompany, or infrequently

follow the development of a stroke, or they can

occur by themselves without leading to a stroke.

About two thirds of all patients with TIAs are men

with hypertension, reflecting the higher incidence of

atherosclerosis in this group. Occasionally, in

younger adults, TIAs may occur as relatively benign

phenomena, without recognizable features of

atherosclerosis or risk factors for it.

Differential diagnosis

Approximately 20 % of infarcts that follow TIAs Approximately 20 % of infarcts that follow TIAs

occur within a month after the first attack, and occur within a month after the first attack, and

approximately 50 percent within a year.approximately 50 percent within a year.

CAUSES OF TRANSIENT FOCAL NEUROLOGICAL ATTACKS1-Focal cerebral ischaemia (i.e. TIA) 2- Migraine with aura

3- Partial epileptic seizures

4- Structural intracranial lesions

    Tumour

    Chronic subdural haematoma

    Vascular malformation

    Giant aneurysm

5- Multiple sclerosis

6- Labyrinthine disorders (e.g. Meniere's disease, benign positional vertigo)

7- Peripheral nerve or root lesion

8- Metabolic:

    Hypoglycaemia

    Hyperglycaemia

    Hypercalcaemia

    Hyponatraemia

9- Psychological

Migrainous aurasMigrainous auras

come on slowly, spread and intensify over several come on slowly, spread and intensify over several

minutes, and fade in 20–30 min. The symptoms minutes, and fade in 20–30 min. The symptoms

tend to begin in one domain (particularly vision), tend to begin in one domain (particularly vision),

fade and move on to another. Also symptoms tend fade and move on to another. Also symptoms tend

to be positive (e.g. flashing lights, tingling) rather to be positive (e.g. flashing lights, tingling) rather

than the typically negative symptoms of a TIA (e.g. than the typically negative symptoms of a TIA (e.g.

weakness, visual loss, numbness).weakness, visual loss, numbness).

Partial epileptic seizuresPartial epileptic seizures

The symptoms ‘march’ across a hand or foot, and up the limb The symptoms ‘march’ across a hand or foot, and up the limb

in a minute or so and may, eventually, be accompanied by in a minute or so and may, eventually, be accompanied by

focal motor seizures or secondary generalization. Sudden focal motor seizures or secondary generalization. Sudden

speech arrest seems to be more often epilepticspeech arrest seems to be more often epileptic than due to than due to

ischaemia, which is more likely to cause dysphasic ischaemia, which is more likely to cause dysphasic

Thank you