0071643192.pdf

A 58-year-old female is brought to the ED as a “stroke alert.” Her husband

states that she woke up 1 hour prior to arrival with slurred speech and

weakness in her right arm and leg. On physical exam she has aphasia,

R-sided hemiparesis, and sensory deficits. Labs are drawn, and the patient is

rushed to the CT scanner where a left middle cerebral artery distribution stroke

(ischemic) is diagnosed. Is this patient a thrombolysis candidate?

While the patient is presenting within 3 hours of perceived onset of symp-

toms, we do not know the actual time the stroke occurred. The patient went to

sleep 10 hours before arriving in ED, and thus stroke onset is assumed to be up to

10 hours prior to arrival, not 1 hour. This patient is not a thrombolysis candidate.

STROKE

A stroke is any process that disrupts the flow of oxygen and substrate-rich blood
to the brain. Commonly an infarcted area of brain is surrounded by a region of
tenuous blood flow, the ischemic penumbra. The focus of stroke management
is to maintain the blood supply to this region, thereby limiting infarct size.
Overall, 85% of strokes are ischemic and 15% are hemorrhagic.

Anatomy of Cerebral Blood Flow (CBF) (See Figure 15.1)

■ Anterior circulation (from carotid arteries, 80% of CBF)
■ Frontoparietal lobes
■ Anterior aspect of temporal lobes

NEUROLOGY

Anterior communicating

Anterior cerebral

Internal carotid

Middle cerebral (stem)

Lenticulostriate

Middle cerebral (superior division)

Middle cerebral (inferior division)

Posterior communicating

Posterior cerebral

Superior cerebellar

Anterior inferior cerebellar

Basilar

Posterior inferior cerebellar

Vertebral

Circle

of Willis

FIGURE 15.1. Anatomy of cerebral blood flow.

(Reproduced, with permission, from Aminoff MJ, Greenberg DA, Simon RP. Clinical Neurology,
6th ed. New York: McGraw-Hill, 2005:288.)