Ischemic Stroke - Hennepin County Medical Center

Case Reports
She is continent of bowel and bladder. A left
field cut is easily demonstrated and she has
obvious left hemi-neglect on sensory testing.
The patient is articulate and can express herself
quite clearly but often interrupts others and
appears to be somewhat disinhibited in social
situations. The patient is scheduled for longterm
physical and rehabilitation therapy to
regain as complete functioning as possible.
Discussion
This patient, whose outcome was decidedly better
than may have been estimated initially, presented
several difficult management challenges.
The patient presented with a history and physical
examination very suggestive of stroke, a
luxury not always available to the clinician.
While clinical exam findings are unquestionably
useful, the diagnosis is usually confirmed
with imaging. A cranial CT scan without contrast
is critical to differentiating ischemic from
hemorrhagic stroke. An ischemic stroke can
begin to show changes such as a hyperdense
artery sign, sulcal effacement, loss of graywhite
interface, mass effect, and acute hypodensity
as soon as three hours after the event,
but more often between 6-12 hours. Presence
of early ischemic changes does not change
the management with intravenous fibrinolytic
therapy within the three-hour time window. An
electrocardiogram helps diagnose atrial fibrillation
(which account for 60% of cardio-embolic
strokes) and myocardial infarction.
Out-of-hospital providers and emergency
physicians need to document as best as they
are able the exact time of stroke onset and
presence of any neurologic deficits, since
these findings may rapidly progress or resolve
by the time the patient arrives at the hospital.
Such information is critical for the decision in
administration of fibrinolytics. Management of
blood pressure should use pre-established
guidelines and will vary depending on whether
the patient is a candidate for fibrinolytic therapy.
The sBP shoud be less than 185 mmHg and
the dBP less than 110 mmHg before giving fibrinolytics
because of concern for increased
intracranial hemorrhage risk with higher blood
pressures. If fibrinolytics are given, strict blood
pressure control is indicated, with the goal of
having sBP 120 mmHg, according to the most recent
American Heart Association guidelines. Aspirin
given within 48 hours of the stroke onset has
been shown to have mild efficacy in preventing
early recurrent stroke but does not improve
outcomes from the current stroke. Aspirin
should be held for 24 hours after fibrinolytic
therapy in case there is an intracranial hemorrhage.
Improved outcome has not been shown
for treatment with heparin for ischemic stroke
in several clinical trials. Recent studies show
no benefit from heparin, or a small potential
benefit of heparin, that is counterbalanced by
an increased risk of hemorrhage.
In addition to the focal neurologic injury from the
ischemic stroke itself, cerebral edema that
develops following the insult can lead to intracranial
hypertension and further devastating neurologic
effects.
The clinical manifestations of increased
ICP include:
Depressed level of consciousness
Headache
Vomiting
Cushing's triad (bradycardia, respiratory
depression, and hypertension)
Additional focal deficits can be caused by
ischemic injury or herniation. These manifestations
are caused either by direct mass effects
of the increased intracranial volume (e.g. herniation,
Cushing's triad) or the decrease in
cerebral blood flow caused by the ICP.
4 | Approaches in Critical Care | December 2008