07/08. tbl. 100. árg. 2014

Cerebral ischemia/infarction - diagnosis and treatment

Heilablóðþurrð/-drep - greining og meðferð

Four hundred individuals suffer from ischemic stroke every year in Iceland, more than one daily. Cerebral ischemia is an emergency. Around two million brain cells die every minute after an occlusion of a cerebral artery. Therefore, it is of utmost importance that the patient is transported quickly to hospital, not least to receive thrombolytic treatment. Even though thrombolytic treatment can be given up to four and a half hours after the ictal event, time is brain and the effect of thombolysis reduces dramatically as times passes. For every two patients who are treated inside one hour, one recovers fully. When the treatment is administred between three and four and a half hours only one in 14 recovers fully. All patients with an acute stroke should be admitted to a stroke unit where a multidisciplinary focus on stroke causation and treatment is present, with emphasis on early rehabilitation. Secondary preventive treatment focusing on anti-thrombotic, hypertensive, diabetic, cholesterol lowering treatment, carotic endarterectomy and life style changes should be initiated as soon as possible.

Figure 1. All figures are computerized tomographies and show the same individual who came to the emergency department one hour after suffering from a right hemiparesis and aphasia.

Figure 1a. (CT without contrast) shows a thrombus (media sign) in the left middle cerebral artery.

Figure 1b. CT angiography shows an occlusion in the left middle cerebral artery (arrow).

Figure 1c. A CT perfusion study (cerebral blood flow, CBF) shows reduced perfusion in the left middle cerebral artery territory (blue, arrow). The blue area is penumbra (tissue at risk for infarction).

Figure 1d. CT without contrast shows early signs of ischemia in the left middle cerebral artery territory (hypodensity, flattened sulci and low differentiation between white and gray matter).

Figure 2. CT scan without contrast (2a) shows no sign of infarction but diffusion weighted MRI (2b) shows a clear infarction in the left thalamus (arrow).

Figure 3. Magnetic resonance imaging of a patient with a left hemiparesis. Figures 3a (DWI:B1000) and 3b (ADC map) show an infarction in the territory of the right middle cerebral artery.

Figure 4. CT scan without contrast shows a cerebral hemorrhage in the right cortex and basal ganglia after thrombolysis.

Figure 5. Figure 5a is a CT scan without contrast after hemicranectomy in an individual with a large infarction in the territory of the right middle cerebral artery. The brain protrudes outside the cranium because of the size of the infarction and edema. A three dimensional CT scan (5b) illustrates well the opening of the skull. Figure 5b was performed a few months later than figure 5a. Therefore it does not show the same protrusion as in figure 5a. The patient made a remarkable recovery despite having a severe hemiparesis in the beginning.

Table 1. Inclusion and exclusion criteria for intravenous thrombolysis

Inclusion criteria

Diagnosis of acute ischemic stroke causing measurable neurological deficit

Onset of symptoms <4.5 hours before beginning treatment

Exclusion criteria

Only minor or rapidly improving stroke symptoms (clearing spontaneously)

Severe symptoms (≥25 on the NIH stroke scale)

Symptoms suggest subarachnoid hemorrhage

CT demonstrates an intracranial hemorrhage

Significant head trauma or prior stroke in previous 3 months

Recent gastrointestinal or urinary tract hemorrhage (within previous 21 days)

Major surgery within previous 14 days

Elevated blood pressure (systolic >185 mm Hg or diastolic >110 mm Hg)

Active internal bleeding

Current use of anticoagulant with INR >1.7

Heparin received within 48 hours, resulting in abnormally elevated aPTT

greater than the upper limit of normal

Platelet count <100 000/mm3

Blood glucose concentration <50 mg/dL (2.7 mmol/L)

CT demonstrates a large infarction (hypodensity >1/3 cerebral hemisphere)

Intracranial neoplasm, arteriovenous malformation, or aneurysm

Key words: cerebral ischemia, cerebral infarction, transient ischemic attack, Tissue plasminogen activator.

Þetta vefsvæði byggir á Eplica