April 24, 2017 Martin

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STROKE:

5th LEADING CAUSE OF DEATH IN THE UNITED STATES

1st LEADING CAUSE OF SERIOUS LONG-TERM DISABILITY

COSTS $34 BILLION ANNUALLY TO THE UNITED STATES

APPROXIMATELY 795,000 AMERICANS HAVE A STROKE EVERY YEAR

AND ALMOST 130,000 PEOPLE DIE ANNUALLY FROM A STROKE [1]

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Current Diagnostic Challenge

There are two types of strokes – ischemic stroke and hemorrhagic stroke (Figure 1). Ischemic stroke occurs when the blood vessels in the brain are blocked by an occlusion [2]. This occlusion can be either a blood clot or a plague fragment, and prevent proper blood, oxygen, and nutrients supply to the brain, causing brain cells to die. Ischemic stroke is responsible for 87% of all cases of strokes. Hemorrhagic stroke, on the other hand, occurs when weakened blood vessels leak or burst [2]. The leaked blood fills the cranium and applies pressure on the brain, leading to brain damage. Although less common than ischemic stroke, hemorrhagic stroke is responsible for 40% of all fatal cases of stroke [2].

Figure 1: Ischemic Stroke versus Hemorrhagic Stroke [3]. Ischemic stroke occurs when a blood clot stops the flow of blood to an area of the brain. Hemorrhagic stroke occurs when blood leaks into brain tissue due to the rupture of weakened or diseased blood vessels.

The symptoms for both ischemic stroke and hemorrhagic stroke are very similar. However, the treatments for these types of stroke are very different. The current treatment for ischemic stroke is the administration of thrombolytic agents, otherwise known as blood thinners [4]. These agents help to break down blood clots and restore cerebral circulation. However, the application of these agents can be deadly in hemorrhagic stroke patients. In that case, the blood thinners will amplify the bleeding by preventing clots from forming around the rupture point. In contrast, hemorrhagic strokes generally require surgery to close up or remove the ruptured blood vessels [4]. Thus, proper diagnosis of the disease is critical. Currently, doctors have to make these life threatening decisions by performing a Computed Tomography (CT). These scans require a specialist to diagnose the type and severity of the patient’s stroke and are only done when a patient reaches the hospital, creating a large time lapse between the onset of stroke and the beginning of treatment.

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References

  1. Stroke Facts. Centers for Disease Control and Prevention. 2015 Mar 24 [accessed 2016 Dec 9]. https://www.cdc.gov/stroke/facts.htm
  2. Types of Stroke. Centers for Disease Control and Prevention. 2015 Mar 24 [accessed 2016 Dec 9]. https://www.cdc.gov/stroke/types_of_stroke.htm
  3. Types of Stroke. UF Health Shands Comprehensive Stroke Center. 2016 [accessed 2016 Dec 9]. https://com-neurology-stroke.sites.medinfo.ufl.edu/for-patients/types-of-stroke/
  4. Stroke Treatment. Mayo Clinic. 2015 Mar 24 [accessed 2016 Dec 9]. http://www.mayoclinic.org/diseases-conditions/stroke/diagnosis-treatment/treatment/txc-20117296

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For More About Stroke

  1. American Stroke Association: http://www.strokeassociation.org                                                                                     
  2. Mayo Clinic: http://www.mayoclinic.org/diseases-conditions/stroke/home/ovc-20117264                                   
  3. Centers for Disease Control and Prevention’s Division for Heart Disease and Stroke Prevention: http://www.cdc.gov/dhdsp/index.htm                                               
  4. National Institute of Neurological Disorders and Stroke: http://www.ninds.nih.gov                                               
  5. National Stroke Association http://www.stroke.org/