Definition of Stroke
• A stroke or Cerebrovascular accidents is defined by abrupt
onset of a neurological deficit that is attributable to a focal
• Stroke is the third most common cause of death in the
developed world after cancer and ischaemic heart disease,
and is the most common cause of severe physical disability.
References : Harrison 18th ed
• Stroke is classified into two major types:
1. Ischemic stroke: Brain ischemia due to thrombosis,
embolism, or systemic hypoperfusion
2. Hemorrhagic stroke: Brain hemorrhage due to
intracerebral hemorrhage or subarachnoid hemorrhage.
• Approximately 80 % of strokes are due to ischemic cerebral
infarction and 20 % to brain hemorrhage.
BRAIN ISCHEMIA 1
• Thrombosis generally refers to local in situ obstruction of an artery.
• Embolism refers to particles of debris originating elsewhere that block
arterial access to a particular brain region .
• Systemic hypoperfusion is a more general circulatory problem,
manifesting itself in the brain and perhaps other organs.
• References 1: Caplan LR. Basic pathology, anatomy, and pathophysiology of stroke. In: Caplan's Stroke:
A Clinical Approach, 4th ed, Saunders Elsevier, Philadelphia 2009. p.22.
Hemorrhagic stroke: types
1. Intracerebral hemorrhage refers to bleeding directly into
the brain parenchyma
2. Subarachnoid hemorrhage refers to bleeding into the
cerebrospinal fluid within the subarachnoid space that
surrounds the brain
• Note: Hemorrhage is characterized by too much blood
within the closed cranial cavity, while ischemia is
characterized by too little blood to supply an adequate
amount of oxygen and nutrients to a part of the brain.1
Reference 1: Caplan LR. Intracranial branch atheromatous disease: a neglected, understudied, and
underused concept. Neurology 1989; 39:1246.
• Cerebral infarction is mostly due to
thromboembolic disease secondary to
atherosclerosis in the major extracranial
arteries (carotid artery and aortic arch).
• About 20% of infarctions are due to embolism
from the heart, and a further 20% are due to
intrinsic disease of small perforating vessels
(lenticulostriate arteries), producing so-called
Cincinnati Prehospital Stroke Scale
1. Facial droop: Have the person smile or show his or her teeth.
•Normal: Both sides of face move equally
•Abnormal: One side of face does not move as well as the other (or at all)
2. Arm drift:
•Normal: Both arms move equally or not at all
•Abnormal: One arm does not move, or one arm drifts down compared with the
•Normal: Patient uses correct words with no slurring
•Abnormal: Slurred or inappropriate words or mute
Patients with 1 of these 3 findings as a new event have a 72% probability of an
ischemic stroke. If all 3 findings are present the probability of an acute stroke is
more than 85%
Hurwitz AS, Brice JH, Overby BA, Evenson KR (2005). "Directed use of the Cincinnati Prehospital Stroke Scale by laypersons". Prehosp Emerg Care 9 (3): 292–6