Stroke

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Classification Hemorrhagic stroke Ischemic stroke
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Epidemiology and Demographics
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Aysha Anwar, M.B.B.S[2]; Tarek Nafee, M.D. [3]; Sara Mehrsefat, M.D. [4],Seyedmahdi Pahlavani, M.D. [5]

Overview

Stroke is the rapidly developing loss of brain functions due to a disturbance in the blood vessels supplying blood to the brain. This can be due to ischemia (lack of blood supply) caused by thrombosis or embolism, or due to a hemorrhage.

Stroke is a medical emergency and can cause permanent neurological damage, complications and death if not promptly diagnosed and treated. It is the third leading cause of death and the leading cause of adult disability in the United States and Europe. It is predicted that stroke will soon become the leading cause of death worldwide. WHO defines stroke as, a neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours.

Risk factors for stroke include advanced age, hypertension (high blood pressure), previous stroke or transient ischaemic attack (TIA), diabetes mellitus, high cholesterol, cigarette smoking, atrial fibrillation, migraine with aura, and thrombophilia. In clinical practice, blood pressure is the most important modifiable risk factor of stroke; however many other risk factors, such as cigarette smoking cessation and treatment of atrial fibrillation with anticoagulant drugs, are important. Treatment of ischemic stroke is occasionally with thrombolysis, but usually with supportive care (physiotherapy and occupational therapy) and secondary prevention with antiplatelet drugs (aspirin and often dipyridamole), blood pressure control, statins and anticoagulation (in selected patients). Hemorrhagic stroke is a medical emergency, rapid diagnosis and management is crucial because early deterioration is common in the first few hours after ICH onset.

Causes

The following table lists causes for stroke.

Causes
Disease	Lethal causes	Common causes	Less common causes
Transient ischemic attack (TIA)	Emboli from cardiac source (mostly secondary to AF)	Atherosclerotic plaque Thrombosis	Arterial dissection
Ischemic stroke	Atrial fibrillation Eclampsia Infective endocarditis Myocardial infarction Pulmonary embolism	Aneurysm Arteriovenous malformations Atherosclerosis Atrial fibrillation Embolism Hypertension Subarachnoid hemorrhage Thrombosis Transient ischemic attack Traumatic brain injury Warfarin	Takayasu arteritis Vasculitis Vasoconstriction Infective endocarditis Lacunar infarcts Left atrial myxoma
Intracerebral hemorrhage	---	Long-standing hypertension Cerebral amyloid angiopathy	Arteriovenous malformations (AVMs) Aneurysms Cocaine Amphetamines Vasculitis Liver disease Anticoagulant medication Thrombolytic therapy Brain tumor Hemorrhagic transformation of an ischemic stroke Moyamoya disease Tumors Encephalitis
Subarachnoid hemorrhage	Rupture of an aneurysm Saccular aneurysms (most common cause) Fusiform aneurysms Mycotic aneurysms	Rupture of an aneurysm Saccular aneurysms (most common cause) Fusiform aneurysms Mycotic aneurysms	Arteriovenous malformation Dural arteriovenous fistula Perimesencephalic Intracranial arterial dissection Amyloid angiopathy Cerebral venous thrombosis Cerebral vasculitis Reversible vasoconstriction syndrome Cerebral hyperperfusion syndrome after carotid endarterectomy Reversible posterior leukoencephalopathy syndrome Brain or cervical tumors Illicit drug use (cocaine, amphetamines)
Subdural hemorrhage	Rupture of bridging vessels	Trauma (motor vehicle accidents, falls, and assaults)	Aneurysmal subarachnoid hemorrhage Arteriovenous malformation Meningioma Dural metastases Coagulopathy Neurosurgical procedures Cocaine abuse
Epidural hemorrhage	Rupture of middle meningeal arteries	Trauma (motor vehicle accidents, falls, and assaults)
Intraparenchymal hemorrhage	---	Trauma (motor vehicle accidents, falls, and assaults)	Rupture of an aneurysm Saccular aneurysms (most common cause) Fusiform aneurysms Mycotic aneurysms Arteriovenous malformation
Intraventricular hemorrhage (IVH)	---	Secondary to intracerebral hemorrhage Trauma (motor vehicle accidents, falls, and assaults) Vascular malformations (usually arteriovenous malformations or arteriovenous fistulae)	Intraventricular tumors (papilloma, neurocytoma, meningioma, metastases, astrocytoma, ependymoma) Intraventricular aneurysms Moyamoya disease Pituitary apoplexy Vasculitis

Classification

Transient ischemic attack

• A transient ischemic attack is caused by the temporary disturbance of blood supply to a restricted area of the brain, resulting in brief neurologic dysfunction that usually persists for less than 24 hours.

Stroke

Stroke

Ischemic

Hemorrhagic

Large vessel thromboembolism

Cardioembolic

Small vessel or Lacunar infarct

Intra-axial

Extra-axial

Intracerebral (ICH)

Subarachnoid hemorrhage (SAH)

Subdural Hemorrhage

Epidural Hemorrhage

Intraparenchymal hemorrhage

Intraventricular hemorrhage (IVH)

Cerebral microbleeds

Differential diagnosis

Diseases	Symptoms				Physical Examination					Past medical history	Diagnostic tests			Other Findings
	Headache	↓LOC	Motor weakness	Abnormal sensory	Motor Deficit	Sensory deficit	Speech difficulty	Gait abnormality	Cranial nerves		CT /MRI	CSF Findings	Gold standard test
Brain tumor	+	-	-	-	+	+	+	-	+	Weight loss, fatigue	+	Cancer cells	MRI	Cachexia, gradual progression of symptoms
Hemorrhagic stroke	+	+	+	+	+	+	+	+	-	Hypertension	+	-	CT scan without contrast	Neck stiffness
Subdural hemorrhage	+	+	+	+	+	-	-	-	+	Trauma, fall	+	Xanthochromia	CT scan without contrast	Confusion, dizziness, nausea, vomiting
Neurosyphilis	+	-	+	+	+	+	-	+	-	STIs	+	↑ Leukocytes and protein	CSF VDRL-specifc CSF FTA-Ab -sensitive	Blindness, confusion, depression, Abnormal gait
Complex or atypical migraine	+	-	+	+	-	-	+	-	-	Family history of migraine	-	-	Clinical assesment	Presence of aura, nausea, vomiting
Hypertensive encephalopathy	+	+	-	-	-	-	+	+	-	Hypertension	+	-	Clinical assesment	Delirium, cortical blindness, cerebral edema, seizure
Wernicke’s encephalopathy	-	+	-	-	-	+	+	+	+	History of alcohal abuse	-	-	Clinical assesment and lab findings	Ophthalmoplegia, confusion
CNS abscess	+	+	-	-	+	+	+	-	-	History of drug abuse, endocarditis, immunosupression	+	↑ leukocytes, ↓ glucose and ↑ protien	MRI is more sensitive and specific	High grade fever, fatigue,nausea, vomiting
Drug toxicity	-	+	-	+	+	+	-	+	-	-	-	-	Drug screen test	Lithium, Sedatives, phenytoin, carbamazepine
Conversion disorder	+	+	+	+	+	+	+	+		History of emotional stress	-	-	Diagnosis of exclusion	Tremors, blindness, difficulty swallowing
Metabolic disturbances (electrolyte imbalance, hypoglycemia)	-	+	+	+	+	+	-	-	+	-	-	Hypoglycemia, hypo and hypernatremia, hypo and hyperkalemia	Depends on the cause	Confusion, seizure, palpitations, sweating, dizziness, hypoglycemia
Meningitis or encephalitis	+	-	-	-	-	+	+	-	-	History of fever and malaise	-	↑ Leukocytes, ↑ Protein ↓ Glucose	CSF analysis	Fever, neck rigidity
Multiple sclerosis exacerbation	-	-	+	+	-	+	+	+	+	History of relapses and remissions	+	↑ CSF IgG levels (monoclonal bands)	Clinical assesment and MRI	Blurry vision, urinary incontinence, fatigue
Seizure	+	+	-	-	+	+	-	-	+	Previous history of seizures	-	Mass lesion	Clinical assesment and EEG	Confusion, apathy, irritability,

Epidemiology and Demographics

Stroke in USA

• Stroke is a leading cause of serious long-term disability
• In USA, the incidence and mortality rates of stroke has significantly decreased compared to previous years.
• From year 2003 to 2013, the mortality rates due to stroke declined by 18.5%.
• In 2013, stroke became the fifth leading cause of death.
• The case fatality rate of stroke is estimated to be 41.7 deaths per 100, 000 population
• The incidence of new (610, 000) or recurrent stroke (185, 000) is estimated to be 795000 people annually or 250 cases per 100, 000.
• It is estimated that one incidence of stroke happens every 4 sec with death occurs every 4 min.
• About 87% of all strokes are ischemic strokes
• Stroke costs the United States an estimated $34 billion each year

Worldwide

• According to WHO, the incidence of stroke is estimated to be 15 million people annually, worldwide..
• Out of these, 5 million die and 5 million are left permanently disbaled..

Age

• Stroke can occur in all age groups. However, the incidence of stroke is less among individuals age less than 40 years of age and the risk increases with increasing age.
• According to WHO, stroke also occurs in about 8% of children with sickle cell disease..
• In 2009, 34% of people hospitalized for stroke were younger than 65 years
• The incidence of stroke in people aged 18 to 50 years is estimated to be approximately 10%.

• The rate of decline in mortality rates of stroke in different age groups is as follows:

• • Older then 65 years: from 534.1 to 245.2 per 100,000
  • 45-65 years of age: from 43.5 to 20.2 per 100,000
  • 18 to 44 years of age: from from 3.7 to 2.0 per 100,000

Gender

There is increased incidence of stroke in men as compared to women.

Race

• The risk of incidence of first stroke is twice in African-American population as compared to Caucasians with increased mortality rates.

Geographical distribution

• There is increased incidence and mortality rates of stroke in developing countries as compared to developed countries due to low socioeconomic status and heath facilities.
• In the USA, the highest death rates from stroke are in the southeastern United States.

Diagnosis

• Diagnosis is based on history of symptoms development, physical examination and imaging findings.
• CT scan and magnetic resonance imaging (MRI) are both reasonable for initial evaluation.
• CT scan without contrast is the initial test performed to diagnose ischemic stroke and rule out hemorrhagic stroke.
• CT is very sensitive for identifying acute hemorrhage and is considered the gold standard.
• Gradient echo and T2 susceptibility-weighted MRI are as sensitive as CT for detection of acute hemorrhage and are more sensitive for identification of prior hemorrhage.
• MR diffusion weighted imaging is the most sensitive and specific test for diagnosing ischemic stroke and may help detect presence of infarction in few minutes of onset of symptoms. It may also help differentiate viable tissue from infarct area if combined with MR perfusion. For diagnosing ischemic stroke in the emergency setting, MRI scan has the sensitivity and specificity of 83% and 98% respectively.
• MRI scan is superior to CT scan for being more sensitive and specific in detection of lacunar and posterior fossa infarcts, differentiation between acute and chronic stroke and detection of microbleeds. Another additional advantage is absence of ionising radiation compared to CT scan. Some of the disadvantages of MRI scan may include lack of availability in acute setting, higher cost, inability to use it in patients with metallic implants. MRI with contrast cannot be used in patients with renal failure.