Stroke is a sudden loss of your cerebral function due to an interruption or bursting of blood flow to one part of the brain. The disturbance causes the brain tissue to get an insufficient oxygen and nutrient needed to function properly.
Most often, stroke is the result of a clot that obstructs the blood vessels causing the brain tissue to die, cerebral infarction. In some cases however, the stroke can be the result of a rupture of a blood vessel in the brain, hemorrhagic stroke. Ischemic stroke represents approximately 80% of stroke cases; the remaining 20% are hemorrhagic stroke.
Stroke Causes and Risk Factors
Stroke is the result of blockage of blood flow in the brain due to presence of plaque or clot in the arterial wall (atherosclerosis). Atherosclerosis is a medical condition in which deposits of cholesterol accumulate within your blood vessels making the flowing of blood difficult. These deposits are found particularly in the carotid arteries of your neck, the coronary arteries of your heart and arteries of your legs. No matter where they locate, these clots prevent blood from circulating in your body. Depending on the cause of the accident, stroke can be ischemic or hemorrhagic.
Hemorrhagic stroke – this type of stroke is a hemorrhagic cerebrovascular disease – it occurs when there is bleeding in the brain or bleeding around the brain tissue (subarachnoid hemorrhage). Brain hemorrhage (bleeding in the brain) occurs as a result of a ruptured blood vessel. The most common cause of cerebral hemorrhage is an untreated chronic hypertension. Although rare, structural abnormalities of your blood vessels (vascular malformations or aneurysms) may be responsible for the occurrence of hemorrhagic stroke.
Ischemic stroke – ischemic stroke occurs when blood supply to the brain is interpreted due to the presence of a clot in a blood vessel that supplies vital nutrients to the brain. That is, the clot blocks the artery that feeds blood and oxygen to the brain tissue. Ischemic stroke includes two subtypes of stroke:
Transient ischemic attack (TIA) – a mini-stroke that occurs due to a brief interruption of blood supply to a part of your brain; TIA usually disappears completely in less than 24 hours.
Reversible ischemic neurologic deficit (RIND) – RIND is a neurologic dysfunction that lasts longer than 24 hours, but less than 72 hours
Many factors may increase your risk of having a stroke:
Age – as you get older, your risk of stroke increases considerably
Obesity – being overwight is the main cause for blood clot formation; having blood clot increases not only your risk of stroke but also heart attack.
Family history – your risk of stroke may be higher if one or both of your parents have had a stroke before age 65.
Diseases – there is a high rate of stroke among people suffering from hypertension, heart disease, diabetes, high cholesterol, migraine, chronic stress and atrial fibrillation (a form of abnormal heart rhythm).
Ethnicity – African American, Hispanic, Asian and South Asian face higher rates of hypertension and diabetes, which puts them at higher risk of stroke
Lifestyle – bad habits such as smoking, physical inactivity, consumption of unhealthy foods and high consumption of alcohol (more than two drinks per day) increases your risk of having a stroke
History of stroke or transient ischemic attack (TIA) – about one third of those who survived a stroke or a transient ischemic attack will experience another stroke within 5 years.
Drugs – taking certain drugs such as Tamoxifen (used in the treatment of breast cancer) and Phenylpropanolamine (used as a decongestant) can increases your risk of stroke. It is believed that some oral contraceptives and hormone replacement therapy may increase the risk of stroke; but there is no conclusive evidence of those claims.
Stroke Warning Signs, Symptoms and Complications
Most of the times, stroke gives no warning symptoms; the disease attack you suddenly, leaving no time to see a health care provider. In some cases, however, symptoms occur.
It is crucial to know the signs and symptoms of stroke because they appear suddenly and can precede a stroke attack of a few minutes, hours or rarely days. It is important to recognize the five main symptoms of a stroke to seek medical help immediately. The five main stroke symptoms are:
- Dizziness accompanied by loss of balance or coordination
- Paralysis or sudden numbness of your face, leg or an arm (usually on one side of the body)
- Sudden and unusual headache that occur without apparent cause
- Sudden onset of a speech disorder or difficulty understanding others
- Sudden loss of vision in one eye or rarely in both eyes.
A stroke is a serious medical condition and may lead to coma or irreversible immobility. You can also develop a depression which can be accompanied by an inability to control your feelings. Therefore, if you have a stroke attack, every second counts. It is extremely important to see a health care provider as soon as possible to increase your recovery or survival chances.
If you have already major symptoms of stroke, your doctor will seek to know your medical history and recent events related to these symptoms. In addition to physical examination and neurological examination, other tests will be performed to confirm the diagnosis.
Computerized tomography (CT) – a brain scan can be performed to distinguish between ischemic stroke and hemorrhagic stroke. This identification is very important to determine the type of treatment you will be recommended to follow. In addition, the Ct scanning can help your health care provider to detect early signs of cerebral ischemia, restriction of blood flow to a part of your brain.
MRI (magnetic resonance imaging) – MRI is an important tool in the diagnosis of stroke. It helps identify small infarction that may be unnoticed to the scanner. It allows your doctor to locate, in the brain, infectious or inflammatory lesions, abnormal vessels and tumors. In addition, MRI allows your physician to precisely detect other arterial anomalies in your brain, spine, neck, joints and soft tissues.
Cerebral Arteriography – this exam is performed after an intra-arterial injection of a dye in the arteries providing blood and oxygen to your brain. During the procedure, the doctor will insert a thin catheter into an artery at the top of your thigh or groin. The exam allows your physician to examine blood circulation in the arteries in your neck and brain. The injection of the dye may give you a headache or flushing of one side of your face.
Angiography – This imaging medical technique is used to study your blood vessels that are not visible on standard x-rays. In General, angiography is done on an empty stomach.
Carotid ultrasound – this exam is sometimes recommended to evaluate the circulation of blood in the vessels of your neck and brain, it allows your doctor to detect, if there is any, arterial blockage.
Other exams – in addition, your physician may also recommend a chest x-ray and echocardiogram (ultrasound) to confirm the diagnosis.
It is very important to recognize the signs and symptoms of stroke to seek medical help immediately:
When it comes to stroke, it is crucial to seek medical support as soon as you can; don’t try home remedies. In addition, before under control of a health care provider, avoid taking any dose of aspirin; this could worsen the problem if you have hemorrhagic stroke. Aspirin has blood-thinning effect; it is harmful in hemorrhagic, but useful in Ischemic stroke. That is, if you are sure you have ischemic stroke, you can take a dose of aspirin before seeing your doctor. All stroke attacks should be treated immediate to avoid brain damage and facilitate your recovery.
Visiting an emergency room immediately when you experience symptoms of a stroke is crucial because there are treatments that can dissolve clots (thrombolysis), and restore blood flow in the brain and prevent further brain damage or recurrent stroke. Most common blood-thinning drugs used in stroke treatment include aspirin, warfarin (Coumadin) and heparin.
The treatment differs depending on the type of stroke you have:
Thrombolytic agents – those substances are used are to dissolve clot and unblock clogged vesselsto restore normal blood flow. In addition, thrombolytic agents are used to prevent the progression of brain damage. These drugs can be administered within 3 hours after onset of symptoms and are administered intravenously by a health care specialist. One of the most common clot-dissolving medicines used in the US is tissue plasminogen activator (tPA).
Tissue plasminogen activator (t-PA) – tissue plasminogen activator (t-PA) is a very effective medication in the treatment of ischemic stroke. It is used to dissolve blood clot and allows normal circulation of blood and oxygen to the brain tissue. For better results, t-PA should be used within 3 hours of the stroke attack. In fact, some patients are completely recovered after taking the drug.
This drug has been available for about ten years, but it represents a significant progress in the fight against ischemic stroke; t-PA reduces mortality from stroke significantly. However, tPA is not recommended in the treatment of hemorrhagic stroke.
Depending on the severity of the disease, or if the t-PA does bring a positive result, your doctor can perform a carotid Endarterectomy (surgery on an artery of your neck to restore proper blood flow to your brain) or angioplasty (a medical procedure to restore blood flow through your artery that has been blocked by a clot).
Carotid Endarterectomy – surgery on an artery of your neck to restore proper blood flow to your brain
Angioplasty – medical procedure to restore blood flow through your artery that has been blocked by a clot.
Surgery is performed to treat hemorrhagic stroke or prevent another attack. Usually, your surgeon will recommend aneurysm clipping or aneurysm embolization.
Aneurysm clipping – this surgical procedure is performed by placing a tiny clamp at the aneurysm, abnormal widening or ballooning of a segment of a blood vessel
Aneurysm embolization – embolization is performed as an alternative to surgery. During the procedure, a neurointerventional radiologist makes a small incision in your groin through which he/she enters a tiny catheter and pushes it through your femoral artery into your brain vessels. He/she fills the dilated segment of the artery, which makes blood flow into the aneurysm sac become difficult.
Useful tips to reduce the risk of occurrence or recurrence of stroke:
- Quit smoking
- Exercise regularly
- Avoid or reduce alcohol consumption
- Eat a have a healthy diet
- Avoid saturated ats and processed foods
- Avoid stress and depression
- Control your blood pressure by exercising and taking your medication as recommended by your doctor and pharmacist
- Monitor your blood sugar regularly if you are diabetic
- Take your medication as prescribed by your doctor and pharmacist if you suffer from congestive heart failure or atrial fibrillation.
1 – GBD 2013 Mortality and Causes of Death, Collaborators (17 December 2014). “Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013.”. Lancet 385: 117–71. doi:10.1016/S0140-6736(14)61682-2. PMC 4340604. PMID 25530442.
2 – Feigin VL, Rinkel GJ, Lawes CM, Algra A, Bennett DA, van Gijn J, Anderson CS (2005). “Risk factors for subarachnoid hemorrhage: an updated systematic review of epidemiological studies”. Stroke 36 (12): 2773–80. doi:10.1161/01.STR.0000190838.02954.e8. PMID 16282541.
5 – Shuaib A, Hachinski VC (September 1991). “Mechanisms and management of stroke in the elderly”. CMAJ 145 (5): 433–43. PMC 1335826. PMID 1878825.
7 – Adams HP, Bendixen BH, Kappelle LJ, Biller J, Love BB, Gordon DL, Marsh EE (January 1993). “Classification of subtype of acute ischemic stroke. Definitions for use in a multicenter clinical trial. TOAST. Trial of Org 10172 in Acute Stroke Treatment”. Stroke 24 (1): 35–41. doi:10.1161/01.STR.24.1.35. PMID 7678184.
8 – Osterweil,, Neil. “Methamphetamine induced ischemic strokes”. Medpagetoday. Retrieved 24 August 2013.
10 – National Institute for Health and Clinical Excellence. Clinical guideline 68: Stroke. London, 2008.
11 – Nor AM, Davis J, Sen B, Shipsey D, Louw SJ, Dyker AG, Davis M, Ford GA (November 2005). “The Recognition of Stroke in the Emergency Room (ROSIER) scale: development and validation of a stroke recognition instrument”. Lancet Neurology 4 (11): 727–34. doi:10.1016/S1474-4422(05)70201-5. PMID 16239179
12 – National Institute of Neurological Disorders and Stroke (NINDS) (1999). “Stroke: Hope Through Research”. National Institutes of Health
13 – Miwa K, Hoshi T, Hougaku H, Tanaka M, Furukado S, Abe Y, Okazaki S, Sakaguchi M, Sakoda S, Kitagawa K (2010). “Silent cerebral infarction is associated with incident stroke and TIA independent of carotid intima-media thickness”. Intern. Med. 49 (9): 817–22. doi:10.2169/internalmedicine.49.3211. PMID 20453400.
14 – Herderscheê D, Hijdra A, Algra A, Koudstaal PJ, Kappelle LJ, van Gijn J (September 1992). “Silent stroke in patients with transient ischemic attack or minor ischemic stroke. The Dutch TIA Trial Study Group”. Stroke 23 (9): 1220–4. doi:10.1161/01.STR.23.9.1220. PMID 1519274
15 – Vermeer SE, Koudstaal PJ, Oudkerk M, Hofman A, Breteler MM (January 2002). “Prevalence and risk factors of silent brain infarcts in the population-based Rotterdam Scan Study”. Stroke 33 (1): 21–5. doi:10.1161/hs0102.101629. PMID 11779883
16 – Wardlaw JM, Murray V, Berge E, del Zoppo G, Sandercock P, Lindley RL, Cohen G (May 23, 2012). “Recombinant tissue plasminogen activator for acute ischaemic stroke: an updated systematic review and meta-analysis”. Lancet. Online first (9834): 2364–72. doi:10.1016/S0140-6736(12)60738-7. PMC 3386494. PMID 22632907