Stroke Cerebral Infarct
Stroke or cerebral infarct
Stroke or cerebrovascular disease or brain attack, is widely prevalent and the second leading cause of death and disability all over the world. Characterized by sudden lack of brain functions it may manifest in many different ways depending on the area of the brain affected. Usually due to lack of blood supply or ischemia most of the times, it can also present due to bleeding into the brain or hemorrhage with loss of normal brain function.
Ischemic strokes account for the vast majority of strokes, almost 70-80% while hemorrhagic strokes account for 20-30% of the strokes.
When the stroke affects the motor area in the brain, symptoms include weakness, incoordination and inability to move arms or legs, facial weakness manifested by drooping or drooling, and slurring of speech or inability to swallow. When the sensory areas are affected numbness, or tingling can occur. When the temporal lobe or speech area is affected difficulty understanding and difficulty producing speech may be prominent especially if the stroke affects the left / dominant hemisphere of the brain. Even left handed people mostly tend to have left hemisphere dominance in regards to language functions. If the posterior part of the brain or occipital lobes are affected partial vision loss and confusion can occur. A simple test to assess stroke symptoms consists of the acronym FAST : face, arm, speech and time (time is of the essence when treatment is considered).
Risk factors for ischemic stroke include high cholesterol, smoking, high blood pressure, diabetes, arrhythmias - atrial fibrillation, sleep apnea, obesity, inactivity, inflammatory conditions, hormone replacement, birth control pills, migraines, etc.
Ischemic strokes can be due to either due to clots migrating from the heart or aorta (embolic type) or due to large or small vessel narrowing due to cholesterol plaques (atherothrombotic type). If a small vessel is affected then usually a small area of brain is affected and is better known as a lacunar stroke. When a large vessel or large clot related blockage occurs a larger wedge shaped area of brain can be affected or cortical stroke. Embolic strokes can occur in multiple vessel territories and can present with confusing array of symptoms. If a large vessel stroke occurs it is usually in the same vascular territory.
There are three main neck vessels supplying the brain. The cartotid arteries on each side and the basilar artery ( which arises from the confluence of two vertebral arteries) at the back. These join and form a circle of vessels known as the circle of willis. This circle then branches to three vessels, anterior cerebral, middle cerebral and posterior cerebral arteries, one of each for each side of the brain. The circle of willis provides redundancy in case one of the neck vessels get blocked.
Hemorrhagic strokes can be of several types too depending on the location of the bleed. If over the covering of the brain (dura) the bleed is an epidural bleed. If below the dura but outside the brain parenchyma it is a subdural bleed. If it is between the folds of the brain surface it is a subarachnoid hemorrhage SAH- usually due to aneurysmal bleeds. If it is inside the brain then it is an intracerebral hemorrhage or lobar hemorrhage. If inside the ventricles it is an intraventricular bleed and so on. Most bleeds are due to high blood pressure peaks. Other causes would include trauma, blood thinners, and occasionally abnormalities in the blood vessel walls including aneurysms, arteriovenous malformations, etc.
Diagnosis is made with the help of a clinical examination by a physician and or neurologist with ancillary testing. Many stroke mimics exist including hypoglycemia, fainting episodes, seizures, migraines, and multiple sclerosis to name a few common ones.
Testing
In addition to initial blood glucose levels, lipid panels, EKGs, and bedside examinations, the most important immediate test is a CT scan of the brain without contrast. This allows for determination if there is a bleed. If absent this excludes a hemorrhagic stroke but not an ischemic or embolic one since the changes in the brain can take upto 12 hours before this becomes apparent on a CT. Further detailed imaging techniques to look at the blood vessels include CT angiography and CT perfusion imaging to assess areas with poor blood flow.
MRI brain imaging is reserved for non emergent evaluation once treatment has been initiated to further confirm the presence of a stroke and to help localize the area of brain involvement. MR Angiography can also help display vessel anatomy of the head and neck.
Additonal evaluation often time includes an Echocardiogram either transthoracic or transesophageal TEE to evaluate the heart function, valves and any clots or shunts ( Atrial septal defects, patent foramen ovale and rarely pulmonary arteriovenous malformations or AVMs) that may have caused the stroke. In addition a Carotid ultrasound can help screen any narrowing or blockages of the main neck vessels. Loop recorders, holters and King of Heart Monitors are helpful in monitoring the cardiac rhythm to capture and episodes of atrial fibrillation a condition notorious for developing cardiac clots.
Treatment
For hemorrhagic strokes, it is important to immediately
-control any high blood pressure, and
-evaluate for any platelet deficiencies, and any clotting abnormalities that may need immediate medications to reverse these effects.
-Platelet transfusions to help fix platelet abnormalities and fresh frozen plasma, cryoprecipitates and other prothrombin complex concentrates are available to help in stopping the bleed.
-Neurosurgery consultants make decisions on whether any surgical procedures can help relieve the compression, either craniectomy or burr hole drainage or ventriculostomy drains to help relieve the cerebrospinal fluid flow related pressure build up. If an aneurysm or AVM is found then endovascular and or neurosurgical procedures can be performed to coil or clip the aneurysm respectively, embolize and resect the AVMs respectively. These procedures are risky and at times deferred if the patient is already showing signs of severe brain damage or herniation (a condition when the brain swelling pushes the brain down through the foramen magnum leading to irreversible brainstem damage). ICP monitors and medications to help lower the intracranial pressures ICP may be of limited help too. Nimodipine is helpful in stopping vasospasm in subarachnoid hemorrhage SAH patients.
If the stroke is non hemorrhagic or ischemic this raises the possibility of breaking down the clot if the patient is within 3hrs of symptom onset, provided the patient was seen to be normally functioning within 3 hrs (please note the time of going to sleep is regarded as the onset time if someone wakes up with the symptoms). For those less than 80 and without diabetes or prior strokes and not on anticoagulants a 4.5hr window may apply. If all criteria are met then intravenous or IV TPA or Tissue plasminogen activator may be an option. If this does not help and a large vessel blockage is noted then endovascular therapy in select centers is a consideration with use of catheters (MERCI, Penumbra devices) to pull out or dislodge the clot or with TPA injected into the clot area or intraarterial IA TPA. Side effects of TPA include the risk of bleeding and possible death in approx 1 out of 20 patients given the medication per large studies. One third more patients make a near normal recovery when given the TPA vs not giving it.
If however the presentation to the ER is out of the TPA window then an antiplatelet medication such as Aspirin or Plavix and IV fluids and BP management, with careful monitoring for deleterious effects of stroke including but not limited to the prevention of DVTs deep vein thrombosis, protecting against aspiration pneumonia and bed sores, etc are key to a quicker recovery. Rarely tracheostomy and PEG percutaneous enterogastrostomy tube feeding is employed for severe stroke patients if ascertained that they may have a chance at meaningful recovery.
In young otherwise healthy patients with strokes, it is important to look deeper into the etiology. Blood tests for a hypercoagulable states are undertaken, Loop recorders to assess any underlying atrial fibrillation, TEEs are done in some cases to assess cardiac sources of clots, or patent foramen ovales PFOs or septal defects and additional vascular imaging is undertaken to assess if there are abnormalities of the vessel walls such as vasculitis, fibromyalgia, moya moya, etc. Sickle cell disease, drug and cocaine use, and inflammatory conditions, infective endocarditis, etc are some of the commoner causes of stroke in the young.
For prevention of stroke antiplatelet agents are employed, either Aspirin or plavix (clopidogrel) or aggrenox ( ASA and XR dipyridamole). A statin or cholesterol lowering agent is also very helpful in preventing further strokes or cerebral infarcts. If Atrial fibrillation is detected an anticoagulant or blood thinner such as Coumadin, pradaxa, xarelto, eliquis is necessary to avoid clot development. Management addressing all risk factors including high cholesterol, smoking, high blood pressures, diabetes, sleep apnea, obesity, inactivity, etc is very important.
Tips for Stroke
Healthy activity and workouts. Get on a Stationary Exercise Bike
Healthy Diet
Healthy sleep, including assessing for sleep apnea. Consider a
Weight loss and maintenance of appropriate body weight
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Management of all underlying risk factors
Smoking cessation
Antiplatelet therapy with Aspirin, plavix (clopidogrel), aggrenox, etc
King of Heart Monitor or Loop recorder testing to assess any occult atrial fibrillation that can cause strokes and requires long term anticoagulation with Coumadin, pradaxa, xarelto, eliquis, etc.
Regular check ups
Avoiding excess alcohol use
And finally treating any inflammatory conditions, gout, etc are important in prevention of stroke.
Following a stroke, speech and physical therapy is imperative.
Botox and baclofen may help those with increased body tone or spasticity post stroke.
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