NV emergencies and Strokes Flashcards
Stroke mimics (6)
HYPOglycemia Electrolyte imbalance, esp. Na+ Epidural/subdural Hematoma Brain abscess/tumor post-seizure migraine
Stroke prevention
- manage risk factors: high blood pressure, cigarette smoking, atrial fibrillation and physical inactivity.
meds: antiplatelets, anticoagulants, antihypertensives
Define the terms (TIA) (RIND) (CVA) Describe what they mean
“transient ischemic attack (TIA)-,” “reversible ischemic neurologic deficit (RIND)(>24 h, but
Describe the classifications of stroke
TIA
Ischemic(clots)-persistent blockage of blood vessel due to thrombus or embolism (thrombotic,embolic, lacunar types)
Hemorrhagic (bleeds)- rupture of blood vessel (intracerebral and subarachnoid)
etiology, presentation, evaluation, and management of thrombotic stroke
- caused by a cerebral thrombos that develops gradually in a diseased aa and obstructs it
- Risk Factor: atherosclerosis, especially carotid aa and MCA)
- signs/ symptoms develop more gradually than in embolic
- often occur at night and patient awaken with symptoms
ischemic stroke risk factors
HTN A-fib(embolic) atherosclerosis (thromb) sickle cell disease insulin dependent DM high cholesterol
Ischemic stroke symptoms, DX and TX
Symptoms depend on the effected aa:
Unilateral paralysis (weakness, clumsiness, heaviness; most commonly face and hand; affected body side is opposite to the affected artery
language/speech disturbance
monocular blindness; blurred vision in ONE side of the field of vision; nystagmus; involved visual field is opposite to the side of the affected artery
double vision dur to misalignment of the eyes
unilateral numbness
vertigo; imbalance
loss of consciousness
Dx:
CT scan without contrast (differentiate ischemic(dark areas) from hemorrhagic (white areas)
MRI more sensitive to infarcts and identifies them quicker, but takes longer and not suitable;e for emergency)
Acute Intervention:
reopen blocked aa:
-directly removing clot by surgery (up to 8 h)
-THROMBOLYTIC therapy (IV tPA-fibrinolytic therapy) up to 3 h, or 4.5 h in eligible patients(risk of hemorrhage increases with time from onset)-60-70% are more likely to have favorable outcome if done ASAP: time is brain
-risk: the longer the blockage the stronger the blood flow when the blockage removed-risk of reperfusion hemorrhage).
If NOT on tPA-give ASPIRIN, or other antiplatelets (Plavix, Aggrenox; anticoagulation therapy ISN’t useful in acute stroke
prevention of second injury: decompressive craniectomy for large infarcts due to edema;
control BP up to 220/110 to maintain perfusion to minimize damage to ischemic tissues
Lacunar strokes
small vessel strokes, occlusion of arterioles due to small emboli
SUBCORTICAL structures, not cerebral cortex
-symptoms:
focal, contralateral pure motor or pure sensory
-pure motor(internal capsule lesion)
-pure sensory( Thalamus)
ataxic hemiparesis( incoordination ipsilaterally)
Embolic stroke
- VERY RAPID onset
- caused by solid, liquid or gaseous mass carried to a vessel from another area, most often blood clots
- Risk factor: A-fib(arrhythmia that can lead to blood clots, stroke, heart failure; the atria beat irregularly instead of beating effectively to move blood into the ventricles. It allows blood to slow down or pool and increases the risk of clotting, and so increases the risk of stroke) + damaged carotid and veretebral aa
- sudden onset and rarely accompanied by headache
- anticoag better than antiplatelet
Thrombolytic therapy
THROMBOLYTIC therapy (IV tPA-fibrinolytic therapy) up to 3 h, or 4.5 h in eligible patients(risk of hemorrhage increases with time from onset)-60-70% are more likely to have favorable outcome if done ASAP. contraindications: uncontrolled HTN, bleeding disorder, on anticoagulants, recent trauma or surgery, IRN >1.7
ICH
intracerebral (within brain)- ICH, ⅓ will survive, only 20% will gain functional independence
rupture of vessels within brain tissue – outflow of blood into brain tissue, increased ICP that causes damage to the brain tissue, often tears and separates brain tissue
Etiology: hypertension; amyloid angiopathy (proteins called amyloid build up on the walls of the arteries in the brain)anticoag therapy
most common locations for hypertensive ICH: pons, BG, thalamus, cerebellum; CT= acute blood is white; for amyloid: lobar, peripheral)
Symptoms:
SUDDEN Onset
severe HEADACHE;
HTN
altered mental status
high ICP causes nausea, vomiting, headache, somnolensce, syncope
seizure
focus neurological deficits corresponding to the site of bleed
Dx: CT or MRI to differentiate ischemic from ICH; MRI shows HYPOintensity (BLACK) in the area of bleed, CT shows HYPERdensity (WHITE)
supportive care, BP as low as can tolerate
SAH
subarachnoid ( fluid filled spaces around blood vessels outside brain, bifurcations of aa in the circle of Willis)
Risk factors: head trauma or congenital abnormalities (HTN and aneurism;polycystic kidney disease; smoking, HTN
blood in subarachnoid space impairs drainage of CSF and causes rise in intracranial pressure- HERNIATION of brain tissue may occur
most disability due to cognitive/emotional problems
symptoms:
asymptomatic until aneurism ruptures
SUDDEN SEVERE headache, neck stiffness
syncope, nausea and vomiting
often no focal neurological findings
DX:
CT head FIRST!= HYPERdense blood in subarachnoid space
Lumbar Puncture: (Blood or xantocromia in CSF= SAH)
Intervention:
clipping/coiling of aneurism
control ICP and BP(low)obstruction of CSF flow can be fatal, so venriculostomy used to divert CSF
late complication: vasospasm, prevented with Ca channel blockers
Brain stem stroke
A person may have vertigo, dizziness and severe imbalance without the hallmark of most strokes – weakness on one side of the body. The symptoms of vertigo dizziness or imbalance usually occur together; dizziness alone is not a sign of stroke. Brain stem stroke can also cause double vision, slurred speech and decreased level of consciousness.
Only a half-inch in diameter, the brain stem controls all basic activities of the central nervous system: consciousness, blood pressure, and breathing. All of the motor control for the body flows through it. Brain stem strokes can impair any or all of these functions.
More severe brain stem strokes can cause locked-in syndrome, a condition in which survivors can move only their eyes.
Discuss the indications and contraindications of anticoagulant therapy with heparin or warfarin
(Coumadin) in the treatment of ischemic infarct strokes.
Anticoagulants, such as warfarin (Coumadin) and heparin, slow clot formation by competing with Vitamin K. This inhibits the circulation of certain clotting factors with the exotic names of factors II, VII, IX and X.Advantages:
Anticoagulants are considered more aggressive drugs than antiplatelets. They are recommended primarily for people with a high risk of stroke and people with atrial fibrillation. Although anticoagulants tend to be more effective for AF patients, they are generally recommended only for patients with strokes caused by clots originating in the heart. Anticoagulants tend to be more expensive and carry a higher risk of serious side effects, including bruising and skin rash and bleeding in the brain, stomach and intestines.
Disadvantages:.
In comparison to antiplatelets, anticoagulants tend to be affected more by other drugs, vitamins and even certain foods, making anticoagulant therapy somewhat troublesome for stroke survivors. Because warfarin competes with Vitamin K, patients taking it should consult their doctors about possible dietary restrictions, as even some vegetables might cause an imbalance if eaten in excess.. Many prescription drugs make warfarin either stronger or weaker.
Anticoagulant therapy with warfarin also requires regular blood tests to ensure the correct drug dose. A weak dosage increases the risk of stroke and heart attack, but too much puts someone at risk for bleeding. Generic brands may not be the same strength as the one prescribed by your doctor.
Compare and contrast various anti-platelet agents (aspirin, dipyridamole, ticlopidine) for
efficacy as primary or secondary prophylaxis for ischemic infarct strokes stroke.
Antiplatelet agents, including aspirin, clopidogrel, dipyridamole and ticlopidine, work by inhibiting the production of thromboxane. Aspirin is highly recommended for preventing a first stroke, but it and other antiplatelets also have an important role in preventing recurrent strokes.
According to a statement by the American Heart Association, taking aspirin within two days of an ischemic stroke reduces the severity of the stroke. In some cases, it prevents death. For long-term (meaning for the rest of your life unless otherwise specified by your physician) prevention, antiplatelet therapy is recommended primarily for people who have had a transient ischemic attack (TIA or “mini” stroke) or acute ischemic stroke.
Despite the potential benefits, antiplatelet therapy is not for everyone. People with a history of liver or kidney disease, gastrointestinal disease or peptic ulcers, high blood pressure, bleeding disorders or asthma may not be able to take aspirin or may require special dosage adjustments.
