Stroke

What is a stroke?

Neurologic deficit lasting greater than 24 hours caused by reduced blood flow (cerebral infarction).

What is a transient ischemic attack (TIA)?

Neurologic deficit lasting less than 24 hours (cerebral ischemia).

What are the risk factors for a stroke?

Hypertension (#1)

A-fib

Carotid stenosis

Smoking

Diabetes

Male sex

Estrogen supplementation

Hyperlipidemia

Obesity

Overuse of EtO and drugs.

What are the 2 types of stroke?

Ischemic (more common, 84%) and hemorrhagic (other 16%)

What are the 3 subtypes of ischemic stroke?

Atherosclerotic, cardioembolic and small vessel disease.

What are the 5 major arteries of the brain?

Anterior cerebral artery (ACA), middle cerebral artery (MCA), posterior cerebral artery (PCA), internal carotid artery (ICA) and common carotid artery (CCA)

The frontal lobe receives blood from which arteries?

ACA and MCA.

What areas of the brain does the PCA cover?

Parietal and occipital lobes. A stroke here can cause issues with vision loss, and association zones with understanding speech.

What are Lenticulostriate arteries?

Perforating arteries that go towards the middle of the brain (towards the thalamus and smaller parts of the brain). This is what causes lacunar strokes!

What causes watershed strokes?

Hypotension! These areas are at the ends of 2 arteries so they are vulnerable already to low blood flow so hypotension makes it worse.

What is the number 1 cause of stroke?

Atherosclerosis. Mural thrombus forms at the site of a plaque and obstructs. Plaque rupture leads to clot with embolization downstream.

How does the time of plaque/clot development impact the stroke?

If plaque/clot takes a long time to develop, the brain can form collateral circulation, which means the effects won't be as intense. But if it is ACUTE formation, there's no time for collateral circulation so effects are worse.

What do distal obstructions tend to lack?

Collateral flow.

What are causes of cardiac emboli?

Wall motion abnormalities (dyskinetic myocardium)

Alcoholic cardiomyopathy

Valvular heart disease

Bacterial endocarditis

SLE endocarditis

Prosthetic valves

A-fib

Paradoxical embolus from a R-L shunt (patent foramen ovale)

What is internal carotid artery disease?

Most plaques develop here, a very proximal region. There is a lack of collateral flow from the circle of Willis (which causes the symptoms)

What causes ICA disease?

Long history of smoking, HTN, DM.

What can occur in transient ICA disease?

Monocular blindness (amaurosis fugax), like a curtain coming over the eye. Usually improves.

What are the clinical manifestations of an ACA stroke?

UMN weakness (leg > arm)

Neglect

Urinary incontinence

Abulia

Lack of verbal fluency but preserved ability to repeat

What are the phyiscal findings in an ACA stroke?

Frontal signs (rooting reflex, grasp reflex, perseveration)

UMN signs!

What are the classifications of a MCA stroke?

Can be proximal or distal (proximal is worse!)

Can be dominant or non-dominant. Dependent on handedness and determines how much function will be retained after stroke.

Which part of the MCA corresponds to Broca's area?

Superior MCA.

Which part of the MCA corresponds to Wernicke's area?

Inferior MCA.

What are the clinical manifestations of a proximal dominant MCA stroke?

Global aphasia

Contralateral weakness (arm > leg)

Dysphagia

Hemisensory loss

What are the clinical manifestations of a distal dominant MCA stroke?

Upper branch: Broca's aphasia

Lower branch: Wernicke's aphasia

What are the clinical manifestations of a non-dominant MCA stroke?

Visual-spatial neglect

Anosognosia (can't recognize faces)

Spatial disorientation

Apraxia

Hemi-neglect could also happen.

How common is a PCA stroke?

Only 5-10% of ischemic strokes.

What are the visual effects that occur after a PCA stroke?

Visual field loss: hemianopsia (unilateral) or cortical blindness (bilateral)

Visual agnosia (cannot recognize items by sight but can by other senses)

Balint's syndrome (visual simultagnosia, optic ataxia and apraxia of gaze)

Prosopagnosia

Dyslexia

Hemiachromatopsia (unilateral color blindness)

What are the cognitive, motor and sensory effects that occur after a PCA stroke?

Memory problems

Contralateral hemiparesis

Thalamic involvement: hemisensory loss or Dejerine-Roussy (thalamic pain syndrome)

What is the vertebrobasilar arterial system?

It perfuses the medulla, cerebellum, pons, midbrain, thalamus and occipital cortex. Occlusion of the large vessels here usually leads to major disability or death.

What are effects of a vertebrobasilar stroke?

The further down the stroke happens, the worse the effect!

Patients will walk around like they're drunk.

Crossed syndromes: contralateral motor and ipsilateral sensory loss.

Quadriplegia

Hemiplegia

Ataxia

Dysphagia

Dysarthria

Gaze abnormalities

Cranial neuropathies

LOCKED IN SYNDROME!

What can vertebrobasilar strokes be mistaked for?

Vertigo, or something in the ears. Always look at history and have this in your differential!! Don't miss a stroke!!!

What is small vessel disease also known as?

Lacunar stroke

What causes a lacune?

An occlusion of a single, deep penetrating artery generated by a specific vascular pathology. They occur most frequently in the basal ganglia and internal capsule, thalamus, corona radiata and pons.

What are the risk factors for a lacunar stroke?

DM, HTN, obesity, hyperlipidemia

What can an accumulation of lacunar strokes lead to?

Small vessel dementia.

What are the effects of a lacunar stroke?

Pure motor loss (contralateral hemiparesis)

Pure contralateral hemi-sensory loss

Sensorimotor

Clumsy-hand dysarthria

Prognosis is usually good.

What is included in the workup of ischemic strokes?

Plain head CTs (to look for limit of stroke and rule out hemorrhagic, SUPER IMPORTANT!)

Serial head CTs

MRI if aneurysm suspect

EKG and telemetry (if a-fib suspected)

What are some labs to order in a workup of ischemic stroke?

PT, INR, PTT (especially if giving tPA)

Random blood glucose (SUPER IMPORTANT! hypoglycemia can cause stroke)

Cardiac isoenzymes (concurrent MI possible)

VDRL, RPR if you suspect syphillis

Collagen vascular tests (in select patients, like young or hx of vascular connective disease)

What are the acute treatment options for ischemic stroke?

Intravenous thrombolysis (IVT) or mechanical endovascular thrombectomy (EVT)

Describe IVT

Give tPA to dissolve clot after getting head CT. Must be administered within 4.5 hours of the first symptom, with a targeted door to needle time of 60 minutes or less.

Describe EVT

Manually extracting the clot. Standard of care for large vessel occlusions, and can be performed up to 6 hours.

When would you give a post-stroke patient anticoagulation treatment?

Not recommended routinely, only if there are high risk factors like: known intra-artial clot, a-fib, mechanical valve with clot, known hypercoagulable state.

Why do you usually not treat high blood pressure in a stroke patient?

You can cause another stroke, like a Watershed stroke. If you treat BP, it must be CRITICAL, you do NOT want to cause hypotension.

What is the long-term therapy for stroke prevention?

Reduce risk factors. You can also get a carotid endarterectomy.

What is a major risk factor for a primary intracerebral hemorrhage?

Hypertension. Also alcoholism, smoking, anticoagulant use.

How do primary intra-cerebral hemorrhages appear in plain head CTs?

Radiodense areas. ALWAYS do a head CT to check for a hemorrhagic stroke!!!!!

Describe a ruptured middle meningeal arterial stroke

Can occur after a blow to the head, like in a bar fight. Patients will lose consciousness, have a short moment of lucidity and then fall back into a coma.

What are subarachnoid hemorrhages known as?

Saccular aneurysms (berry aneurysms).

What are the symptoms of a subarachnoid hemorrhage?

"Worst headache in your life"

Neck rigidity

Photophobia

Fundoscopic exam will show papilledema

What is the workup and treatment for subarachnoid hemorrhage?

Workup: arteriography

Rx: surgery and nimodipine to reduce spasm.