Neurovascular disorders

Alexandra Nedelcoff-GhiranlieffErasmus

Content Aneurysms Arteriovenous malformations (AVMs) Carotid cavernous fistulas Carotid, vertebral and cerebral arterial

stenoses Strokes

Aneurysms

1 Classification1.1 Saccular aneurysms1.2 Fusiform aneurysms1.3 Microaneurysms

2 Signs and symptoms2.1 Subarachnoid haemorrhage2.2 Microaneurysms

3 Risk factors3.1 Genetic associations

4 Pathophysiology4.1 Saccular aneurysms

5 Complications5.1 Rupture5.2 Vasospasm

6 Diagnosis7 Treatment

7.1 Surgical clipping7.2 Endovascular coiling7.3 Cerebral bypass surgery

8 Prognosis9 Epidemiology

An  intracranial aneurysm (also

called cerebral or brain aneurysm) is a 

cerebrovascular disorder in which weakness in the wall of a cerebral artery

 or vein causes a localized dilation or

ballooning of the blood vessel.

 Classification

Cerebral aneurysms are classified both by size and shape. Small aneurysms have a diameter of less than 15mm. Larger aneurysms include those classified as large (15 to 25mm), giant (25 to 50mm), and super giant (over 50mm)

Saccular aneurysms Saccular aneurysms, also known as berry aneurysms = round outpouching

- most common form of cerebral aneurysm. Fusiform aneurysms Fusiform dolichoectatic aneurysms = a widening of a segment of an artery

around the entire blood vessel, rather than just arising from a side of an artery's wall.

- usually they do not rupture. Microaneurysms

Microaneurysms, also known as Charcot-Bouchard aneurysms - typically occur in small blood vessels (less than 300 micrometre diameter), most often the lenticulostriate vessels of the basal ganglia, and are associated with chronic hypertension. - common cause of intracranial hemorrhage

 Signs and symptoms

A small, unchanging aneurysm will produce few, if any, symptoms. Before a larger aneurysm ruptures:

- a sudden and unusually severe headache, nausea, vision impairment, vomiting, and loss of consciousness, or the individual may be asymptomatic (i.e., experiencing no symptoms at all)

Subarachnoid haemorrhageIf an aneurysm ruptures, blood leaks into the space around the brain. This is called a subarachnoid hemorrhage. Onset is usually sudden with no prodrome. - classically presenting as a "thunderclap headache" worse than previous headaches. Symptoms of a subarachnoid hemorrhage differ depending on the site and size of the aneurysm:

a sudden severe headache that can last from several hours to days

nausea and vomiting drowsiness, confusion and/or loss of consciousness Visual abnormalities Meningism

Microaneurysms A ruptured microaneurysm may cause an 

intracerebral hemorrhage, presenting as a focal neurological deficit.

Rebleeding, hydrocephalus (the excessive accumulation of cerebrospinal fluid), vasospasm (spasm, or narrowing, of the blood vessels), or multiple aneurysms may also occur. The risk of rupture from an unrruptured cerebral aneurysm varies according to the size of an aneurysm, with the risk rising as the aneurysm size increases.

Risk factors Intracranial aneurysms may result from diseases

acquired during life(hypertension, smoking, excess alcohol consumption, cocaine use, trauma, infections and obesity)

or from genetic conditions: - autosomal dominant polycystic kidney, disease,neurofibromatosis type I,Marfan syndrome, multiple endocrine neoplasia type I, pseudoxanthoma elasticum, hereditary hemorrhagic telangiectasia and Ehlers-Danlos syndrome type II and IV.

Pathophysiology - Saccular aneurysms - lack of tunica media and elastic lamina around

its dilated location (congenital), with wall of sac made up of thickened hyalinized intima and adventitia.

~ 25% patients = multiple aneurysms, predominantly where is familial pattern

affected arteries : Anterior communicating artery, Posterior communicating artery, Middle cerebral artery, Internal carotid artery, Tip of basilar artery

Complications

Rupture

Vasospasm

Diagnosis

angiography,  magnetic resonance imaging,  CT scans, cerebrospinal fluid (CSF) analysis (shows

presence of blood)

Treatment

Surgical clipping Endovascular coiling Cerebral bypass surgery

Epidemiology

incidence = 1 per 10,000 persons in the United States (approximately 27,000 cases a year), with incidence highest in 30-60 year-olds.

occurs more in women, by a ratio of 3 to 2, and are rarely seen in pediatric populations.

Arteriovenous malformation(AVMs)

 an abnormal connection between arteries and veins, bypassing the capillary system.

occurrs in the central nervous system, but can appear in any location. cal problems.

 Although many AVMs are asymptomatic, they can cause intense pain or bleeding or lead to other serious medical problems.

AVMs are usually congenital and belong to the RASopathies. The genetic transmission patterns of AVM, if any, are unknown. AVM is not generally thought to be an inherited disorder, unless in the context of a specific hereditary syndrome.

Diagnosis

Computerized Tomography (CT) , Magnetic Resonance Imaging (MRI)  MRA (Magnetic Resonance Angiogram)

Treatment symptomatic, AVM-specific treatment may also involve

endovascular embolization, neurosurgery or radiation therapy. 

The Spetzler-Martin grading system developed at the Barrow Neurological Institute is utilized by neurosurgeons to determine operative versus nonoperative management of AVMs.

Carotid-cavernous fistula(CCF)

results from an abnormal communication between the arterial and venous systems within thecavernous sinus in the skull. It is a type of arteriovenous fistula.

arterial blood under high pressure enters the cavernous sinus, the normal venous return to the cavernous sinus is impeded and this causes engorgement of the draining veins, manifesting most dramatically as a sudden engorgement and redness of the eye of the same side.

Causes

- closed or penetrating head trauma, surgical damage, rupture of an intracavernous aneurysm, or in association with connective tissue disorders, vascular diseases and dural fistulas.

Classification

Type Description

A Fistulous supply from the internal carotid artery

BSupply from the dural branches of internal carotid artery

C from meningeal branches of ext carotid artery

D combined ICA+ECA

Presentation

 bruit (a humming sound within the skull due to high blood flow through the arteriovenous fistula), progressive visual loss, and pulsatile proptosis or progressive bulging of the eye due to dilatation of the veins draining the eye. Pain is the symptom that patients often find the most difficult to tolerate.

Patients usually present with sudden or insidious onset of redness in one eye, associated with progressive proptosis or bulging.

Diagnosis

CT scans show diffuse enlargement of all the extraocular muscles resulting from venous engorgement and a characteristically enlarged superior ophthalmic vein.

Selective arteriography is used to evaluate arteriovenous fistulas.

Treatment endovascular therapy: transarterial or transvenous . Occasionally: direct transorbital puncture of the cavernous sinus or cannulation

of the draining superior orbital vein are used when conventional approaches are not possible.

Direct CCF may be treated by occlusion of the affected cavernous sinus (coils, balloon, liquid agents), or by reconstruction of the damaged internal carotid artery (stent, coils or liquid agents).

Indirect CCF may be treated by occlusion of the affected cavernous sinus with coils, liquid agents or a combination of both.

Stroke“neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours"

Classification Ischemic Hemorrhagic

Ischemic blood supply is decreased, leading to dysfunction of the brain tissue

in that area. There are four reasons why this might happen: Thrombosis (obstruction of a blood vessel by a blood clot forming

locally) Embolism (obstruction due to an embolus from elsewhere in the

body, see below), Systemic hypoperfusion (general decrease in blood supply, e.g., in 

shock) Venous thrombosis.

Hemorrhagic

Hemorrhagic accumulation of blood anywhere within the

skull vault. A distinction is made between intra-axial hemorrhage(blood inside the brain) and extra-axial hemorrhage (blood inside the skull but outside the brain). Intra-axial hemorrhage is due tointraparenchymal hemorrhage or intraventricular hemorrhage (blood in the ventricular system).

Signs and symptoms

typically start suddenly, seconds to minutes, and in most cases do not progress further.

The symptoms depend on the area of the brain affected. Some forms of stroke can cause additional symptoms. For example, in intracranial hemorrhage, the affected area may compress other structures. Most forms of stroke are not associated with headache, apart from subarachnoid hemorrhage and cerebral venous thrombosis and occasionally intracerebral hemorrhage.

Loss of consciousness, headache, and vomiting hemiplegia and muscle weakness of the face numbness reduction in sensory or vibratory sensation initial flaccidity (hypotonicity), replaced by spasticity

 (hypertonicity), hyperreflexia, and obligatory synergies

altered smell, taste, hearing, or vision (total or partial) drooping of eyelid (ptosis) and weakness of 

ocular muscles decreased reflexes: gag, swallow, pupil reactivity to

light decreased sensation and muscle weakness of the face balance problems and nystagmus altered breathing and heart rate weakness in sternocleidomastoid muscle with inability

to turn head to one side weakness in tongue (inability to protrude and/or move

from side to side)

aphasia (difficulty with verbal expression, auditory comprehension, reading and/or writing Broca's or Wernicke's area typically involved)

dysarthria (motor speech disorder resulting from neurological injury)

apraxia (altered voluntary movements) visual field defect memory deficits (involvement of temporal lobe) hemineglect (involvement of parietal lobe) disorganized thinking, confusion, hypersexual

 gestures (with involvement of frontal lobe) lack of insight of his or her, usually stroke-related,

disability altered walking gait altered movement coordination vertigo and or disequilibrium

Causes Thrombotic stroke Embolic stroke Systemic hypoperfusion Venous thrombosis Intracerebral hemorrhage Silent stroke

PathophysiologyMicrograph showing cortical pseudolaminar necrosis, a finding seen in strokes on 

medical imaging and at autopsy. H&E-LFB stain.

Micrograph of the superficialcerebral cortex showing neuron loss and reactive astrocytes in a person that suffered a stroke. 

H&E-LFB stain.

Diagnosis Physical examination medical history of the symptoms and a neurological status,  NIH stroke scale.

Imaging For diagnosing ischemic stroke in the emergency setting:[42]

CT scans (without contrast enhancements) sensitivity= 16%specificity= 96%MRI scan sensitivity= 83%specificity= 98%For diagnosing

hemorrhagic stroke in the emergency setting: CT scans (without contrast enhancements) sensitivity= 89%specificity= 100%MRI scan sensitivity= 81%specificity= 100%

Risk factors

Blood pressure Atrial fibrillation Blood lipids Diabetes mellitus Anticoagulation drugs Surgery Diet

Management Definitive therapy is aimed at removing the

blockage by breaking the clot down (thrombolysis), or by removing it mechanically (thrombectomy).

Tight control of blood sugars in the first few hours does not improve outcomes and may cause harm. High blood pressure is also not typically lowered as this has not been found to be helpful.

Hemicraniectomy