Exam 3

Meninges - Dura mater

Tough fibrous layer under the skull; like canvas.

Meninges - Arachnoid

Thin, transparent layer

Meninges - Pia Mater

Closest to brain; covers and adhered to brain surface, extending into sulci; carries blood vessels

Subdural space

Beneath the dura mater

subarachnoid space

blood vessels & CSF

Subdural Hematoma/Hemorrhage (SDH)

Under dura layer but above arachnoid layer

SDH with Brain Herniation

A displacement of brain tissue leading to disfiguring of brain structures.

If left untreated, brain can be pushed down into opening that allows the entrance of brainstem.

Causes of SDH

• Head injury

• Chronic alcohol use

• Very young or very old age

SDH Symptoms

• Unconsciousness

• Lateralizing sign

• Confusion

• Nausea/vomiting

• May be acute (rapid) or chronic (delayed)

Meningitis

• Inflammation of the meninges

• Viral: Usually benign course; full recovery

• Bacterial: much more dangerous course

Meningitis (Common symptoms)

• fever

• headache

• stiff neck

• photophobia (sensitivity to light)

Bacterial Meningitis

• Untreated: results in death

• Evolves rapidly and with loss of consciousness

Ventricles

2 Lateral Ventricles

Third Ventricle

Fourth Ventricle

Ventricles/CSF

Ventricles contain about 20% CSF → The rest flows through subarachnoid space in brain and spinal cord.

Choroid plexus- continually produces CSF (approx. 5 tsp/hour).

CSF flows throughout the ventricular system → drains into large veins at the tom of the head.

CSF Disorder: Hydrocephalus

• Communicating - absorption to veins decreases but flow btwn ventricles is OK

• Noncommunicating - flow is the problem, ventricle blockage, not absorption

Hydrocephalus Treatment

Shunt - catheter emptied into gut

Disorder of Circulation

Cerebrovascular accident (CVA) or Stroke

Major cerebral arteries

Basilar Artery (Posterior circulation)
Internal Carotid arteries (anterior circulation)

Major arteries that enter brain tissue

• Posterior Cerebral Artery (PCA)

• Middle Cerebral Artery (MCA)

• Anterior Cerebral Artery (ACA)

Stroke Warnings

Sudden onset of

• weakness side of body/face

• Numbness on side of body

• Trouble speaking

• Trouble seeing

• Trouble walking, dizziness

Signs are lateralized and affect physical, cognitve, and behavioral functioning.

2 Major Types of CVAs

Obstructive

Hemorrhagic

Obstructive stroke types

Thrombotic- plaque lining wall of artery indicate to platelets to clot.

Embolic - Blood clot forms somewhere else and travels to a smaller artery, blocking it.

Obstructive stroke outcomes

Brain damage lateralized to one hemisphere and can be localized within one hemisphere.

Size and location determine symptoms

Brain damage cause by

• oxygen and glucose deprivation

• Neurotransmitter cascade (Massive NTM release and cells swell then die from excitotoxicity)

Obstructive stroke risk factors

• Age

• High blood pressure

• Diabetes

• High cholesterol

• Smoking

• Prior stroke

Obstructive stroke treatment

No effective treatment

• tPA (Tissue plasminogen Activator)- “clot buster”

• Medical Thrombectomy- mechanically removing the clot through an artery in the groin

Hemorrhagic Strokes

• More dangerous

• Disruption in blood flow

• Increased ICP

Hemorrhagic Strokes (3 types)

• Subarachnoid Hemorrhage (SAH)

• Subdural hemorrhage/hematoma (SDH)

• Intracerebral hemorrhage (ICH)

Subarachnoid Hemorrhage (SAH)

Initial

• HA and/or loss of consciousness

• Nausea and vomiting

Outcome

• 40-50% die within 3 months

• High risk of seizures

Causes of SAH

• Trauma

• Burst aneurysm

Aneurysms

• Occur in up to 5% of population

• 90-95% occur in Circle of Willis

• Asymptomatic until rupture

Aneurysm Treatment

• No acute treatment - general care

• Clipping or coiling/embolization

• Rehabilitation for long term cognitive, physical, and behavioral deficits