Section 4 - Meninges

Question 1

Why can space-occupying lesions be traumatic?

Answer 1

Meninges are very durable, but increase in brain volume can compress healthy tissue.

Question 2

What is a congenital dermal sinus?

Answer 2

Failure of ectoderm to pinch off from the neuroectoderm and meninges; commonly causes recurrent meningitis

Question 3

What can cause an extradural (epidural) hematoma?

Answer 3

Head trauma - periosteal dura can loosen and damage middle meningeal artery or accessory meningeal artery

Question 4

What happen in an epidural hematoma?

Answer 4

Extravascular blood dissects periosteal dura from skull - epidural hematoma. Looks SHORT AND WIDE.

Question 5

What are symptoms of an epidural hematoma?

Answer 5

• Similar to increase in ICP (headache, disorientation, confusion, lethargy, unresponsiveness)

Question 6

What is Talk and Die syndrome?

Answer 6

Patient is initially rendered unconscious. He/she has a lucid interval (awake and conversant), but then deteriorates and dies suddenly. Happens with EPIDURAL HEMATOMA.

Question 7

What is a dural border / subdural hematoma?

Answer 7

Bleeding below meningeal dura within dural border cell layer (adjacent to arachnoid) –> cell layer splits and creates space at dura-arachnoid interface. LONG AND THIN hematoma.

Question 8

What causes a dural border / subdural hematoma?

Answer 8

Typically, bleeding from a bridging vein passing through subarachnoid space to enter venous sinus.

Question 9

Acute subdural hematoma is caused by:

Chronic subdural hematoma is caused by:

Answer 9

• hemorrhage or contusion

- brain atrophy with chronic bleeds (elderly)

Question 10

What is a hygroma?

Answer 10

Tearing of arachnoid membrane due to skull trauma causes the CSF to dissect and open dural border cell layer

Question 11

What causes a subdural hematoma?

Answer 11

Head trauma shifts the brain enough to tear a large vein before in enters the sinus OR hemorrhage of vessels within the subarachnoid space.
- Blood can migrate to cisterns or outline brain divisions or dural reflections

Question 12

What is the main sign of a subarachnoid hematoma?

Answer 12

Blood in the CSF

Question 13

A nontraumatic or spontaneous subarachnoid hemorrhage is caused by:

Answer 13

Rupture of intracranial aneurysm

Question 14

A primary aneurysm is:

A secondary aneurysm is:

Answer 14

• one dilated from birth

- one dilated by systemic problems (hypertension)

Question 15

List symptoms of aneurysm rupture:

Answer 15

• THUNDERCLAP HEADACHE
• neck stiffness
• vomiting/nausea
• depression
• loss of consciousness

Question 16

List warning signs of an impending subarachnoid hemorrhage (leaking aneurysm):

Answer 16

• Intermittent headache
• Nausea/vomiting
• Fainting spells (syncope)

Question 17

What is a duret hemorrhage?

Answer 17

Small, linear bleeding in ventral/paramedial brainstem (pons and medulla) from traumatic downward displacement of brainstem.

Question 18

What is a herniation syndrome?

Answer 18

Intracranial event (hemorrhage, rapid tumor growth, traumatic brain injury) that causes increased intracranial pressure by forcing brain over the edge of a dural reflection.

Question 19

Subfalcine or cingulate herniation:

supratentorial

Answer 19

Lesion in one cerebral hemisphere may expand toward midline, deform falx cerebri, force cingulate gyrus under edge of falx into opposite hemisphere

Question 20

Subfalcine/cingulate herniation reflects deficits of ______

Answer 20

Occlusion of anterior cerebral artery

Question 21

Central (transtentorial) herniation:

supratentorial

Answer 21

Diencephalon forced downward through tentorial incisures or notch into the brainstem.

Question 22

Central (transtentorial) herniation causes:

Answer 22

Change in respiration, loss of motor/sensory function, loss of consciousness, 90% serious disability/death. EMERGENCY.

Question 23

Uncal herniation:

supratentorial

Answer 23

Rapidly expanding lesion forces uncus over edge of tentorium cerebelli –> midbrain damage.

Question 24

What are consequences of uncal herniation?

Answer 24

• Decreased level of consciousness
• Dilation of pupil and loss of eye movement (CN III ipsilateral)
• Contralateral hemiplegia (corticospinal fibers)
• Abnormal reflexes

CLINICAL TRIAD:

• unresponsive pupil (CN III)
• Hemiplegia (cerebral peduncles)
• Coma (midbrain reticular formation)

Question 25

Sphenoidal herniation: | supratentorial

Answer 25

Displacement of ventral frontal lobar tissue over sphenoid ridge

Question 26

Subfalcial herniation: | supratentorial

Answer 26

Beneath the falx cerebri, usually of the cingulate gyrus

Question 27

Upward cerebellar herniation: | infratentorial

Answer 27

Pressure increase in posterior fossa forces cerebellum upward through tentorial incisura --> damage midbrain, occlude SCA (infarct cerebellar things), obstruct cerebral aquedect (hydrocephalus)

Question 28

Tonsillar herniation: | infratentorial

Answer 28

Tonsils of cerebellum forced downward (pressure in posterior fossa) through foramen magnum.

Question 29

Effects of tonsillar herniation?

Answer 29

- Pressure on medulla in ventrolateral reticular area --> respiratory/cardiac centers damaged, leading to death (Cheyne-Strokes respiration, hypertension, hyperventilation, loss of consciousness)

Question 30

Closed head injury can cause ______

Answer 30

Concussion/contusion on brain --> momentary loss of consciousness. Brain is on trabecular tethers and can move from sudden blow. Injury either at point of blow or contrecoup.

Question 31

What is a meningioma?

Answer 31

Slow-growing, benign tumor (potentially calcified) that can result from abnormal growth of adjacent bone. Surgical removal preferred.

Question 32

What typically gives rise to meningiomas?

Answer 32

Arachnoid cap cells in the villi along base of skull

Question 33

Neurofibromatosis associated with multiple meningiomas may also have ______

Answer 33

bilateral vestibular schwannomas

Question 34

Symptoms of meningioma:

Answer 34

- CN abnormalities - Edema - Brain structure compression - seizures, personality or behavioral changes, long tract involvement

Question 35

If lumbar cistern not accessible, how can CSF be examine?

Answer 35

Needle insertion through atlantooccipital membrane to cisterna magna.

Question 36

Where does bacterial meningitis normally start? (site of infection)

Answer 36

Subarachnoid space (leptomeningitis for arachnoid and pia; pachymeningitis for dura)

Question 37

Symptoms of acute bacterial meningitis:

Answer 37

- Elevated temp - Fever alternation - Headache - Photophobia - Depressed consciousness - Nuchal rigidity - Increased CSF pressure, cloudy (WBC), increased protin, bacteria - Hydrocephalus

Question 38

Symptoms of chronic bacterial meningitis:

Answer 38

(TB or fungal infection) - Headache - Fever - Irritability - Wakefulness at night

Question 39

What is Kernig's sign?

Answer 39

One of the physically demonstrable symptoms of meningitis is Kernig's sign. Severe stiffness of the hamstrings causes an inability to straighten the leg when the hip is flexed to 90 degrees. (This would hurt me normally, so idk what that says about me).

Question 40

What is Brudzinski's sign?

Answer 40

One of the physically demonstrable symptoms of meningitis is Brudzinski's sign. Severe neck stiffness causes a patient's hips and knees to flex when the neck is flexed.

Question 41

Symptoms of viral meningitis:

Answer 41

- Usually younger patients (no antivirals available) - Fever - Headaches of increasing intensity - Confusion - Altered consciousness - Seizures - Rigidity - Cranial nerve palsies

Question 42

What can lead to arterial blood in the cavernous sinus?

Answer 42

Congenital aneurysm or arteriovenous malformation in internal carotid OR basilar skull fracture can lead to arterial blood in cavernous sinus.

Question 43

What are symptoms of arterial blood in cavernous sinus?

Answer 43

- Venous congestion (chemosis) of the eye - Exophthalmos - Pulsations (pulsating exophthalmos) - Compression of related nerves (3, 4, 6, V1, V2)