Ch 1: Clinical Correlates pg 20-25

Question 1

what is clinically important about the dural venous sinuses?

Answer 1

most of the cerebral venous blood collects in the dural sinuses and drains into the internal jugular veins

also the site of resorption of CSF from subarachnoid space through arachnoid granulations that protrude into sinuses

Question 2

how can skull trauma cause a subdural hematoma?

Answer 2

can cause shearing of bridging veins (cerebral veins that drain into dural sinuses and transverse the subdural space)–>venous blood may accumulate in the subdural space–>subdural hematoma

Question 3

how will a subdural hematoma look on a CT scan?

Answer 3

crescent-shaped hematoma

• venous blood supply is slowly accumulating

Question 4

how can skull trauma cause an epidural hematoma?

Answer 4

may lacerate a middle meningeal artery

Question 5

what will a hematoma caused by a lacerated middle meningeal artery look like?

Answer 5

biconvex, lens-shaped epidural hematoma

Question 6

an epidural or subdural hematoma can compress part of the brain and cause….

Answer 6

tentorial herniation, tonsillar herniation, or subfalcine herniation

Question 7

what is a tentorial herniation and what symptoms may be seen?

Answer 7

• uncus (medial part of temporal lobe) herniates through the tentorial notch of the dura and compresses the brainstem
• PCA may also be compressed
• contralateral hemiparesis, dilated/blown pupil (compression of CN III), deterioration of cardiovascular and respiratory functions (–>coma)

Question 8

what is kernohan’s phenomenon?

Answer 8

brainstem is compressed against opposite side of the tentorial notch–>hemiparesis that is ipsilateral to the herniation (85% have compressed ocular nerve compression)

Question 9

what is tonsilar herniation ad what symptoms may be seen?

Answer 9

• tonsil of cerebellum herniates inferiorly toward the foramen magnum and compresses the medulla
• respiratory compromise and death

Question 10

what is subfalcine herniation?

Answer 10

cingulate gyrus herniates medially under the falx cerebri (fold of meningeal dura in the interhemispheric sulcus) and may compress an ACA

Question 11

what connects the lateral ventricles to the third ventricles?

Answer 11

interventricular foramen of Monro

Question 12

what connects the third ventricles to the 4th ventricles?

Answer 12

cerebral aqueduct

Question 13

where do CSF exit the ventricles?

Answer 13

only the 4th ventricle contains openings where CSF can exit and enter the subarachnoid space

Question 14

what is hydrocephalus?

Answer 14

increase in the volume of CSF–>dilation of 1 or more ventricles

Question 15

what causes a communicating hydrocephalus?

Answer 15

impaired adsorption of CSF at the arachnoid granulations or a tumor in the subarachnoid space that impedes CSF flow–>inc volume of CSF in ventricles and subarachnoid space

Question 16

what causes a normal pressure hydrocephalus? who is it most commonly found in? what symp are seen?

Answer 16

form of communicating hydrocephalus that is common in elderly and also caused by impaired adsorption–>chronically enlarged ventricles

mental decline, urinary incontinence, abnormal gait (wacky, wet, wobbly)=apraxic gait (no weakness but patient shuffles)

Question 17

what causes noncommunicating hydrocephalus? where in the ventricular system does it commonly occur?

Answer 17

obstruction to CSF flow inside the ventricular system

• common in cerebral aqueduct of infants
• also intraventricular foramen or 4th ventricles foramens

Question 18

what is hydrocephalus ex cavuo?

Answer 18

increase in ventricular size and an increase in the volume of CSF secondary to a pathological loss of brain tissue

Question 19

in MS and inflammatory CNS disease, what chemical composition changes are seen in CSF?

Answer 19

oligoclonal immunoglobulin bands are detected

Question 20

in acute bacterial infections and meningeal tumors what chemical composition changes are seen in CSF?

Answer 20

decrease in glucose concentration

Question 21

in patients with bacterial meningitis, what changes in the CSF are seen?

Answer 21

WBC elevated (>4000/mm^3)

Question 22

in patients with subarachnoid hemorrhage or bloody lumbar puncture, what changes in CSF are seen?

Answer 22

RBC present

Question 23

what can increase intracranial CSF pressure?

Answer 23

• space occupying lesion in skull or vertebral canal such as tumors, hematomas, or hemorhages from vascular disease/trauma, abcesses and AVMs
• CSF 200-600 mm H2O

Question 24

what are signs of increased intracranial pressure?

Answer 24

• headaches, mental status changes with altered level of consciousness, papilledema, projectile vomiting
• Cushing’s triad: hypertension, bradycardia, irregular respirations