Hydrocephalus and increased ICP

Question 1

Which structures exert pressure onto the brain?

Answer 1

Brain tissue
CSF
Intracranial circulating blood volume

Question 2

What can physiologically cause the ICP to fluctuate?

Answer 2

Valsalva manouvre

Bending over

Question 3

What is a normal ICP?

Answer 3

7-15 mmHg

Question 4

What are the bodies immediate compensatory mechanisms for increased ICP?

Answer 4

Decrease CSF by moving it out of the foramen magnum

Decrease in blood volume by increasing venous outflow via the sinuses

Question 5

What are the delayed compensatory mechanisms for increased ICP?

Answer 5

Decrease in ECF; brain swelling

Question 6

How is cerebral perfusion pressure calculated?

Answer 6

MAP - ICP

Question 7

What occurs to CPP in hypotension?

Answer 7

CPP will fall

Question 8

What CPP is compatible with consciousness?

Answer 8

20; below this and you will be comatose

Question 9

How is cerebral blood flow autoregulated?

Answer 9

Pressure; arterioles dilate or constrict in response to changes in BP or ICP
Metabolic; arterioles dilate in response to chemicals such as lactic acid or Co2

Question 10

What is the action of CO2 on cerebral blood flow?

Answer 10

Potent dilator
Increased Co2 or increased BP = vasodilation
Decreased CO2 or hypotensive = vasoconstriction

Question 11

What is a short term mechanism for decreasing ICP?

Answer 11

Hyperventilation, blow off Co2 and therefor vasoconstrict the blood vessels

Question 12

What can cause an increased ICP?

Answer 12

Mass effect
Brain swelling
Increased CVP

Question 13

What can cause a mass effect within the brain?

Answer 13

Tumour
Infarct
Contusion
Haematoma
Abscess

Question 14

What can cause swelling within the brain?

Answer 14

Ischaemia
Anoxia
Acute liver failure
Encephalopathy
IIH 
Hypercarbia

Question 15

What can cause increased CVP?

Answer 15

Venous sinus thrombosis
Heart failure
Obstruction of jugular veins
High abdo pressure (ICP tends to be higher in pregnancy)

Question 16

What can cause non-communicating (obstructive) hydrocephalus?

Answer 16

Masses
Chiari Syndrome (ectopia of cerebellar tonsils)
Increased production; choroid plexus papilloma

Question 17

What can cause communicating hydrocephalus?

Answer 17

SAH
Meningitis
Malignant meningeal disease

Question 18

What are the early signs of increased ICP?

Answer 18

Decreased consciousness
Headache
Pupillary dysfunction +/- papilloedema
Changes in vision; decreased visual acuity, tunnel vision
N+V

Question 19

What are the late signs of increased ICP?

Answer 19

Coma
Fixed, dilated pupil
Hemiplegia
Bradycardia; cushing's reflex
Hyperthermia; dysfunctional hypothalamus
Increased urinary output

Question 20

What are the goals of therapy in managing patients with raised ICP?

Answer 20

Maintain CPP

Prevent ischaemia and brain compression

Question 21

What is the management for increased ICP?

Answer 21

Maintain head in midline to facilitate maximal venous outflow
Loosen tube ties, cervical collars
HoB 30-45 degrees elevation
Avoid gagging, coughing etc
Decrease environmental stimuli
Treat hyperthermia
Maintain fluid balance and normal electrolytes
Maintain normocarbia; short term can hyperventilate to decrease ICP and increase CPP

Question 22

What is the medical management for an increased ICP?

Answer 22

Diuretics; mannitol, hypertonic saline, furosemide, urea
Barbiturate coma; phenobarb
Antiepileptics
Surgical decompression

Question 23

What surgical treatment can be performed to decreased ICP?

Answer 23

Remove mass lesion; if abscess evacuate within 24 hours

CSF diversion; VP shunt

Question 24

What is communicating hydrocephalus?

Answer 24

Dilatation of ventricles throughout all the ventricular systems within the brain

Question 25

What is non-communicating hydrocephalus?

Answer 25

Obstructive; commonly at the cerebral aqueduct

Question 26

What are the different types of congenital hydrocephalus?

Answer 26

Aqueductal stenosis Colloid cyst Intraventricular haemorrhage

Question 27

What are the hallmarks of normal pressure hydrocephalus?

Answer 27

Elderly population Hakim's triad: abnormal gait (wide based, shuffling gait_, urinary incontinence (lack of frontal disinhibition), dementia

Question 28

What are the differential diagnosis of normal pressure hydrocephalus?

Answer 28

``` All other forms of dementia Cervical myelopathy All urinary problems PD Senile depression ```

Question 29

What can be seen on the scans of those with normal pressure hydrocephalus?

Answer 29

Large ventricles Brain atrophy Large sylvian fissures Disproportionately large subarachnoid spaces Angle between ventricles less than 90 degrees

Question 30

What investigations should be done for normal pressure hydrocephalus?

Answer 30

``` MOCA/ MMSE/ adam brooke Physio assessment of walking; 10m walk test LP; opening pressure Lumbar drain test; let out 30ml Lumbar infusion studies ```

Question 31

What is the treatment for normal pressure hydrocephalus?

Answer 31

VP shunt | Medium-low or low-pressure valve

Question 32

What is IIH?

Answer 32

Idiopathic intracranial hypertension | Increased opening pressure on LP

Question 33

Will there be ventricular dilatation in IIH?

Answer 33

NO - if you see dilatation then it is NOT IIH

Question 34

What are risk factors for developing IIH?

Answer 34

``` Women of child-bearing age Overweight CSF imbalance Hormonal Venous pressure; transverse/sigmoid sinus stenosis ```

Question 35

What are the signs and symptoms of IIH?

Answer 35

Headache; photophobia, don't like looking up Double vision Visual blurring; field defects to result in tunnel vision Tinnitus Radicular pain Papilloedema

Question 36

What is the treatment for IIH?

Answer 36

``` Weight loss Possible bariatric surgery Carboanhydrase inhibitor; acetazolamide Topiramate Diuretics CSF diversion; LP or VP shunt Interventional radiology; intracranial venous sinus plasty, intracranial venous sinus stenting ONSF (optic nerve sheath fenestration) ```

Question 37

What are the differentials of IIH?

Answer 37

Any other type of pain, any other reason for ICP | Cervical radiculopathy

Question 38

What investigations should be done in IIH?

Answer 38

LP CT/MRI head CTV/MRV to look at venous stenosis Fundoscopy +/- ophtho review