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NEURO > CSF and hydrocephalus > Flashcards

CSF and hydrocephalus Flashcards

1
Q

what is hydrocephalus

A

excess CSF within the intracranial space and, specifically, the intraventricular spaces within the brain

causing dilation of the ventricles, and a wide range of symptoms.

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2
Q

where and how is CSF produced

A

produced in the choroid plexus in the brain

metabolically active process (require ATP)

sodium is pumped into the subarachnoid space and water follows from the blood vessels

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3
Q

where are choroid plexus located

A

lateral ventricles (temporal horn roofs, floor of bodies)

posterior 3rd ventricle roof

caudal 4th ventricle roof

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4
Q

how much CSF if produced per day

A

450-600 cc

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5
Q

how much CSF is present at any one time

A

~150cc

~25 within brain ventricles

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6
Q

what is the usual relationship between CSF production and resorption

A

normally production = resorption

exists in a delicate balance

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7
Q

what is the pathway of the CSF out of the ventricles

A
  • lateral ventricles
  • foramen of monro
  • 3rd ventricle
  • cerebral aqueduct
  • 4th ventricle
  • formina of luschka/magendie
  • subarachnoid space around brain/spinal cord
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8
Q

where is CSF resorbed

A

resorbed into the venous blood system at arachnoid granulations along the dural venous sinuses

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9
Q

how do the arachnoid granulations resorb CSF

A

contain villi which function as pressure dependent one way valves

a passive process driven by the pressure gradient between the intracranial space (ICP) and veneer system (CVP)

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10
Q

what are the two main types of hydrocephalus

A

communicating (CoH)
- non-obstructive

non-communicating (NCH)
- obstructive

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11
Q

why is CoH known as non-obstructive hydrocephalus

A

CSF pathway open from start to finish

- from choroid plexus to arachnoid villi

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12
Q

why is NCH known as obstructive hydrocephalus

A

CSF can’t travel freely from start to finish

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13
Q

what are the two types of problem that cause CoH

A
  1. problem is in CSF resorption - i.e. can’t keep pace with CSF production

doesn’t need to be a large insult as balance very sensitive
- ventricular system dilates uniformly, ICP rises

  1. overproduction of CSF - disrupts balance

rare but can be caused by choroid plexus papillomas

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14
Q

what are the signs and symptoms of CoH in young children with unfused cranial sutures

A

disproportional increase in head circumference compared to the rest of the face/body

failure to thrive

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15
Q

what are the signs and symptoms of CoH in children with fused sutures/adults

A

symptoms of increased intracranial pressure;

  • headaches
  • nausea, vomiting
  • papilloedema
  • gait disturbance
  • 6th cranial nerve palsy
  • upgaze difficulty
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16
Q

what can cause CoH

A

infection - eg bacterial meningitis

subarachnoid haemorrhage - blood and blood breakdown products cause scarring of arachnoid granulations

post operative

head trauma

17
Q

how can CoH present

A

GRADUAL - from a “gentle” disruption of the balance between CSF production and resorption over time

ACUTE - due to large insult that causes acute disruption of the balance - CSF resorption suddenly reduced

  • medical emergency as neurological decline very rapid
18
Q

what type of problem causes NCH

A

ANY physical obstruction to the normal flow of CSF BEFORE it leaves the ventricles

19
Q

what are the causes of NCH

A

aqueductal stenosis

tumours/cancers/masses

cysts

infection

haemorrhage/haematoma

congenital malformations/conditions

20
Q

how can NCH present

A

GRADUAL - processes (ie masses) developing over a long period of time - cause gradual symptoms

ACUTE - e.g. intraventricular bleed can cause acute obstruction - rapid mental status decline

21
Q

what are the radiographical findings that can help diagnose hydrocephalus

A
  1. dilation of the temporal horns of the lateral ventricles
  2. ballooned 3rd ventricle
  3. periphral sulci effaced (not seen)
22
Q

what is the treatment for hydrocephalus

A

surgical:

acute - external ventricular drain (EVD)

permanent shunt if EVD cannot be successfully weaned

removal of obstructing lesion

23
Q

what is an EVD and what are the associated risks

A

a catheter passed through the scale and skull into the lateral ventricle

drains CSF to a collection system at the bedside

high infection risk

24
Q

what is the mainstay treatment for CoH

A

permanent shunt
- ventriculo-peritoneal (VP) - most common

  • lumbar-peritoneal (LP) - but can cause over drainage
  • ventriculo-atrial (VA) - if peritoneal failure
25
Q

what is the mainstay treatment for NCH

A

shunt placement

removal of obstructing lesion

third ventriculostomy

26
Q

what is third ventriculostomy

A

performed in conjunction with VP shunt

hole is surgically opened in floor of 3rd ventricle - CSF flows into interpeduncular cistern and pre-pontine space (bypasses cerebral aqueduct)

27
Q

what must you keep in mind when taking a history from a patient with a headache and a VP shunt

A

headache NOT automatically caused by shunt malfunction/infection

BUT can be the cause as 40% shunts fail in the first year

28
Q

how can a VP shunt fail

A

Mechanical failure from occlusion/disconnection,

migration,

overdrainage/underdrainage,

infection,

skin erosion

29
Q

what is normal pressure hydrocephalus (NPH)

A

hydrocephalus where ICP remains normal but CoH seen on CT/MRI

one of the rare and preventable/reversible causes of dementia

under diagnosis can lead to a diagnosis of alzheimers or age-related dementia

30
Q

what is the classic triad presentation of NPH

A

Hakim/Adams triad
+ wet, wobbly, wacky

  1. urinary incontinence
  2. gait disturbance - wide stance, short shuffling steps
  3. quickly progressing dementia
31
Q

how can NHP be diagnosed

A

CT/MRI - shows CoH

Lumbar puncture - normal opening pressure

gait assessment

MMSE - mini mental state examination

symptoms improve with CSF removal

good history taking and time with patients family

32
Q

what is the treatment for NPH

A

programmable VP shunt placement first choice

LP shunts ted to overdrain and are difficult to assess and revise

33
Q

what is the prognosis for NPH

A

outcome better if symptoms present for a shorter period of time

least likely symptom to improve is dementia

order of symptom improvement
gait>incontinence>memory

NEURO (51 decks)

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