Hydrocephalus Flashcards

1
Q

Define Hydrocephalus?

A

Excess CSF in the intracranial space (specifically the intraventricular spaces) causing dilation of the ventricles and many symptoms

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2
Q

What are the major types of Hydrocephalus?

A
  • Communicating Hydrocephalus (CoH), CSF can travel all the way from the choroid plexus to the arachnoid granulations
  • Non-communicating Hydrocephalus (NCH), also known as obstructive hydrocephalus
  • Normal Pressure Hydrocephalus (NPH), its own clinical entity
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3
Q

What are the causes for CoH?

A

Production > Reabsorption

Mostly its due to a reduction in reabsorption:

  • Infection (e.g. bacterial meningitis)
  • Subarachnoid Haemorrhage (Scars Arachnoid villi)
  • Post-op
  • Head Traums

Very Rarely it can be caused by a choroid plexus papilloma increasing CSF production

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4
Q

How does CoH present?

A

Symptoms of raised ICP:

  • N&V
  • Headache
  • Papilledema
  • Gait Disturbance
  • 6th Cranial Nerve Palsy
  • Upgaze difficulty

In infants the skull will get excessively big too as sutures havent yet fused

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5
Q

What causes Non-Communicating Hydrocephalus? (NCH)

A

In order of likelihood:

  • Aqueductal Stenosis
  • Tumours/Masses (E.g. pineal tumour or Ependymoma)
  • Cysts (e.g. colloid cyst at foramen of monro)
  • Infection
  • Haemorrhage or Haematoma
  • Some very rare Congenital Malformations
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6
Q

Is NCH rapid or gradual onset?

A

Depends on the cause:

  • A tumour will show a gradual increase in symptoms
  • An intraventricular bleed blocking flow will cause rapid mental status decline (Sleepy -> Obtunded -> Needed Intubated)
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7
Q

What is the earliest detectable sign of hydrocephalus?

A

Dilation of the Lateral Ventricle’s Temporal Horns on a radiograph

Usually they should be virtually invisible

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8
Q

What signs of hydrocephalus are there on a radiograph?

A
  • Temporal horn dilation
  • Ballooning of Lateral & 3rd ventricles
  • Lateral sulci effaced (erased)
  • Evans Ratio >30%
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9
Q

What is the Evans Ratio?

A

Ratio of Max width of ant horns of lateral ventricles – Max width of skullcap at level of foramen of monro

A ratio over 0.3 indicates ventriculomegaly

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10
Q

How do we treat hydrocephalus?

A

Acutely:
- External Ventricular Drain (EVD)

CoH:
A shunt must be emplaced long term (often preceded by an EVD acutely)

NCH:

  • Surgical removal of obstruction
  • If not possible then a shunt
  • Third Ventriculostomy (often combined with VP shunt)
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11
Q

What kinds of shunts are there for hydrocephalus?

A

Ventriculo-Peritoneal (VP)

  • Most common
  • Drains CSF to peritoneal cavity where its absorped

Lumbar-Peritoneal (LP)
- Can overdrain

Ventriculo-Atrial (VA):
- Dangerous

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12
Q

How does an EVD work?

A

Catheter placed through scalp into lateral ventricle draining CSF to the patients bedside

Allows you to adjust the amount drained and measure the current ICP

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13
Q

What is a 3rd ventriculostomy?

A

Treatment for NCH
Surgically open a hole in the floor of the 3rd ventricle
Allows CSF to bypass the cerebral aqueduct

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14
Q

How much do VP shunts fail?

A

40% in 1st yr (50% by 5 yrs)

  • Infection
  • Skin erosion
  • Occlusion
  • Disconnection
  • Over/underdrainage
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15
Q

What is NPH?

A

Normal Pressure Hydrocephalus

Its its own clinical entity

Important as its a preventable cause of dementia and is often mistaken for Alzheimer’s or aging

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16
Q

How does NPH present?

A

Hakin-Adam’s Triad:

  • Urinary Incontinence (“wet”
  • Gait Disturbance (“Wobbly”) i.e. a wise stance with short shuffling steps and slow turning
  • Quickly progressing dememtia (“Whacky”)
17
Q

How would you investigate a case of NPH?

A
  • CT/MRI would appear as CoH

- LP would show normal opening pressure (symptoms improve as you remove CSF)

18
Q

How do you treat NPH?

A

Programmable VP shunt to remove CSF.

The earlier you treat it the better the prognosis with gait most likely to improve, then incontinence then memory.