[22] Raised ICP Flashcards

1
Q

What is raised ICP?

A

When the pressure inside the skull (and thus the brain and CSF) is increased

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2
Q

What is a normal ICP at rest in a supine adult?

A

7-15mmHg

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3
Q

Is raised ICP acute or chronic?

A

Can be either

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4
Q

What are the ways in which the body can regulate the ICP?

A
  • Changes in CSF production and absorption
  • Autoregulation
  • Chemoregulation
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5
Q

What happens in autoregulation (re: ICP)?

A

Vasoconstriction and vasodilation can occur in response to changes in blood pressure

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6
Q

What happens in chemoregulation (re: ICP)?

A

There is vasodilation in response to low cerebral pH

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7
Q

What are changes in ICP attributed to?

A

Changes in the volume of one or more of the constituents within the cranium

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8
Q

What can change in volume within the cranium to lead to raised ICP?

A
  • Blood
  • CSF
  • Brain (and other tissue)
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9
Q

What are the common causes of raised ICP?

A
  • Localised mass lesions
  • Neoplasms
  • Abscess
  • Focal oedema
  • Disturbance of CSF circulation
  • Obstruction to major venous sinuses
  • Diffuse brain oedema and swelling
  • Idiopathic intracranial hypertension
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10
Q

What is an example of a localised mass lesion that can lead to raised ICP?

A

Traumatic haematoma

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11
Q

Give examples of neoplasms that can cause raised ICP?

A
  • Glioma
  • Meningioma
  • Metastases
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12
Q

What can lead to focal oedema causing raised ICP?

A
  • Trauma
  • Infarction
  • Tumour
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13
Q

What are the types of CSF disturbance?

A
  • Obstructive hydrocephalus

- Communicating hydrocephalus

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14
Q

What happens in obstructive hydrocephalus?

A

There is blockage to the circulation of the CSF causing back pressure to build up

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15
Q

What happens in communicating hydrocephalus?

A

There is impaired absorption of the CSF but no obstruction to flow

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16
Q

What can cause obstruction to major venous sinuses?

A
  • Depressed fractures overlying the venous sinuses

- Cerebral venous thrombosis

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17
Q

What can lead to diffuse brain oedema and swelling?

A
  • Encephalitis
  • Meningitis
  • Diffuse head injury
  • Subarachnoid haemorrhage
  • Reye’s syndrome
  • Lead encephalopathy
  • Water intoxication
  • Near drowning
18
Q

What are the typical presenting signs and symptoms of raised ICP?

A
  • Headache
  • Papilloedema
  • Vomiting
  • Changes in mental state
19
Q

Describe a typical headache seen in raised ICP?

A
  • Nocturnal or starts on waking

- Worse on coughing or moving head

20
Q

What can also be seen on fundoscopy as well as papilloedema?

A
  • Blurred disc margins
  • Loss of venous pulsations
  • Disc hyperaemia
  • Flame-shaped haemorrhage
21
Q

How does vomiting present in early raised ICP?

A

With nausea

22
Q

What can happen to vomiting later in raised ICP?

A

Progress to projectile

23
Q

What changes to mental state can occur in raised ICP?

A
  • Lethargy
  • Irritability
  • Slow decision making
  • Abnormal social behaviour
24
Q

What are the late signs of raised ICP?

A
  • Motor changes (hemiparesis)
  • Raised BP
  • Widened pulse pressure
  • Slow irregular pulse
25
Q

What investigations may be useful in assessing raised ICP?

A
  • CT/MRI scan
  • Blood glucose
  • Renal function
  • U&E’s
  • ICP monitoring
26
Q

Why can CT/MRI be useful in assessing raised ICP?

A

To look for an underlying lesion

27
Q

What can ICP monitoring be useful for?

A

Diagnosing and guiding treatment

28
Q

When is ICP monitoring most commonly used?

A

Management of a severe closed head injury

29
Q

When is ICP monitoring appropriate?

This is a bad card no way around it sorry

A
  • Severe head injury and abnormal CT scan
  • Severe head injury and normal CT scan if two of; over 40, motor psoturing, systolic BP <90mmHg
  • Subarachnoid haemorrhage with hydrocephalus
  • Reye;s syndrome
  • Brain tumour
  • Idiopathic intracranial hypertension
30
Q

What are the differentials for raised ICP?

A

Other causes of headache

31
Q

What are some other causes of headache?

A
  • Tension headache
  • Migraine
  • Cluster headache
32
Q

What are some possible first line therapies for raised ICP?

A
  • Avoiding pyrexia
  • Managing seizures
  • CSF drainage
  • Head of bed elevation
  • Analgesia and sedation
  • Mannitol
  • Hyperventilation
33
Q

How should seizures be managed in raised ICP?

A

Aggresively with standard anticonvulsant loading regimens

34
Q

How are patients with raised ICP usually sedated?

A

IV propfol, etomidate or midazolam

35
Q

How are patients with raised ICP given pain relief?

A

Morphine or alfentanil

36
Q

What is mannitol?

A

An intravascular osmotic agent

37
Q

What problems are associated with mannitol use?

A

Hypovolaemia and hyperosmotic state

38
Q

What second line therapies may be used to treat raised ICP?

A
  • Barbiturate coma
  • Optimised hyperventilation
  • Hypothermia
  • Decompressive craniotomy
39
Q

Who with raised ICP are high dose barbiturates harmful to?

A

Those with head injuries

40
Q

What are the potential complications of raised ICP?

A
  • Seizures
  • Stroke
  • Neurological damage
  • Death