ICP

1. Presentation & Management of
Raised Intracranial Pressure
By
Zain Alabedeen B. Jamjoom, M.D.
Professor of Neurosurgery

2. Normal Intracranial Pressure
Normal ICP ~10 mmHg
(supine at the level of the foramen of Monro)
Pulsatile
Fluctuates with the respiration
ICP >20 mmHg is definitely pathological
20 November 2007 Raised ICP 2

3. Normal ICP Waveform
t (sec)
ECG
Resp.
ICP
20 November 2007 Raised ICP 3

4. Cerebral Blood Flow (CBF)
Pressure
Flow =
Resistance
CBF = Cerebral perfusion pressure (CPP)
Cerebral vascular resistance (CVR)
CPP = Mean syst. art. BP - Mean ICP
20 November 2007 Raised ICP 4

5. Intracranial Cavity
Its volume is virtually constant.
It is filled to capacity with fluids & solid
material that are non-compressible.
Therefore:
Increase in one constituent or an
expanding mass within the intracranial
space results in raised ICP (Monro-Kellie
Doctrine).
20 November 2007 Raised ICP 5

6. Intracranial Cavity
Content
Brain:
– Neurones 500 - 700 ml
– Glia 700 - 900 ml
– Extracellular fluid 100 - 150 ml
Blood: 100 - 150 ml
Cerebrospinal fluid: 100 - 150 ml
Constituents are non-compressible
but partially displaceable
20 November 2007 Raised ICP 6

7. ICP/Volume Curve
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8. Intracranial Cavity
3 compartments
2 supratentorial
spaces, separated
by the falx cerebri,
and
1 infratentorial
space, separated
from supratentorial
spaces by the
tentorium.
20 November 2007 Raised ICP 8

9. Intracranial Mass
Shifts
(Cerebral
Herniations)
20 November 2007 Raised ICP 9

10. Transtentorial (Uncal) Herniation
Bilateral
Unilateral
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11. The Tentorial
Hiatus
Oculomotor nerve
Posterior cerebral artery
Cerebral peduncle
Reticular formation
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12. Transtentorial Herniation
rd
Compression of 3 CN:
– Dilatation of ipsilateral pupil.
Compression of the mid-brain:
– Impairment of consciousness.
– Hemiparesis (usually contralateral, but
occasionally ipsilateral).
– Hypertension + Bradycardia (Cushing response).
– Respiratory failure.
Compression of post. cerebral artery:
– Infarction of occipital lobe
20 November 2007 Raised ICP 12

13. Syndrome
of Unilateral
Uncal
Herniation
Early Phase
20 November 2007 Raised ICP 13

14. Syndrome
of
Unilateral
Uncal
Herniation
Late Phase
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15. A main cause of uncal herniation
is Extradural Hematoma
20 November 2007 Raised ICP 15

16. Clinical Symptoms & Signs of
Raised ICP
Headache
Nausea and vomiting
Papilledema
Impairment of consciousness
th
6 cranial nerve palsy: False
localizing sign
Impaired level of consciousness
20 November 2007 Raised ICP 16

17. Signs of Raised ICP
Papilledema
Normal Papilledema
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18. Signs of Raised ICP
Abducent Nerve Palsy
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19. Clinical Symptoms & Signs of
Raised ICP in Infants
Large head (Macrocephaly)
Tense & enlarged anterior
fontanel
Separated skull sutures
Prominent scalp veins
“Sun set” of eyes
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20. Macrocephaly
20 November 2007 Raised ICP 20

21. Investigations
Method of choice:
URGENT brain CT scan.
Skull X-rays:
– Separated sutures
– Silver beaten appearance
Lumbar puncture is
CONTRAINDICATED.
20 November 2007 Raised ICP 21

22. Separated Skull Sutures
20 November 2007 Raised ICP 22

23. Silver Beaten Appearance
20 November 2007 Raised ICP 23

24. Causes of Increased ICP
Increased volume of normal intracranial
constituents:
– Brain: Cerebral edema.
– Cerebrospinal fluid: Hydrocephalus.
o
– Blood volume: Vasodilatation 2 to CO2
A space-occupying lesion:
- Tumor - Hematoma
- Abscess - Cyst
Idiopathic:
– Pseudotumor cerebri
20 November 2007 Raised ICP 24

25. Cerebral Edema
20 November 2007 Raised ICP 25

26. Hydrocephalus
20 November 2007 Raised ICP 26

27. Intracranial
Tumor
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28. Intracranial Tumors
Intrinsic:
– Arise from brain tissue
– Majority are gliomas (Grades I to IV)
Extrinsic:
– Arise from intracranial tissue other than brain
– Include: Meningioma, Pituitary adenoma,
Schwannoma
Location:
– Adults: mainly supratentorial
– Children: mainly intratentorial
20 November 2007 Raised ICP 28

29. Brain Abcsess
20 November 2007 Raised ICP 29

30. Brain Abscess
Develop as a result of a localized
bacterial cerebritis followed by necrosis
and encapsulation.
Mechanisms:
– Hematogenous
– Extension from neighbouring structures
– Penetrating injuries
Symptoms of infection may be absent in
50% of cases
20 November 2007 Raised ICP 30

31. Treatment of Raised ICP
General measures for reducing
raised ICP
Definitive treatment:
Removal of the cause
20 November 2007 Raised ICP 31

32. General Measures to Reduce Raised ICP
o
Head elevation 30o up in neutral position.
Diuretics:
– Mannitol : 20% 1g/kg iv single dose or
0.25-0.5g/kg Q8h
– Furosemide : 1mg/kg iv sinlgle dose or
0.25-.05mg/kg Q8h
Normovolemia: IV infusion of cristalloid
Controlled hyperventilation:
– pCO2 reduction to 30 - 35 mmHg.
Sedation & Muscle relaxation.
CSF withdrawal. No lumbar puncture
20 November 2007 Raised ICP 32

33. Ventriculo-peritoneal Shunt
20 November 2007 Raised ICP 33

34. Excision of Intracranial Tumor
20 November 2007 Raised ICP 34

35. Drainage of Brain Abscess
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36. Benign Intracranial Hpertension
“Pseudotumor cerebri”
Young, obese women
Pathogenesis not clear
Precipitating factors:
– Hypoparathyroidism
– Vitamin A excess (Tx of acne)
– Pernicious anemia
– Drugs: oral contraceptives, tetracycline,
sulphamethoxazole, indomethacin, a.o.
20 November 2007 Raised ICP 36

37. Benign Intracranial Hypertension
Presenting Features
Headache
Visual disturbance
– Blurred vision
– Diplopia
Papilledema
Optic atrophy
6th nerve palsy
20 November 2007 Raised ICP 37

38. Benign Intracranial Hypertension
Investigations
CT – scan: WNL
Lumbar puncture & measurement of
CSF pressure: Elevated
CSF biochemical & cytological: WNL
MRI & MRA: WNL
Continuous intracranial pressure
measurement (in doubtful cases)
20 November 2007 Raised ICP 38

39. Benign Intracranial Hypertension
Treatment
Weight reduction
Discontinuation of potentially causative
drugs ( e.g. contraceptives, vitamin A)
Diuretics (e.g. LasixR)
Acetazolamide (DiamoxR): Initially 500
mg, later 250 Q6h
Intermittent release of CSF
20 November 2007 Raised ICP 39

40. Benign Intracranial Hypertension
Indication of Surgery
Persistent papilledema despite Tx
Failing vision
Intractable headache despite Tx
20 November 2007 Raised ICP 40

41. Benign Intracranial Hypertension
Surgical Treatment
Lumbo-peritoneal shunt
Optic nerve sheath decompression
20 November 2007 Raised ICP 41

42. Complications of Untreated
Raised ICP
Death
Neurological disability
– Blindness
– Mental impairment
– Motor disability
Disfigurement
20 November 2007 Raised ICP 42

43. Neurological Disability
20 November 2007 Raised ICP 43

44. Measurement of Intracranial
Pressure
Epidural
Subdural
Intraparenchymal
Intraventricular
20 November 2007 Raised ICP 44

45. Intraventricular Pressure Measurement
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46. A-waves or Plateau waves
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47. Measurement of Intracranial
Pressure Indications
Severe head trauma
Intracerebral hemorrhage
Extensive cerebral edema
– e.g. after infarct, hypoxia, intoxication, etc.
Following major intracranial operations
In the assessment of dementia and
benign intracranial hypertension
20 November 2007 Raised ICP 47

48. References
Essential Neurosurgery
by: Andrew Kaye
Neurology and Neurosurgery Illustrated
by: Lindsay - Bone - Callander
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49. 20 November 2007 Raised ICP 49