Jan. 3rd, 2012

1. Dr. Khalid Shokor Mahmood
Neurosurgeon
January, 2012

3. Definition
 Hydrocephalus is an abnormal enlargement of the ventricles
due to an excessive accumulation of CSF resulting from a
disturbance of its flow, absorption or, uncommonly,
secretion.
 The normal volume of CSF is 140 ml. CSF is produced by
the choroid plexus in the ventricles at a rate of about 500 ml
in 24 hours.

5. CSF circulation
 The CSF flows from the lateral ventricles through
the foramen of Monro into the 3rd ventricle, via the
aqueduct of Sylvius into the 4th ventricle and then
through the foramina of Magendie and Luschka
into the subarachnoid space and basal cisterns.
 It flows over the cerebral hemispheres and is
largely absorbed by the arachnoid villi of the dural
sinuses.

10. Classification
 Obstructive hydrocephalus: when there is an
obstruction to the flow of CSF through the
ventricular system.
 Communicating hydrocephalus: when there is no
obstruction to the flow of CSF within the ventricular
system but the hydrocephalus is due either to
obstruction to CSF flow outside the ventricular
system or to failure of absorption of CSF by the
arachnoid granulations.

11. Causes
1 Obstructive hydrocephalus:
 lateral ventricle : thalamic glioma
 3rd ventricule: gliomas or colloid cyst of the 3rd ventricle
 aqueduct of Sylvius: primary stenosis or secondary to a tumour
 4th ventricular: posterior fossa tumour: medulloblastoma, ependymoma, acoustic
neuroma.
2 Communicating hydrocephalus:
 obstruction to flow of CSF through the basal cisterns
 failure of absorption of CSF
 The most common causes of communicating hydrocephalus are
infection (especially bacterial and tuberculous) and subarachnoid
haemorrhage (either spontaneous, traumatic or postoperative).

15. Presenting features
Hydrocephalus in infants
 3-4 per 1000 births ( congenital abnormalities).
 The most common congenital cause is stenosis of the
aqueduct of Sylvius. This is a major cause of
hydrocephalus in children with spina bifida and
myelomeningocele who also have a Chiari
malformation. Congenital atresia of the foramen of
Luschka and Magendie (Dandy–Walker cyst) is a
rare cause.
 The acquired forms of hydrocephalus occur most
frequently after intracranial bleeding, particularly in
premature infants, in meningitis and because of
tumours.

16. Hydrocephalus in infants
The major clinical features in infants are:
 failure to thrive
 increased skull circumference
 tense anterior fontanelle
 ‘cracked pot’ sound on skull percussion
 transillumination of cranial cavity with strong light
 when severe, impaired conscious level and vomiting
 ‘setting sun’ appearance due to lid retraction and
impaired upward gaze from 3rd ventricular pressure on
the midbrain tectum
 thin scalp with dilated veins.

22.  Adult hydrocephalus (either acute or gradual)
1. Acute-onset adult hydrocephalus
 This type of presentation occurs particularly in patients
with tumours causing obstructive hydrocephalus. The
major presenting features are due to the signs and
symptoms of raised ICP as described earlier:
 headache
 vomiting
 papilloedema
 deterioration of conscious state.
 Upgaze will often be impaired due to pressure of the dilated 3rd
ventricle on the superior colliculus of the tectum.

23. Adult hydrocephalus
2. Gradual-onset adult hydrocephalus
 The symptoms of raised intracranial pressure are only
very gradually progressive and late diagnosis is
common.
 Early features in the adolescent involve deteriorating
school performance as a result of headaches, failing
mental function, memory loss and behavioural
disturbances.
 Endocrine abnormalities
 Progressive visual failure will occur, secondary to
papilloedema and optic atrophy.
 In elderly patients a chronic form of hydrocephalus is called
‘normal-pressure hydrocephalus’

24. Radiological investigation
 If the lateral ventricles and 3rd ventricle are all very dilated,
and the 4th ventricle is small, it is likely that the obstruction is
at the level of the aqueduct of Sylvius. An enhanced CT scan
or MRI will help determine the cause, as it will better define
the presence of an obstructing tumour. In a communicating
hydrocephalus all the ventricles are dilated.
 CT scan
 Magnetic resonance imaging.
 Ultrasonography.
 Plain skull X-ray.

28. Treatment
 In general, the treatment of hydrocephalus is a CSF
shunt or a 3rd ventriculostomy. If there has been
rapid neurological deterioration this will need to be
performed as an emergency.
 If the hydrocephalus is due to an obstructing tumour
that is surgically accessible, resection of the mass
may lead to resolution of the hydrocephalus and a
shunt might not be necessary.

29. Treatment
CSF shunt
 The usual method of CSF diversion is a
ventriculoperitoneal shunt, in which a catheter is
placed into the lateral ventricle and is connected to
a subcutaneous unidirectional pressure-regulated
valve which is attached to a catheter threaded
subcutaneously down to the abdomen and inserted
into the peritoneal cavity.
 Modern valves can have their draining pressures
adjusted percutaneously and shunts are being
developed allowing intracranial pressure to be
monitored percutaneously.

39. Treatment
Postoperative care
 The postoperative management is similar for any
intracranial procedure. Initially the patient is
nursed flat, to avoid rapid decompression of the
ventricular system. Deterioration of neurological
state or failure to improve will require an urgent
CT scan to confirm that the catheter has been
placed accurately into the ventricular system and to
exclude the possibility of intracranial
complications such as intracerebral haematoma.

40. Complications of ventriculoperitoneal shunt
The major possible complications are:
• infection of the shunt
• obstruction of the shunt
• intracranial haemorrhage.

41. Other CSF shunts :
 ventriculoatrial shunts
 ventriculopleural shunts
 lumboperitoneal shunts.

42. Treatment
Third ventriculostomy
 Using an endoscopic technique, a ventriculoscope is
introduced into the lateral ventricle via a frontal burr hole
and advanced through the foramen of Monro. The floor of
the 3rd ventricle just anterior to the mamillary bodies is
then fenestrated, allowing CSF to bypass any obstruction in
the CSF pathway and be reabsorbed by the arachnoid villi.

44. Arrested hydrocephalus
 This is a state of chronic hydrocephalus in which
the CSF pressure has returned to normal and there
is no pressure gradient between the cerebral
ventricles and brain parenchyma. It is uncommon
and is most likely to occur in communicating
hydrocephalus.
 The patients, often children and adolescents, should
be followed carefully. If there is any deterioration
of those parameters a shunt will be necessary.

45. Normal-pressure hydrocephalus
The gradually progressive classic clinical ‘triad’ consists
of:
1 Dementia.
2 Ataxia.
3 Incontinence.
 The syndrome is progressive and the disturbance of
gait, which may be the first and most prominent
symptom, is more of an apraxia than a true gait ataxia.