2. HydrocephalusHydrocephalus
• Derived from the Greek words “hydro”
meaning water and “cephalus” meaning
head.
• Disequilibrium between CSF production
and absorption, leading to raised ICP, and
is often associated with dilated ventricles.
3. Cerebrospinal Fluid PathwayCerebrospinal Fluid Pathway
• Formed by the choroid plexus, by
ultrafiltration (active process independent
of ICP).
• From lateral ventricles into 3rd
ventricle
through inter-ventricular foramen of
Munro.
• From 3rd
ventricle into 4th
ventricle through
aqueduct of Sylvius.
• Foramen of Magendie & Luschka.
4.
5. • Subarachnoid space, Spinal canal.
• Absorbed by Arachnoid villi into the
superior sagittal sinus (pressure-
dependent passive process).
• CSF Volume: 150 ml.
• CSF Production: 20 ml/h.
• Normal ICP: 5-15 mmHg in the adult at
rest.
• CSF act as a hydraulic shock absorber.
6. Types of HydrocephalusTypes of Hydrocephalus
1. Communicating:
• CSF pathways are patent, CSF can
leave the 4th
ventricle & communicate
with subarachnoid space.
• Impaired CSF absorption.
2. Non-communicating: Lesion blocking
CSF pathways.
10. Normal-Pressure HydrocephalusNormal-Pressure Hydrocephalus
• Communicating hydrocephalus.
• Thought to be due to impaired CSF
absorption.
• Mostly in elderly.
• Adam’s triad: ataxia, cognitive decline &
urinary incontinence.
• Ventriculomegaly on imaging.
• Normal CSF pressure.
• Respond to ventriculo-peritoneal shunting.
11. Symptoms of Raised ICPSymptoms of Raised ICP
• Headache: Early morning, Worse on lying
down.
• Nausea & vomiting.
• Visual blurring or double vision.
• Drowsiness.
• Altered level of consciousness.
20. Treatment PrinciplesTreatment Principles
1. Removal of cause.
2. Reducing CSF production.
3. Bypassing the obstruction.
4. Intermittent removal of excess CSF.
5. CSF shunting to a place where it can be
absorbed.
21. TreatmentTreatment
Removing a causative mass lesion:Removing a causative mass lesion:
• Tumour removal & decompression of CSF
pathways, with insertion of external
ventricular drain.
• Patient who presents with impaired
conscious level, treat the hydrocephalus
first with EVD or VP shunt, followed by
tumour surgery.
22. Reducing CSF productionReducing CSF production
1. Carbonic Anhydrase inhibitor:
Acetazolamide.
• Temporary effect.
• Careful monitoring of electrolytes levels.
2. Destroy choroid plexus by open
operation, or using endoscope.
• No widely used.
23. Endoscopic third ventriculostomyEndoscopic third ventriculostomy
• Bypass the obstruction.
• Neuroendoscope inserted into the frontal
horn of lateral ventricle, then into the 3rd
ventricle through foramen of Munro.
• Stoma created in the floor of 3rd
ventricle in
between the mamillary bodies and
infundibular (pituitary) recess.
• CSF can communicate freely between the
ventricular system & interpeduncular
subarachnoid space.
24.
25. • Useful if there is CSF pathways
obstruction below the 3rd
ventricle
(aqueduct stenosis or posterior fossa
mass lesions).
• Less useful for communicating
hydrocephalus, & in infants of less than 6
months of age.
• Success rate: 70%.
26. • Advantage: no tubing is left in the
patient, infection rates are lower.
• ComplicationsComplications::
1. Blockage.
2. Basilar artery rupture.
3. Memory impairment from injury to the
fornix.
28. Ventriculo-peritoneal shuntVentriculo-peritoneal shunt
• Catheter insertion into the lateral ventricle.
• Connected to a shunt valve under the scalp
and finally to a distal catheter, which is
tunnelled subcutaneously down to the
abdomen and inserted into the peritoneal
cavity.
• When CSF pressure exceeds the shunt valve
pressure, CSF flow out of the distal catheter
and be absorbed by the peritoneal lining.
30. Other options for distal catheter placement
include:
1. Right atrium via the jugular vein:
ventriculo-atrial shunt.
2. Pleural cavity: ventriculo-pleural shunt.
31.
32. Shunt ComplicationsShunt Complications
Shunt blockageShunt blockage::
• May affect the ventricular catheter, shunt
valve or distal catheter.
• Causes: choroid plexus adhesion, blood,
cellular debris, misplacement of the
distal catheter in the pre-peritoneal
space (child growth), high protein
content in CSF.
33. Shunt InfectionShunt Infection::
• 1 - 15% of inserted shunts.
• Staphylococcus epidermidis.
• Risk factors: very young children, open
myelomeningocele, longer operative time,
excessive staff movement into and out of
theatre.
• Most infections become apparent clinically
by 6 weeks and over 90% are apparent
within 6 months.
34. • Cause: meningitis, peritonitis,
septicaemia, endocarditis.
• Treatment:
Shunt removal, external CSF drainage,
treatment of infection prior to re-insertion
of the shunt at a different site.
• Antibiotic-impregnated catheters resulted
in reduction in shunt infection rates.
• Prophylactic antibiotics.
36. Follow up of shunt patient:Follow up of shunt patient:
• Every 3 months in 1st
year following shunt
placement.
• Every 6 months in 2nd
year.
• Then yearly.
37.
38. External drainsExternal drains
• Placed within the ventricle (EVD) or the
lumbar thecal sac (lumbar drain).
• For temporary CSF drainage.
• Can be used to administer intrathecal
antibiotics to treat CSF infection.
39. PrognosisPrognosis
• Depends on the cause of hydrocephalus.
• Simple aqueduct stenosis treated early,
prognosis of normal IQ & neurologic
function is good.
• Repeated episodes of raised ICP &
ventriculitis, results in low IQ & neurologic
function.
40. ReferencesReferences
• Bailey & Love’s Short Practice of Surgery, 25th
edition, Chapter 40, P. 623-628.
• Sabiston Textbook of Surgery, 18th
edition,
Chapter 72.
• Schwartz's Principles of Surgery, 8th
edition,
Chapter 41.
• Greenfield’s Surgery, 4th
edition, Chapter 114, P.
2067-2068.
• Clinical Surgery, Cuschieri, 2nd
edition, Chapter
40, P. 632-633.
• Principles of Neurosurgery, Rengachary, 2nd
edition, Chapter 8 & 9, P.117-134.
Notes de l'éditeur
Present along the medial wall of body & inferior horns of lateral ventricles, roof of 3rd ventricle, 4th ventricle roof.
20 % of CSF production occurs by transependymal spread through the ventricular walls from the cerebral extracellular fluid, and from the spinal dural nerve root sheaths.
Vs. cerebral atrophy: early dementia, late ataxia.
Ventricular enlargement more prominent than enlargement of the CSF subarachnoid spaces over the cerebral convexity is typical in NPH.
The differentiation between NPH and cerebral atrophy is important because of the increased risk for subdural haematoma with shunting in cerebral atrophy.
Macewan’s sign: Cracked pot sound on percussion over dilated ventricle
Child with ‘sun-setting’ eye sign due to hydrocephalus.
impaired upgaze may be seen as part of Parinaud’s syndrome, pressure on the dorsal midbrain.
swollen optic disc with blurred margins.
Plain skull X-Ray: copper-beating indicative of chronic raised intracranial pressure
MRI: anatomical detail of lesions causing hydrocephalus, useful in the diagnosis of aqueduct stenosis. A midline T2-weighted MRI scan can be used to assess the suitability of a patient for a third ventriculostomy by identifying the relationships of the floor of the third ventricle, basilar artery and clivus.
Ct scan shows the hydrocephlaus, MRI shows the cause, and tt decision
Lateral skull radiograph showing copper-beating, which is indicative of chronic raised intracranial pressure.
Pineal region tumour causing obstructive hydrocephalus.
Axial CT scan, showing a neonate with hydrocephalus and markedly dilated ventricles. The temporal horns, normally just visible, are particularly enlarged.