CSF pathway anatomy and etiopathogenesis and treatment of hydrocephalus.

1. CSF PATHWAY AND
HYDROCEPHALUS
By : Dr Abhishek Kumar Rai
DNB Neurosurgery Resident
Sakra World Hospital

2. CEREBROSPINAL FLUID
• Cerebrospinal fluid (CSF) is a clear, colorless body fluid found
in the brain and spinal cord.
• Adult – 280 ml (IF), 140 ml (csf)
• CSF – 80 ml (cerebral SAS) + 30 ml venticles + 30 ml (spinal
SAS)
• Rate of production of CSF – 0.4 ml/min or 500-600 ml/d.
• Opening CSF pressure – 3-4 mmhg (Infant) and 10-15 mmhg.

3. CSF FORMATION

4. CSF PATHWAY FORMATION

5. CSF RESORPTION

6. BRAIN CISTERNS

8. HYDROCEPHALUS
Hydrocephalus is a condition wherein
excess of CSF accumulates within the
ventricular system of the brain, leading
to increased ICP.
The first description of internal or
ventricular hydrocephalus was made by
Rhazes (850–923 AD).

9. HYDROCEPHALUS: CLASSIFICATION
I. Dandy and Blackfan subdivided hydrocephalus into :
 Communicating
 Obstructive

10. HYDROCEPHALUS: CLASSIFICATION
I. Hydrocephalus may be due to
A. Over production of CSF (a rare entity)
B. Obstructive: wherein there is obstruction to the flow of CSF in the
• Lateral ventricles
• Foramen of Monroe
• Third ventricle
• Aqueduct of Sylvius
• Fourth ventricle
• Subarachnoid spaces
C. Absorption defect

11. HYDROCEPHALUS: CLASSIFICATION
ii. Based on the site of blockage to the CSF flow the hydrocephalus may
be:
A. Monoventricular or unilateral
B. Biventricular (both lateral ventricles)
C. Triventricular (third and both lateral ventricles)
D. Panventricular (fourth, third and both lateral ventricles)

12. HYDROCEPHALUS: CLASSIFICATION
iii. Etiology
1. Congenital
2. Traumatic
3. Inflammatory
4. Neoplastic
5. Degenerative

13. HYDROCEPHALUS: CAUSES
1. Foramen of Monro
Gliosis
Colloid cysts
2. Third ventricle
Colloid cysts
Gliomas
Craniopharyngiomas
Choroid plexus papilloma
Germinoma

14. HYDROCEPHALUS: CAUSES
3. Fourth ventricle
Medulloblastomas
Ependymomas
Astrocytomas
Dandy-walker cysts
4. Basilar obstruction
Arachnoiditis
Chiari malformations

15. HYDROCEPHALUS: CAUSES
5. Absorptive obstruction
Arachnoiditis (posthemorrhagic, postmeningitic)
Venous thrombosis
6. Cerebral aqueduct
Aqueductal stenosis
Aqueductal forking
Subependymal
Gliosis
Periaqueductal
Gliomas

16. MONRO KELLY DOCTRINE
A change in any one of these components
results in adjustment to the other two
which is called compliance

17. HYDROCEPHALUS: ETIOPATHOGENESIS
 Incidence of congenital hydrocephalus is 0.2–0.5/1,000 live births.
 A higher incidence has been reported in elderly primiparus mothers.
 An inheritable form of aqueductal stenosis has been described in
males (X-linked hydrocephalus).
The other mechanism of hydrocephalus is over production, seen in
papilloma of the choroid plexus.

18. HYDROCEPHALUS: ETIOPATHOGENESIS
 Impaired absorption is another mechanism where
 Venous sinus occlusions
 Vein of Galen malformations
 developmental anomalies like craniostenosis with malformations of
the skull base
Absence or disease of the arachnoidal villi, resulting in disturbance of
absorption can also result in hydrocephalus

19. HYDROCEPHALUS: ACUTE SYMPTOMS
HEADACHE
NAUSEA AND VOMITING
DETERIORATION IN GAIT OR BALANCE
PAPILLEDEMA
UPGAZE PALSY- SUNSET SIGN
PERINAUD’S SYNDROME
ABDUCENS PALSY

20. HYDROCEPHALUS: CHRONIC SYMPTOMS
HEADACHE
URINARY INCONTINENCE
DETERIORATION IN GAIT OR BALANCE
PAPILLEDEMA
COGNITIVE AND ATTENTION DEFICITS
PARINAUD’S SYNDROME
EMPTY SELLA

21. HYDROCEPHALUS: PAEDIATRIC AGE GROUP
Prior to closure of the cranial sutures and obliteration of the
fontanelle, hydrocephalus results in disproportionate head growth.
 General irritability
 Poor feeding
 Slow attainment of milestones
 Bulging fontanelle
 Separation of cranial suture
 Prominent scalp veins
 Sun-set sign in eyes
Papilledema

22. INVESTIGATION
1. Ultrasound, is the imaging modality of choice in the investigation
and monitoring of the infant with an open fontanelle.
2. Plain X-rays of skull :
 A large skull with different shapes of the vault
 Sutural separation
 Cranio lacunae
 Flat anterior cranial fossa
 Thinning of vault bones may be seen
 Sellar changes and beaten silver appearance may be seen as a sign of
raised ICP.

24. INVESTIGATION
3. Ventriculography demonstrate
 Size of the ventricles
 Site of the obstruction
 CSF dynamics.
4. Cerebral angiography

25. INVESTIGATION
5. CT or MRI
a. Sylvian, interhemispheric fissures and cerebral sulci are not visible.
b. Obliteration of the basal cisterns and effacement of the cortical
sulci.
c. Both temporal horn are >2mm and the ratio FH/ID>0.5
d. Ballooning of frontal horns of lateral ventricles (Mickey mouse
ventricles)
e. Periventricular low density on CT or periventricular high intensity
signal on T2w1 MRI suggesting transependymal absorption or
migration of CSF at tips of the frontal, occipital and temporal horns.

27. INVESTIGATION
f. Evans Ratio- Ratio of frontal horn to maximal biparietal
diameter>30%.
g. Sagittal MRI may show upward bowing of corpus callosum.
6. Electroencephalography (EEG)

29. TREATMENT
Medical Management.
Spinal Tap.
Surgical Management

30. MEDICAL MANAGEMENT
 Diuretic therapy- Tried in infants with bloody CSF to see if there is
any resumption of normal CSF absorption.
 Acetazolamide and furosemide started simultaenously, to counteract
acidosis start alkasol(2meq of K/ml ,no Na +)

31. SPINAL TAPS
 Hydrocephalus after intraventricular hemorrhage : transient serial
taps may temporize until reabsorption resumes but LP can only be
performed for communicating HCP.
 If reabsorption does not resumes when protein is <100mg/dl then it
is unlikely to start as before.

32. SURGICAL MANAGEMENT

33. ENDOSCOPIC THIRD VENTRICULOSTOMY
Indications-
1. Obstructive HCP.
2. Shunt infection(removal of shunt).
3. Patients with subdural hematomas (shunt removed before TV is
performed).
4. Slit ventricle syndrome.
Contraindication- Communicating HCP

34. ENDOSCOPIC THIRD VENTRICULOSTOMY
Complications-
1. Hypothalamic injury.
2. Transient 3rd and 6th nerve palsies.
3. Uncontrollable bleeding.
4. Cardiac arrest.
5. Traumatic basilar artery aneurysm.
Success rate- overall=56% (range is 60% - 94% for nontumoral
aqueductal stenosis). Success rate is lower in infants as they may have
underdeveloped sub arachnoid space.

36. ENDOSCOPIC CHOROID PLEXUS
COAGULATION
First done by Dandy(open)
 Indications-
1. Communicating slowly progressing HCP in infants- 64% cured.
2. Choroid plexus papilloma/hyperplasia.
3. Necrotizing enterocolitis.
4. Intractable shunt failure.
 Contraindication- Obstructive HCP.

37. ENDOSCOPIC FENESTRATION
 Septostomy – for U/L HCP
 Multiloculated HCP.
 Aqueductoplasty or aqueductal stenting.
 Cysts with secondary HCP- Arachnoid cyst, Cysticercal cysts (3/4
ventricle)
 Colloid cyst of third ventricle.
 Pineal region tumors- ETV + Biopsy

38. TYPES OF SHUNTS
 VP shunt
 VA shunt
 Torkildsen shunt- ventricles to cisternal space.
 Miscellaneous– Ventriculopleural, gallbladder, ureter or bladder.
 LP shunt
 Cyst or subdural shunt

39. SLIT VENTRICLE SYNDROME
 The lateral ventricles may collapse in some patients secondary to
overshunting or remain at a fixed size because of subependymal
gliosis.
This may lead to intermittent or complete shunt malfunction.
Patients may experience raised ICP without ventricular enlargement,
and therefore imaging findings may be falsely reassuring in such cases
(unresponsive ventricles).
Treatment :
a. Subtemporal decompression
b. Endoscopic third ventriculostomy