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1. Top 5 Symptoms and causes of
hydrocephalus
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and Hydrocephalus at
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2. Definition
 Hydrocephalus means abnormal or
excessive accumulation of CSF in
the intracranial cavity.
 To understand Hydrocephalus , we
have to take an idea about the
cerebrospinal fluid (CSF) circulation.

3. CSF Circulation
 CSF is a dynamic fluid, its main function
is to keep the internal environment of
Central Nervous System (C.N.S)
constant. It also play a role in mechanical
protection of the brain and spinal cord.
 Because CSF is dynamic fluid it is
secreted and reabsorbed continuously.
CSF is secreted by choroid plexus, the
main bulk of choroid plexus is present in
the Lateral Ventricles, but there is
choroid plexus also in the Third Ventricle
and Fourth Ventricle.

4. CSF Circulation (Cont.)
 The rate of formation of CSF is about 0.3-
0.35 ml/min i.e. it is about 500 cc/day
although the constant amount of CSF
present in the ventricles and subarachnoid
space is about 150 cc. This means that
most of the amount secreted is reabsorbed
again.
 CSF pass from lateral ventricles through
Foramina of Monro to the third ventricle,
then through Aqueduct of Sylvius to the
fourth ventricle ( Fig. 1).

5. Figure 1: CSF Circulation

6. CSF Circulation (Cont.)
 The fourth ventricle have three apertures
or foramina, One mid-line (Foramen of
Magendi) and two lateral foramina
(Foramena of Luschka) (Fig. 2). Through
these Foramina CSF passes from the
ventricular system to the subarachnoid
space .
 It accumulate first in Cisterna Magna, part
of CSF descends downwards around the
spinal cord, but the majority passes
upwards through the Tentorial Hiatus over
the surface of both cerebral hemispheres
to be absorbed by the Arachnoid villi in the
Superior sagittal sinus (SSS).

7. Figure 2: CSF Circulation

8. CSF Circulation (Cont.)
 So, CSF is secreted from the blood
by choroid plexus and reabsorbed in
the blood by Arachnoid villi, this
explains the physiological dynamic
function of CSF that keeps the
internal environment of CNS
constant. ( Fig. 3).

9. Figure 3: CSF Circulation

10. Pathogenesis of
Hydrocephalus
 Any disturbance in CSF secretion,
circulation and absorption will results in
abnormal accumulation, so the
pathogenesis may be :
 Obstruction of CSF pathway (main
factor).
 Excessive formation of CSF as in case of
choroid plexus papilloma ( rare ).
 Decreased absorption as in SSS
thrombosis around arachnoid villi.

11. Etiology of CSF pathway
Obstruction
 Congenital anomalies: this is Commonly
seen in the area of Aqueduct, such as
forking of Aqueduct, gliosis or obstruction.
N.B. CNS is the commonest system in the
body liable to congenital anomalies.
 Post–traumatic or Post–Hemorrhagic:
Subarachnoid hemorrhage, whether
spontaneously (as in Ruptured Intracranial
aneurysm or AVM) or after head trauma
may result in inflammatory reactions,
adhesions, and obstruction of
subarachnoid space and so Hydrocephalus

12. Etiology of CSF pathway
Obstruction (Cont.)
 Post–Inflammatory or Post-meningitic:
Inflammation of Meninges usually heals by
Fibrosis and adhesions within the
subarachnoid Spaces, so obstruction of
CSF pathway.
 Neoplasm: Any abnormal mass such as
tumor or abscess along the pathway of
CSF may result in obstruction.
N.B: In some cases of Hydrocephalus, we
can not diagnose the underlying etiological
cause, this is what is called Hydrocephalus
of undetected cause. These cases are
mostly due to mild unnoticed Head trauma
or sub clinical Meningitis.

13. Questions?
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and Hydrocephalus at
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