This document discusses hydrocephalus, which refers to an excessive accumulation of cerebrospinal fluid (CSF) within the ventricular system of the brain. It defines the different types of hydrocephalus as either primary or secondary, communicating or non-communicating. Primary hydrocephalus results from obstruction of CSF flow, overproduction of CSF, or deficient reabsorption of CSF. Non-communicating hydrocephalus involves enlargement of only part of the ventricular system due to obstruction at sites like the third or fourth ventricle. Causes, symptoms, and features of the different types of hydrocephalus are described.

1. HYDROCEPHALUS

2. Overview of CSF production
Choroid plexus
Circulates in ventricular system
Through foramina of Luschka & Magendie
Enter cisterna magna
Absorbed by arachnoid granulations

3. Definition
• Hydrocephalus refers to accumulation of
excessive CSF within the ventricular system.
• increased volume of CSF within the skull,
accompanied by dilatation of ventricles

4. INCIDENCE
• Dilatation occurs due to intermittent rise in CSF
mostly occurring at night
• Occurring in old age commonly in combination
with gait apraxia, dementia & urinary
incontinence

5. TYPES
PRIMARY
Communicating
hydrocephalus
Non- Communicating
hydrocephalus
SECONDARY

6. Primary hydrocephalus
• Actual increase in CSF within the skull along
with elevated ICP
• MECHANISMS:
– Obstruction to flow of CSF
– Overproduction of CSF
– Deficient reabsorption of CSF
• Commonest cause : obstruction to flow

7. Non- Communicating hydrocephalus
• Enlargement of only a portion of ventricular
system
• Major sites of obstruction
– 3rd ventricle
– Exit foramina in 4th ventricle
CSF can’t pass to subarachnoid space
Enlargement

8. Causes of Non- Communicating
hydrocephalus
1) Congenital non-communicating hydrocephalus
– Stenosis of aqueduct
– Arnold chiari malformation
– Progressive gliosis of Aqueduct
– Intra- uterine meningitis

9. Causes of Non- Communicating hydrocephalus
2) Acquired non—communicating hydrocephalus
• Occur due to expanding lesions of skull
– Tumor adjacent to ventricular system :
ependymoma, choroid plexus papilloma,
medulloblastoma etc.
– Inflammatory lesions : cerebral abscess, meningitis
– Hemorrhage : parenchymal hemorrhage, intra-
ventricular hemorrhage, epidural & subdural
hematoma

10. Communicating hydrocephalus
• Entire ventricular system is enlarged
• Causes are mostly non-obstructive like
–Overproduction of CSF : choroid plexus
papilloma
–Deficient reabsorption of CSF : following
meningitis, sub-arachnois hemorrhage &
dural sinus thrombosis

11. Communicating hydrocephalus
• When causes are obstructive:
Obstruction at subarachnoid space at base of
brain
Enlargement of ventricular system
CSF flows freely between dilated ventricles and
spinal canal

12. Hydrocephalus ex vacuo
• Dilatation of ventricular system with
compensatory increase in CSF volume
secondary to a loss of brain parenchyma

13. Secondary hydrocephalus
• Less common
• Compensatory increase in CSF due to loss of
neural tissue without associated rise in ICP
• Seen in cerebral atrophy & infarction

14. GROSS features
• Dilation of ventricles depending upon site of
obstruction
• Thining & stretching of brain
• Engorgement of Scalp veins overlying enlarged
head
• Fontanelle remain open

15. MICROSCOPIC features
In severe hydrocephalus,
• Damage to ependymal lining of ventricles
• Periventricular interstitial edema

16. CLINICAL FEATURES
• Develops in infancy before closure of cranial
sutures which leads to increase head
circumference
• In Hydrocephalus developing after closure of
sutures, there is increase in ICP & dilatation of
ventricles without change in head
circumference

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