an overview on Hydrocephalus : introduction, pathophysiology and associated conditions.

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

17. THANK YOU