Pediatric Hydrocephalus

Brief description of hydrocephalus, types, pathology and management options

1. Pediatric Hydrocephalus
Dr. Mohamed Hassanein

2. Objectives
Definition
Epidemiology
Anatomy & Physiology
Classification
Pathology
Etiology
Clinical feature
Diagnosis
Management

3. Hydrocephalus
Definition
•An excessive accumulation of CSF within the ventricular space at an
inappropriate pressure due to a disturbance of formation, flow or
absorption.

•Derived from the Greek words "hydro" meaning water and "cephalus"
meaning head.

•If left untreated  Abnormal widening of brain spaces  potentially
pressure on brain & increased intra-cranial pressure (ICP)  brain
damage or death
Classic concept of hydrocephalus is characterized by
• Increased CSF volume
• Dilatation of the CSF pathways
• Increased intracranial pressure

4. •As a single congenital disorder:
The incidence has been reported as 0.5 to 1.5 per 1,000 births.
Epidemiology (Pediatric Hydrocephalus)
• Secondary to other insult (prematurity, tumor, trauma):
The incidence increases to 0.9 to 3.5 per 1,000 births.
•The incidence has declined in developed countries
Antenatal imaging and genetic testing  Pregnancy termination
Maternal folate supplementation  ↓ Neural tube defects
Better perinatal management of prematurity ↓IVH
•Males = females

5. Anatomy
Pathway of CSF Flow
lateral ventricles → Foramina of
Monro → 3
rd
ventricle → Sylvian
aqueduct → 4
th
ventricle →
Foramina of Luschka and Magendie
→ SA space → Resorption into
venous system.
CSF: Clear fluid flows through the
ventricles, exits into cisterns (serve
as reservoirs), bathes the surfaces
of the brain and SC, and then
reabsorbs into the bloodstream.

7. Anatomy

8. Physiology
CSF Production
•Dialysis of blood in the choroid
plexus (diffusion & active transfer).
•Other sources: ependymal lining ,
ECF, capillaries, nerve root sleeves.
•Produced at a rate of 20ml per hour.
CSF Volume
•Neonate: 20 - 40 ml
•Infant: 60 - 90 ml
•Child: 100 -120 ml
•Adult: 150 -170 ml 120 - 150 ml in cranial and spinal SA spaces
30 - 40 ml in the ventricles
Safe Spinal Tap ???

9. CSF Absorption
•Across the arachnoid villi (microscopic) into
the venous channels of the SSS
(Clumps of arachnoid villi = arachnoid granulation)

•Significant amount also drains through:
The cribriform plate
Skull base lymphatics
Spinal nerve root sleeves

•Absorbed at a rate of 20ml per hour.

•Turned over approximately 3-4
times/day.

Physiology

10. CSF analysis (from the lumbar region)

•Protein: 15 to 45 mg/dl
(↓ concentration in childen and in cisternal & ventricular spaces)

•Glucose: 50-80 mg/dl (two-thirds of blood glucose)

•Mononuclear cells: 0-5 per cm.
•RBCs: 0-10 per cm in adult (higher in neonates)

CSF Pressure (lying on side)
•Neonate: -1 - 1.5 mm Hg ( 10-20 mm water)
•Infant: 2-6 mm Hg (20-80 mm water)
•Child : 3-7 mmHg (50-150 mm water)
•Adult: 10-15 mm Hg (135-200 mm water, 200-300 mm with sitting up)

Physiology

11. CSF Function

•Supports the brain (Wt = 1500 gm → ≈ 50 gm).

•Acting as a cushion "shock absorber“.

•Delivers nutrients to the brain and removes waste.

•Flows between the cranium and spine and compensate for
changes in ICP (=10% of IC contents)

•Immune function: Immunoglobulins.

•Other; homeostasis (temp, osmotic pressure), distribution
of neurotransmitters, endocrine effects.

Physiology

12. Classifications of HCP

13. FUNCTIONAL CLASSIFICATION

Two main subdivisions

1.Obstructive
 Block within the ventricular system
 Block proximal to the arachnoid granulations (AG)
(Foramen of monro, aqueduct, 4
th
ventricle or its outlet)
 Enlargement of ventricles proximal to block
2. Communicating
 CSF circulation blocked at level of AG
 Ventricles communicating with SA space
 Obstruction of CSF absorption

14. Congenital vs Acquired
Congenital hydrocephalus
Present at birth, associated with developmental defects
Acquired hydrocephalus
Occurs after development of the brain and ventricles
Simple vs complex
Intraventricular vs Extraventricular

15. Pathology
1- Increased pressure → enlargement of the ventricles (frontal and
occipital horns), then remaining CSF-containing spaces follows.

2- flattening of the gyri & compression of the sulci against the cranium.

3- obliterating the subarachnoid space over the hemispheres.

4- The vascular system is compressed, and the venous pressure in the
dural sinuses increases → interstitial edema of the periventricular
white matter.

Compensatory mechanism  Spreading of the cranial sutures that
limits ↑ICP & expansion of the ventricular system in infants.

16. Etiology of Pediatric Hydrocephalus
Congenital (60% of patients)

1- Aqueductal stenosis
Primary : forking, septum, atresia (infancy)
Secondary (gliosis): IU infection, GM hemorrhage
2- Chiari malformations
A. Type 2 (MM): in 30% of congenital HCP
B. Type 1 : 4th ventricle outlet obstruction
3- Neural tube defects

4- Dandy Walker malformation: atresia of foramina of L&M

5- Intrauterine infection: rubella, CMV, toxoplasmosis, syphilis

6- X-linked inherited disorders: Bickers-Adams synd., males, 3%.

17. Acquired
1- Infection
•Meningitis (bact., TB): Aqueductal stenosis, leptomeningeal fibrosis
•Intraventricular cysticercosis (+ mechanical obstruction)

2- Hemorrhage (adhesive arachnoiditis)
prematurity, trauma, vascular malformations, SAH
3- Tumors
Posterior fossa, craniopharyngioma, brainstem/chiasmal glioma
less common: pineal, colloid, choroid papilloma, pituitary
4- Iatrogenic: (post op, hypervitaminosis A)
5- Idiopathic
Etiology of Pediatric Hydrocephalus

18. Clinical Features
Symptoms in infants

•Poor feeding
•Irritability
•Reduced activity
•Vomiting


Symptoms in children
Headaches & vomiting (↑skull rigidity)
Neck pain (tonsillar herniation)
Blurred vision (papilledema/ optic atrophy)
Double vision (sixth nerve palsy)
Stunted growth and sexual maturation
(third ventricle dilatation→ hypothalamus)
Difficulty in walking & LL spasticity (stretch
of the periventricular pyramidal fibers)
Incontinence & Mental slowness

19. Signs
Infants
Head enlargement
Head circumference is ≥ the
98
th
percentile for age.

Deformed sutures

Dilated scalp veins

Tense fontanelles

Setting-sun sign

Increased limb tone
Children
1.Papilledema: raised ICP, optic atrophy and
vision loss.
2.Failure of upward gaze: pressure on the
tectal plate . When the pressure is severe
 dorsal midbrain syndrome (Parinaud)
3.Macewen sign: A "cracked pot" sound is
noted on percussion of the head.
4.Unsteady gait: This is related to spasticity
in the lower extremities.
5.Large head: Sutures are closed, but chronic
increased ICP will lead to progressive
macrocephaly.
6.Sixth nerve palsy is secondary to increased
ICP.

21. Diagnosis
Serial measurement of head circumference (OFC)

Indicators

•Upward deviation of curve
•Head growth > 1.25cm/wk
•OFC = 2 SD above normal
•Out of proportion with body length or weight, even if
normal for age

22. Preferred in newborn
•Through open Fontanelle
•Mobility
•No radiation exposure
•Prenatal diagnosis
•Lat vent > post fossa
Ultrasonography
Neuro-imaging

23. •Flattened Sylvian &
interhemispheric fissures

•Cerebral sulci are not
visible


CT Criteria
•Both temporal horn are
>2mm
•The ratio FH/ID>0.5

24. •Ratio of FH to maximal bi-parietal diameter (BPD)
•Measured in the same CT slice
•If > 0.3  Suggests hydrocephalus

25. •Ballooning of frontal horns
& and 3
rd
ventricle.
(Mickey mouse ventricles)


•Periventricular low density
on CT or high intensity
signal on FLAIR MRI 
Trans-ependymal flow??

26. Upward displacement of
corpus callosum



Thinned out corpus callosum
Decreased mamillo-pontine
distance ( normal >5.5mm)

27. Inferior displacement of the
floor of the 3rd ventricle



Outward bowing of the walls
& recesses of 3
rd
ventricle
(infundibular, optic and pineal recesses)

28. Management
MEDICAL

Diuretics (acetazolamide-furosemide)
•Improve resumption of normal CSF absorption (bloody CSF)
•Used for short periods in slowly progressive HCP
•Used in patients too unstable for surgery (max 6 mons)
•S/E: electrolyte imbalance, lethargy, tachypnea, paraesthesia.

Fibrinolytic

29. Serial Spinal/ Ventricular Tapping
•LP performed only in communicating HCP

•Can be performed for post hemorrhagic HCP (transient in 50%)

•HCP can resolve following resumption of normal CSF absorption

•If HCP did not resolve with CSF protein < 100 mg/dL 
spontaneous resorption is unlikely

•Ventricular tap

30. Surgical treatment
Goals
•Minimizing brain damage
•Improving CSF flow & decreasing ICP
•Improve neurologic function
•Good cosmetic result
•” not “normal sized ventricles

Options
1.Shunting
2.Endoscopic procedures
3.Eliminating the cause of obstruction

31. Shunting
Diverts CSF from the ventricles into the systemic circulation or to a
cavity (peritoneum, pleura, gall bladder, ureter).
Ventriculo-peritoneal shunting

•Most commonly used.
•Preferred for growing children
and most adults.
•Lateral ventricle is the usual proximal
location.
•The peritoneal cavity accept loop of tubing
to accommodate the axial growth
Ventriculo-atrial shunting: through jugular vein into SVC

33. Contraindication for shunting
•Active ventriculitis.
•Fresh ventricular hemorrhage
•Active systemic infection.
•Open meningeocele (infection)

34. Complications of shunt (various)
•Infections: Staph. epidermis and Staph. aureus.
•Obstruction of the catheter/ Misplacement/ fracture.
•Over shunting (SD bleed, slit ventricles)
•Seizures (5% in 1
st
year)
•Conduit for metastasis.
•Silicone allergy, skin erosion.

Approximately 40% of shunts malfunction occurs within the
first year after placement

35. Advantages
•Independence from a shunt
•Rapid recovery
•low-cost and durable
Endoscopic 3
rd
Ventriculostomy (ETV)
A fenestration is made in the floor of the 3
rd
ventricle to
connect it to the subarachnoid space
Overall success rate =56% (60-90% )
Highest success with acquired AS
Success rate is lower in
•Under-developed subarachnoid space (young).
•Pre-existing pathology (tumor, previous shunt, previous SAH,
WBRT, adhesions)

36. Endoscopic 3
rd
Ventriculostomy (ETV)
Indications
•Obstructive HCP
•Treatment of choice for acquired aqued. stenosis
(20% of patients still require shunting)
•Shunt complications
Infection(removal of hardware).
Subdural hematomas

Contraindication
Communicating HCP

37. Factors that increase probability of ETV success:
• Obstructive hydrocephalus
• Child older than one year old
• Recent onset of obstruction
• Normal ventricular anatomy
• Enlarged ventricles
• absence of history of SAH or meningitis
Endoscopic 3
rd
Ventriculostomy (ETV)

38. Complications
•Hypothalamic injury.
•Memory disorders
•Transient 3
rd
and 6
th
nerve palsies.
•Uncontrollable bleeding.
•Cardiac arrest (2%).
•Traumatic basilar artery aneurysm.
•Stoma occlusion

Endoscopic 3
rd
Ventriculostomy (ETV)

39. Endoscopic choroid plexus coagulation
First done by Dandy
open, high mortality

Indications
•Communicating slowly progressing HCP
•Choroid plexus papilloma/hyperplasia.
•Intractable shunt failure.

Contraindication
Obstructive HCP.

40. Endoscopic Procedures
•Septostomy  Unilateral, Multi-loculated
HCP.
•Aqueductoplasty / Stenting.
•Cysts with secondary HCP
(Arachnoid, Cysticercal).
•Colloid cyst of third ventricle.
•Pineal region tumors  ETV + Biopsy.

41. Prognosis
•Difficult to predict and related directly to the cause of HCP.

•Survival in untreated hydrocephalus is poor.

•Approximately 50% die before 3 years of age, and 70% die
before reaching adulthood.

•Treatment markedly improves the outcome for HCP not
associated with tumor

•Functional outcome depends upon: associated CNS
malformations, degree of prematurity, epilepsy, motor
impairments and success of treatment.