HYDROCEPHALUSPresaented by :Faisal Hussain .Majid Ahmed .

Lecture Objective:

Definition Epidemiology. Anatomy and Physiology Classification . Pathogenesis . Etiology . Clinical feature . Diagnosis Management .

Definition and Epidemiology:

Definition : Hydrocephalus is a disorder in which the cerebral

ventricular system contains an excessive amount of cerebrospinal fluid (CSF) and is dilated because of increased pressure.

Epidemilogy: The prevalence of congenital and infantile

hydrocephalus has been estimated as 0.48 to 0.81 per 1000 live and still births

Anatomy:

Physiology:

CSF Production:site: choroid pluxes

Amount : 20ml/h .

Rate: 0.1 to 26 ml/h . wich affected by : age and weight

Total volume : Range from 50 to 150 ml .

CSF produced by active secretion and diffusion.

CSF Absorption : CSF is absorbed into the systemic circulation primarily across

the arachnoid villi into the venous channels of the sagittal sinus

Classification: Non communicating (obstructive ) The obstruction occurs at the Interventricular

foramina, the aqueduct of Sylvius, or the fourth ventricle and its outlets .

Note: The proximal area of ventricle system is diliated .

Communicating (non obstructive); due to :1- decrease absorption : inflammation of the

subarachnoid villi .2- increased secretion .e.g choroid pluxes papilloma

Pathology: Acute obstruction : 1- causes increased pressure and rapid enlargement of the ventricular

system. The frontal and occipital horns of the lateral ventricles enlarge first.

Symmetric dilatation of the remainder of the intracerebral CSF-containing spaces follows.

2-Iflattening of the gyri and 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. 5-. contributes to the development of interstitial edema of the

periventricular white matter. 6-Another compensatory mechanism that limits expansion of the ventricular

system in infants is spreading of the cranial sutures. chronic hydrocephalus the force of the fluid is distributed over the greater surface area of the

enlarged ventricular system

Etiology:

Congenital : A - Neural tube defect : e.g myelomeningocele has the following

1- obstruction of fourth ventricular outflow

2- flow of CSF through the posterior fossa due to the Chiari malformation

3- aqueductal stenosis .

B- Isolated hydrocephalus :

aqueductal stenosis in wich this stenosis may due to malformation or inflamation .

c- X-linked hydrocephalus :

aqueductal stenosis

D- CNS malformation : 1- Chiari II  portions of the brainstem and cerebellum are displaced

caudally into the cervical spinal canal. This obstructs the flow of CSF in the posterior fossa

2- Dandy Walker syndrome :atresia of the foramine of

Luschka and Magendie

3- Vein of Galen malformation : compression of the cerebral aqueduct .

Etiology : continued

Congenital continued : E- Intrauterine infection .  rubella, cytomegalovirus, toxoplasmosis, and syphilis F- Syndromi Hydrocephalus : 13 ,18 ,9 Acquired : 1- Infection e.g. meningites and encephalities . 2- Tumor : especially posterior fossa medulloblastomas,

astrocytomas, and ependymomas.

3- hemorrhage :a- subarachnoid space b- into the ventricular system

Symptoms: Symptoms

in infants

1. Poor feeding

2. Irritability

3. Reduced activity

4. Vomiting

Symptoms in children1. Slowing of mental capacity2. Headaches (initially in the morning) that are more

significant than in infants because of skull rigidity3. Neck pain suggesting tonsillar herniation4. Vomiting, more significant in the morning5. Blurred vision: This is a consequence of papilledema and

later of optic atrophy6. Double vision: This is related to unilateral or bilateral

sixth nerve palsy7. Stunted growth and sexual maturation from third

ventricle dilatation: This can lead to obesity and to precocious puberty or delayed onset of puberty.(hypothalmous)

8. Difficulty in walking secondary to spasticity: This affects the lower limbs preferentially because the periventricular pyramidal tract is stretched by the hydrocephalus.

9. Drowsiness

Signs: Children1. Papilledema: if the raised ICP is not

treated, this can lead to optic atrophy and vision loss.

2. Failure of upward gaze: This is due to pressure on the tectal plate through the suprapineal recess. The limitation of upward gaze is of supranuclear origin. When the pressure is severe, other elements of the dorsal midbrain syndrome (ie, Parinaud syndrome) may be observed, such as light-near dissociation, convergence-retraction nystagmus, and eyelid retraction (Collier sign).

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. Unilateral or bilateral sixth nerve palsy is secondary to increased ICP.

Infants1. Head enlargement: Head

circumference is at or above the 98th percentile for age.

2. Dysjunction of sutures: This can be seen or palpated.

3. Dilated scalp veins: The scalp is thin and shiny with easily visible veins.

4. Tense fontanelle: The anterior fontanelle in infants who are held erect and are not crying may be excessively tense.

5. Setting-sun sign: In infants, it is characteristic of increased intracranial pressure (ICP). Ocular globes are deviated downward, the upper lids are retracted, and the white sclerae may be visible above the iris.

6. Increased limb tone: Spasticity preferentially affects the lower

limbs.The cause is stretching of the periventricular pyramidal tract fibers by hydrocephalus.

Diagnosis:

Serial head measurement . The diagnosis is confirmed by

neuroimaging In a newborn, ultrasonography is the

preferred technique due to mobility and has no radition .

Infant and children CT and MRI . A lumbar puncture (LP) should be

performed in case of meningities or encephalities .

Differential Diagnosis:

Intracranial Hemorrhage Intracranial Epidural Abscess Epidural Hematoma Subdural Empyema Subdural Hematoma Brainstem Gliomas Meningioma Pseudotumor Cerebri: Pediatric Perspective Pituitary Tumors

Management:

Shunt : RT lateral ventricle to peritoneum . The catheter is connected to a one-way

valve system

Complication :

1-Infection: Staphylococcus epidermidis ,  S. aureus, enteric bacteria, diphtheroids, and Streptococcus species.

2- malfunction .

Management : continued

Medical Management :

Diuretics . Fibrinolytic therapy . Serial lumbar punctures .