3 Definition and Epidemiology : 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
5 Physiology: CSF Production: CSF Absorption : site: choroid pluxes Amount : 20ml/h .Rate: 0.1 to 26 ml/h . wich affected by : age and weightTotal 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
6 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
7 Pathology: Acute obstruction : chronic hydrocephalus 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 hydrocephalusthe force of the fluid is distributed over the greater surface area of the enlarged ventricular system
8 Etiology : Congenital : A - Neural tube defect : e.g myelomeningocele has the following1- obstruction of fourth ventricular outflow2- flow of CSF through the posterior fossa due to the Chiari malformation3- aqueductal stenosis .B- Isolated hydrocephalus :aqueductal stenosis in wich this stenosis may due to malformation or inflamation .c- X-linked hydrocephalus :aqueductal stenosisD- CNS malformation : 1- Chiari II portions of the brainstem and cerebellum are displacedcaudally into the cervical spinal canal. This obstructs the flow of CSF in the posterior fossa2- Dandy Walker syndrome :atresia of the foramine ofLuschka and Magendie3- Vein of Galen malformation : compression of the cerebral aqueduct .
9 Etiology : continued Congenital continued : E- Intrauterine infection . rubella, cytomegalovirus,toxoplasmosis, and syphilisF- Syndromi Hydrocephalus : 13 ,18 ,9Acquired :1- Infection e.g. meningites and encephalities .2- Tumor : especially posterior fossa medulloblastomas,astrocytomas, and ependymomas.3- hemorrhage :a- subarachnoid spaceb- into the ventricular system
10 Symptoms: Poor feeding Irritability Reduced activity Vomiting Symptoms in infantsPoor feedingIrritabilityReduced activityVomitingSymptoms in childrenSlowing of mental capacityHeadaches (initially in the morning) that are more significant than in infants because of skull rigidityNeck pain suggesting tonsillar herniationVomiting, more significant in the morningBlurred vision: This is a consequence of papilledema and later of optic atrophyDouble vision: This is related to unilateral or bilateral sixth nerve palsyStunted growth and sexual maturation from third ventricle dilatation: This can lead to obesity and to precocious puberty or delayed onset of puberty.(hypothalmous)Difficulty in walking secondary to spasticity: This affects the lower limbs preferentially because the periventricular pyramidal tract is stretched by the hydrocephalus.Drowsiness
11 Signs : Infants Children Head enlargement: Head circumference is at or above the 98th percentile for age.Dysjunction of sutures: This can be seen or palpated.Dilated scalp veins: The scalp is thin and shiny with easily visible veins.Tense fontanelle: The anterior fontanelle in infants who are held erect and are not crying may be excessively tense.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.Increased limb tone: Spasticity preferentially affects the lower limbs.The cause is stretching of the periventricular pyramidal tract fibers by hydrocephalus.ChildrenPapilledema: if the raised ICP is not treated, this can lead to optic atrophy and vision loss.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).Macewen sign: A "cracked pot" sound is noted on percussion of the head.Unsteady gait: This is related to spasticity in the lower extremities.Large head: Sutures are closed, but chronic increased ICP will lead to progressive macrocephaly.Unilateral or bilateral sixth nerve palsy is secondary to increased ICP.
12 Diagnosis : Serial head measurement . The diagnosis is confirmed by neuroimagingIn 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 .
14 Management : Shunt : RT lateral ventricle to peritoneum . The catheter is connected to a one-way valve systemComplication :1-Infection: Staphylococcus epidermidis , S. aureus, enteric bacteria, diphtheroids, and Streptococcus species.2- malfunction .
15 Management : continued Medical Management :Diuretics .Fibrinolytic therapy .Serial lumbar punctures .