4 Hydrocephalus…. CSF physiology Secreted at the choroid plexus of the ventriclesAbsorbed at arachnoid villi and channeled into the venous circulation720 ml CSF is secreted in a day
5 CSF CirculationIt is produced in the brain by modified ependymal cells in the choroid plexus (approx %),The remainder is formed around blood vessels and along ventricular wallsIt circulates from the choroid plexus through the interventricular foramina (foramen of Monro) into the third ventricle,Then through the cerebral aqueduct (aqueduct of Sylvius) into the fourth ventricle, where it exits through two lateral apertures (foramina of Luschka) and one median aperture (foramen of Magendie)It then flows through the cerebellomedullary cistern down the spinal cord and over the cerebral hemispheres.
6 CSF Circulation..Traditionally, it has been thought that CSF returns to the vascular system by entering the dural venous sinuses via the arachnoid granulations/villi. However, there is suggestion that the CSF flow along the cranial nerves and spinal nerve roots allow it into the lymphatic channels; this flow may play a substantial role in CSF reabsorbtion, particularly in the neonate, in which arachnoid granulations are sparsely distributed.
7 Hydrocephalus… Types Communicating Hydrocephalus No blockage in the CSF flowNon-communicating HydrocephalusBlockage of CSF flowCommonly at the level of aqueduct or foramina of Luschaka and Magendie
9 Dandy-Walker malformation Characterized byAgenesis or hypoplasia of the cerebellar vermis,Cystic dilatation of the fourth ventricle,Enlargement of the posterior fossa.Approximately 70-90% of patients have hydrocephalus, which often develops postnatallyDandy-Walker malformation may be associated with atresia of the foramen of Magendie and, possibly, the foramen of Luschka
10 Arnold-Chiari Syndrome A downward displacement of the cerebellar tonsils and the medulla through the foramen magnum.Portions of cerebellum and brain stem herniate into cervical spinal canal
11 Types of Arnold-Chiari Malformation Type I: generally asymptomatic during childhood, but often manifests with headaches and cerebellar symptoms.Type II: usually accompanied by a myelomeningocele leading to partial or complete paralysis below the spinal defect. Abnormal development of the cerebellar vermis and medulla occur, and they both descend into the foramen magnum. Hydrocephalus is also nearly always present.Type III causes severe neurological defects. It is associated with an encephaloceleType IV involves a failure of brain development
13 Hydrocephalus…. Hydrocephalus Ex Vacuo also called normal pressure hydrocephalusVentricular dilatation due to cerebral atrophyNo increase in CSF pressure
14 Clinical features Inappropriate enlargement of head size Delayed closure of fontanel and suturesProminent foreheadProminent scalp veinsSunset sign in eyesSigns and symptoms of raised ICPPersonality and behavioral changes
16 Hydrocephalus…. Diagnosis Serial measurement of head circumference (An increase in head circumference more than cm in every 2 weeks in first 3 months of life-diagnostic)-USG head-CT/ MRI of head
17 Differential diagnosis of large head Megalencephaly: Hurler’s syndrome, metachromatic leukodystrophy, Tay Sach’s diseaseNo signs of raised ICPVentricles are not enlargedNormal CSF pressureChronic subdural hematomaFamilial macrocephaly
18 Treatment of Hydrocephalus General nursing careMedical management to decrease CSF volume and CSF pressure : Acetazolamide, oral GlycerolManagement of raised ICPTreatment of the causeSurgical treatment : ventriculo-peritoneal shunt, removal of the cause of obstruction
19 Neural Tube DefectsCongenital structural anomalies characterized by failure of proper closure of neural tube and covering mesoderm and ectoderm
20 Neural Tube Defects Very common structural congenital anomaly Incidence is 1.5 per 1,000 live birthsRisk in second sibling is 5 per live 100 births
21 Neural Tube Defects Etiology Decreased maternal folate intake Multifactorial inheritanceOther maternal risk factors including alcohol, radiation exposure, DM, Valproate, Carbamazepine and zinc deficiencyChromosomal abnormalities like trisomy of 13 and 15
22 Neural Tube Defects Clinical features Commonest defect is spina bifida Others might be anencephaly, encephalocele….Defect will be obvious at birthCommonly associated with other anomaliesLower body paralysisBowel and bladder dysfunctionLearning disabilitiesHydrocephalus
24 Neural Tube Defects (NTD) Spina bifidaSpina bifida occulta: the mildest form of spina bifida (occulta means hidden). Most children with this type of defect never have any health problems, and the spinal cord is often unaffected.
25 Spina bifidaMeningocele : involves the meninges, the membranes responsible for covering and protecting the brain and spinal cord. If the meninges push through the hole in the vertebrae, the sac is called a meningocele.
26 Spina bifida..Myelomeningocele : the most severe form of spina bifida. It occurs when the meninges push through the hole in the back, and the spinal cord also pushes though. Most babies who are born with this type of spina bifida also have hydrocephalus,
27 Spina bifida..Because of the abnormal development of and damage to the spinal cord, a child with myelomeningocele typically has some paralysis. The degree of paralysis largely depends on where the opening occurs in the spine. The higher the opening is on the back, the more severe the paralysis tends to be.
28 Diagnosis of NTDPrenatal diagnosisAlpha fetoprotein level in maternal serum between weeks of pregnancyAmniocentesis for alpha fetoprotein level in amniotic fluid in early pregnancyUSG of the fetus
29 Diagnosis of NTD Postnatal diagnosis USG of head, sac, kidney CXR and X-Ray spineC/S of the leaking CSF and swab C/S from the lesionRoutine investigations
31 Treatment of NTD Decision of treatment depends on Degree of paralysis Presence of hydrocephalusKyphosisOther congenital anomaliesEvidence of infection of CNS
32 Treatment of NTD Surgery EARLY CLOSURE PREVENTS NEUROLOGICAL DETERIORATIONOPEN LESION WITH CSF LEAK SHOULD BE CLOSED WITHIN 24 HOURSCLOSED LESION SHOULD BE REPAIRED WITHIN 48 HOURSINFECTED LESION SHOULD BE REPAIRED ONLY AFTER CSF BECOMES STERILE ( should be given parenteral antibiotics)
33 Treatment of NTD Lorber’s criteria for selective surgery Surgery is not done in case ofSevere paraplegia at or below L3 levelKyphosis/ scoliosisGross hydrocephalusAssociated gross anomaliesIntracerebral birth injuriesNeonatal ventriculitis before closure of the back90% would die within the neonatal period
34 PreventionFolic acid supplementation to all pregnant women– 0.4 mg/ dayIf there is history of previous birth of NTD babies then 5 mg/ day folic acidCounseling of the family with previous child with NTDRisk of recurrence- 3.5% with 1 affected child10% with 2 affected child25% with 3 affected childFolate supplementation reduces recurrence risk by 70%