Presentation on theme: "PHYSIOLOGY OF CSF AND PATHOPHYSIOLOGY OF HYDROCEPHALUS"— Presentation transcript:
1PHYSIOLOGY OF CSF AND PATHOPHYSIOLOGY OF HYDROCEPHALUS
2Introduction Dynamic component of CNS Invaluable tool to diagnosis Physiological reservoir of human proteomeReflects the physiologic state of CNS
3Historical account Hippocrates described fluid in brain Galen described ventriclesVesalius showed the anatomyMegendi performed first cisternal puncture in animalsQuinke performed first LPDandy was credited first ventricular punctureQuekensted did first cisternal puncture in humans.
4Functions of CSF Mechanical cushion to brain Source of nutrition to brainExcretion of metabolic waste productsIntracerebral transport mediumControl of chemical environmentAutoregulation of intracranial pressure
5Production of CSF Choroidal Extrachoroidal Ependyma ? Neighboring brain substanceIn children with foramen of megendi and lushka block, spinal thecal sac still is bathed in CSF.choroid plexectomy does not releieve hydrocephalus.
6Facts of interestOnly choroidal CSF production is tightly regulated active processCSF secretion shows diurnal variation with peak in the morning.
7Factors affecting production Vascular bed autoregulationIntracranial pressureBrain metabolismDrugs
8Absorption of CSF Arachanoid granulations Along the olfactory nerves Extracellular spaces in brainBrain substance ( glial cells).
26Decreased absorption Due to anatomical block in the pathways Block at arachanoid granulations level
27Increased venous pressure Evidence with this theoryVOGMExperimental studies in animalsEvidence against this theoryLigation of various sinuses doesn’t cause HCPExperimental studies
28Pathology of hydrocephalus Atrophy of white matterSpongy edema of brainFibrosis of choroid plexusesStretching and denuding of ependymaFenestration of septum pellucidumThinning of interhemispheric commisures
29Acute HCP Cerebral, IV or cerebellar hematoma Paraventricular tumors GunshotsSubarachanoid hemorrhageAcute head injuriesShunt malfunction.
30Progression Ventricular dilatation Occipital and frontal horns f/b temporalsAnterior and posterior recess of TVFourth ventricleThird ventricular balloning
31Hydrocephalic edema Available space in the cavity consumed Stretching and denuding of ependymaEdema of white matter
32Mechanism Stasis of brain interstitial fluid Reflux of CSF into the periventricular areaIncrease in cerebral capillary permeability
33Progression Dorsal angles of lateral ventricle 3-6 hrs Centrum semiovale19-24 hrsDiffuseafterwards
34Chronic HCP Compensatory mechanisms in chronic HCP Expansion of skull Contraction of cerebral vascular volumeWhite matter atropy and ventricular enlargementDecreased rate of CSF formation.Diversion of CSF flow to alternative pathways
35Changes in cerebral circulation Increased venous pressureDelayed emptying of cerebral veinsNarrowing of cerebral arteriesProlongation of circulation timeReduced cerebral blood flowLowering of CMRO2Reduced glucose metabolism
36Clinical features Age Expansibility of skull bones Type of HCP Duration of HCP
37Pediatric hydrocephalus Enlargement of headThin and glistening scalpTense, bulging fontanallesDilated and tortuous scalp veinsunilateral or bilateral abducent palsiesCracked pot or macewen`s signHypopituitarism and growth retardationTransillumination of skull
38Adult acute HCP Headache, nausea, vomitting Alteration of sensorium Visual obscurationsPerinaud`s syndromeProgression to herniation syndromes
40Normal pressure hydrocephalus “Hydrocephalus with normal CSF opening pressure on lumber puncture and absence of papilloedema”
41PathophysiologyIntermittant rise of CSF pressure causing ventricular dilatation.Intraventricular pressure head is decreased
42Basis of clinical symptoms Gait problemsUrinary incontinenceMemory problems
43Arrested hydrocephalus DefinitionsCSF pressure has normalizedPressure gradient between ventricles and parenchyma has been dessipatedVentricular size remains stable or decreaseNew neurological deficits do not appearAdvancing psychomotor development with age.
44Pediatric NPH Enlarged head usually in or above ninth percentile History of delayed psychomotor developmentMild to moderate mental retardationGlib verbal abilitiesMild spastic paraparesis
45Hydrocephalus ex vacuo Cerebral atrophy and dilatation of sulciIntracranial pressure is normalAbsence of periventricular edemaAbsence of retrograde filling Isotope cisternography