Hidrocefalia

2. Hidrocefalia • Es un trastorno en el que una cantidad excesiva de líquido cefalorraquídeo se acumula dentro de los ventrículos cerebrales y / o espacios subaracnoideos. debido a los trastornos de la circulación del LCR

3. EPIDEMIOLOGÍA - • La prevalencia de la hidrocefalia congénita e infantil en los Estados Unidos y Europa se ha estimado en 0,5 a 0,8 por 1.000 nacidos vivos. • Aproximadamente 15 a 25 por ciento de estos casos están asociados con mielomeningocele (espina bífida)

4. • Los factores asociados con un mayor riesgo de hidrocefalia infantil incluyen • ●El peso al nacer <1500 g • ●La prematuridad (edad gestacional ≤ 30 semanas) • ●Materna diabetes • ●Bajo nivel socioeconómico • ●El sexo masculino • ●Raza / etnia ,el riesgo se reduce en asiáticos

5. clasificación 1. HIDROCEFALIA COMUNICANTE: ocurre cuando el flujo del LCR se ve bloqueado después de salir de los ventrículos al espacio subaracnoideo. se denomina comunicante porque el LCR aún puede fluir entre los ventrículos, que permanecen abiertos. La reabsorción del LCR está alterada en las vellosidades aracnoideas por infecciones o hemorragia. Dependiendo de la velocidad de instauración y de la edad del paciente, puede ser una hidrocefalia aguda, que puede complicarse con herniación cerebral, una hidrocefalia crónica, con signos y síntomas de aparición lenta e hipertensión endocraneana. Los criterios clínicos de sospecha diagnóstica son: trastornos de la marcha, demencia (cursa con retraso mental en los niños y demencia en los adultos) e incontinencia urinaria.

6. 2. HIDROCEFALIA NO COMUNICANTE: “OBSTRUCTIVA” dependiendo de que el sistema ventricular se encuentre o no aislado de las cisternas de la base , se produce cuando el flujo del LCR se ve bloqueado a lo largo de una o más de las vías estrechas que conectan los ventrículos. CAUSAS: “estenosis acueductal”, más frecuente en hidrocefalia congénita. Otra causa: malformación de Arnold- Chiari, tumor en tronco del encéfalo, cerebelo y región pineal o por hemorragias cerebrales y subaracnoideas o cicatrices posmeningitis.

7. CONGÉNITAS: se halla presente al nacer y puede ser ocasionada por factores ambientales durante el desarrollo del feto o por predisposición genética. ADQUIRIDAS: puede afectar a personas de todas las edades por una lesión o enfermedad. .

9. 3. Según la edad de presentación se puede diferenciar la hidrocefalia del adulto y de la infancia. Las causas más frecuentes en el adulto son: la patología tumoral (gliomas, meningiomas, quiste coloide, etc.), los abscesos cerebrales, los traumatismos craneales y los hematomas intracraneales.

10. 4. según la forma de instauración: a. AGUDA: primeras 3 á 6 hrs, estabilizándose a las 24-48 horas. Hemorragias ventriculares en el hombre. Ej. ruptura de malformación Arteriovenosa con formación de hematoma Intra Cerebral puede producir obstrucción aguda del foramen de Monro, produciéndose dilatación de Ventrículos laterales. b. SUB-AGUDA: 3 días a 3 semanas la dilatación ventricular es lenta, con atrofia de la sustancia blanca lo que es reversible si no hay destrucción Neuronal y axonal. En niños pequeños se produce además separación de suturas. c. CRÓNICA: Obstrucción por 3 ó más semanas de duración, La dilatación ventricular se hace a expensas del cerebro. El edema de la sustancia blanca es importante, con atrofia progresiva de las células gliales, mielina, axonas, en contraste con etapas precoces de la hidrocefalia.

11. Otras formas de hidrocefalia afectan principalmente a los adultos, y son: HIDROCEFALIA EX VACUO: Ocurre cuando hay daño cerebral, ocasionado por una enfermedad cerebrovascular o una lesión traumática, en estos casos, puede haber una verdadera atrofia o malacia cerebral focal. HIDROCEFALIA A PRESIÓN NORMAL : Ocurre comúnmente en las personas mayores y está caracterizada por síntomas asociados a otras condiciones que ocurren a menudo en los ancianos, tales como pérdida de memoria, demencia, trastorno de la marcha, incontinencia urinaria y una reducción general de la actividad normal de la vida diaria.

12. Etiología

13. • Estenosis del acueducto

14.

15. • Estenosis del acueducto ligada al X

16.

17. Mielomeningocele y malformación de Arnold Chiari tipo II

18. • Malformación de Chiari tipo I

19. • Malformación de Dandy Walker

20. • Malformación de la vena de Galeno

21. • Quistes aracnoides

22. • Hidrocefalia posthemorrágica

23. • Infección intrauterina

24. • Tumores

25. • Hidrocefalia de presión normal

26. CUADRO CLÍNICO • Macrocefalia • Fontanela amplia y tensa • Suturas craneanas separadas • Circulación colateral • Ojos en sol naciente • Vómitos • Estrabismo • Nistagmus • Irritabilidad.

27. DIAGNÓSTICO • Ultrasonografía • Tomografía Computada • Resonancia Magnética

28. Ventriculostomía endoscópica

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The most common cause of hydrocephalus in children is aqueductal stenosis, and it accounts for 70 % of cases. Enlargement of the lateral and third ventricles with a normal fourth ventricle. This constriction of the aqueduct of Sylvius is best seen on MRI scan (sagittal view). Stenosis of this passageway may be congenital or acquired, although in 50–75 % of cases, the Cause may be unknown. It may be associated with Chiari I malformation, vein of Galen malformation, or Dandy-Walker malformation. Aqueductal Stenosis may also be due to an X-linked Recessive gene, L1CAM mutation ocurring only in males. Acquired cases of aqueductal stenosis may be the result of hemorrhage, inﬂammation from infection, or obstruction from a nearby tumor or cyst.
Better delineates the extent of obstructive hydrocephalus, with enlargement (often marked) of the lateral and third ventricles. The aqueduct may show funnelling superiorly. The 4th ventricle is not dilated. In cases of secondary obstruction the underlying abnormality may also be eviden. Isolated hydrocephalus is frequently caused by aqueductal stenosis
X-linked hydrocephalus — The most common genetic form of congenital hydrocephalus is X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (aqueductal stenosis), which accounts for about 5 percent of cases of congenital hydrocephalus [12]. Approximately 50 percent of affected boys have adducted thumbs, which is helpful in making the diagnosis. Some have other CNS abnormalities such as agenesis (or dysgenesis) of the corpus callosum, small brainstem, pachygyria, polymicrogyria, or absence of the pyramidal tract [14]. This disorder is due to mutations in the gene encoding L1, a neuronal cell adhesion molecule that belongs to the immunoglobulin superfamily and that is essential in neurodevelopment [15]. The gene for L1 has been mapped to Xq28. Mutations in L1 also result in other conditions, known as the L1 spectrum, that are characterized by neurologic abnormalities and by mental retardation. These include MASA spectrum (Mental retardation, Aphasia, Shuffling gait, Adducted thumbs), X-linked spastic paraplegia type 1, and X-linked agenesis of the corpus callosum.
Myelomeningocele is a neural tube defect that occurs during embryonic development resulting in failure of the neural tube to close. This malformation Involves the entire CNS. At the level of The spinal defect, there is a midline lesion containing meninges, spinal cord, nerves, and CSF. Chiari II malformation occurs in almost all infants born with myelomeningocele. malformation of the hindbrain, fourth ventricle, and brainstem and includes herniation of these structures into the cervical spinal canal. Hydrocephalus develops in about 85 % of children with myelomeningocele. Approximately 50 % have signi ﬁ Cant hydrocephalus at birth. About 80–90 % will eventually require a CSF shunt or an endoscopic third ventriculostomy. Infants and children who die from this complex condition usually die from the Chiari II malformation and brainstem dysfunction
the cerebellar tonsils are elongated and herniated into the cervical spinal canal Hydrocephalus occurs in 10 % of children with Chiari I malformation, most likely due to blockage of CSF ﬂ ow at the craniovertebral junction. A small posterior fossa may also alter CSF ﬂ ow.
Dandy-Walker is found in 2–4 % of all children with hydrocephalus The abnormalities associated with these conditions include cystic dilation of the fourth ventricle, Partial or complete absence of the cerebellar vermis, Upward displacement of the tentorium, and Usually hydrocephalus. Dandy-Walker malformation/variant may also be associated with other intracranial abnormalities in 70 % of patients. These abnormalities Include agenesis of the corpus callosum, aqueductal stenosis, schizencephaly, holoprosencephaly (failure of the prosencephalon, the embryonic forebrain, to suf ﬁ ciently divide into the double lobes of the cerebral hemispheres, resulting in a single-lobed brain and severe craniofacial defects). Congenital heart defects, renal malformations, polydactyly/syndactyly, cleft palate, perineal malformations, Klippel-Feil malformation, and facial hemangiomas. Hydrocephalus occurs in 90 % of children with Dandy-Walker malformation/variant The pathophysiology of the hydrocephalus is now felt to be multifactorial. Contributing factors include aqueductal stenosis, basal arachnoiditis from an inﬂammatory process, abnormally Developed subarachnoid space, and venous Hypertension from direct pressure from the posterior Fossa cyst, ). Hydrocephalus develops in 70 to 90 percent of patients with Dandy-Walker malformation and is caused by atresia of the foramina of Luschka and Magendie
It is a venous aneurysm of the vein of Galen fed by numerous aberrant branches of the carotid or vertebrobasilar vessels. In addition, arteriovenous malformations may occur within the feeding vessels. often present at birth with congestive heart failure and hydrocephalus. Hydrocephalus may be caused by the venous malformation causing obstruction of the cerebral aqueduct. Elevated intracranial venous pressure may also decrease CSF reabsorption and cause hydrocephalus.
a benign congenital cyst occurring within the brain. The cyst forms during fetal development with the splitting of the arachnoid membrane Such cysts are often found incidentally when a child has a scan for some other reason. If the cyst enlarges, it may compress the surrounding structures and cause symptoms from mass effect. Depending on the location, as the cyst expands, it may compress nearby CSF pathways and cause hydrocephalus
germinal matrix hemorrhage. The germinal matrix is a very vascular. area in the fetal brain, in the subependymal region located at the level of the foramen of Monro. The germinal matrix gradually involutes after 34 weeks’ gestation and nearly disappears by 40 weeks. Hydrocephalus develops in 20–74 % of infants with IVH. — Another important cause is hemorrhage into the subarachnoid space or, less commonly, into the ventricular system, by ruptured aneurysms, arteriovenous malformations, trauma, or systemic bleeding disorders. The hemorrhage induces an inflammatory response followed by fibrosis (image 7A-B). The main mechanism for hydrocephalus is impaired absorption of CSF (communicating hydrocephalus), although some obstruction to CSF flow also may occur. Posthemorrhagic hydrocephalus occurs in approximately 35 percent of preterm infants with intraventricular hemorrhage (IVH). It can be obstructive, communicating, or both and can be transient or sustained, with slow or rapid progression
Intrauterine infections such as rubella, cytomegalovirus, toxoplasmosis, lymphocytic choriomeningitis (LCM), and syphilis can result in congenital hydrocephalus. The mechanism is inflammation of the ependymal lining of the ventricular system and the meninges in the subarachnoid space [12]. This may lead to impaired absorption of CSF and/or to obstruction of CSF flow through the aqueduct or basal cisterns. After the neonatal period, gram-positive bacteria are the leading cause of meningitis. Common causes of acquired hydrocephalus are CNS infections, such as bacterial meningitis or viral infections including mumps, and tumors, especially posterior fossa medulloblastomas, astrocytomas, and ependymomas. These conditions are associated with obstructed flow of CSF through the ventricular system and with impaired CSF absorption
About 60 % of brain tumors in children are located infratentorially or in the posterior fossa, occurring in the cerebellum, fourth ventricle, or brainstem. The most common tumors of this region include medulloblastoma, astrocytoma, and ependymoma. It results from obstruction of CSF ﬂ ow, particularly if the tumor is in The fourth ventricle or exerting pressure on the Fourth ventricle About 40 % of pediatric brain tumors occur in the supratentorial area. The most common site is the suprasellar region (craniopharyngioma and optic pathway glioma), followed by the cerebral hemispheres, thalamus and basal ganglia, pineal region, intraventricular spaces, and meninges. Hydrocephalus is associated with some of these tumors and is usually due to obstruction of CSF ﬂ ow at the aqueduct of Sylvius. Tumors that grow within the ventricles may cause hydrocephalus as a result of overproduction of CSF. There are two types of choroid Plexus tumors: choroid plexus papilloma and Choroid Plexus carcinoma
prevalence of NPH to be about 0.5% in those over 65 years old, with an incidence of about 5.5 patients per 100,000 of people per year. peak onset generally in the sixth to seventh decades. This is an uncommon entity and is extremely challenging to manage. It is diagnosed when neurological improvement is attained by external ventricular drainage. Patients usually have symptomatic ventriculomegaly and surprisingly low intracranial pressure. This condition may result from tumors, chronic hydrocephalus, subarachnoid hemorrhage, and infections. Management is with low pressure shunt. There are two types of normal pressure hydrocephalus: idiopathic and secondary. The secondary type of NPH can be due to a subarachnoid haemorrhage, head trauma, tumour, infection in the central nervous system, or a complication of cranial surgery. NPH is caused by an increase in intracranial pressure (ICP) due to an abnormal accumulation of CSF in the ventricles of the brain, which can cause the ventricles to enlarge (ventriculomegaly). The intracranial pressure gradually falls but still remains slightly elevated, and the CSF pressure reaches a high normal level of 150 to 200 mm H2O Because of this, patients do not exhibit the classic signs that accompany increased intracranial pressure such as headache, nausea, vomiting, or altered consciousness, although some studies have shown pressure elevations to occur intermittently. However, the enlarged ventricles put increased pressure on the adjacent cortical tissue and cause myriad effects in the patient. The classic symptom triad (gait disturbance, urinary incontinence, and dementia) was first described by Hakim and Adams in 1965. is predominantly frontal lobe in nature and of the subcortical type of dementia.
Endoscopic third ventriculostomy (ETV) is a procedure in which a perforation is made to connect the third ventricle to the subarachnoid space. This has been used in the initial treatment of selected cases of obstructive hydrocephalus and as an alternative to shunt revision. Some experts consider it the treatment of choice for aqueductal stenosis, although about 20 percent of patients still require shunting [28]. ETV is not useful for patients with communicating hydrocephalus (due to impaired CSF absorption). The success of the procedure depends upon the cause of hydrocephalus and upon previous complications [37-39]. When successful, ETV provides a treatment for hydrocephalus that is relatively low-cost and durable. In an observational study, the quality of life one year after the procedure was similar for patients treated with ETV compared with those treated with VP shunting [40]. In an analysis of 618 ETV procedures performed at 12 international institutions, the overall success of ETV was 66 percent six months after the procedure [41]. Older age at the time of the procedure (eg, greater than one year of age) was by far the strongest predictor of success, and noninfectious etiologies (eg, myelomeningocele, intraventricular hemorrhage, aqueductal stenosis, or tectal tumor) and lack of previous shunt were also important predictors. Based upon these data, the investigators retrospectively developed and validated an ETV success score that predicts the likelihood of early success. For the patients with successful ETV at six months, more than 80 percent are still successful five years later. In a follow-up study, the same investigators found that the best ETV candidates (high ETV success score) had substantially better outcomes after ETV compared with shunt. By contrast, for those with a low ETV success score, the risk of ETV failure is initially higher than the risk of shunt failure but becomes lower than the risk of shunt failure six months after the intervention [42]. Criteria for selection of patients for ETV versus shunting are not fully established. In our practice, we use the following approach: ●We generally perform ETV for patients with fourth ventricular outlet obstruction or with clear aqueductal stenosis and for those with pineal region tumors and tectal tumors, because these respond well to ETV. ●We generally do not perform ETV in patients with a history of intraventricular hemorrhage, meningitis, or previous shunting, because the likelihood of success is low. However, if patients with these disorders also have acquired aqueductal stenosis, we generally attempt ETV prior to pursuing shunting, because we have had moderate success with this approach. ●We generally do not perform ETV in infants with obstructive hydrocephalus who are younger than three months of age, because the likelihood of success is around 25 percent in this age group, as compared with a 45 percent success rate in infants between three and six months of age [43] and with a success rate of 64 percent in those between 6 and 12 months of age [41]. Complications of third ventriculostomy are mainly perioperative and include inability to complete the procedure, hemorrhage, hypothalamic dysfunction (diabetes insipidus, syndrome of inappropriate antidiuretic hormone secretion, or precocious puberty), meningitis, and cerebral infarction. In a systematic review, permanent morbidity after the procedure was 2.1 percent, and mortality was 0.22 percent [44]. If ETV is performed, it is important to monitor the patient postoperatively with serial clinical examinations and imaging to determine if the procedure was successful. If the hydrocephalus progresses, a shunting procedure generally is performed, because repeating the ETV acutely is not likely to be successful [11].

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