NEUROANATOMY Things to Know

 NEUROANATOMY

Things to Know

u Hydrocephalus ("hydro" meaning water, and "cephalus" referring to the head) :-A condition in which excess cerebrospinal fluid (CSF) builds up within the ventricles of the brain and may increase pressure within the head.

u Causes of Hydrocephalus:

Can be inherited genetically or may be associated with developmental disorders, including spina bifida (congenital defect of the spine) and encephalocele(hernia of the brain).

u Other causes can include

q Bleeding within the brain

q Brain tumors

q Head injuries,

q Complications of premature birth such as hemorrhage, or diseases    such as meningitis or other infections

u Hydrocephalus can occur at any age, but is most common in infants and adults age 60 and older.

u GRAVIDA :-No. of pregnancies that woman has had, regardless of outcome.

uPARA:-No. of births that woman has had after around 20 weeks of gestation.

u VENTRICULOMEGALY:-“ Hydrocephalus in ventricles”

u AMNIONCENTESIS:-Sampling of amniotic fluid by hollow needle inserted into the uterus, to screen for developmental abnormalities in a fetus.

uB-V ANGLE (Brainstem-Vermis):-Simple and reproducible measurements that provide valuable additional information for the categorization of upward rotation of the fetal cerebellar vermis.

CASE REPORT

uA 38 year old gravida 1 para 0 woman was referred to our hospital under suspicion of fetal hydrocephalus at 14 weeks and 2 days of gestation.

 Medical and family histories were non-contributory, other than pregnancy was established by in-vitro fertilization with intracytoplasmic sperm injection. 

At 14 weeks and 2 days of gestation, ultrasound examination demonstrated ventriculomegaly and cranial posterior fossa fluid collection.

 Amniocentesis was also done and showed 46, XX with normal karyotype. A cranial MRI was done after stillbirth and showed

MRI OF PATIENT 

NORMAL

DIAGNOSIS

u GIVEN:

q38 year old gravida 1 para 0 woman with 14 weeks and 2 days of gestation

q Pregnancy –By IVF through intracytoplasmic sperm injection.

q Ultrasound examination demonstrated ventriculomegaly and cranial posterior fossa fluid collection.

q Amniocentesis -46, XX with normal karyotype.

CHANCES TO SUFFER FROM

u Congenital anomalies of Posterior cranial fossa:

q Blake's pouch cyst,

q Dandy–Walker malformation,

q Arachnoid cyst,

q Mega cisterna magna

q Vermian–cerebellar hypoplasia

However, Observing a differential diagnosis in fetal cases is difficult BUT from the research , it concluded that by measuring the B‐V angle is useful for making a differential diagnosis.

uB‐V angle is quite wide compared with the other neuroanatomic disorders’ MRI that can be get from medical journals. The B‐V angle increases with increasing severity of the condition;thus, the present case may be a severe condition.

DIFFERENTIAL DIAGNOSIS

WORK IN PROGRESS

uCompare to Blake Pouch cyst and other neuroanatomic disorder, Dandy-Walker malformation has poor prognosis

u There is great significance in being able to make the diagnosis in early pregnancy to save infant.

u Dandy–Walker malformation was suspected by researching about B‐V angle measurement at 14 weeks of gestation, and a diagnosis of Dandy–Walker malformation that was made based on MRI findings following stillbirth.

POINTS THAT TO BE NOTED

u From the Patient’s MRI, it can be observed that the B-V angle is high compared to normal angle.

u Cerebellum and Fourth ventricle is abnormal due to enlargement of Posterior Cranial Fossa.

uThe B‐V angle increases with increasing severity of the condition;thus, the present case may be a severe condition.

uAs in the present case, chorionic villus sampling became possible due to the successful diagnosis in an early period of gestation, thus confirming the possibility of making an early diagnosis of this malformation

TRIAL N ERROR

u Moreover, the Dandy–Walker malformation often accompanies chromosomal abnormalities, such as trisomy 21 and trisomy 18 BUT in this case by way of Amniocenetesis, it found that no chromosomal abnormalities or genetic abnormalities were observed.

uSo NO ROLE of In-vitro Fertilization through intracytoplasmic sperm injection for Abnormal Ultrasound Examination.

u Generally fetal diagnoses have been carried out following the 20th week of gestation, at which point the cerebellar vermis becomes complete but now its possible prior to 20th week of gestation

OBSERVATION

u When the B‐V angle of a normal fetus and a Dandy–Walker malformed fetus are compared at around 15 weeks gestation, the angle is significantly greater in the Dandy–Walker malformed fetus.

In addition, in comparison to Blake's pouch cysts, a significantly higher B‐V angle is found in Dandy–Walker fetuses.

u Therefore Dandy–Walker malformation strongly suspected in cases exhibiting a B‐V angle of above 45 degrees.Blake's pouch cysts are another malformation of the posterior cranial fossa.

 However, the prognosis thereof is relatively good,and therefore it is extremely important to differentiate these different diseases early in pregnancy.

FINAL COMMITMENT

ØDANDY-WALKER MALFORMATION:

uThe Dandy–Walker malformation is a malformation of the posterior cranial fossa which carries a poor prognosis and is associated with a triad of cyst‐like expansion of the fourth ventricle, a cerebellar vermis defect, along with an increased tentorium cerebelli.

CSF CIRCULATION

u Normal Pathway of CSF :-

u Lateral Hemisphere à(Foramen of Monro) à3rdVentricle à(Foramen of Aqueduct) à4thVentricle àSpinal cord

u Affected CSF pathway due to Anomalies:-

u Due to anomalies of excess fluid collection in Cerebellum and 4th Ventricle, CSF remain in brain itself and not able to reach spinal cord in normal level, leads to enlargement of posterior fossa.

Pathophysiology

ØCharacteristics of Dandy-Walker syndrome include:

u Enlarged fourth ventricle:Cystic fourth ventricular dilation is present. The dilation of the fourth ventricle may be due to outflow obstruction of the fourth ventricle or to atresia of the foramina of Luschka and Magendie, but it may also be due to hypoplasia of the cerebellar vermis.

u Hypoplastic vermis:The cerebellar vermi may         be hypoplastic or absent.

Molecular/Genetic Pathology

u Uncertain genetics:Several genes have been associated with Dandy-Walker malformations, including FOXC1 on human chromosome 6p25 and the linked ZIC1 and ZIC4 genes on human chromosome 3q24 . None, however, has been linked decisively with the malformation yet.

MANAGEMENT / TREATMENT:-

uBasic treatment is to just do extra safety of infant and pregnant mother till child’s birth. Then there should be MRI and ULTRASOUND after birth to confirm the conditions and diagnosis any complications affecting baby.

u Certain ways to treat baby after birth like Medications, Speech therapy, Physical Therapy, Surgical insertion of a ventriculoperitoneal shunt, Occupational therapy, Special Education.

uAs per now, Neurologists and Neurosurgeons in the Fetal Brain Program have extensive experiencing in diagnosing and managing Dandy Walker malformations.

PATEL, DISHANT

PATEL, JAIMINKUMAR

PATEL, CHINTANKUMAR

PATEL, ABHISEKH

OZA, DEVANG

PAIPA, BANLANG

DESIRE, NCUBE

NEEREPURATH,VISHNU MOHAN