Cerebrovascular Disease (Meningocele, Arnold Chiari Malformation, Brain Herniation Syndrome)
Feb 22, 2023
Cerebrovascular disease is a prevalent condition that affects a large number of people, particularly older adults. It can cause a range of serious complications, including stroke, which can lead to long-term disability and death. Early diagnosis and treatment are crucial to reduce the risk of such complications.
In this blog we’ll cover neural tube defects, meningocele, arnold chiari malformation and brain herniation syndrome. Read on.
Neural Tube Defects
Types
SPINA BIFIDA OCCULTA
SPINA BIFIDA APERTA
Also Called as Closed spina bifida
Associated with incomplete Closure of one or more vertebra without Herniation of meninges or Spinal cord
Divided in 3 types
MENINGOCLELE
Myelomeningocele
Myeloschisis
Meningocele
Herniation of meninges through a defect in Posterior vertebral arches
Spinal Cord is : Normal , Normal Position in Spinal Canal
C/F:
Fluctuant midline swelling.
Brilliantly trans-illuminant.
Occurs along vertebral Column in the lower back.
Covered by Skin.
Dx:
X-ray-Vertebral Defect can be seen
Rx:
Immediate Surgery
Leaking CSF
Thin Skin covering
Delayed Surgery
Asymptomatic with normal Neurological finding & full thickness skin covering.
MYELOMENINGOCELE
Most severe form of Dysraphism involving vertebral column
Characterized by Herniation of both Meninges & Spinal Cord
Incidence of myelomeningocele: 1:4000 Live Birth
Most common Site: LUMBOSACRAL Region
Etiology
Genetic predisposition.
If one child is affected, risk of occurrence – 3 to 4%.
If two children are affected, risk of occurrence – 3 to 10%.
Maternal Periconceptional use of folic acid supplementation decreases incidence of NTD in Pregnancies at high Risk by 50%
Drugs that increases risk of Neural tube defects
Phenytoin
Carbamazepine
TMP-SMT (Trimethoprim-Sulfamethoxazole)
Phenobarbital
Primidone
Valproate
C/F
Dysfunction of skeleton, GIT, Genitourinary tract in addition to CNS & PNS
Extent of Neurological Deficit depend on
Site of M/M
Associated Lesions
Prevention
0.4mg Folic Acid Supplementation/Day – in all females of childbearing age & about to become pregnant
ARNOLD CHIARI MALFORMATION
TYPE I CHIARI MALFORMATION
TYPE II CHIARI MALFORMATION
TYPE I CHIARI MALFORMATION
Displacement of cerebellar Tonsil into cervical canal.
Associated with Syringomyelia of Cervical Canal.
Not associated with HYDROCEPHALUS
Adolescence/Adult Life
C/F
Recurrent Headache.
Neck Pain
Urinary Frequency
Progressive Lower Extremity Spasticity
TYPE II CHIARI MALFORMATION
It is An Anomaly of HINDBRAIN
Elongation of 4th Ventricle
Kinking of Brain stem
Displacement of (Inferior vermis; Pons; Medulla) into cervical canal.
Associated with HYDROCEPHALUS & MYELOMENINGOCELE
Investigation
X-ray-Small Posterior Fossa with WIDENED Cervical Canal.
MRI-Cerebellar Tonsil Protruding into Cervical Canal & Hind Brain Anomalies.
Rx
Surgical Decompression
DANDY-WALKER MALFORMATION
Mc Posterior Fossa Malformation
Characterized by Developmental Failure of roof of Fourth ventricle
Consists of
Cystic Expansion of Fourth Ventricle in Posterior Fossa
Midline Cerebellar hypoplasia
Characteristic Triad of DWH
Hypoplasia of Vermis
Cephalad Rotation of Vermian remnant and Cystic Dilation of Fourth Ventricle – Extending posteriorly
Enlarged Post Fossa with Torcular Lambdoid inversion
C/F
A/W Hydrocephalus
MC manifestation – MACROCEPHALY
RAPID increase in head Size with Prominent occiput
Evidence of long tract signs, Cerebellar ataxia
Delayed Motor or cognitive milestone due to associated structural Abnormalities
Associations
A/W CNS Abnormalities – 70% cases
Agenesis of Posterior cerebellar vermis & Corpus collosum
Cortical dysplasia
Polymicrogyria
IOC for Diagnosis – MRI
Rx
Shunting of Cystic cavity in pts. Of Hydrocephalus
CAUSES OF CEREBROVASCULAR ACCIDENTS
Ischemic (85%)
Hemorrhagic (15%)
Embolic (75%)
Thrombotic (25%)
Parenchymal (10%)
SAH (1-2%)
EDH (1%)
SDH(<1%)
Intracerebral Hemorrhage (Parenchymal)
MC Type of Intracranial hemorrhage
MC cause of HTN – Rupture of small Perforating arteries & arterioles
MC site – Basal ganglia (Putamen)
MC site – Basal ganglia (Putamen)
Subarachnoid Hemorrhage
2nd MC causes of I/C Hemorrhage
MC Cause is Trauma > Rupture of Berry Aneurysm
MC site of Berry Aneurysm is – Anterior circulation of Circle of Willis
MC Site of Extra Cranial Aneurysm – Infrarenal abdominal Aorta
BERRY ANEURYSM
MC type of I/C Aneurysm
Saccular in appearance
Arise from Bifurcation of I/C arteries
85% Anerysm occur in Anterior circulation of Circle of Willis
Babinski sign, Hemiparesis C/L to original Hemiparesis
CENTRAL HERNIATION
Diencephalon (THALAMUS & Related Structures)
↓
Forced through Tentorium.
Sequential Compression of upper midBrain > Pons > Medulla
Physical Signs of central herniation
Early Sign
Erratic Respiration
Small Reactive Pupil
Increased Tone of limbs
B/L Extensor Plantar
Late Sign
Cheyne-stokes Respiration
Decorticate Rigidity
Very late sign
Fixed & Dilated Pupils
Decerebrate Rigidity
SUBFALCINE HERNIATION
Displacement of Cingulate gyrus beneath free edge of falxcerebri
Signs
Loss of Consciousness – Leads to Coma
C/L weakness
Loss of Brainstem Reflexes
TONSILLAR/DOWNWARD CEREBELLAR HERNIATION
Displacement of cerebellar tonsils Via Foramen magnum
Leads to coma & B/L Posturing
DURET HEMORRHAGE
↑ Intracranial Tension (ICT)→ Cause Downward herniation of Brainstem ↓ Stretching of perforators of Basilar artery. ↓ Leads to Bleeding
Small area of bleed in Ventral & Paramedian Part of upper Brainstem (Midbrain & PONS)
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