Dvlm + SC Lesions Flashcards
Neural tube defects arise from an incomplete closure of the NEURAL TUBE. What vitamin deficiency is this associated with?
LOW FOLATE LEVELS - Prior to conception
How do you protect a pregnant woman against NEURAL TUBE DEFECTS?
Ensure adequate vitamin folate (VitB9) supplementation
How are neural tube defects detected during prenatal care? What is the one exception?
ELEVATED AFP in maternal blood + amniotic fluid ELEVATED AchEsterase (Fetal Ach-esterase in CSF flows through defect into amniotic fluid) Exception = SPINA BIFIDA OCCULTA
What is the neural tube defect that results as a disruption of the CRANIAL END of the neural tube?
ANENCEPHALY = absence of skull + brain
FROG-LIKE APPEARANCE of the fetus - prominent eyes. What neural tube defect is this?
ANENCEPHALY (Absence of brain and skull)
How does ANENCEPHALY result in MATERNAL POLYHYDRAMNIOS?
Absence of CNS-controlled swallowing centers -> Baby can NOT swallow some of the amniotic fluid
What is the neural tube defect associated with failure of the POSTERIOR VERTEBRAL ARCH to close (i.e. disruption of the CAUDAL end of the tube)?
SPINA BIFIDA
Name the 3 types of neural tube defects that resulted from a disruption of the CAUDAL end of the neural tube (i.e. spina bifida).
SPINA BIFIDA OCCULTA
MENINGOCELE
MENINGOMYELOCELE
Which neural tube defect presents simply with a SKIN DIMPLE or PATCH OF HAIR overlying the vertebral defect? What will AFP levels show?
SPINA BIFIDA OCCULTA - Failure of bony spinal canal to close BUT NO HERNIATION (usually at lower vertebral levels)
NORMAL AFP
Which neural tube defect arises from a CYSTIC PROTRUSION of the MENINGES through the vertebral defect?
MENINGOCELE
Which neural tube defect arises from a CYSTIC PROTRUSION of the MENINGES/SPINAL CORD through the vertebral defect?
MENINGOMYELOCELE
What is the most common cause of HYDROCEPHALUS in newborns? Where is the blockage?
CEREBRAL AQUEDUCT STENOSIS -> Blocks CSF drainage from 3rd into 4th ventricle -> Accumulation of CSF in ventricular space = HYDROCEPHALUS
**UW: How does CONGENITAL HDYROCEPHALUS present in an infant?
ENALRGING HEAD CIRCUMFERENCE - Due to cranial suture lines not being fused
BULGING FONTANELLE + MACROCEPHALY + POOR FEEDING + DVLM DELAY + SPASTICITY/HYPER-REFLEXIA
What is the difference between COMMUNICATING and NON-COMMUNICATING HYDROCEPHALUS?
COMMUNICATING HYDROCEPHALUS: Normal CSF communication between ventricle system, ABNORMAL CSF resorption (particularly in subarachnoid granulations).
DEFECTIVE CSF resorption can not keep up with normal CSF production
NON-COMMUNICATING (OBSTRUCTIVE) HYDROCEPHALUS: Normal CSF resorption, ABNORMAL communication between ventricles due to space-occupying lesion or tumor in cerebellum/midbrain creating obstruction at Foramen of monroe, cerebral aqueduct, or foramen of luschka/magendie
POSTERIOR FOSSA MALFORMATION: What is the CONGENITAL FAILURE of the CEREBELLAR VERMIS to develop (AGENESIS)?
DANDY WALKER MALFORMATION
POSTERIOR FOSSA MALFORMATION: What are two of the most common associations of DANDY WALKER SYNDROME?
- NON-COMMUNICATING HYDROCEPHALUS (enlarged 4th ventricle)
2. SPINA BIFIDA
POSTERIOR FOSSA MALFORMATION: What are the 2 high-yield items seen on an MRI of a DANDY-WALKER MALFORMATION?
- ABSENCE OF CEREBELLUM
2. MASSIVELY DILATED 4th ventricle (enlarged posterior fossa)
POSTERIOR FOSSA MALFORMATION: What is the congenital extension of CEREBELLAR TONSILS through the foramen magnum? Can it present with hydrocephalus?
CHIARI II MALFORMATION
YES, it can present with hydrocephalus as it compresses on cerebral aqueduct (AQUEDUCTAL STENOSIS)
POSTERIOR FOSSA MALFORMATION: What are the 2 most common associations with CHIARI II MALFORMATION?
- Associated with LUMBOSACRAL MENINGOMYELOCELE (Paralysis/sensory loss at and below site of lesion)
- Associated with SYRINGOMYELIA
POSTERIOR FOSSA MALFORMATION: How does CHIARI I MALFORMATION differ from CHIARI II MALFORMATION? What is CHIARI I malformation most likely associated with? What is CHIARI II malformation most likely associated with?
CHIARI I: =>3-5 cerebellar tonsilar ectopia (downward displacement)
Most associated with SYRINGOMYELIA (CENTRAL CORD SYNDROME)
CHIARI II: SIGNIFICANT herniation of cerebellar tonsils + vermis + (possibly lower brainstem) + AQUEDUCTAL STENOSIS (HYDROCEPHALUS)
Most associated with LUMBOSACRAL MENINGOMYOCELE
What does SYRINGOMYELIA first affect? If it expands, what two areas can it affect next?
- ANTERIOR COMMISSURE - Bilateral STT fibers carrying pain and temperature sensation = BILATERAL “CAPE-LIKE” loss of pain/temperature sensation in UE (C8-T1)
- Expansion 1: LMN of anterior horn: LMN signs (Muscle weakness, atrophy, Decreased reflexes)
- Expansion 2: Lateral horn carrying Hypothalamospinal tract (sympathetic nerves) resulting in HORNER SYNDROME
What is the clinical triad of HORNER SYNDROME?
MIOSIS: Loss of SNS innervation to pupillary dilator muscle = pupillary constriction
PTOSIS: Loss of SNS innervation to superior tarsus muscle = lipid drooping
ANHIDROSIS: Loss of SNS innervation to sweating of face and neck = decreased sweating
Pt presents with 2-day history of fever, sore throat, abdominal pain, N/V. Two days later, pt presents with FLACCID PARALYSIS and MUSCLE ATROPHY, weakness with hypotonia, fasciculations, impaired reflexes, negative babinski sign (downgoing toes). What is the underlying etiology?
POLIOMYELITIS
Pt had poliovirus infection -> First infected oropharynx -> Small Bowel -> Eventually spreads to CNS from blood -> Damaged ANTERIOR MOTOR HORN contain LMN.
Pt has both UMN and LMN signs. What does pt have? What is the early sign of this disease? How do you distinguish this from SYRINGOMYELIA?
ALS
Early sign = HAND WEAKNESS/ATROPHY
Distinguishing form syringomyelia: NO LOSS OF PAIN/TEMPERATURE SENSATION as in syringomyelia (which also presents with LMN signs if it expands into the anterior horn)
