Neuro Flashcards
What is spina bifida?
Cleft spine, a type of neural tube defect
Incomplete development of brain, spinal cord +/- meninges
What is spina bifida occulta?
- Mildest, most common
- 1 or more vertebrae malformed
- Skin over the top
- 10-20% of general population
- No/mild signs (hairy patch/dimple/dark spot)
What are the types of spina bifida?
Occulta
Closed neural tube defect
Meningocele
Myelomeningocele
What is a closed neural tube defect
- Malformations of fat/bone/meninges
* No symptoms/urinary/bowel dysfunction
Describe meningocele
- Spinal fluid and meninges protrude through a vertebral opening
- May/may not be covered in skin
- No symptoms -> complete paralysis
Describe myelomeningocele
- Most severe
- Spinal cord/neural elements are exposed through opening in spine
- Partial/complete paralysis below level
- There is often caudal displacement of the lower brainstem into the upper cervical canal through the foramen magnum. This deformity impedes the flow and absorption of cerebrospinal fluid (CSF) and causes hydrocephalus, which occurs in more than 90% of infants with myelomeningocele.
Causes of spina bifida?
- Genetic
- Nutritional (folic acid in 1st trimester)
- Environmental
- Teratogenic process causes failed closure and abnormal differentiation of the embryonic neural tube.
- Neural tube defects occur between the 17th and 30th day of gestation, at a time when the mother may not be aware that she is pregnant and the fetus is estimated to be about the size of a grain of rice.
Signs and symptoms of spina bifida in infants
• Lethargy • Poor feeding • Irritability • Stridor • Ocular motor incoordination • Development delay Brainstem signs (poor swallowing, apnea) can occur in Chiari malformation and brainstem stretching
Signs and symptoms of spina bifida in older children
- Cognitive or behavioural changes
- Decreased strength
- Increased spasticity
- Changes in bowel or bladder function
- Lower cranial nerve dysfunction
- Back pain
- Worsening spinal or lower extremity orthopaedic deformities
Differential diagnosis of spina bifida
- Mass lesions of the cord
- Diastematomyelia
- Cord cavitation and narrowing
- Adhesions
- Dural bands
Treatment of spina bifida
- Prenatal detection
- Surgical closure in first days of life
- Untreated infants die in 1st year of life with meningocele
- Antibiotics
- Ventriculoperitoneal shunt placement
- Anticholinergics for neurogenic bladder
What is hydrocephalus?
Disturbance in CSF formation/flow/absorption leading to an increase in volume occupied by this fluid in the CNS
Signs of hydrocephalus
- Poor feeding
- Irritability
- Reduced activity
- Vomiting
- Head enlargement (>98th percentile for age)
- Dysjunction of sutures
- Tense fontanelle
- Setting sun eyes
- Increased limb tone
- Seizures
Types of hydrocephalus
Communicating-> flow of CSF blocked after it exits the ventricles (eg spina bifida)
Non-communicating-> obstruction occurs in one of the narrow passages connecting the ventricles (aqueductal stenosis)
Causes of hydrocephalus
- Genetic aqueductal stenosis
- Spina bifida/neural tube defects
- Encephalocele
- Intraventricular haemorrhage
- Meningitis
- Tumours
- Traumatic head injury
Types of shunt used in hydrocephalus treatment
- Ventriculoperitoneal (VP) shunt (most common)
- Ventriculoatrial (VA) shunt (or “vascular shunt”)
- Lumboperitoneal shunt: Only used for communicating hydrocephalus, CSF fistula, or pseudotumour cerebri)
What drugs are used to treat hydrocephalus due to haemorrhage?
Acetazolamide and furosemide