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
What are the features that define a febrile convulsion
A generalised clonic or a generalised tonic-clonic seizure occurring in a child with fever
• Child aged 6months- 5 years
• The child is otherwise neurologically healthy and without neurologic abnormality by examination or by developmental history
• The fever is not caused by meningitis, encephalitis, or any other illness affecting the brain
Is a febrile convulsion part of epilepsy?
No but:
Children who have simple febrile seizures are at an increased risk for epilepsy. The rate of epilepsy by age 25 years is approximately 2.4%, which is about twice the risk in the general population.
What is the differential of a febrile convulsion?
Epileptic seizure
Stroke
Meningitis/encephalitis
What is cerebral palsy?
Injury to early developing brain, often antenatally. Injury is static but signs/symptoms change as the brain develops
A chronic, incurable and non-progressive disorder of movement &/or posture that presents early (<2yrs) and continues throughout life
1/400 births (more boys), commonest cause of physical disability in childhood
What are the causes of cerebral palsy
Prenatal: • Genetic • Infection in utero • Chorioamnionitis • Toxins • Trauma • Placental insufficiency • Pre deceased twin Perinatal: • Prematurity • Infection (meningitis) • Hyperbilirubinaemia (kernicterus) • Perinatal hypoxic encephalopathy Post natal: • Infection • Vascular accident (pneumothorax, hypocarbia) • Head injury
3 classifications of cerebral palsy
Spastic
Ataxic
Dyskinetic
What is spastic cerebral palsy?
- Abnormal posture/movement
- Increased tone (leg scissoring, foot deformity)
- Pathological reflexes
- Pyramidal deficit from motor areas of cerebral cortex
What is ataxic cerebral palsy?
- Abnormal posture/movement, hypotonia
- Loss of orderly muscular coordination so movements are performed with abnormal force, rhythm and accuracy
- Extrapyramidal deficit from cerebellum
What is dyskinetic cerebral palsy?
- Abnormal posture, hypertonia when awake, hypotonia when asleep
- Involuntary, uncontrolled, recurring, occasionally stereotyped movements
- Classified into dystonic (fixed twisted posture as trunk most affected) and athetoid (involuntary, slow, writhing, rhythmic movements of arms, legs and hands)
- Extrapyramidal deficit from basal ganglia
What is the GMFCS classification system in cerebral palsy?
gives levels for how much support is needed
-> eg walking without limitations= level 1, Requires extensive use of assisted technology and physical assistance = level 5.
Name 2 neurologically significant skin markings in infants
- Café au lait: neurofibromatosis
* Port wine stain: haemangioma, can affect eye with glaucoma, associated with abnormal meningeal perfusion
What is an epileptic seizure?
Clinical manifestation of epileptic activity of neurons in the brain. Movement, awareness, behaviour, senses, emotional changes, aura
What needs to be ruled out in a child presenting after a possible seizure?
- Hypoglycaemia
- Hypocalcaemia
- Arrhythmia
What is the difference between a simple and a complex seizure?
- Simple (consciousness retained)
* Complex (consciousness affected)
What is an automatism?
Set of brief unconscious behaviours
May include simple gestures, such as finger rubbing, lip smacking, chewing, or swallowing
What is used when trying to induce and diagnose an absence seizure?
Hyperventilation (blowing a windmill)
When is EEG used? Is it useful?
If more than 1 unprovoked seizure
0.3-3.5% false positive
What safety advice is given to newly diagnosed epilepsy?
No unsupervised baths
Avoid alcohol
Let lifeguards know when swimming
What is given for emergency use in an epileptic seizure?
Emergency buccal midazolam
Is an 8 months old showing hand preference normal?
No
Hand preference under 1 yr old is abnormal
After a fall where he hit his head, what is the most worrying sign:
A) nasal discharge
B) enlargement of parietal bruise
C) fractured nose
D) laceration around eye needing stitches
A) nasal discharge (could be CSF)
What is a seizure classed as status epilepticus?
30 mins of continuous seizure of cluster with no break
Is an 18m old showing hand preference pathological?
No, after 12m normal
Complications of an LP (6)
Failure to obtain a specimen / need to repeat LP/ Traumatic tap (common)
Post-dural puncture headache (fairly common) - up to 5-15%
Transient/persistent paresthesiae/numbness (very uncommon)
Respiratory arrest from positioning (rare)
Spinal haematoma or abscess (very rare)
Tonsillar herniation (extremely rare in the absence of contraindications above)
LP contraindications
- Coma
- Signs of raised ICP: e.g. drowsy, diplopia, abnormal pupillary responses, unilateral or bilateral motor posturing or papilloedema NOTE: a bulging fontanelle, in the absence of other signs of raised ICP, is not a contraindication
- Cardiovascular compromise/ shock
- Respiratory compromise
- Focal neurological signs or seizures
- Recent seizures (within 30 minutes or not regained normal conscious level afterwards).
- Coagulopathy/thrombocytopenia
- Local infection (in the area where an LP would be performed)
- The febrile child with purpura where meningococcal infection is suspected.
CSF bacterial versus viral values
Bacterial Meningitis: Cloudy & Turbid WCC: Raised neutrophils Red Cells: Normal Protein: High or Very High Glucose: Very Low
Viral Meningitis: Appearance: Normal White Cells: Raised lymphocytes Red Cells: Normal Protein: Normal or High Glucose: Normal or Low
CSF after SAH
Appearance Usually blood stained White Cells:Normal Red Cells: Very High Protein: Normal or High Glucose: Normal or Low Bilirubin present
