neurology 3 Flashcards
What is hydrocephalus? Sites of obstruction
obstruction to the flow of CSF - dilation of ventricular system proximal to site of obstruction
Obstruction may be within ventricular system or aqueduct which would present as obstructive.
or at the site of arachnoid villi which would be communicating
Causes of obstructive hydrocephalus
Congenital malformation:
aqueduct stenosis
atresia of the outflow foramina in th 4th ventricle
Chiari malformation
Posterior fossa neoplasm or vascular malformation
Intraventricular haemorrhage in preterm infant
Causes of communicating hydrocephalus
Subarachnoid haemorrhage
Meningitis eg. pneumococcal/ tuberculous
Clinical features of hydrocephalus
Disproportionately large head circumference
Excessive rate of head growth (failure of suture formation)
Skull sutures separate (anterior fontanelle bulges and scalp veins become distended)
Fixed downwards gaze or sun setting of eyes (advanced)
Signs of increased ICP
Common causes of macrocephaly
= head circumference >98th centile
Tall stature Familial macrocephaly Raised ICP Hydrocephalus Chronic subdural haematoma Cerebral tumours Neurofibromatosis
Cerebral gigantism (sotos syndrome)
CNS storage disorder eg. mucopolysaccharidosis (Hurler syndrome)
Most children are normal and often have parents with large heads
Why is rapidly increasing head circumference worrying?
Even if below 98th centile, it indicates:
Hydrocephalus
Subdural haematoma
Brain tumour
Prompt investigation:
If anterior fontanelle is still open, then with INTRACRANIAL US
Otherwise CT or MRI
What are the common causes of microcephaly
Head circumference <2nd centile
Familial - present from birth and normal
Autosomal recessive condition - with developmental delay
Caused by congenital infection
Acquired after an insult to the developing brain (perinatal hypoxia, hypoglycaemia or meningitis)
Often accompanied by CP and seizures
What are secondary headaches (differentiate from primary - causes/features)
attributed to: head/neck trauma Cranial or cervical vascular disorder Intracranial haemorrhage Raised ICP infection (meningitis, encephalitis) Hypercapnia HTN
Headache worse when lying down and morning vomiting is characteristic of space occupying lesion
Sometimes night-time waking
Change in mood, personality or educational performance
Visual defects (craniopharyngioma) Cranial nerve abnormalities (causing diplopia, new-onset squint, facial nerve palsy) Abnormal gait Head-tilting Growth failure Papilloedema (late)
Features of migraine tension-type headaches (primary)
Symmetrical
gradual onset
“Tightness”, band or pressure
Usually no other symptoms
90% Migraine without aura: episode 1-72h
bilateral
Pulsatile
Over temporal or frontal area
Accompanied by: GI disturbance, N+V, abdo pain, photophobia
10% migraine with aura: Visual/sensory/motor. Most often visual though.
These episodes last few hours.
Genetic predisposition
What are the common aural phenomena with migraine tension-type headaches in children
Visual:
negative phenomena: hemianopia or scotoma
Positive phenomena: fortification spectra (eg. zigzag lines)
Abnormal examination results and history in raised ICP
Toe-heel walking
Finger nose coordination affected
Eye movements
Papilloedema
Unequal, unreactive pupils
Abnormal respiratory pattern
Systemic HTN and bradycardia
Tense fontanelle
Abnormal body posture or muscle flaccidity
History is usually short:
vomiting
morning headache
visual disturbance
Investigations and management of suspected raised ICP
MRI is gold standard for masses obstructing CSF flow.
CT can also be used, but it does not identify thrombosis of a cerebral sinus
Treat with:
head positioned midline and end of bed tilted 20-30°
Isotonic fluids at 60% maintenance
Intubation and ventilation if GCS <9
Mannitol or 3% saline as osmotic diuretics
Maintain normothermia and high normal BP
an intracranial mass lesion may require neurosurgical intervention
Pathophysiology of subdural haematoma
tearing of veins as they cross the subdural space
-characteristic in NAI (eg. shaken baby or sometimes from falling from very high)
Signs and symptoms of acute subdural haematoma
Encephalopathy (irritability, crying, inconsolable, lethargy, meningism, decreased or increased tone, seizures, less conscious)
Breathing abnormality/apnoea
Pallor/shock
Tense fontanelle (ICP)
Early post-traumatic seizures
Retinal haemorrhages usually present
Signs and symptoms of subacute or chronic SDH
Expanding head circumference
Vomiting
FTT
Neurological deficits
