NEUROLOGICAL MALFORMATIONS AND INFECTIONS Flashcards
What is hydrocephalus?
Enlargement of the cerebral ventricles, due to excessive accumulation of CSF.
How do we classify the causes of hydrocephlaus?
- malfomations that communicate with the sub-arachnoid space (extraventricular)
- those that do not (intraventricular)
What are the intraventicular causes of hydrocephalus?
Congenital malformations: - Aquaduct stenosis - Dandy-Walker syndrome (no cerebellar vermis - back of cerebellum, large 4th ventricle and cyst at base of skull) Intraventricular haemorrhage Ventriculitis Brain tumour
What are the extraventricular causes of hydrocephalus?
Subarachnoid haemorrhage
Tuberculous meningitis
Arnlod-Chiari malformation (displacement of the cerebellar tonsil through the foramen magnum)
What are the clinical features of hydrocephalus in an infant?
Disproportionately large head circumference
Rate of growth is excessive
Bulging of anterior fontanelle
Sutures become seperated
Prominent scalp veins
Eyes deviate inwards (setting-sun sign - late sign)
What are the clinical features of hydrocephalus in an older child?
Headache Vomiting Irritability Papilloedema Lethargy Abnormality of pupillary size and reaction Decerebrate/decorticate posturing
How is the diagnosis of hydrocephalus attained?
Imaging - USS if the anterior fontanelle is patent otherwise CT/MRI
How would one treat hydrocephalus?
What are the complications of the treatment?
Ventriculoperitoneal shunt
Infection and obstruction
What is craniosynostosis?
Premature fusion of cranial sutures
Which suture is most commonly involved in craniosynostosis and what shaped head does the affected patient end up with?
Sagittal
Long narrow skull
What are the three main types of neural tube defect?
Spina bifida occulta
Meningocele
Myelomeningocele
Where are most neural tubes found?
Lumbosacral region
What is an encephalocoele?
Extrusion of the brain and meninges through a midline skull defect
What is anencephaly?
The cranium and brain fail to develop (detected on antenatal ultrasound and termination is usually offered)
What is spina bifida occulta?
When the dorsal vertebral arch fails to fuse properly.
What are the clinical features to look for regarding spina bifida?
Overlying skin lesion
Tuft of hair
Small dermal sinus
Back pain on exertion in older children if it is mild and therefore picked up later
What is a meningocoele?
Failure of vertebral arch to fuse with added feature of smooth, intact skin covered cystic swelling is filled with CSF.
What is the prognosis of a meningocoele?
There is usually no neurological deficit or hydrocephalus and excision and closure is usually performed at 3 months. They are very rare.
What is a myelomeningocele?
This accounts for more than 90% of overt spina bifida. Again failure of vertebral arch to fuse but this time the lesion is open with both herniation of the cord and meninges. CSF leakage is common. Neurological deficits will always be present.
What are the neurological deficits seen in myelomeningocele?
Motor and sensory loss in the lower limbs
Neuropathic bladder and bowel control loss
Other than the neurological deficits, what other features are often seen in infants born with myelomeningoceles?
Arnold-Chiari malformations - extraventricular hydrocephalus caused by hernia of lower cerebellar tonsils through foramen magnum.
Scoliosis
How do you treat patients with myelomeningocele?
Surgery. This will prevent infection however, this can never reverse neurological deficits
What are the three bacteria that more commonly cause meningitis in neonates?
Group B streptoccocus
E. coli
Listeria monocytogenes
What are the main bacteria that cause meningitis in slightly older children?
N. meningitidis
S. pneumoniae
H. inluenzae type b
