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346 Chapter 7: Nervous system

Bone operations to correct position and stabilise Epilepsy or mental retardation occur in up to 5% of pa-

joints tients; 30–40% of patients develop a scoliosis which may
5 Neurosurgical techniques are occasionally used for se- require surgical intervention
vere deforming spasticity to reduce spasm.
Investigations
Prognosis It is a clinical diagnosis. MRI scanning is used if root
Most children with cerebral palsy survive to adulthood. pain or focal neurology develops, to look for malignant
Longer-term survival depends on their degree of dis- change in a neurofibroma or to assess if a neurofibroma
ability, with those who never manage to feed or mobilise is amenable to superficial resection.
doing much worse, and often dying of aspiration pneu-
monia. Management
Surgery for cosmetic reasons and to correct bone defor-
Neurofibromatosis type 1 mity.

Definition
An inherited disorder characterised by multiple skin Neurofibromatosis type 2
neurofibromas,alsocalledVonRecklinghausen’sdisease.
Definition
Incidence Autosomal dominant condition characterised by the de-
1in 3500 making it the most common autosomal dom- velopment of bilateral acoustic neuromas.
inant condition.
Incidence
Aetiology/pathophysiology 1in 100,000 individuals.
Autosomal dominant condition caused by a group of
mutations in the NF1 gene on the long arm of chro- Aetiology
mosome 17 (product neurofibromin). It has complete An autosomal dominant condition caused by a muta-
penetrance, but variable expression. It is thought that tion in the NF2 gene on chromosome 22 which codes
NF1 is a tumour supressor gene. for a protein termed schwannomin or merlin. This pro-
tein acts as a tumour suppressor gene by an unknown
Clinical features mechanism.
Diagnosis when two or more of
six or more caf´ e-au-lait spots. Pathophysiology

two or more neurofibromas of any type or 1 plexiform Schwannomin has similarities with cytoskeletal compo-

(nerve root) neurofibroma. nents that link to the actin/spectrin complex, it is there-
freckling of axillary or inguinal regions. fore suggested that the cell–cell interaction is abnormal

optic glioma. and hence contact inhibition is prevented.

two or more Lisch nodules (iris hamartomas).

distinctiveosseouslesions(focalkyphoscoliosis,pseu- Clinical features

doarthrosis and dysplasia or thinning of the long bone Patients may have a few, large caf´ eau lait spots. Unlike
cortex). NF1 the main feature is bilateral acoustic neuromas. The
afirst degree relative with NF1 diagnosed as above. earliest presenting symptom is unilateral hearing loss or

tinnitus. Hearing loss may be sudden, vertigo is rare,
Complications patientswithlargetumoursexperienceheadaches,visual
There is an increased rate of benign and malignant disturbances, and ataxia.
tumours, particularly CNS tumours. Plexiform neu-
rofibromas may undergo malignant change (called Complications
schwannomas or neurofibrosarcomas). Note that cuta- Patients also have a tendency to form other brain tu-
neous neurofibromas do not undergo malignant change. mours such as meningiomas and gliomas.