Page 332 - Medicine and Surgery

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328 Chapter 7: Nervous system

Complications levels causes paraplegia and bilateral symmetrical anaes-
Weakness of respiratory muscles with risk of pneumo- thesia below the level of the lesion.
nia and respiratory failure. Swallowing difficulties pre- Motor: LMN signs at level, UMN signs below the level.
dispose to aspiration pneumonia. Sensory:The sensory level, below which there is loss of
cutaneous sensation, indicates the site of a spinal cord
Investigations lesion.
There are no specific diagnostic tests. Denervation may Sphincter control:Loss of bladder and bowel control.
be confirmed by electromyography, the CSF is usually Causes include fracture dislocation of vertebrae, pene-
normal although protein may be raised. MRI of the cer- trating trauma, transverse myelitis or compression due
vical spine is indicated if there are predominantly upper to atumour.
limb signs with or without lower limb upper motor neu-
rone signs.
Hemisection of the spinal cord
Management Brown–S´equard syndrome
Supportive measures such as splints and crutches may Motor: Ipsilateral LMN signs at level and UMN signs
be useful, and communication aids for dysarthria. Rilu- below.
zole, a glutamate antagonist has been shown to improve Sensory: Below the level of the lesion there is ipsilateral
prognosis by a few months. vibration and proprioceptive loss, and contralateral loss
of pain and temperature sensation. Light touch is often
Prognosis reduced.
Remission is unknown, the disease progresses gradually Causes include multiple sclerosis, trauma, tumour (an-
and causes death, often from bronchopneumonia. Sur- gioma) and degeneration due to radiation.
vival for more than 3 years is unusual although there
are rare ‘benign’ forms of the condition with prolonged
Posterior columns
survival.
Disease of the posterior columns causes an unsteady gait
(sensory ataxia) due to loss of position sense in the legs
Disorders of the spinal cord anduncertaintyoffootposition.Sensationtolighttouch
and proprioception are lost.
Causes include:
Spinal cord lesions Subacute combined degeneration of the cord (vita-
min B 12 deficiency): There are UMN signs in the lower
Spinal cord lesions usually produce upper motor neu-
limbs due to the disease also affecting the lateral corti-
rone signs with associated sensory deficit (see Fig. 7.3).
cospinal tracts. There may be an associated peripheral
Nerveroots at the level of the lesion may also be affected
neuropathy which may reduce or abolish tendon re-
resulting in some lower motor neurone signs.
flexes, masking the expected UMN findings.
The motor pathways and vibration and propriocep-

Multiple sclerosis.
tion cross in the medulla, so that lesions in the spinal
Tabes dorsalis (3˚ syphilis): Degeneration of the dor-
cord cause ipsilateral deficits.
sal roots initially followed by posterior column
Pain and temperature nerves enter the spinal cord,

involvement. It is characterised by shooting
ascend a few segments and then cross the centre of
pains, with loss of proprioception, numbness or
the cord to ascend in the contralateral anterior horn,
paraesthesia.
so that lesions in the spinal cord cause contralateral
HIV infection.
deficits.
Transverse section of the spinal cord Central cord lesion (syringomyelia)
Injury at a cervical level causes quadriplegia and total Syringomyeliaisafluid-filledcavityinthespinalcordas-
symmetrical anaesthesia. Injury at thoracic or lumbar sociated with Arnold–Chiari malformations, spinal cord