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330 Chapter 7: Nervous system

Specific loss of these cells occurs in motor neurone dis- Table 7.11 Causes of spinal cord compression
ease (see also below) and poliomyelitis.
Lesion Examples
Tumours
Motor neurone disease – ‘amyotrophic lateral Vertebral Metastases or myeloma
sclerosis’ Extradural Lymphoma, metastases (lung,
The commonest pattern of MND affects the anterior breast, prostate)
horn cells and the lateral corticospinal tracts. It is char- Extramedullary Meningioma, neurofibroma
Intramedullar Glioma, ependymoma
acterised by mixed UMN and LMN signs. Patients of-
Disc lesions Trauma, chronic
tenpresent with spastic quadriparesis, brisk reflexes and degenerative, prolapse
upgoing plantars (UMN signs), fasciculation may be Infections Epidural abscess, tuberculosis,
present. With progression, muscle wasting and fascic- granuloma
ulation may become more obvious. No sensory signs, Epidural haemorrhage Spontaneous or traumatic
although sensory symptoms may be reported.
plantars. There is variable sensory loss below the level of
Anterior spinal artery occlusion
the lesion.
Motor: Flaccid paraplegia, urinary retention.
Conusmedullaris: Compression of the sacral seg-
Sensory:Loss of pain and temperature sensation (the
ments of the cord causes early disturbance of bladder
dorsal column sensory pathways may be totally or only
and bowel control, there is reduced sensation over the
partly spared).
perianal region.
It is associated with atherosclerosis and dissecting ab-
Cauda equina lesion: Compression below L1 affects
dominal aortic aneurysm. Total loss of blood flow causes
the spinal nerves and cauda equina resulting in a flac-
an acute presentation, milder UMN & LMN symptoms
cid, asymmetrical paraparesis. Reflexes are loss and
may occur in ‘transient ischaemic attacks’, which may
there is loss of sensation over the perianal region
partially recover.
(saddle anaesthesia). However, bladder and bowel
control are preserved until relatively late.
Spinal cord compression
Investigations
Definition
Plain spinal films may show bone disease, urgent MRI
Spinalcordcompressionisamedicalemergency,aswith-
spine or myelography (injection of water-soluble con-
out rapid relief of the compression, permanent neuro-
trast into the lumbar subarachnoid space) is required in
logical deficit results.
acute cases. MRI is most useful as it can demonstrate
most causes of spinal cord compression.
Aetiology
Causes are shown in Table 7.11.
Management
Identification and treatment aimed at the underlying
Clinical features
cause. In as many as 20% of cases, the cord compression
Patients may present with clumsiness, weakness, loss of
is the initial presentation of an underlying malignancy.
sensation, loss of bowel or bladder control which may
Radiotherapy is used for metastases, in other causes ur-
begin as urinary hesitancy and urgency progressing to
gent neurosurgical decompression is required to max-
painless urinary retention. Back pain may precede the
imise return of function.
presentation with cord compression for many months
and there may be radicular pain at the level of compres-
sion (radiating around the chest for thoracic lesions and Prognosis
into the limb(s) for cervical and lumbar lesions). On Prognosis is related to the degree of damage and speed
examination there may be a spastic paraparesis or tetra- of decompression. Bladder control that has been lost for
paresis with weakness, increased reflexes and upgoing more than 24 hours is usually not regained.