Medical Diseases of the Spinal Cord

Question 1

what is a myelopathy?

Answer 1

an injury to the spinal cord due to severe cord compression

Question 2

what are the possible causes of myelopathy?

Answer 2

intrinsic or extrinsic - surgical or medical

Question 3

what are the possible the surgical causes of myelopathy?

Answer 3

tumour, vascular abnormality, degenerative (spine), trauma

Question 4

what are the possible congenital/genetic medical causes of myelopathy?

Answer 4

hereditary spaces paraparesis or spin-cerebella ataxia

Question 5

what are the possible acquired medical causes of myelopathy?

Answer 5

inflammation- demylination (MS), autoimmune (antibody mediated eg aquaporin 4), sarcoid, vascular- ischaemic or haemorrhagic, infective- viral eg herpes simplex, EBV etc, bacterial eg TB, lymes, syphilis, other= schistosomiasis, metabolic- B12 deficiency, malignant- infiltrative into the spinal cord or paraneoplastic, idiopathic

Question 6

what are the symptoms of a myelopathy?

Answer 6

motor signs, sensory signs and autonomic signs

Question 7

what are the motor signs of myelopathies?

Answer 7

UMN- increased tone, increased reflexes and extensor plantar response, pyramidal pattern of weakness- upper limb flexors are strong and extensors are weak but in the leg the extensors are stronger than the flexors and the foot inverters are stronger than the evertors - only below the level of any lesion, often bilateral as the spinal cord is narrow so damage usually affect both sides - spastic tetra paresis= damage high in the cervical region= all 4 limbs are weak but in thoracic region= spastic paraparesis where only leg involvement

Question 8

what are the sensory signs of myelopathy?

Answer 8

loss of sensation and sensory signs below the level of damage

Question 9

what happens if there is a hemicord lesion?

Answer 9

Brown-Sequard syndrome= particular pattern of sensory disturbance= ipsilateral loss of vibration and join position sense and UMN weakness and contralateral loss of pain and temperature

Question 10

what is a syrinx?

Answer 10

fluid filled cavity which tends to affect near the midline of the grey matter of the spinal cord close to where the spinothalamic tract cross the midline so only loss of pain and temperature sensation on the ipsilateral side

Question 11

what happens if there is a lesion of the dorsal column?

Answer 11

eg in MS can get lesions in the dorsal column which will only affect the joint position and vibration sense as the corticospinal tract is affected only

Question 12

what happens if there is a lesion in the anterior part of the spinal cord?

Answer 12

often seen if anterior spinal artery is blocked (spinal stroke) and will only affect the anterior part of the spinal cord and so below the level of the lesion we will lose pain and temperature sensation as there is damage to the spinothalamic tract and corticospinal tracts will also be affect so will have motor signs below the level of the lesion too

Question 13

what are the autonomic signs of a myelopathy?

Answer 13

bladder/bowel problems eg retention of urine without pain, irritable bladder frequency and incontinence, bowel disturbance with constipation or incontinence

Question 14

what investigations would we do for a myelopathy?

Answer 14

localise with imaging- MRI is the best option unless contraindication or unavailable and investigate the cause with routine bloods and CSF examination if worried about infection

Question 15

how does a spinal stroke occur?

Answer 15

due to damage to the vascular supply to the spinal cord- anterior part of the cord is supplied by the anterior spinal artery and the posterior cord is supplied by the posterior artery

Question 16

describe the composition of the anterior spinal artery.

Answer 16

a branch of the vertebral artery and one of the lumbar arteries which meet in the thoracic region which tends to be where most spinal strokes occur

Question 17

what are the causes of a spinal stroke?

Answer 17

atheromatous disease, thromboemoblic disease, arterial dissection, hypotension, vasculitis etc

Question 18

how does a spinal stroke present?

Answer 18

sudden onset or over several hours, may have vascular risk factors, pain in the back or radicular (starts in the posterior spine and radiates around to the anterior abdomen), weakness (if damage to motor tracts), numbness and paraesthesia (if damage to sensory tracts), urinary symptoms

Question 19

what imaging would we use for spinal strokes?

Answer 19

MRI- may not see anything but look for the cause but over time may see changes

Question 20

how are spinal strokes treated?

Answer 20

no acute treatment so reduce the risk of recurrence= maintain adequate BP, reverse hypovolaemia/arrhythmia, anti platelet therapy, manage vascular risk factors in long term

Question 21

what is the prognosis of spinal strokes?

Answer 21

fairly rapid improvement in the 1st 24 hours then the chances of major recovery are goof but if not then low - 60% left with significant disability

Question 22

what does absorption of B12 require?

Answer 22

intrinsic factor (a binding protein secreted by gastric parietal cells)

Question 23

why can B12 deficiency occur?

Answer 23

vegan diet, pernicious anaemia (autoimmune condition which antibodies to IF prevent B12 absorption), total gastrectomy, Crohn’s and tape worms

Question 24

if B12 deficiency is too low for too long then what effect does it have on the nervous system?

Answer 24

most likely to cause myelopathy first and then peripheral neuropathy= myeloneuropathy but if left long enough with affect the brain, eyes and optic nerves

Question 25

what are the nervous system symptoms of B12 deficiency?

Answer 25

often firstly paraethesia (numbness) of the hands and feet- often a weird mix of spinal cord and peripheral nerve signs - dorsal columns and so joint position and vibration sense tend to be more affected than the anterior part

Question 26

what investigations would we do for B12 deficiency?

Answer 26

FBC, MCV (see if raised), blood film, B12 (difficult to measure and uncertainty about what a low B12 is)

Question 27

what treatment would we give for B12 deficiency?

Answer 27

intramuscular B12 (quicker the better- if get in early can have complete recovery)