SCD; Syringomyelia;

Question 1

SCD occurs because of B12 deficiency affecting which affected columns? [3]

Answer 1

dorsal column involvement, lateral corticospinal tracts and spinocerebellar tracts of the spinal cord

Spinocerebellar; Corticospinal and Dorsal column

Question 2

Describe the clinical features of SCD [3+]

Answer 2

dorsal column involvement
* distal tingling/burning/sensory loss is symmetrical and tends to affect the legs more than the arms
* impaired proprioception and vibration sense

lateral corticospinal tract involvement:
* muscle weakness, hyperreflexia, and spasticity
* upper motor neuron signs typically develop in the legs first
* brisk knee reflexes
* absent ankle jerks
* extensor plantars

spinocerebellar tract involvement
* sensory ataxia → gait abnormalities
* positive Romberg’s sign

Question 3

Descrirbe what is Syringomyelia (‘syrinx’ for short) and syringobulbia? [2]

Answer 3

Syringomyelia (‘syrinx’ for short)
- describes a collection of cerebrospinal fluid within the spinal cord

Syringobulbia is a similar phenomenon in which there is a fluid-filled cavity within the medulla of the brainstem. This is often an extension of the syringomyelia but in rare cases can be an isolated finding.

Question 4

What are the causes of syringomyelia? [4]

Answer 4

Chiari malformation: strong association
- a problem in which a part of the brain (the cerebellum) at the back of the skull bulges through a normal opening in the skull where it joins the spinal canal. T

trauma
tumours
idiopathic

Question 5

Which spinal tract is classically affected first in syringomyelia [1]

Answer 5

crossing spinothalamic tracts in the anterior commissure of the spinal cord are the first tracts to be affected.

Question 6

Describe the classic presentation of syringomyelia [+]

Answer 6

Classical presentation of a syrinx is a patient who has a ‘cape-like’ (neck and arms) loss of sensation to temperature but preservation of light touch, proprioception and vibration.
- Classic examples are of patients who accidentally burn their hands without realising
- This is due to the crossing spinothalamic tracts in the anterior commissure of the spinal cord being the first tracts to be affected.

Other symptoms:
* spastic weakness (predominantly of the upper limbs)
* paraesthesia
* neuropathic pain
* upgoing plantars and bowel and bladder dysfunction

Prolonged syringomyelia:
Scoliosis will occur over a matter of years if the syrinx is not treated. It may cause a Horner’s syndrome due to compression of the sympathetic chain, but this is rare

Question 7

How do you Ix syringomyelia? [2]

Answer 7

Investigation requires a full spine MRI with contrast to exclude a tumour or tethered cord.

A brain MRI is also needed to exclude a Chiari malformation.

Question 8

Tx of syringomyelia? [1]

Answer 8

Treatment will be directed at treating the cause of the syrinx.

In patients with a persistent or symptomatic syrinx, a shunt into the syrinx can be placed.