Syringomyelia

Question 1

Syringomyelia Presentation

Answer 1

Examine this patient’s upper limbs neurologically. He has been complaining of numb hands.

Question 2

Clinical signs of Syringomyelia

Answer 2

1. Weakness and wasting of small muscles of the hand
2. Loss of reflexes in the upper limbs
3. Dissociated sensory loss in upper limbs and chest: loss of pain and temperature sensation (spinothalamic) with preservation of joint position and vibration sense (dorsal columns)
4. Scars from painless burns
5. Charcot joints: elbow and shoulder
   Additional signs
6. Pyramidal weakness in lower limbs with upgoing (extensor) plantars
7. Kyphoscoliosis is common
8. Horner’s syndrome (see Ophthalmology section)
9. If syrinx extends into brain stem (syringobulbia) there may be cerebellar and lower cranial nerve signs

Question 3

Effect of Syrinx expansion:

Answer 3

Syrinx expands ventrally affecting:

1. Decussating spinothalamic neurones producing segmental pain and temperature loss at the level of the syrinx.
2. Anterior horn cells producing segmental lower motor neurone weakness at the level of the syrinx.
3. Corticospinal tract producing upper motor neurone weakness below the level of the syrinx.
4. It usually spares the dorsal columns (proprioception).

Question 4

Discussion of Syringomyelia

Answer 4

1. Syringomyelia is caused by a progressively expanding fluid filled cavity (syrinx) within the cervical cord, typically spanning several levels.
2. The signs may be asymmetrical.
3. Frequently associated with an Arnold–Chiari malformation and spina bifida.
4. Investigation = spinal MRI.

Question 5

Cervical roots

Answer 5

C 5/6 Elbow flexion and supination&raquo_space; Biceps and supinator jerks C 5/6
C 7/8 Elbow extension&raquo_space; Triceps jerk C 7/8
T 1 Finger adduction

Question 6

Upper limb dermatomes

Answer 6

Hints:
C6 thumb
C7 middle finger
C8 little finger

Question 7

Charcot joint (neuropathic arthropathy)

Answer 7

1. Painless deformity and destruction of a joint with new bone formation following repeated minor trauma secondary to loss of pain sensation.
2. The most important causes are:
   ⚬⚬ Tabes dorsalis: hip and knee
   ⚬⚬ Diabetes: foot and ankle
   ⚬⚬ Syringomyelia: elbow and shoulder
3. Treatment: bisphosphonates can help