Syringomyelia

Question 1

Syringomyelia

Answer 1

Overview
development of cavity (syrinx) within the spinal cord
if extends into medulla then termed syringobulbia
strongly associated with the Arnold-Chiari malformation

Question 2

Syringomyelia - Features

Answer 2

Features
may be asymmetrical initially
slowly progressives, possibly over years
motor: wasting and weakness of arms
sensory: spinothalamic sensory loss (pain and temperature)
loss of reflexes, bilateral upgoing plantars
also seen: Horner’s syndrome

S = S = S syringomyelia = sensory = spinothalamic

Differential of
- mixed UMN and LMN signs e.g. absent ankle reflexes + upping plantars

Question 3

Syringomyelia - Diagnosis

Answer 3

The presence of loss of pain and temperature sensation in a ‘cape like’ distribution is highly suggestive of syringomyelia. A fluid filled cavity within the cord develops, typically between C2 to T9, compressing the cord from inside to out. Consequently the spinothalamic tracts are the first to be affected in a symmetrical distribution.

There are a number of aetiologies, but it should be noted that there is an association with Arnold Chiari malformation Type 1. It is sensible to investigate for a compressive cord lesion in the first instance; imaging of the brain may be considered if syringomyelia is detected. An MRI cervice-thoracic cord would be the most sensitive method of detecting syringomyelia.

Example Question:
A 35 year old mechanic attends the emergency department following an injury at work. He has suffered a serious laceration to the upper arm. While suturing, the doctor notices multiple cuts and burns on both arms.

On examination there is marked wasting of brachioradialis and the small muscles in both hands, with mild hyporeflexia of the biceps and brachioradialis tendons. He is weak in both arms, distally more so. His lower limb and cranial nerve examination is unremarkable. On testing upper limb sensation, vibration and proprioception are intact but there appears to be reduced pain and temperature sensation over the C3/C4/C5 deramatomes. What is the most useful investigation?

Question 4

Syringomyelia - Diagnosis: Example Question

Answer 4

A 32-year-old woman presents with reduced sensation. She has noticed that slowly over six months she has not felt when hot water has splashed on her hands, despite blistering occurring afterwards. Her husband has become concerned and asked her to seek a medical opinion. She denies any other problems, including weakness, weight-loss or her activities of daily living being affected. She has a past medical history of asthma but only rarely needs her salbutamol inhaler. She has no other medications or allergies. On examination, she has sensory loss over her hands and arms when tested for temperature and pain. There is a dermatomal distribution affecting dermatomes C4 to C6 which is symmetrical. Cranial nerve and lower limb examination is normal. Spinal examination shows no tenderness. What is the most likely diagnosis?

	Multiple sclerosis
	Cervical disc prolapse
	Vasculitis
	Myasthenia gravis
	> Syringomyelia

The correct answer is syringomyelia. The fact that she has primarily loss of spinothalamic function in a cervical nerve distribution with a distinct sensory loss makes syringomyelia the most probable diagnosis. Weakness can occur as well. Syringomyelia is caused by a tubular cyst within the central spinal cord, most commonly affecting the cervical region. It compresses corticospinal and spinothalamic tract as well as anterior horn cells. Presentation can be variable causing loss of temperature sensation, pain, paralysis, stiffness and weakness. Due to the common location of the cyst, this is most likely to affect hands, arms and shoulders. In half of the patients, there is only mild or no disability.

Multiple sclerosis is unlikely as there is no evidence of lesions separated by attacks. The absence of neck pain or tenderness makes a disc prolapse unlikely, whilst the absence of systemic features makes vasculitis unlikely. Myasthenia is associated with fatigability rather than a sensory loss.

Question 5

Pain and Temp loss?

Answer 5

Think Spinothalamic Tracts

Think Syringomyelia

Question 6

Syringomyelia

Answer 6

Primary loss of spinothalamic function in a cervical nerve distribution (‘cape-like’) with a distinct sensory loss makes syringomyelia the most probable diagnosis.

Weakness can occur as well.

Syringomyelia is caused by a tubular cyst within the central spinal cord, most commonly affecting the cervical region. It compresses corticospinal and spinothalamic tract as well as anterior horn cells.

Presentation can be variable causing loss of temperature sensation, pain, paralysis, stiffness and weakness.

Due to the common location of the cyst, this is most likely to affect hands, arms and shoulders. In half of the patients, there is only mild or no disability.