Spinal cord lesions

Question 1

ascending tracts

Answer 1

sensory
- dorsal column
- spinothalmic

Question 2

descending tracts

Answer 2

motor
- corticospinal

Question 3

where does the spinal cord end and become the cauda equina

Answer 3

L1

Question 4

cauda equina

Answer 4

collection of peripheral nerves that travel within the spinal cord

Question 5

Dorsal columns

Answer 5

• The dorsal columns travel in the posterior section of the spinal cord and carry information about fine touch, vibration sense, and proprioception.
• When the cars carrying this information enter the spinal cord, they don’t really bother changing lanes until they are almost at their destination.
• The fibres remain ipsilateral and do not decussate until they reach the medulla of the brainstem.

Question 6

Spinothalamic tracts

Answer 6

• The spinothalamic tracts travel in the anterior part of the spinal cord and carry information regarding pain and temperature.
• Cars carrying this information cross over into the outside lane almost immediately and stay in this lane until they reach their destination: the fibres decussate as soon as they enter the spinal cord and ascend contralaterally.

Question 7

decussation in the dorsal columns vs spinothalamic

Answer 7

Question 8

one significant descending tract

Answer 8

corticospinal tract

Question 9

The corticospinal tract

Answer 9

• Carries motor information from the motor centres of the frontal lobe down to the skeletal muscles; cars are driving down the motorway, away from the brain, towards other areas.
• Like to the spinothalamic tracts discussed above, when the fibres of the corticospinal tracts get onto the motorway, most immediately change lanes and remain in the opposite lane until they reach their destination: the fibres travel contralaterally.

Question 10

blood supply to the spinal cord

Answer 10

Anterior spinal artery
- supplies anterior 2/3 (bilateral symptoms)

2 Posterior spinal arteries
- - supplies posterior 1/3 (unilateral symptoms)

Question 11

blood supply to the spinal cord

Answer 11

Anterior spinal artery
- supplies anterior 2/3 (bilateral symptoms)

2 Posterior spinal arteries
- - supplies posterior 1/3 (unilateral symptoms)

Question 12

Signs that may indicate that the problem is in the spinal cord rather than other parts of the nervous system.

Answer 12

• Mixed upper and lower motor neurone signs
• Sensory level
• Sphincter involvmeent
• Autonomic dysfunction
• Pattern of clinical signs

Question 13

Mixed upper and lower motor neuron signs

Answer 13

As the spinal cord is part of the central nervous system, there will be upper motor neuron signs (increased tone, clonus, hyperreflexia, extensor plantars). The spinal nerves leaving the spinal cord at the level of the lesion may also be damaged.

As these nerves are part of the peripheral nervous system there will also be lower motor neuron signs (muscle wasting, fasciculations, flaccid paralysis, reduced reflexes) at the level of the lesion.

Aside from some rare genetic syndromes, the other common diagnosis that may include both upper and lower motor signs is motor neuron disease which is, itself, thought to primarily affect the anterior horn cells of the spinal cord.

Question 14

Sensory level

Answer 14

There may also be a sensory level, a well-demarcated transverse line below which sensation is abnormal. For example, a lesion at the T10 level of the spinal cord may produce a sensory level around the level of the umbilicus.

Question 15

Sphincter involvement

Answer 15

Sphincter involvement

Sphincter involvement makes problems in the brain or the brainstem less likely (although not impossible) but both spinal cord and cauda equina lesions can disrupt urinary and bowel function.

• A lesion of the spinal cord results in urinary retention and constipation. The best way to think of this is as increased sphincter tone, preventing the passage of urine or faeces.
• Conversely, a cauda equina lesion would result in urinary and faecal incontinence with flaccid paralysis of the urethral sphincter.

Question 16

Autonomic dysfunction

Answer 16

Spinal cord lesions are relatively unique in that they can cause severe autonomic dysfunction, called autonomic dysreflexia.

The presence of autonomic dysfunction indicates that the lesion is above the level of T6. Patients will often present with hypertension, bradycardia, urinary retention, and constipation, as well as sweating and flushing above the level of the lesion.

Question 17

are spinal cord lesions unilateral or bilateral

Answer 17

Often bilateral

Whereas lesions in the brain tend to cause unilateral deficits, lesions of the spinal cord are often bilateral.

However, because of the different routes taken by different tracts, spinal cord lesions are often, but not always, asymmetrical.

Question 18

location of spinal cord lesion: if all 4 limbs affected

Answer 18

cervical

Question 19

location of spinal cord lesion: lower limbs

Answer 19

thoracic

Question 20

location of spinal lesion: respiratory difficulities and diaphragm has been affected

Answer 20

above C3

Question 21

causes of spinal cord lesions

Answer 21

vascular
infection
trauamtic
autoimmune
metabolic/nutritional
neoplastic
degenerative
genetic

Question 22

Vascular

Answer 22

• Spinal artery occlusion (e.g. spinal stroke)
• Aortic dissection
• Arrhythmia (e.g. atrial fibrillation)

Question 23

Infection

Answer 23

• Abscess
• Viral infection (e.g. polio – rare with immunisation), HIV, HTLV
• Syphilis
• Tuberculosis
• Para or post-infectious transverse myelitis

Question 24

Traumatic

Answer 24

Any trauma

Question 25

Autoimmune

Answer 25

**Multiple sclerosis** Neuromyelitis optica Sarcoidosis

Question 26

Metabolic/nutritional

Answer 26

B12 deficiency Copper deficiency

Question 27

Neoplastic

Answer 27

Malignant compression of the spinal cord

Question 28

Degenerative

Answer 28

Degenerative disc disease e.g. Intervertebral Disc Herniation

Question 29

When an entire cross-section of the spinal cord is damaged, there is said to be a

Answer 29

complete **transection** In this scenario, there is interruption of all ascending and descending tracts bilaterally, resulting in bilateral loss of motor function, and complete loss of all modes of sensation below the level of the lesion.

Question 30

Brown-Sequard syndrome

Answer 30

Cause: damage to one lateral hald of the spinal cord (most commonly cervical) Pahtophysiology - different tracts decussate in different locations - therefore classicial clinical rpesentation of a thorasic spinal cord hemispection is of spastic paralysis and loss of pain and temperature senstation in one leg, --> due to interruption of the coritcospinal and spinothalamic tracts - Due to the variable decussation levels, there will also be loss of fine touch, proprioception and vibration sense in the other (dorsal column) BILATERAL BUT ASYMMETRICAL

Question 31

how can we use our knowledge of the tracts to detect which half of the spinal cord is damage di Brown-Sequard syndrome

Answer 31

We know that the dorsal columns enter the spinal cord and ascend ipsilaterally (that is, the cars do not change lanes once they are on the motorway). Therefore, the spinal cord lesion must be on the same side of the body as the dorsal column symptoms.

Question 32

anterior cord syndrome

Answer 32

Stroke in the anterior spinala artery - ASA supplies 2/3s of the spinal cord - Bilateral SYmptoms Presentation - Bilateral disruption of the spinothalamic tract (loss of pain and temprature sensation) - Bilateral disruption pof of corticospinal tracts (spastic paralysis and UMN signs) what wont be affected: dorsal columns (posterior position

Question 33

Posterior cord syndrome

Answer 33

Conversely to anterior cord syndrome, it is also possible to develop a posterior spinal cord syndrome. This causes unilateral damage to the dorsal columns. The corticospinal tracts can also be affected but the spinothalamic tracts will be spared. This is often the clinical picture seen in subacute combined degeneration of the spinal cord as a result of B12 deficiency.2

Question 34

Syringomyelia

Answer 34

Also called central cord syndrome , occurs due to the development of a **fluid-filled cyst** (a syrinx) around the spinal canal. Syringomyelia is primarily a problem with CSF flow and is commonly associated with the Chiari malformation.4 As the spinal canal is immediately surrounded by decussating fibres making up the spinal white matter, it is these that are initially affected. Despite beginning in the central white matter, it may expand and eventually affect the corticospinal and spinothalamic tracts. The pattern of deficit seen in patients with syringomyelia initially seems confusing as it is different from other syndromes. The upper limbs are affected first whilst the lower limbs are spared until much later. As the fibres of the spinothalamic tract enter the spinal cord and immediately decussate, they pass close to the spinal canal, meaning they are often the first of these white matter fibres to be compressed and damaged. **As the cervical cord is the most likely location of the lesion, there is classically said to be a “cape-like” loss of pain and temperature sensation. **

Question 35

Spinal cord concussion

Answer 35

Spinal cord concussion Another spinal cord pathology includes spinal cord concussion. This is a transient loss of spinal cord function, usually resolving within 48 hours.

Question 36

Spinal stenosis

Answer 36

Spinal stenosis occurs when the spinal canal narrows to compress the spinal cord. It most commonly affects the lumbar region and presents with glute/leg pain on walking or standing (often referred to as spinal claudication), classically relieved by forward flexion or sitting.

Question 37

how can we use our knowledge of the tracts to detect which half of the spinal cord is damage di Brown-Sequard syndrome

Answer 37

We know that the dorsal columns enter the spinal cord and ascend ipsilaterally (that is, the cars do not change lanes once they are on the motorway). Therefore, the spinal cord lesion must be on the same side of the body as the dorsal column symptoms.