Neural Syndromes

Question 1

Describe associated symptoms of UMN/spastic weakness

Answer 1

• Increased tone
• Pyramidal pattern of weakness (relative preservation of upper limb flexors and lower limb extensors)
• Hyper-reflexia
• Exacerbated deep tendon reflexes / Clonus
• Babinski sign +ve
• Hoffman’s Sign +ve
• Superficial abdominal reflexes are absent
• Cremasteric reflex (L1) is absent
• Minimal muscle atrophy secondary to disuse
• Difficulty placing foot on edge

Question 2

Describe LMN/flaccid weakness

Answer 2

• Decreased tone
• Non pyramidal weakness
• Diminished or loss of deep tendon reflexes
• Babinski sign -ve
• Hoffman’s sign -ve
• Marked muscle atrophy
• Muscular fasciculations present (When there is slow destruction of LMN cell)
• Muscular contracture (shortening of the paralysed muscles)

Question 3

Describe syndromes based on location of lesion

Answer 3

• Complete (Based on vertical level) - Paraplegia, Quadriplegia
• Diaphragm weakness (C3, C4 level)

Question 4

Briefly describe incomplete syndromes and list some examples

Answer 4

• Based on the level and which tracts are affected
• Central cord syndrome, Anterior cord syndrome, Posterior cord syndrome, Brown-Sequard syndrome

Question 5

Describe neural syndromes based on aetiology

Answer 5

• Trauma
• Chronic Compression of spinal cord - Extradural / Intradural - [Extramedullary / Intramedullary]
  - examples of extramedullary: neurofibroma, subdural haematoma
  - intramedullary: haematoma, ependymoma

Question 6

Describe spinal shock syndrome

Answer 6

• Acute severe damage to the cord
• Usually in context of trauma
• Cord function below the level of the lesion is lost - Flaccid paralysis + sensory impairment
• Hypotension occurs when the lesion is at high level of the cord resulting in loss of sympathetic vasomotor tone
• Spinal shock usually persist for < 24 hours (sometimes 1 to 4 weeks)
• Anal reflex - absent anal reflex would indicate the existence of spinal shock (But if sacral segments of the cord are damaged, it would nullify this test since the neurons giving rise to the inferior haemorrhoid nerve to the anal sphincter would be non-functioning)
• When spinal shock diminishes, upper motor neuron signs are noted below the cord lesion

Question 7

Describe complete transection of the spinal cord

Answer 7

• Combination of LMN injury at the level of the cord lesion and UMN injury below the level of cord lesion
• Complete loss of sensation and motor function below the level of the lesion
• Bilateral LMN paralysis and muscular atrophy in the segment of the lesion
• Bilateral spastic paralysis below the level of the lesion
• Bilateral loss of all sensation below the level of the lesion (Because of the lateral and anterior spinothalamic tracts cross obliquely, the loss of thermal and light touch sensation occurs two or three segments below the lesion distally)
• Loss of bowel and bladder function due to loss of descending autonomic fibres
• Lesions below the cord at L2-L3 level - Cauda equina lesion - LMN, autonomic and sensory fibers are involved

Question 8

Describe anterior cord syndrome

Answer 8

• Fracture, Anterior spinal artery involvement (e.g. stroke)
• Bilateral LMN paralysis in the segment of the lesion and muscular atrophy
• Bilateral spastic paralysis below the level of the lesion
• Bilateral loss of pain, temperature and light touch sensation below the level of the lesion
• Tactile discrimination, vibratory and proprioceptive sensation are preserved

Question 9

Describe central cord syndrome

Answer 9

• Hyperextension injury to the spine
• “Sacral Sparing”, with bilateral spastic paralysis below the level of the lesion - lower limb fibres or less affected than the upper limb fibres, because of the lamination of the descending fibres in the lateral corticospinal tracts
• Bilateral loss of pain, temperature, light, touch and pressure sensations below the level of the lesion with characteristic “Sacral Sparing” due to the laminated arrangement of the ascending fibres in the lateral and anterior spinothalamic tract
• The sparing of the lower part of the body is noted by the presence of peri-anal sensation, good anal tone, and ability to move the toes distally

Question 10

Describe B-S syndrome

Answer 10

• Hemi-section of the cord
• Trauma
• Ipsilateral LMN paralysis in the segment of the lesion and muscle atrophy
• Ipsilateral spastic paralysis below the level of the lesion
• Ipsilateral band of loss of sensation in the segment of the lesion
• Ipsilateral loss of tactile discrimination and vibration & proprioceptive sensation below the level of the lesion
• Contralateral loss of pain and temperature sensation below the level of the lesion (since the lateral spinothalamic tract crosses obliquely, the sensory loss occurs two or three segments below the lesion distally)
• Contralateral BUT not complete loss of tactile sensation below the level of the lesion (because tactile information travels through both tracts, and is thus preserved)

Question 11

Describe syringomyelia

Answer 11

• Hemi-section of the spinal cord
• Syringomyelia
• Asymmetric dilatation of the central canal of the cord
• Chiari Malformation (herniating cerbellum?), Trauma, Spinal cord tumours
• Loss of pain and temperature sensation in dermatomes on both sides of the body related to the affected segments of the cord - “Shawl-like” distribution
• Tactile discrimination, vibration and proprioception are normal
• LMN weakness is noted in the small muscles of the hand - due to the lesion expanding and destroying the anterior horn cell.
• Bilateral spastic paralysis of both legs may occur late with exaggerated, deep tendon, reflexes and Babinski’s sign
• Horner’s syndrome – due to interruption of the descending autonomic fibres

Question 12

List some mimics of spinal cord lesions

Answer 12

• Bilateral frontal lobe lesion - Falcine meningioma e.g. no seizures but paraplegia present
• Guillian Barre syndrome
• Conversion disorder
• Proximal Myopathy
• Myasthenia Gravis

Question 13

Describe cauda equina syndrome

Answer 13

• The lumbar and sacral nerve roots are involved
• Radicular type pain in the legs, buttocks, perineal region
• LMN-type motor deficit
• Asymmetric sensory deficit
• Sphincter involvement is a late finding and is mild
• The prognosis for recovery is better vs conus medullaris
• Usually L5-S1

Question 14

Describe conus medullaris syndrome

Answer 14

• Lesions affecting the terminal portion of the spinal cord and its roots.
• Combination of central and peripheral nervous system involvement
• Bilateral symmetrical sensory loss which may be dissociated– involvement usually proceeds in an ‘inside-out’ fashion
• Lower levels affected earlier resulting in a classic saddle distribution of sensory loss
• Sphincter involvement occurs early (urinary and faecal incontinence)
• motor weakness is not a prominent finding – it may be mild symmetrical and involves L5, S1 innervated muscle groups

Question 15

Describe radiculopathy

Answer 15

• Dysfunction of a nerve root
• Usually from nerve root compression
• Can be from diabetic neuropathy or an inflammatory process
• Radicular pain - sharp, shooting, electric shock-like
• May be associated with numbness, tingling, or weakness in the distribution of the nerve
• Cervical and lumbar spine are most commonly involved