10.10 Spinal Cord Disorders Flashcards
How does the level of the lesion and the sensory level found on examination correspond?
The level of the lesion and the sensory level found on examination do not necessarily correspond.The sensory level is often lower, and in the chronic phase of incomplete lesions, may regress.
With acute severe lesions where will the clinically detectable sensory level be?
Close to the lesion
With chronic milder lesions where will the clinically detectable sensory level be?
At level often far away from lesion
What does the interruption of the ascending sensory pathways produce?
Sensory loss
What does interruption of the descending motor pathways produce?
Upper motor neuron syndrome
What does the UMN bladder cause?
Upper motor neuron bladder
Small volume:
- frequency
- urgency
- urge incontinence
What does a LMN bladder cause?
Lower motor neuron bladder
Large Volume:
- Difficulty intitiating flow
- overflow
- incontinence
What does the interruption of the descending autonomic pathways causes?
Bladder and bowel dysfunction
What pathways are affected when the anterior spinal artery is clamped?
- corticospinal
- spinothalamic
What will develop with an acute and chronic insult to the UMN?
Acute - spinal shock (floppy weakness)
Chronic - UMN syndrome
Define spinal shock
- Severe cord injury causes spinal shock in the acute phase
- Motor -ABSENT reflexes, and 0-1/5 power
- Sensory- Sensory level close to the level of the lesion
- Autonomic dysfunction - Acute urinary retention
Clinical manifestations of Chronic UMN syndrome
Motor
- ⬆️reflexes, clonus, and power lost in UMN pattern
- Other reflexes: Babinski, flexor spasms, extensor spasms
- Spasticity (velocity-dependent, clasp-knife increase in tone)
- The limbs may be held in extension or flexion posturing depending on the dominant pattern of spasticity
- No or mild atrophy (disuse)
Sensory
- Sensory level, not always clear
Autonomic dysfunction
- Spastic UMN bladder (small volume + urgency)
Spasms
- In paraplegic patients, spasticity and hyperreflexia are often accompanied by increased cutaneomuscular reflex excitability, through polysynaptic propriospinal pathways
- Pulling a on a pair of trousers may be enough to produce spasms of the hip and knee flexors, sometimes accompanied by autonomic effects (sweating, hypertension, emptying of the bladder)
- Loss of tonic supraspinal input from the corticospinal and reticulospinal tracts account for this phenomena
Transverse myelopathy
- Interruption of the ascending sensory tracts → combined sensory loss
- Interruption of the descending motor tracts → paraparesis, the UMN syndrome
- Interruption of the descending autonomic tracts → bowel and bladder dysfunction
- It is more typical for the section to be incomplete and irregular, and the clinical findings reflect the extent of damage
Anterior cord syndrome
- Interruption of the spinothalamic tract → Sensory level to pinprick
- Posterior part of spinal cord intact → sparing of JPS (joint position sense)
- Example: spinal cord infarct with anterior spinal artery
- Ischemic injury to the spinal cord affects areas with high metabolic demand, such as the anterior horn cells and grey matter, before leading to complete cord necrosis
- most common cord clinical presentation of myelopathy
Central cord syndrome
Pathogenesis
Causes
- Spinal cord injury starts centrally
- Loss of pain and temperature in a cape- like distribution, sparing of JPS
- Involvement of corticospinal tracts cause paraparesis and UMN syndrome
- Damage to anterior horn cells → Atrophy over several segments
- Damage to the autonomic pathways at C8-T2 → Horner syndrome
- Lateral extension leads to interruption of the descending motor pathways → UMN signs
Causes
Cervical spondylosis (hyperextension injury), syringomyelia, intramedullary spinal cord tumours, spinal cord haemorrhage
Dorsalateral cord syndrome
Pathogenesis
Causes
- Interruption of the corticospinal tract → paraparesis, UMN syndrome
- Interruption of the dorsal columns → Loss of JPS
Causes
Vit B12 deficiency, copper deficiency myelopathy, AIDS associated (vacuolar) myelopathy, HTLV-1 associated myelopathy, extrinsic cord compression (cervical spondylosis
Brown-séquaed syndrome
Causes
Manifestations
Causes
- Herniated cervical disc, Multiple Sclerosis, penetrating stab wounds, tumours (primary or metastatic)
Manifestations
- Reduced pain and temp
- Reduced joint position sense
Conus medullaris syndrome
- End of the cord consists of S2, 3, 4 segments
- Damage to conus results in loss of bowel and bladder function
Causa equina syndrome
not cord syndrome
- Cauda equina consists of lumbar and sacral roots
- Damage to the roots cause
- Patchy LMN signs
- Patchy sensory loss in dermatomes
- Variablelossofbladderandbowelfunction
Conus medullaris syndrome vs causa equina syndrome
Conus Medullaris Syndrome
- Pain is late and symmetrical (thighs, buttocks and perineum)
- Symmetrical weakness typically of the pelvic floor muscles
- Symmetrical saddle anesthesia
- Early sphincter compromise
Cauda Equina Syndrome
- Early radicular pain, often unilateral or asymmetrical
- With extensive lesions, there is weakness of the glutei, posterior thigh muscles, anterolateral muscles of the leg and foot
- Asymmetric sensory loss in the saddle region (anal, perineal and genital regions) extending to the posterior aspect of the thigh
- Late sphincter dysfunction
False localizing signs
Define
Examples
- False localizing sensory and motor findings can occur with upper and mid-cervical cord lesions
Examples
- Midline disc protrusion at the C3-C4 level may be associated with numbness of the fingertips and palms, clumsiness of the hands, and a tightening sensation at the midthoracic level
- Extradural lesions above C4 level may cause finger and hand dysesthesias and hand atrophy
- Spondylotic cervical myelopathy with numb, clumsy hands
- Thus, when clinically deducing the site of a lesion, remember the lesion may be at the site inferred on clinical examination, OR HIGHER
Classify the causes of spinal cord dysfunction
Lesions may be
1. Outside of the cord (extramedullary) - common; causes cord compression
- Outside the dura (extradural)
- Inside the dura (intradural)
2. Inside the cord (intramedullary) - uncommon; causes compression
Common conditions that causes cord dysfunction
- Syphillis
- Metastases
- Syringomyelia
- Multiple sclerosis
- Systemic inflammatory disorders
- Post/parainfectious myelopathy
- Vit B12 deficiency
Extramedullary vs Intramedullary
Extramedullary cord lesions
• Radicular pain is common, may occur early
• Vertebral pain is common
• Central pain is less common
• UMN signs occur early
• LMN signs unusual, if present: segmental
• Paresthesiae occur in ascending progression
• Sphincter dysfunction late
• Trophic changes are unusual
Intramedullary cord lesions
• Radicular pain is unusual
• Vertebral pain is unusual
• Central pain* is common
• UMN signs occur late
• LMN signs may be prominent and diffuse
• Paresthesiae occur in descending progression
• Dissociated sensory loss, sacral sparing
• Early sphincter dysfunction in conus lesions
• Trophic changes are common
