Diseases of the spinal cord Flashcards
What are the collective terms for motor disorders of the Spinal cord and Spinal roots?
Spinal cord disorders - myelopathies
Corresponds to Upper motor neurone disease
Spinal root disorders - nerve root/radiculopathies
Corresponds to Lower motor neurone disease
What are the motor signs for an upper motor neuron pathology (spinal cord pathology) and lower motor neurone pathology (root)?
Upper motor neurone - cord:
- No wasting
- Hypertonia
- Hyperreflexia, Extensor plantar
- Pyramidal pattern of weakness
Lower motor neurone - roots:
- Wasting
- Hypotonia
- Hyporeflexia, flexor plantar
- Weakness
What sensory signs will be seen in a spinal cord pathology?
Myelopathies cause a sensory deficit
Hemicord lesions cause Brown-Sequard syndrome:
- Ipsilateral (ie supply from dorsal column):
- Decreased Vibration sensitivity
- Decreased Joint position awareness
- Weakness
- Contralateral (ie supply from Spinothalamic tract):
- Decreased pain sensation
- Decreased temperature sensation
What are the expected sensory and autonomic signs of a spinal root pathology (radiculopathy)?
Dermatomal sensory loss corresponding to the spinal nerve root that is affected
Bladder/bowel dysfunction associated with autonomic loss
Why is C5 nerve root damage an important nerve root pathology to be aware of the signs of?
What are the signs of this?
C5 spinal nerve often compressed leading to problems in the arms:
- Wasting & weakness of C5 innervated muscles
- Deltoids (shoulder abduction weakened)
- Pyramidal pattern of weakness below
- Hypertonia in legs > arms
- Decreased bicep reflex but increased lower reflexes
- Sensory deficit
This model of signs can be applied to other nerve root pathologies as well just applying to their muscles
The causes of myelopathies and radiculopathies can be grouped as Intrinsic (ie within the actual spinal cord/nerve) or Extrinsic
What are the extrinsic causes?
Pathology from something external to the spinal cord/nerve:
- Surgery - ie iatrogenic
- Tumours
- Vascular abnormalities
- Degenerative disorders of the spine
- Trauma
What tumours may cause myelopathies or radiculopathies?
How do they do this?
Extradural:
- Most common
- Typically a metastasis from elsewhere
Intradural:
1) Extramedullary tumours:
- Meningiomas
- Neurofibromas
2) Intramedullary
* Ependymomas
Can either directly compress the Spinal Cord/Nerve
Or Vertebral body destruction by bony metastasis can cause cord compression
What vascular abnormalities can cause extrinsic damage to the spinal cord/nerves?
Haemorrhage
Arteriovenous malformation (AVM)
Dural fistula
Both AVM & dural fistulas are abnormal connections between arteries and veins
What are the intrinsic (medical) causes of Myelopathies or radiculopathies?
- Congenital/genetic causes
- Acquired causes (groups of causes):
- Inflammatory - incl. Multiple Sclerosis
- Vascular - incl. Ischaemia
- Infective
- Metabolic - Vitamin B12 deficiency
- Malignant - both infiltrative & paraneoplastic
- Idiopathic
What are the congenital causes of spinal cord/nerve pathologies?
Friedrich’s ataxia
Spinocerebellar ataxias
Hereditary paraparesis
What are the inflammatory causes of spinal nerve/nerve pathologies?
Demyelination - Multiple sclerosis!!!
Autoimmune (antibody-mediated) - eg aquaporin, lupus
Sarcoid
What are the vascular causes of Spinal cord/nerve pathology?
Ischaemia!!! & haemorrhage
What are the infective causes of spinal cord/nerve pathology?
Viral:
- HIV, Herpes Simplex/zoster, EBV, CMV, Measles
Bacterial:
- TB, Lyme (borrelia), syphilis, brucella
Other:
- Schistosomiasis
Why does Vitamin B12 cause spinal cord/nerve damage?
Vitamin B12 is essential to the synthesis of myelin
No myelin = not good
What are the causes of spinal cord ischaemia/spinal cord stroke?
Good luck remembering this lol hehe
Atheromatous disease (including aortic aneurysms)
Thromboembolic disease - endocarditis, AF
Arterial dissection (aortic)
Systemic hypotension
Hyperviscosity syndromes / prothrombotic disease
Vasculitis
Arteriovenous abnormalities
Endovascular procedures
Meningovascular syphilis
Decompression sickness - ‘the bends’
How does Spinal cord stroke present?
Symptoms & signs:
- Back pain / radicular pain (“radiated” Dermatomally)
- May have Visceral referred pain
- Numbness & paraesthesia
- Urinary symptoms
Signs:
- Weakness - typically just in lower limbs
History:
- CVS history/vascular risk factors
- Onset may be sudden or over several hours
What urinary symptoms may be experienced with spinal cord stroke?
Retention followed by bladder and bowel incontinence as spinal shock settles
Identify the arteries that supply the spinal cord in the diagram below
There is also the central sulcal artery - occlusion of this can present as a partial Brown-Séquard syndrome
How would motor and sensory function be affected by a spinal cord stroke involving the anterior spinal artery
Anterior spinal artery - most common
Loss of:
- Motor (CST) - paralysis below the level of the lesion (usually mid-thoracic)
- Pain & temp sensation (LST)
- Light touch (VST)
Dorsal columns spared - thus no effect to:
- Deep touch
- Proprioception
- Vibration
SC stroke involving the posterior spinal artery would be a contrast to this
What is Spinal shock?
A combination of areflexia/hyporeflexia and autonomic dysfunction that sometimes accompanies spinal cord injuries
What is the prognosis for spinal cord stroke?
Unless significant motor recovery in first 24 hours chance of major recovery is low
Pain may be persistent and significantly contribute to disability
20% mortality, only 35-40% have more than minimal recovery
Multiple sclerosis is a condition in which there is demyelinating myelitis
How would Demylenating myelitis (MS) generally present?
(not symptoms but just generally)
Symptoms corresponding to DM is the most common presentation for MS itself
Presentation is sub-acute, with slower onset (than ischaemia eg)
More common in younger patients than vascular causes - ischaemia etc
May also have previous neurological history
What imaging modality is best for identifying myelitis in MS?
MRI
What are the causes of Vitamin B12 deficiency?
Diet (vegans) - Meat, fish etc are sources of B12
Pernicious anaemia: autoimmune condition in which antibodies to IF prevent B12 absorption
Total gastrectomy, Crohn’s, tape worms
