Makindo Medical Notes.com

About

• Any disorder of the spinal cord is termed a myelopathy
• Suspect when there are bilateral signs involving arms and legs
• Extrinsic damage to the spine above L1 will damage cord and roots
• Extrinsic damage to the spine below L1 will damage roots - See Cauda equina

Cord lesions and clinical correlation

• Extradural
  • Lies outside the dura. Trauma, Malignancy - Breast, Prostate, Lung, Myeloma, Kidney, Colon, Thyroid, Myeloma, Lymphoma. Epidural abscess, haematoma.
  • Central disc prolapse and an AV Malformation. Pain is typical as there is pressure on meningeal structures as well as sensory nerves.
  • Vascular compromise is possible with pressure on the cord and can cause an anterior spinal cord syndrome infarction the anterior 2/3rds. Urgent evaluation is needed.
  • There is spasticity and hyperreflexia below the lesion and reflex loss at the disease level.
• Intradural extramedullary
  • Increasing evidence of corticospinal weakness with spasticity and hyperreflexia below the lesion.
  • May affect both limbs arms and legs depending on the level involved.
  • Sensory symptoms due to spinothalamic involvement e.g. loss of pain sensation.
  • Commonest cause is a thoracic meningioma or a neurofibroma "dumbbell" lesion.

Intradural intramedullary :- There are four patterns of disease

• 1. Complete transverse cord lesion: loss of motor and sensory. Flaccid paralysis acutely and then hyperreflexia and spasticity. Reflex loss at the level of the lesion with wasting and fasciculations. Complete touch sensation loss implies both spinothalamic and dorsal column loss and an extensive lesion. Demonstrate a sensory level.
• 2. Anterior cord: Damage to the anterior spinal artery leads to loss of anterior and lateral spinothalamic, corticospinal tracts, anterior horn cells. There is weakness in all limbs depending on the level but preserved dorsal column function with some touch, vibration and proprioception. Seen with dissecting abdominal aneurysms and AAA surgery compromising spinal blood supply.
• 3. Posterolateral column: Loss of dorsal columns and corticospinal tracts. Seen with B12 deficiency and MS and HIV associated myelopathy. Sensory ataxia, spasticity and hyperreflexia.
• 4. Central cord disease: Central intramedullary tumour s, syringomyelia, cervical hyperextension injury. Classically affects crossing spinothalamic fibres. Gives cape-like area of loss of pain sensation over shoulders and upper arms. Dorsal column sensation is intact. Anterior horn cells may be affected so there may be some weakness and areflexia. As it expands and corticospinal tracts are affected there is spasticity and hyperreflexia. May be some bladder dysfunction

Onset

• Instant : Trauma, Spontaneous bleed from AVM/Warfarin
• Hours : Infection, Inflammatory
• Weeks: Tumour, Degenerative

Clinical

• Onset with trauma or inflammation or infection can be instant or over hours
• Progressive fatigue or stiffness in legs
• Progressive worsening of gait
• Urinary dysfunction is usually late
• Sensory disturbance in one or both legs
• Band like sensation around thorax or abdomen points to lesion level
• Back pain can help localise the cause

Clinical Localisation

• C5 - radial side of forearm and reduced biceps reflex and power
• C6 - deficit in the thumb and first finger and decreased bicep and brachioradialis
• C7 - deficit in middle and ring finger and reduced triceps jerk
• C8 - Deficit in little finger and reflexes are normal
• T1 - T12 - pain in distribution but no weakness. Can cause chest wall pain. Mistaken as cardiac pain.
• L2 - sensory deficit lateral and anterior thigh weak psoas and quadriceps. Reflexes normal
• L3 - sensory deficit lower medial thigh weak psoas and quadriceps. Reduced knee jerk
• L4 - sensory deficit medial lower leg. Decreased knee jerk
• L5 - Lateral lower leg. Weak. No reflex abnormality
• S1 - lateral foot and with weak gastrocnemius. Reduced ankle jerk

Examples of levels of lesions

• C4-C5: Complete quadriplegia and some diaphragm weakness
• T1: normal Upper limb function and bilateral lower limb weakness

Example to show roots exit lower done

• C7 level the roots to T1 are formed and exit
• T10 level the roots to T12 are formed exit
• L1 the roots to S1 are formed and exit.

Myelopathy by cause

• Acute Cord compression [ED]: see topic
• Acute central disc lesion [ED] : see topic
• Epidural abscess [ED]: see topic
• Transverse myelitis [II] : see topic
• Spinal cord Infarction [II] : see topic
• Cervical spondylosis [EE]: See topic
• Spinal cord Arteriovenous Malformations: See topic

Investigations

• B12 deficiency, transverse myelitis and vascular events.
• MRI is the imaging strategy of choice In practice, the whole cord should be imaged as there are often additional metastases or disease present at other sites. Investigations
• Newer CT imaging has improved and may be useful when MR not possible or unavailable
• Plain X-Ray films should also be considered
• CSF analysis (MS), EMG (Motor neurone disease, B12 levels etc

Management

• Skin care to prevent pressure ulcers and problems.
• Passive movement of limbs to prevent contractures and joint stiffness
• TED stockings and LMWH to prevent DVT/PE
• Urinary catheterisation to prevent retention initially. May use reflex bladder drainage and conveen or intermittent self-catheterisation
• Hydration and fluids.
• Dietary fibre, laxatives and suppositories and manual evacuation to manage bowels
• Avoid weight gain.
• Spasticity which is often variable and baclofen can be useful
• Sexual dysfunction often difficult to improve though fertility preserved
• Long term mobility aids and wheelchair. OT assessment and equipment to help at home. House adaptation. Access to respite care