Syringomyelia and Chiari I Malformation Flashcards
Clinical features of syringomyelia
A. Inspection
1. Kyphoscoliosis or left thoracic scoliosis - involvement of median motor nuclei supplying paraspinal muscles
2. Surgical scars over spine - prior surgery for cervical spondylosis or prior syrinx decompression
B. LMNL signs (anterior horn) - at level of syrinx - test UL
1. Fasciculations
2. Charcot joint (neuropathic joints) commonly elbows and shoulders - swollen, deformed, abnormal ROM, crepitus
3. Trophic and vasomotor changes over hands
- Painless scars and ulcers over digits (loss of pain)
- Callosities over knuckles, thickened skin (loss of pain)
- Oedema and excessive sweating (autonomic dysfunction)
- Digital amputations
(La main succulente - cold, oedematous, cyanosed)
4. Progressive distal to proximal wasting and weakness
- Wasting and weakness of hand muscles, dorsal guttering
- Hyperextension deformities at MCPJ, flexion deformities at IPJ (clawed hands)
- Progresses proximally to forearms, shoulder girdles (winging)
5. Absent deep tendon reflexes
(Converse with MND - wasting with hyperreflexia)
6. Dissociated sensory loss of pain/temperature with preserved vibration and proprioception - syrinx interrupts anterior decussating spinothalamic tract but not posterior column (crosses at medulla)
7. Cape-like or suspended distribution - corresponding to cervical or thoracic syrinx
(ask pinprick SHARP or DULL, not felt yes or no, test from C5-T1 and below to demonstrate location)
Variations
1. If syrinx expands posteriorly - loss of all sensation
2. If syrinx expands laterally - unilateral spinothalamic sensory loss
C. UMNL - below level of syrinx -> test LL
1. Spastic paraparesis - hypertonia, hyperreflexia, weakness
D. Localisation
1. Test sensation of trunk beyond T1 to determine lowest point of syrinx
2. Horner’s syndrome - sympathetic neuron in intermediolateral cell column at C8-T1
3. Horizontal eye movement (INO) - MLF involvement at C5
4. Medulla syringobulbia
- CN9-12 - palatal weakness, tongue fasciculation and wasting, nasal speech, sternomastoids
- Facial sensation (balaclava helmet) sensory loss - outer face sensory loss, sparing inner face
E. Complications
1. Scoliosis
2. Charcot joint
Explain the clinical signs in syringomyelia
At the level of syrinx:
1. Anterior horns affected - LMNL signs
2. Decussating fibres of spinothalamic tract affected - dissociated sensory loss (pain, temperature), with relative sparing of posterior column
Below syrinx:
1. Corticospinal tract affected - UMNL signs
What are other causes of dissociated sensory loss?
- Anterior spinal artery occlusion
- Anterior spinal artery prone to ischaemia especially watershed area of Adamkiewicz (T8-L2)
- Affects spinothalamic and corticospinal tract, sparing posterior column - Small fibre neuropathies
- Impairment of small calibre sensory nerve fibres: thin myelinated A-delta fibres (cold, pain, autonomic) and unmyelinated c fibres (warmth)
- Large calibre fibres (vibration, proprioception) preserved
What is syringomyelia?
- Syrinx - fluid-filled cyst/cavity within the central area of spinal cord.
- Hydromyelia - dilatation of central canal of spinal cord
Originates in spinal cord tissue.
Commonly develops in cervical and thoracic segments
What fluid is contained within the syrinx?
CSF with higher protein content, may be as high as 100mg/dL
What is the typical age of onset of syringomyelia symptoms?
Adults in 3rd - 4th decades
Rarely in childhood
What are common symptoms of syringomyelia?
- Pain, or loss of pain
- Weakness (of all 4 limbs)
- Stiffness (below level of lesion, usually LL)
- Loss of sensitivity in the back, shoulders, and arms.
Causes of syringomyelia
A. CSF blockage
1. Arnold-Chiari malformation
2. Basal arachnoiditis
3. Basilar invagination
4. Meningeal carcinomatosis
5. Arachnoid cyst
6. Foramen magnum tumour
B. Spinal cord injury
- Develops at origin of trauma after many years
- Thoracic > cervical
C. Intramedullary spinal tumours - secretion from tumour or haemorrhage
1. Ependymoma
2. Haemangioblastoma
D. Idiopathic
Associated with Ehlers-Danlos syndrome (EDS)
Differential diagnoses to consider
- Mixed UMN and LMN, spinothalamic sensory loss
- +/- cerebellar signs
- +/- cranial nerve signs
- Syringomyelia and syringobulbia
- Chiari malformation
- Cerebellar syndrome
- Motor neuron disease
- Multiple sclerosis
- Brainstem (unable to explain LMN)
Investigations for syringomyelia
- MRI of brain and spinal cord
- Sleep study for sleep apnoea
- Brainstem auditory evoked potential
- Somatosensory evoked potentials
Treatment approach for syringomyelia
- Multidisciplinary team - Neurology, Neurosurgery, PT, OT
- Watchful monitoring
- Pain management
- Surgical intervention to relieve pressure
A. Cervical decompression - Arnold-Chiari malformation, decompresses foramen magnum
B. Dorsolateral myelotomy
C. Shunt formation
- Syringoperitoneal shunt
- Syringosubarachnoid shunt
- Ventriculoperitoneal shunt
Potential complication of syringomyelia
- Respiratory failure - compression of respiratory innervation
- Severe headache - elevated ICP
- Spinal deformities
What is the prognosis for patients with untreated syringomyelia?
What is the significance of early diagnosis in syringomyelia?
The condition may worsen over time, leading to increased symptoms and complications.
Early diagnosis can help prevent further neurological damage and improve treatment outcomes.
Chiari I malformation and context of syringomyelia
- Hindbrain abnormality - Cerebellar tonsils invagination (pushed down) through the foramen magnum
- Direct compression of neurological structures within the foramen magnum and upper spinal cord
- Associated syringomyelia formation (Morvan disease)
- Obstruction of CSF flow
What are other types of Chiari malformation (total 4 types)
Chiari 2 - herniation of the brainstem and spina bifida
Chiari 3 - herniation of the cerebellum and brainstem with serious consequences on the development of the nervous system
Chiari 4 - incomplete or undeveloped cerebellum with structural alterations of the skull and spinal cord
