- Sensory symptoms and signs : Sensory disturbance is often referred to as dissociated sensory loss, as only certain sensory modalities, usually pain and temperature (spinothalamic tract) are disrupted (17). Conversely, light touch, proprioception, and vibratory sensation (dorsal columns) are often unaffected (17). Sensory disturbance is almost always asymmetric. The most common distribution of sensory disturbance is cape-like over the shoulders and back, and pain is frequently felt in the neck and shoulders (17).
- Central cord syndrome: Central cord syndrome results from the centrally located syrinx, which destroys the fibers located centrally (cervical) before the fibers located laterally (thoracic, lumbar, and sacral, in this order) in the spinal cord (17). This results in early symptoms of the more distal muscles of the fingers and hands followed by late signs in the proximal muscles of the shoulders and trunk (17). Reflexes are diminished early, and there is often late spasticity as the condition worsens. Horner’s syndrome may be present if there is involvement of the intermediolateral cell column (17).
- Brainstem symptoms and signs: When the syrinx extends into the brainstem (syringobulbia), symptoms are common early in the process. These symptoms usually consist of dysfunction of the lower cranial nerves with coughing, aspiration, and dysphagia. For effective treatment, it is important to distinguish between symptoms related to the syrinx and those caused by the pathological process causing the syrinx.
- Scoliosis: Scoliosis may result from compression of the anterior horn cells, resulting in unequal weakness of the paravertebral muscles. Young age, atypical curve, rapid curve progression, and back pain associated with scoliosis should alert clinicians to the possible presence of syringomyelia (31).
- Chronic pain: Syringomyelia, particularly in posttraumatic syringomyelia, is associated with a variety of chronic pain syndromes. However, while it is nearly impossible to determine if the pain is caused by the syrinx or the primary disorder, it appears that successful treatment of the syrinx rarely results in resolution of the pain. This finding suggests that the pain may be related to the initial spinal cord injury resulting from syrinx formation.
Patterns of evolution
- New symptoms unusual: There are no large studies describing the natural history of syringomyelia. A review of all children with MRI-diagnosed syringomyelia at one institution showed that when patients present with minimal symptoms, syrinxes tend to remain stable in the short term (51). Even if the percentage of patients who progress is small, it is recommended that patients are followed with imaging periodically. In a combined review of MRI databases at two institutions, idiopathic syringomyelia followed a benign course in the first few years, stabilizing or improving in 91% of cases. In addition, there appeared to be no correlation between change in size and change in symptoms (52).
- Symptoms function of etiology or location: Depending on the etiology of the syrinx, it may be difficult to separate symptoms due to the syrinx from those caused by the underlying pathology. Presentation can be more acute and ominous in syringobulbia.
Time for evolution
- Slow or no evolution in symptoms: When progressive, the disease tends to follow a gradual, stepwise neurological deterioration extending over many years (53).
- Rate can depend on etiology: The rate of progression of symptoms of secondary syringomyelia (not idiopathic) varies according to the underlying etiology.
- Rarely required: Patients usually present in the outpatient setting and are stable. No emergent intervention is required.
Preparation for definitive intervention, nonemergent
- Imaging of neuraxis: Ensure that the entire neuraxis (spine and brain) has been adequately imaged with and without gadolinium.
Preparation for definitive intervention, emergent
- Rarely required: Emergent surgery is usually not necessary. Even if patients present with recent or acute neurological deficits, it is advisable to wait and treat the syrinx on a semi-elective basis. This approach allows adequate preoperative workup while the spinal cord heals from the acute injury.