Search for a rare disease
Other search option(s)
Syringomyelia is characterised by cerebrospinal fluid (CSF)-filled cavities (syrinx) inside the spinal cord, either as a result of a known cause (secondary syringomyelia, SS) or, more rarely, due to an unknown cause (primary syringomyelia, PS).
ORPHA:3280Classification level: Group of disorders
Estimated prevalence is 8.4/100 000. Cases of autosomal recessive familial syringomyelia have been reported with an estimated incidence of 2% of all syringomyelia cases.
Although syringomyelia can lead to disruption of neural connections in the spinal cord and to neurological damage, 50% of patients (when all types of syrinxes are considered) will experience no or only mild disability. In symptomatic patients, onset is usually marked by pain and sensory disturbances, varying from complete absence of sensation, pins and needles or temperature sensing alterations, to increased sensation to stimuli. Although there are no clear clinical clues at neurological examination, a `cape-like' sensory dissociation (loss of the ability to distinguish between hot and cold with intact light-touch sensation in the upper limbs and torso), as well as reduced upper limb reflexes, are quite specific initial findings when present. Motor symptoms usually range from varying degrees of weakness to spasticity and loss of autonomy. Alterations in bladder and sexual function may also be present.
The aetiology of PS is unknown. SS results from direct cord damage or obstruction of CSF flow in the spinal canal due to several conditions: Chiari malformation type I (CMI) with or without scoliosis, basilar invagination, neurulation defects, postinfective/posttraumatic arachnoiditis, posttraumatic spinal canal compression, postischemic/posttraumatic myelomalacia or the presence of a syrinx cavity adjacent to an intraspinal tumour.
Neurological examination and MRI are required for diagnosis. MRI is the gold standard and reveals a fluid filled cavity with variable degrees of vertical and horizontal extension within the spinal cord ranging from involvement of one level up to extension over the entire spinal cord. The signal characteristics on MRI are usually quite similar to those of CSF.
Management and treatment
Management consists of long-term follow up and surgery in cases of progressive neurological deterioration. The type of surgery is determined by the type and underlying cause of the syrinx. In PS, direct shunting of the syrinx in the spinal subarachnoid space, pleural or peritoneal cavity represents the only treatment modality. In SS, treatment revolves around correction of the underlying cause and is highly dependent on surgeon preference and experience.
PS tends to have a very benign course and well over 2/3 of the patients never develop any disability. In SS, around 50% of CMI patients with syringomyelia remain neurologically stable. In cases with progressive deterioration, surgical intervention usually prevents clinical progression. In cases of posttraumatic syringomyelia due to spinal cord compression, reconstruction of the spinal canal appears to yield similar results. Prognosis is worse for cases in which the only surgical option is direct shunting of the syrinx, as this often leads to neurological deficit and recurrence.