MIM Entry: 186700
%186700 SYRINGOMYELIA, ISOLATED
Syringomyelia (Greek: 'syrinx,' pipe, and 'myelos,' marrow) is a tubular
cavity in the spinal cord. It can occur sporadically in association with
spinal cord tumors, inflammatory arachnoiditis, or posttraumatically. It
is rarely idiopathic (less than 1% of cases). The vast majority of cases
of syringomyelia are cervical, noncommunicating, and associated with an
abnormality at the foramen magnum, particularly the Chiari malformation
type I (CM1; 118420), as well as basilar impression (109500) and
Dandy-Walker malformation (220200) (Speer et al., 2003; Levine, 2004);
these cases have shown familial segregation.
Caraceni and Giovannini (1977) reported 4 sibs with syringomyelia who
had symptom onset in their thirties or forties. Each had variable
clinical features, including segmental loss of pain and temperature
sensation, muscle weakness and atrophy of the upper limbs and hands,
nystagmus, urinary incontinence, and lower limb hyperreflexia and
spasticity. Radiographic studies of some of the patients showed an
enlarged foramen magnum and spinal canal.
Busis and Hochberg (1985) reported 2 sisters with syringomyelia. One
sister reported loss of pain and temperature sensation in the left arm,
shoulder, and face since age 12 years. She also had right Horner
syndrome, rotary nystagmus, and absent left gag reflex. Radiographic
studies showed low-lying cerebellar tonsils and cervical syringomyelia.
Her sister, mother, and brother had similar symptoms, but radiographic
examinations were not performed. The authors recognized that
syringomyelia is often associated with Chiari type I malformation and
basilar impression, but suggested that this family lacked definite
anomalies of the craniocervical junction. Autosomal dominant inheritance
Zakeri et al. (1995) stated that 16 families with syringomyelia had been
reported since 1899 and noted several early references (Redlich, 1916;
Barre and Reys, 1924; van Bogaert, 1929). In an accompanying commentary,
Hoffman (1995) suggested that all familial cases of syringomyelia have a
primary defect in the region of the foramen magnum resulting in Chiari
malformation type I or basilar invagination. Syringomyelia results
secondarily from disordered cerebrospinal fluid (CSF) dynamics occurring
in this area. Accordingly, some affected members of a family may have
isolated basilar skull defects whereas others go on to develop
Gardner (1965) proposed a hydrodynamic mechanism to explain the
development of communicating syringomyelia based on abnormal delayed
opening of the roof of the fourth ventricle, persistence of the
connection between the fourth ventricle and the spinal canal, and high
CSF pressure pulsations exerted by the choroid plexus. The exaggerated
pulsations would be directed into the central canal, resulting in
hydromelia. The central canal could also rupture at various other
points, resulting in syringomyelia (Levine, 2004).
Williams (1969) postulated that obstruction of the subarachnoid space at
the level of the foramen magnum could act as a valve allowing CSF to
flow rostrally more effectively than caudally, resulting in a
craniospinal pressure dissociation and formation of a cavity.
In a postmortem analysis of 105 patients with syringomyelia, Milhorat et
al. (1995) concluded that there are 3 distinct types. The first type (47
cases) encompassed dilations of the central canal that communicated
directly with the fourth ventricle ('hydromelic') and were associated
with hydrocephalus and severe birth defects, such as Chiari type II
malformation and open spina bifida. The second type (23 cases) consisted
of noncommunicating central canal syrinxes ('syringomyelic') that arose
at variable distances below the fourth ventricle and were associated
with disorders that affect CSF fluid dynamics, such as Chiari type I
malformation and basilar impression. The third group (35 cases) included
extracanalicular parenchymal syrinxes that did not communicate with the
central canal and were associated with injurious spinal cord lesions,
such as trauma, infarction, or hemorrhage. The findings established
several forms of spinal cord syrinxes with different etiologies and
Levine (2004) proposed a novel theory of the pathogenesis of
syringomyelia associated with lesions at the foramen magnum. Obstruction
of the subarachnoid space at the foramen magnum leads to transient
abrupt changes of CSF pressure with increased pressure rostral to the
block and decreased pressure caudal to the block. These changes produce
corresponding changes in transmural venous pressure, causing compression
of vessels above the site of compression at the foramen magnum and
dilation of vessels below. This leads to mechanical stress on the spinal
cord resulting in tissue breakdown and partial disruption of the
blood-spinal cord barrier, allowing a plasma infiltrate to accumulate in
the spinal cord forming a syrinx.
Ostertag (1930) found dominant inheritance of syringomyelia in rabbits.
Barraquer and de Gispert (1936); Goldbladt (1910); Karplus (1915);
Kino (1927); Tenner (1928); Van Epps and Kerr (1940)
1. Barraquer, L.; de Gispert, I.: Die Syringomyelie, eine familiaere
und hereditaere Krankheit (13 Faelle in 2 Generationen derselben Familie). Dtsch .
Z. Nervenheilk. 141: 146-157, 1936.
2. Barre, J.-A.; Reys, L.: Syringomyelie chez le frere et la soeur. Rev.
Neurol. 31: 521-530, 1924.
3. Busis, N. A.; Hochberg, F. H.: Familial syringomyelia. J. Neurol.
Neurosurg. Psychiat. 48: 936-938, 1985.
4. Caraceni, T.; Giovannini, P.: Familial syringomyelia: a report
of four cases. Arch. Psychiat. Nervenkr. 224: 331-340, 1977.
5. Gardner, W. J.: Hydrodynamic mechanism of syringomyelia: its relationship
to myelocele. J. Neurol. Neurosurg. Psychiat. 28: 247-259, 1965.
6. Goldbladt, A.: Syringomyelie bei Mutter und Tochter: zugleich
ein Beitrag zur Pathologie des Sympathicus. Dtsch. Med. Wschr. 36:
7. Hoffman, H. J.: Commentary. Surg. Neurol. 44: 53 only, 1995.
8. Karplus, J. P.: Syringomyelie bei Vater und Sohn. Med. Klin. 11:
9. Kino, F.: Ueber heredo-familiaere Syringomyelie (zugleich ein
Beitrag zur topischen Gliederung im Querschnitt des Vorderhorns). Z.
Ges. Neurol. Psychiat. 107: 1-15, 1927.
10. Levine, D. N.: The pathogenesis of syringomyelia associated with
lesions at the foramen magnum: a critical review of existing theories
and proposal of a new hypothesis. J. Neurol. Sci. 220: 3-21, 2004.
11. Milhorat, T. H.; Capocelli, A. L., Jr.; Anzil, A. P.; Kotzen,
R. M.; Milhorat, R. H.: Pathological basis of spinal cord cavitation
in syringomyelia: analysis of 105 autopsy cases. J. Neurosurg. 82:
12. Ostertag, B.: Die Syringomyelie als erbbiologisches Problem. Verh.
Dtsch. Ges. Path. 25: 166-174, 1930.
13. Redlich, A.: Syringomyelie bei zwei Brudern. Wien. Med. Wochenschr. 36:
14. Speer, M. C.; Enterline, D. S.; Mehltretter, L.; Hammock, P.;
Joseph, J.; Dickerson, M.; Ellenbogen, R. G.; Milhorat, T. H.; Hauser,
M. A.; George, T. M.: Chiari type I malformation with or without
syringomyelia: prevalence and genetics. J. Genet. Counsel. 12: 297-311,
15. Tenner, J.: Syringomyelie bei Vater und Tochter. Dtsch. Z. Nervenheilk. 106:
16. van Bogaert, L.: Kyste cerebelleux associe a la syringo-myelo-bulbie
chex une malade dont la soeur presente une syringomyelie cervicale
typique. J. Neurol. Psychiat. 29: 146-152, 1929.
17. Van Epps, C.; Kerr, H. D.: Familial lumbosacral syringomyelia. Radiology 35:
18. Williams, B.: The distending force in the production of 'communicating
syringomyelia'. Lancet 294: 189-193, 1969. Note: Originally Volume
19. Zakeri, A.; Glasauer, F. E.; Egnatchik, J. G.: Familial syringomyelia:
case report and review of the literature. Surg. Neurol. 44: 48-53,
HEAD AND NECK:
Associated with abnormalities at the foramen magnum, especially Chiari
malformation type I (118420)
MUSCLE, SOFT TISSUE:
Muscle atrophy in the limbs;
[Central nervous system];
Spasticity of the lower limbs;
Hyperreflexia, especially of the lower limbs;
Areflexia of the upper limbs;
Upper limb weakness;
Cranial nerve anomalies;
Burning pain in the limbs;
Loss of pain and temperature in a cape-like distribution;
Touch, vibration, and limb position may or may not be affected;
Segmental sensory loss, especially of pain and temperature;
Extensor plantar responses;
Chiari I malformation on MRI (some)
Onset of symptoms in second or third decade;
Many cases are asymptomatic
Cassandra L. Kniffin - revised: 8/21/2006
John F. Jackson: 6/15/1995
Cassandra L. Kniffin - reorganized: 8/18/2006
Cassandra L. Kniffin - updated: 8/8/2006
Victor A. McKusick: 6/2/1986