A 23-yr-old man was injured in a diving accident with a fracture-dislocation of C4, resulting in C5 American Spinal Injury Association grade A tetraplegia. Cervical fusion via posterior fixation and wiring was performed. He was a tobacco smoker at one pack of cigarettes per day, but he had no history of asthma and no clinical respiratory disease. A tracheostomy tube was placed at the time of the initial injury for ventilatory support. After weaning from this device, he was maintained without external ventilatory assistance. Atelectasis and pneumothorax developed at 6 yrs postinjury, and the patient was treated with a thoracotomy tube. He stopped smoking cigarettes after this event.
Nine years after his cervical spine injury, he presented with a chief complaint of dyspnea associated with a sensation of tightness across his chest. Respiratory function was improved in the supine position and worsened with sitting upright. Physical examination revealed a moderately obese young adult man in no acute distress. Blood pressure was 100/74, pulse rate was regular at 64 beats/min, and respirations were 12 breaths/min. Lungs were clear, without wheeze, rhonchi, or crepitation. Cardiac examination was normal. The abdomen was protuberant and moved paradoxically with diaphragmatic excursion. Cough was ineffective and nonproductive. Upper limb motor strength examination was 5/5 in the trapezius and deltoid, 4/5 in the biceps, 1/5 in the wrist extensors, and 0/5 in the triceps, brachioradialis, and hand intrinsic muscles bilaterally. There was an increase in rate-dependent tone in the lower limbs bilaterally, with clonus at the knees and ankles. Sensory level was C5 complete. No leg swelling was identified. Posteroanterior and lateral chest roentgenograms were normal. Ultrasound examination was negative for deep venous thrombosis. Pulmonary function tests revealed mild restrictive lung disease. A pulmonary consultation was obtained and concluded that no evidence of acute or chronic interstitial pulmonary disease was present. Fluoroscopy of the chest demonstrated intact but reduced mobility of the diaphragm bilaterally. Theophyl-line was prescribed with minimal symptomatic response.
A central origin for respiratory dysfunction was considered; magnetic resonance imaging of the cervical spine with T1-weighted images demonstrated a cystic cavity within the spinal cord from C4 through the middle level of the C5 vertebra (Fig. 1). There was no evidence of a syrinx within the thoracic spine or brainstem. Neurosurgical consultation was obtained, and a decompressive myelotomy with shunt placement was performed. Dyspnea improved within a few weeks postoperatively; at 15 mos after surgery, the patient had no complaint of dyspnea, and the aching sensation in his upper chest and shoulder had completely resolved.
Syringomyelia, a fluid-filled cavity within the spinal cord, is a potential complication of traumatic myelopathy.1 Before the introduction of magnetic resonance imaging, this condition was thought to occur in up to 3% of spinal cord–injured patients. Since the introduction of magnetic resonance imaging, detection of a syrinx has improved, and the prevalence has been reported to be between 12% and 22%.2 The pathogenesis of posttraumatic syringomyelia remains unclear, and theories include hemorrhagic necrosis of the spinal cord, liquefaction of a hematoma, cellular enzymatic (particularly lysosomal) activity, ischemic microinfarcts, and posttraumatic edema. Extension of the syrinx may be due to secondary distention of epidural veins or pressure changes leading to movement of cerebrospinal fluid during a Valsalva maneuver.
The most frequent presenting symptoms of posttraumatic syringomyelia are pain, numbness, or increased weakness, and the interval reported between symptom onset and presenting neurologic symptoms ranges from 2 mos to 36 yrs.3 Acute respiratory failure has been reported in cases of communicating syringomyelia associated with a Chiari type 1 malformation. Weakness and dyspnea as co-presenting symptoms have been reported once in the literature in the case of a noncommunicating, posttraumatic syringomyelia.4
Although pain, numbness, or weakness are common presenting symptoms of posttraumatic syringomyelia, the scenario of dyspnea in a patient with spinal cord injury and normal pulmonary and peripheral vascular examinations provides the following teaching points: (1) syringomyelia should be considered as a potential cause of dyspnea in patients with posttraumatic myelopathy, and (2) magnetic resonance imaging is a sensitive and accurate diagnostic aid in identifying a syrinx.
1.Squier MV, Lehr RP: Post-traumatic syringomyelia. J Neurol Neurosurg Psych
2.Schwartz ED, Falcone SF, Quencer RM, et al: Posttraumatic syringomyelia: Pathogenesis, imaging and treatment. Am J Radiol
3.Umbach I, Heilporn A: Post-spinal cord injury syringomyelia. Paraplegia
4.Zager EL, Ojemann RG, Poletti CE: Acute presentations of syringomyelia: Report of three cases. J Neurosurg