Define Syringomyelia
Syringomyelia is a rare but progressive neurological condition characterized by the formation of a fluid-filled cyst called a syrinx within the spinal cord. The syrinx can develop along one or multiple segments of the spinal cord, gradually expanding and exerting pressure on surrounding nerve tissue. This compression can disrupt nerve signaling, leading to various neurological deficits.
Syringomyelia predominantly affects the cervical (neck) and thoracic (upper back) regions, though it can occasionally extend to the lumbar spine or encompass the entire spinal cord. Because it typically progresses slowly, early-stage cases may present with minimal or no symptoms.
The development of syringomyelia is often associated with:
Arnold–Chiari Malformation (ACM)
Spinal cord tumors
Spinal injuries or trauma
Chronic infections and inflammatory conditions
Congenital spinal abnormalities
Causes of Syringomyelia
The pathophysiology of syringomyelia is primarily linked to disruption of cerebrospinal fluid (CSF) flow around the brain and spinal cord. CSF serves both a protective and nutritive function for neural tissue. When CSF flow is obstructed or altered, a syrinx can form.
1. Arnold–Chiari Malformation
Arnold–Chiari Malformation involves the downward displacement of cerebellar and brainstem tissue into the spinal canal. This malformation disrupts CSF circulation and is the most common cause of syringomyelia. In affected patients, syrinxes are usually located in the cervical spinal cord and may cause progressively worsening symptoms.
2. Spinal Cord Injuries
Traumatic damage to the spinal cord can trigger syrinx formation. Common causes include traffic accidents, falls from height, or sports injuries. Post-traumatic obstruction of CSF flow allows the syrinx to enlarge over time.
3. Spinal Tumors
Tumors located within or near the spinal cord can mechanically block CSF circulation, contributing to syrinx formation. The size and location of the tumor often determine the syrinx’s extent and the severity of symptoms. In some cases, surgical tumor removal can reduce the syrinx.
4. Infections and Inflammatory Conditions
Chronic meningitis or other inflammatory processes may cause fibrosis and adhesions within the spinal cord, resulting in syrinx development. This is particularly relevant for patients with bacterial or viral meningitis histories.
5. Congenital Spinal Anomalies
Rare congenital defects such as dural cysts, spina bifida, or tethered cord syndrome can predispose individuals to syringomyelia. In these cases, syrinxes often manifest earlier in life.
Symptoms of Syringomyelia
The symptoms of syringomyelia vary depending on the location, size, and expansion rate of the syrinx. Early stages may present with subtle sensory changes or mild pain, while progressive disease can produce:
Chronic pain: Neck, shoulder, arm, or back pain is the most frequent complaint.
Sensory deficits: Loss of pain and temperature sensation (dissociated sensory loss) is typical.
Muscle weakness and atrophy: Especially in the hands and arms.
Reflex changes: Deep tendon reflexes may decrease or increase.
Muscle spasms and stiffness
Scoliosis: Frequently observed in children and young adults.
Bladder and bowel dysfunction: May develop in advanced stages.
Symptoms often progress gradually but can worsen following trauma, physical exertion, or coughing.
Diagnosis of Syringomyelia
Accurate diagnosis relies on advanced imaging combined with neurological evaluation.
Neurological Examination: Assessment includes muscle strength, reflexes, sensory function, and coordination. This evaluation not only supports diagnosis but also guides treatment decisions, including surgical versus medical management.
Magnetic Resonance Imaging (MRI) and MR Myelography: MRI remains the gold standard for diagnosing syringomyelia, clearly showing the syrinx’s size, location, length, and relation to the spinal cord. MR myelography can further evaluate CSF flow dynamics and detect obstructions caused by malformations, adhesions, or tumors. These techniques are particularly useful in cases associated with Chiari malformation.
Treatment of Syringomyelia
Management of syringomyelia depends on the underlying cause, syrinx size, and severity of symptoms.
1. Surgical Approaches
Decompression Surgery: For patients with Arnold–Chiari malformation, removing part of the posterior cranial fossa and cervical bone relieves pressure and restores CSF flow.
Syringostomy or Syringo-pleural Shunt: Drains the syrinx fluid or diverts it to another cavity to reduce spinal cord compression.
Tumor Resection: In tumor-induced syringomyelia, surgical removal of the tumor may reduce the syrinx.
2. Medical Management
Pain and neuropathic symptom control: Medications like gabapentin, pregabalin, NSAIDs, and muscle relaxants can alleviate discomfort.
Anti-infective or anti-inflammatory therapy: Applied when infections or inflammatory processes contribute to syrinx formation.
Monitoring and Follow-up
For patients with mild or asymptomatic syringomyelia, regular MRI and neurological exams are sufficient. The risk of progression is linked to the syrinx’s size and location, making longitudinal monitoring essential.