Syringohydromyelia is a rare neurological condition characterized by fluid-filled cysts, known as syrinxes, within the spinal cord. These syrinxes expand over time, disrupting normal spinal cord function and leading to various neurological symptoms.
Understanding Syringohydromyelia
The spinal cord serves as a communication pathway between the brain and the rest of the body, relaying sensory information and motor commands. In syringohydromyelia, a syrinx forms within the spinal cord. This cavity expands, putting pressure on surrounding nerve tissue and interfering with nerve impulse transmission.
The terms “syringomyelia” and “hydromyelia” are sometimes used interchangeably, but they refer to slightly different anatomical origins. Syringomyelia describes a distinct cavity within the spinal cord tissue. Hydromyelia refers to an enlargement of the central canal, a naturally occurring, fluid-filled channel. Both conditions involve fluid accumulation that can damage the spinal cord. These cysts most frequently develop in the cervical (neck) region, but they can also extend into the thoracic (mid-back) or lumbar (lower back) regions.
Causes and Contributing Factors
Syringohydromyelia develops when there is an obstruction to the normal flow of cerebrospinal fluid (CSF), the clear fluid that surrounds and protects the brain and spinal cord. When CSF flow is disrupted, it can accumulate within the spinal cord, leading to cyst formation.
The most common cause is Chiari malformation, where brain tissue extends through the opening at the base of the skull and into the spinal canal. This abnormal positioning can block CSF flow, causing a syrinx to form, often in the cervical spine. Other potential causes include spinal cord trauma or tumors located within or near the spinal cord. Conditions like arachnoiditis, an inflammation of the membranes surrounding the spinal cord, and tethered cord syndrome, where the spinal cord is abnormally attached to surrounding tissues, can also contribute to syrinx development. In some instances, the underlying cause remains unidentified, in which case it is referred to as idiopathic.
Identifying the Symptoms
The symptoms of syringohydromyelia are diverse and depend on the syrinx’s size, location, and the extent of nerve damage. Symptoms often develop gradually over many years, although they can sometimes appear suddenly after a trauma.
Sensory Symptoms
Sensory symptoms are common and may include a distinctive loss of pain and temperature sensation, especially in the hands and arms, while the ability to feel touch and pressure remains intact. Individuals may also experience numbness, tingling, or a burning sensation in their extremities.
Motor Symptoms
Motor symptoms can manifest as muscle weakness, particularly in the arms, hands, and shoulders, which may progress to muscle atrophy. Muscle stiffness or spasticity can also occur, making walking difficult.
Other Symptoms
Pain is a frequent complaint, often described as chronic, affecting the neck, shoulders, arms, and sometimes the hands. Less common symptoms include changes in or loss of bowel and bladder function, balance problems, and uncoordinated movements. A curvature of the spine, known as scoliosis, may also develop, and in children, it can be the only symptom.
Diagnosis and Management
Diagnosis begins with a thorough medical history and a neurological examination to assess reflexes, sensation, and muscle strength. The definitive diagnostic tool is Magnetic Resonance Imaging (MRI) of the spinal cord. An MRI can clearly show the presence, size, and location of a syrinx, as well as identify any underlying conditions like a Chiari malformation or spinal cord tumor. Sometimes, a dynamic MRI is performed to observe the flow of cerebrospinal fluid around the spinal cord and within the syrinx.
Management strategies for syringohydromyelia are individualized and aim to alleviate symptoms and prevent further progression of the condition. For individuals with mild or no symptoms, a conservative approach of watchful waiting and regular monitoring with MRI scans may be recommended. Pain management, including medications, can help address chronic pain. Surgical intervention is often considered when symptoms are moderate to severe or when there is evidence of syrinx enlargement. Common surgical procedures include Chiari decompression surgery, which aims to create more space for the brainstem and cerebellum, restoring normal CSF flow and reducing pressure on the spinal cord. Another surgical option is a shunting procedure, where a thin tube is inserted into the syrinx to drain the fluid into another body cavity, such as the abdomen, using a one-way valve. These surgical interventions aim to stabilize the condition and improve neurological function.