Forms of Syringomyelia
There are two basic forms of syringomyelia: communicating and non-communicating. Of these two forms of syringomyelia, communicating syringomyelia is the most common. It is related to a malformation that causes part of the brain to protrude from its normal location into the neck portion of the spinal canal. Non-communicating syringomyelia can occur as a result of meningitis, an injury, or a tumor.
Generally, there are two forms of syringomyelia: communicating and non-communicating syringomyelia.
In most cases, syringomyelia is related to an abnormality of the brain called a Chiari type I malformation, named after the physician who first characterized it. This anatomic abnormality causes the lower part of the cerebellum to protrude from its normal location in the back of the head into the cervical, or neck, portion of the spinal canal. A syrinx (a type of cyst) may then develop in the cervical region of the spinal cord. Because of the relationship that was once thought to exist between the brain and spinal cord in this type of syringomyelia, physicians sometimes still refer to it as communicating syringomyelia.
Symptoms usually begin between the ages of 25 and 40, and may worsen with straining or any activity that causes cerebrospinal fluid (CSF) pressure to fluctuate suddenly. Some patients, however, may have long periods of stability. Some patients with this form of syringomyelia also have hydrocephalus, in which CSF accumulates in the skull, or a condition called arachnoiditis, in which a covering of the spinal cord -- the arachnoid membrane -- is inflamed.
The second major form of syringomyelia -- non-communicating syringomyelia -- occurs as a complication of trauma, meningitis, hemorrhage, a tumor, or arachnoiditis. Here, the syrinx develops in a segment of the spinal cord damaged by one of these conditions. The syrinx then starts to expand. Symptoms of non-communicating syringomyelia can appear months, or even years, after the initial injury, starting with pain, weakness, and sensory impairment originating at the site of trauma.
The primary symptom of post-traumatic syringomyelia is pain, which may spread upward from the site of injury. Symptoms such as pain, numbness, weakness, and disruption in temperature sensation may occur on one or both sides of the body. Syringomyelia can also adversely affect sweating, sexual function, and, later, bladder and bowel control.
Another form of syringomyelia involves a part of the brain called the brainstem. The brainstem controls many of our vital functions, such as respiration and heartbeat. When syrinxes affect the brainstem, the condition is called syringobulbia.