Clinically Isolated Syndrome
Contents
In brief: Clinically isolated syndrome is a first clinical episode compatible with inflammatory demyelination of the central nervous system.
Use in multiple sclerosis
Section titled “Use in multiple sclerosis”A clinically isolated syndrome may involve the optic nerve, brainstem, cerebellum, spinal cord, or another central pathway. The event does not always become multiple sclerosis. MRI, cerebrospinal fluid, optic nerve evidence, and follow-up help estimate whether MS criteria are met or whether another diagnosis is more likely.
Under current criteria, some people can meet MS diagnostic requirements after one clinical event without waiting for a second attack. [1] If criteria are not met, the person may remain under clinical and MRI surveillance based on the pattern and risk.
Course descriptors place CIS before established relapsing MS rather than treating it as a separate lifelong MS type. [2]
Clinical detail
Section titled “Clinical detail”The word “clinically” matters: an episode should be anatomically coherent and supported by examination or objective testing when possible. Vague or nonlocalizing symptoms alone should not be labeled CIS.