AAN 2026 | Navigating diagnostic uncertainty in disorders of cerebrospinal fluid pressure: spinal CSF leaks

My presentation today was alongside my colleague and friend, Dr Deb Friedman. And we went over this sort of spectrum of intracranial hypertension and spontaneous intracranial hypotension. And we talked about a combination of things sort of case-based from the perspective of looking at these diseases in isolation, high pressure and low pressure, but also how do they interact. We’re learning more and more that this is probably a spectrum of disease, not necessarily isolated ones. And so while we have typical definitions for high pressure versus low pressure, we’re learning more and more about what is the underpinning pathophysiologic mechanism behind each and where do they overlap, particularly when it comes to my disease that I treat, spinal CSF leak, patients who have a high pressure state who can transition into a low pressure one, or in patients who have a spinal fluid leak that we treat who then develop rebound high pressure. And what do those signals, those clinical signals mean, and how do we interpret imaging and those clinical findings in that context really going over the subtle imaging underpinnings of these different disease states, what, how do we conceptualize a brain MRI for a person who has a suspected spinal fluid leak? Years ago we thought of this as a diagnostically binary tool, simply someone had a positive brain MRI or they did not. But now we understand that it is just one part of an assessment, of a broader assessment of a patient’s CSF state, for example, that about a fifth of patients with a spinal fluid leak could have a normal MRI of the brain. And what does a normal MRI of the brain even actually mean? It means that the radiologist interpreted it as normal. And so we’re getting more and more tools to understand what are subtle changes in the brain that we can see that could give us clues to whether something is high or low. What are subtle adjunctive tools in the orbits? For example, looking at the dilation or contraction of the perioptic subarachnoid space in the optic nerve sheath and looking at the spine itself, at the meningeal contours, the dural contours, things that were interpreted previously as normal that we are now understanding are clues to spinal fluid leaks in our patients. And then looking at these through the lenses of those overlapping states, of the so-called “popping the balloon” phenomenon, going from a high to a low pressure state, of going from a CSF leak to a period of rebound high pressure. What does that mean? What is the clinical significance there? How do we manage these patients? What sorts of imaging should we be ordering and how do we interpret that imaging?

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