Peter G. Kranz

Try to imagine how your life would be impacted if you were suddenly completely unable to sit up or stand at all without suffering a crushing, debilitating headache. This is the reality for many patients who suffer from spontaneous intracranial hypotension (SIH). SIH is a disease that has become much more widely recognized over the past decade, and substantial work has been done to understand its clinical manifestations, imaging appearance, and potential treatment options. The hallmark manifestation of SIH is positional headache, a headache that resolves or improves substantially when recumbent, and worsens upon standing. Brain MRI findings, which include smooth dural enhancement and signs of brain sagging, are typically able to suggest the diagnosis with a relatively high degree of specificity. Treatment often consists of epidural blood patching, with surgery reserved for selected intractable cases.

And yet, there are many facets of the disease that are not straightforward and remain poorly understood. Underdiagnosis remains a major problem. Many physicians still are unaware of the disease, or have little to no experience in its management. This problem is compounded by the fact that variant clinical presentations exist, such as nonpositional headache, or even symptoms like tinnitus with minimal associated headache. Brain imaging findings of SIH may be variably present, and in some cases absent altogether, in patients with the disease. Furthermore, the pathophysiology of SIH has not been fully elucidated. For example, although many patients have low CSF pressure, which would be predicted by the Monro-Kellie hypothesis, patients presenting with SIH do not uncommonly have pressures in the normal range. Spinal CSF leaks, the presumed etiology in most cases, are never detected in some patients

with clear manifestations of SIH, despite exhaustive investigation. Finally, treatment remains challenging. Many patients recover well from the disease, but substantial numbers of patients suffer relapses and may have to undergo multiple treatments or suffer longer-term symptoms related to low, or sometimes even paradoxically high, CSF pressure following treatment.

For some, the consequences of these deficiencies in our understanding of SIH can be severe. Long-term disability, with the attendant emotional and economic consequences, can have life-altering effects for some sufferers of the disease. My colleague at Duke University Dr. Linda Gray and I have seen many patients who have both suffered from and recovered from this disease. It is our belief that radiologists are uniquely positioned to help these patients because of the central role that imaging plays in establishing the diagnosis, as well as the role that imaging guidance can play in targeted treatment of CSF leaks. Our goal is to enlist allies in the challenging task of understanding the entire spectrum of presentations of CSF pressure-related problems, to elucidate how and why these problems develop, and to understand how that information can be used to determine personalized treatment for each patient.

Read this article at AJNR.org . . .