Recent Updates to Diagnosis and Treatment of Spontaneous Intracranial Hypotension

Spontaneous intracranial hypotension is a neurologic condition that is caused by a spinal cerebrospinal fluid (CSF) leak.The resulting CSF hypovolemia can manifest as a variety of clinical symptoms, with orthostatic headache being the most common.Although this disease has been recognized for decades, modern understanding of the types of causative spinal CSF leaks, diagnostic imaging tests to localize these leaks, and treatment options has evolved substantially in recent years.In this focused review article, we will provide an overview of the current diagnosis and treatment of spontaneous intracranial hypotension.We will emphasize recent improvements in understanding the pathophysiology of spinal leaks, developments in myelographic techniques to localize CSF leaks, and new treatment options for each type of leak.Keywords: Spontaneous intracranial hypotension; CSF leak; CSF-venous fistula; Photon counting CT myelogram system used for this purpose, frequently referred to as the "Bern score," assigns points based on the presence of pachymeningeal enhancement, venous sinus engorgement, subdural fluid collections, reduced mammilopontine distance, reduced prepontine cistern distance, and reduced suprasellar cistern size.It can be used to estimate the likelihood of finding a spinal CSF leak on myelography.Importantly, up to 20% of patients with SIH can present with a normal brain MRI findings [4].An MRI of the spine is also important in patients with suspected SIH, for two main reasons.First, it can detect or exclude the presence of extradural CSF.This includes both well-defined extradural CSF collections, as well as illdefined CSF signal intermixed with epidural fat [5].Welldefined extradural CSF collections, sometimes referred to as spinal longitudinal extradural collections, are common in the setting of chronic dural tears.Conversely, dural tears in the acute setting may only present with ill-defined CSF mixed with epidural fat [6].For the purpose of detecting either, axial and sagittal fast spin echo T2-weighted (T2W) imaging with fat suppression is critical.Furthermore, high-resolution 3D T2W fat suppressed imaging can be added to improve detection of small epidural CSF collections.Second, spine MRI can detect spinal meningeal diverticula (either nerve root sleeve diverticula or arachnoid diverticula), which are associated with some types of spinal CSF leaks [7,8].