Spontaneous Intracranial Hypotension Presenting as a "Pseudo-Chiari 1

Spontaneous intracranial hypotension (SIH) is classified as a decrease in cerebrospinal fluid (CSF) pressure secondary to a CSF leakage and consequent descent of the brain into the foramen magnum. Diagnosing SIH can be difficult due to its overlapping findings with Arnold-Chiari type 1 Malformation (CM1) where the cerebellar tonsils herniate into the foramen magnum. The similarity of both conditions calls for a more reliable imaging technique to localize the CSF leak which could narrow the differential diagnosis and aid in choosing the correct treatment. Here, we present a case of a 28-year-old female, ten weeks post-partum with symptoms similar to SIH. MRI of the brain was remarkable for tonsillar herniation below the foramen magnum. Literature was reviewed for additional neuroradiology techniques that would aid in narrowing our differential diagnosis. Interestingly, computed tomography-, digital subtraction-, and magnetic resonance myelography with intrathecal gadolinium are the preferred techniques for diagnosis of high flow and low flow CSF leaks, respectively. These modalities further aid in choosing the correct treatment while avoiding complications. Literature suggests that treatment for CM1 involves posterior fossa decompression, whereas the mainstay of treatment for SIH involves an epidural blood patch (EBP). Thus, our patient was treated with an EBP and recovered without complication.