Background The majority of patients with spontaneous intracranial hypotension (SIH) are symptomatic. Some patients are discovered incidentally. The proportion of asymptomatic SIH has never been defined. This article reports our institution’s rate of asymptomatic cases among all of our patients with high/intermediate Bern scores on brain MRI, etiology of leak in asymptomatic cases, complications of asymptomatic leaks, and evolution of imaging before and after treatment.

Methods We retrospectively analyzed data from the Cerebrospinal Fluid (CSF) Dynamics clinic spanning September 2020 to July 2023. Bern score was calculated from all available brain MRIs in patients with confirmed leaks. Patients with iatrogenic leaks or no brain MRI were excluded. The charts of asymptomatic patients were reviewed to obtain MRI indications, SIH progression, complications, leak type, and treatment outcomes.

Results Some 8.6% (7/81) patients with high/intermediate Bern scores were asymptomatic at the time of imaging. Two patients declined myelography. Four of seven asymptomatic patients were found to have CSF-venous fistulas and underwent embolization with radiographic improvement. Complications of asymptomatic leaks in this population included subdural hematoma and superficial siderosis.

Conclusions Asymptomatic but clearly present spinal CSF leaks were not uncommon in our group. These results highlight the possibility of a presymptomatic phase in patients with CSF leaks. In our sample, myelography was readily positive for etiology of the leak, and leaks promptly responded to targeted treatment.