bSIH (Bern) Score Calculator for Spontaneous Intracranial Hypotension

bSIH (Bern) Score Explained

The Brain Spontaneous Intracranial Hypotension (bSIH) score is a simple predictive tool based on brain magnetic resonance findings that can be used to predict the likelihood of a spinal cerebrospinal fluid leak in patients with spontaneous intracranial hypotension.

This first of its kind score aims to help clinicians objectively assess whether the patient with suspected SIH requires further invasive tests to identify a CSF leak and is a candidate for epidural blood patch or microsurgical exploration.

Dobrocky et al. integrated 6 brain imaging findings data to create a classification system of the MRI findings and develop the probability score. The study cohort (152 patients) was based on MRI data from consecutive patients investigated for SIH at a single hospital from February 2013 to October 2017.

Three blinded readers retrospectively reviewed the brain MRI scans of patients with SIH and a spinal CSF leak, patients with orthostatic headache without a CSF leak, and healthy control participants, evaluating 9 quantitative and 7 qualitative signs. A predictive diagnostic score based on multivariable backward logistic regression analysis was then derived.

Furthermore, the predictive validity of the bSIH was tested in a prospective cohort of suspected SIH patients.

Out of the six imaging findings, three were weighted as major so are being assigned 2 points each if present and the remaining three were weighted as minor, so 1 point each.

Major Criteria (2 points each)

• Engorgement venous sinus
• Pachymeningeal enhancement
• Suprasellar cistern (≤ 4mm)

Minor Criteria (1 point each)

• Subdural fluid collection
• Prepontine cistern (≤ 5mm)
• Mamillopontine distance (≤ 6.5mm)

Patients were classified into three groups, consisting of low (scores of 0,1 and 2), intermediate (scores of 3 and 4), or high probability (scores of 5 to 9) of having a spinal CSF leak.

bSIH Score Alternative Uses

In the 2022 study, Dobrocky et al. have explored the use of the bSIH in monitoring treatment response in SIH patients with a proven spinal cerebrospinal fluid (CSF) leak after microsurgical closure of the underlying dural breach.

For the cohort of 52 patients, the score was calculated using brain magnetic resonance imaging (MRI) before and after surgical treatment of the underlying CSF leak. Headache intensity was registered on a numeric rating scale (NRS) (range 0–10).

It was found that the mean bSIH score decreased from baseline (6.9) to after surgical intervention (1.3).

Houk et al. set out to investigate the correlations between the bSIH scores and clinical headache severity in spontaneous intracranial hypotension to check whether the score can serve as a measure of disease severity. The study cohort consisted of 57 patients who completed a pretreatment headache severity questionnaire (Headache Impact Test-6) and had pretreatment brain MRI evidence of SIH.

The Pearson correlation coefficients (ρ) were computed to analyze the relationship between the Headache Impact Test-6 and Bern scores. Receiver operating characteristic curves were employed to evaluate how effectively Bern scores can distinguish between different levels of headache severity.

But the study found low correlations between clinical headache severity and Bern scores (ρ = 0.139; 95% CI, -0.127-0.385) and that the bSIH poorly discriminated subjects with greater headache severity from those with lower severity.

References

Original reference

Dobrocky T, Grunder L, Breiding PS, Branca M, Limacher A, Mosimann PJ, et al. Assessing Spinal Cerebrospinal Fluid Leaks in Spontaneous Intracranial Hypotension With a Scoring System Based on Brain Magnetic Resonance Imaging Findings. JAMA Neurol 2019; 76:580–7.

Other references

Dobrocky, T., Häni, L., Rohner, R. et al. Brain Spontaneous Intracranial Hypotension Score for Treatment Monitoring After Surgical Closure of the Underlying Spinal Dural Leak. Clin Neuroradiol 32, 231–238 (2022).

Houk JL, Morrison S, Peskoe S, Amrhein TJ, Kranz PG. Validity of the Bern Score as a Surrogate Marker of Clinical Severity in Patients with Spontaneous Intracranial Hypotension. AJNR Am J Neuroradiol. 2023; 44(9):1096-1100.