Bilateral subdural hematomas in spontaneous intracranial hypotension: A systematic review with case illustration.

BACKGROUND

Spontaneous intracranial hypotension (SIH) is a well-recognized but often underdiagnosed cause of secondary subdural hematoma (SDH), particularly in younger patients who frequently present with bilateral collections. The role of lumbar puncture (LP) remains controversial in this setting, as additional cerebrospinal fluid removal may destabilize intracranial pressure and precipitate or worsen SDH.

METHODS

We performed a systematic review of SIH cases associated with bilateral SDH. When possible, we reconstructed a patient-level dataset to analyze clinical presentation, LP context, management strategies, and outcomes. We also describe a middle-aged man with orthostatic headache and fever who presented with thin, chronic-appearing bilateral SDH in the setting of SIH. Following a diagnostic LP performed to exclude meningitis, he developed a rapidly progressive, extensive bilateral mixed-density SDH requiring urgent burr-hole evacuation.

RESULTS

Fifty-nine studies were included, totaling 485 patients with SIH, of whom 182 had bilateral SDH. From these, we assembled a patient-level cohort of 59 individuals with SIH-associated SDH. The mean age was 47 years, and 81.4% were male. Orthostatic headache was present in 76.3%, whereas coma or stupor occurred in 25.4%. In this cohort, 62.7% had no LP, 30.5% underwent LP only after SDH diagnosis, and 6.8% had clearly post-LP SDH. Management included SDH surgery in 67.8%, epidural blood patch in 67.8%, and open leak repair in 11.9%. The overall SDH recurrence rate was 27.1%, with the highest recurrence (55.6%) in patients who underwent LP after SDH recognition. No deaths were reported.

CONCLUSION

Bilateral SDH in the context of SIH mainly affects younger patients and requires a combined strategy of SDH evacuation (when indicated) and leak-directed therapy. Although true post-LP bilateral SDH appears uncommon, LP may reveal or amplify an already unstable low-pressure state. Given the low certainty and incomplete temporal data in many reports, our findings support cautious consideration and avoidance of routine LP solely to document opening pressure in suspected SIH.