Impact of Surface Hemorrhages on Glymphatic and Dural Lymphatic Function in the Brain

Overview

This case series examined the effects of acute subdural hematoma (aSDH) on glymphatic and dural lymphatic function using intrathecal gadobutrol-enhanced MRI. Findings suggest that dural lymphatic drainage is more substantially impaired than glymphatic influx following aSDH, contrasting with previous observations in subarachnoid hemorrhage (SAH).

Background

The glymphatic and meningeal lymphatic systems play critical roles in brain fluid and solute clearance. While subarachnoid hemorrhage is known to impair glymphatic influx, the impact of other intracranial hemorrhages such as acute subdural hematoma remains unclear. Experimental data indicate differential effects of various brain injuries on glymphatic function, but clinical data on aSDH are scarce. This study investigates glymphatic and dural lymphatic function in a patient with unilateral aSDH compared to controls and patients with SAH.

Data Highlights

Key Findings

• In a 73-year-old patient with unilateral aSDH, glymphatic MRI performed 2.8 months post-hemorrhage showed altered CSF tracer enrichment between affected and unaffected hemispheres.
• Dural lymphatic function, assessed via CSF tracer clearance to blood, was more substantially compromised than glymphatic influx in the aSDH patient.
• Compared to three patients with unilateral SAH, the aSDH patient exhibited distinct patterns of glymphatic and dural lymphatic impairment.
• Reference subjects showed normal glymphatic tracer enrichment and clearance, establishing baseline function for comparison.
• These preliminary observations suggest that different types of intracranial hemorrhages may differentially affect brain clearance pathways.

Clinical Implications

Clinicians should be aware that acute subdural hematoma may lead to prolonged impairment of dural lymphatic drainage, potentially contributing to post-hemorrhagic complications. Glymphatic MRI could serve as a valuable tool to assess brain clearance function after various hemorrhagic injuries, guiding rehabilitation and management strategies. Further studies are warranted to explore therapeutic interventions targeting lymphatic function in these patients.

Conclusion

This case series highlights that acute subdural hematoma can differentially impair dural lymphatic drainage more than glymphatic influx, underscoring the need for further research into brain clearance mechanisms following diverse hemorrhagic insults.

References

1. Oslo University Hospital Neurosurgery Department -- Glymphatic MRI Study 2017-2021
2. Previous studies [6, 10, 15, 17, 25] -- Glymphatic and lymphatic function in brain injury