Abstract

BackgroundPatients with chronic subdural hematoma (CSDH), particularly bilateral hematomas, do not infrequently present with cognitive impairments. While those impairments are usually caused by brain compression by CSDH, other underlying causes may also be responsible for the impairments.

Case DescriptionsA healthy 74-year-old man visited a local hospital with cognitive impairments of subacute onset. He denied the presence of a headache. A brain computed tomography (CT) revealed bilateral CSDH compressing the cerebral hemispheres. After an emergency bilateral burr hole drainage, his symptoms improved only partially, and recurrence of the CSDH occurred within 14 days of the first surgery. A search for the underlying cause of the cognitive impairments was implemented. A CT myelography revealed cerebrospinal fluid (CSF) leakage at the lumbar spine, and after an epidural autologous blood patch therapy, his cognitive impairments resolved quickly and fully.

ConclusionIn the case of bilateral CSDH with early postoperative recurrence, a search for the presence of occult CSF leakage may be warranted. The term “brain sagging syndrome” or “brain sagging dementia” has been proposed to describe cognitive impairments due both to the brain compression by the CSDH and to the brain sagging by the CSF leakage. The absence of orthostatic headache may not necessarily exclude the presence of CSF leakage.

Keywords: Bilateral chronic subdural hematoma, Brain sagging syndrome, Cerebrospinal fluid leakage, Cognitive impairment

INTRODUCTION

Chronic subdural hematoma (CSDH), particularly bilateral hematomas, often manifests as cognitive impairment. The symptoms mostly improve after removing the hematoma surgically. While cognitive impairment is typically caused by compression of both cerebral hemispheres by the hematoma, other underlying causes may also contribute to the impairments. Here, we report a case of bilateral CSDH in which cognitive impairment partially improved after surgery but reappeared shortly afterward with early CSDH recurrence. The impairments were resolved only after addressing the cerebrospinal fluid (CSF) leakage from the lumbar spine, which was causally related to CSDH formation.

CASE DESCRIPTION

A 74-year-old man with no marked medical history experienced confusion while driving. His wife took over driving, and he was brought to the nearest emergency hospital. A brain computed tomography (CT) revealed bilateral CSDH compressing both cerebral hemispheres [ Figures 1a and b ], which were deemed responsible for his symptoms. In retrospect, his wife recalled that he had exhibited cognitive impairments, especially recent memory loss, for several weeks. He was immediately admitted, and an emergency bilateral burr hole drainage was performed to evacuate the CSDH. Postoperative CT on the next day showed near-complete hematoma evacuation [ Figures 1c and d ], and his symptoms improved, though his wife noted that he had not fully recovered to baseline. Brain CT at postoperative day 7 revealed mild re-accumulation of the hematomas [ Figures 1e and f ]. However, this was considered part of the natural postoperative course, and he was discharged home. A few days after discharge, his wife noticed a worsening of recent memory loss, prompting his visit to our hospital on postoperative day 14, and he was admitted to our hospital for further evaluation. He was alert with a Mini– Mental State Examination (MMSE) score of 17, showing marked impairments in recent memory. He exhibited no motor or sensory deficits and denied any headaches. Upon reviewing the previous CT images, particularly of the postoperative day 7, residual intracranial air and persistent brain sagging were noted [ Figures 1e and f ], raising suspicion of occult CSF leakage. Contrast-enhanced brain magnetic resonance imaging (MRI) revealed dural enhancement [ Figure 2a ], further supporting the presence of CSF leakage. CT myelography (CTM) subsequently identified contrast extravasation at the right L3 spinal nerve root [ Figure 2b ], confirming the diagnosis. On the day following CTM, an epidural autologous blood patch was performed. His symptoms improved rapidly after the procedure. On postoperative day 7, his MMSE score was 30, and he was discharged home. A follow-up head CT a month after the blood patch showed marked resolution of brain sagging, with only a small amount of residual hematoma [ Figures 2c and d ], and reoperation for the residual CSDH was considered unnecessary.

Figure 1:

(a and b) Brain computed tomography (CT) before surgery for bilateral chronic subdural hematoma (CSDH). (a) axial view, (b) coronal view. (c and d) Brain CT on postoperative day 1. (c) axial view, (d) coronal view. Note disapperance of the bilateral CSDH. (e and f) Brain CT on postoperative day 7. (e) axial view, (f) coronal view. Note the brain sagging and air accumulation despite the absence of the hematoma.

Figure 2:

(a) A contrast-enhanced brain magnetic resonance imaging (T1-weighted image, coronal view) showing marked meningeal enhancement indicating the presence of cerebrospinal fluid (CSF) leakage. (b) A CT myelography shows the accumulation of contrast material at the right side of the vertebra (white arrowhead) indicating the presence of CSF leakage at that level. (c and d) Brain CT 1 month after autologous blood patch showing resolution of the brain sagging. (c) Axial view, (d) coronal view.

DISCUSSION

CSDH often presents as a cognitive impairment. Bilateral hematomas, compared to unilateral ones, are less likely to cause focal neurological symptoms, and diagnosis may often be delayed, particularly in cases with preexisting cognitive impairments.[ 4 ] While both unilateral and bilateral CSDH are commonly triggered by minor trauma several months prior, bilateral cases are more strongly associated with CSF leakage. A study reported that 13% of bilateral CSDH cases were attributable to CSF leakage.[ 5 ] In the present case, CSF leakage had not been suspected at the initial local hospital, possibly due to the absence of headache. Patients with CSF leaks typically report orthostatic headaches due to intracranial hypotension, with a reported prevalence of over 90%.[ 8 ] The absence of orthostatic headache in the present case remains unclear, but it may be attributable to a small dural defect in the lumbar spine, resulting in a relatively slow CSF leakage and relatively mild intracranial hypotension.

Cognitive impairment in patients with CSDH is primarily caused by cerebral microcirculatory disturbance due to hematoma-induced compression, and impairments usually improve rapidly after surgery.[ 3 ] In the present case, however, despite successful hematoma evacuation, improvement was only partial, with early re-worsening. Imaging findings were notable for persistent sagging of both cerebral hemispheres and residual intracranial air 1 week postoperatively, despite decompression by hematoma removal [ Figure 1e and f ]. The postoperative coronal CT images particularly highlighted the brain sagging [ Figure 1c - f ], raising suspicion of underlying CSF leakage leading to the bilateral CSDH. Intracranial air retention indirectly indicates low intracranial pressure, though it occasionally suggests tension pneumocephalus, which warrants caution.[ 7 ] Subsequent contrast-enhanced brain MRI revealed dural enhancement, leading to the identification of a CSF leak point at the lumbar spinal nerve root through CTM [ Figure 2b ].[ 2 ] Chronologically, we speculate that a dural defect at the lumbar spinal nerve root caused sustained CSF leakage, leading to decreased intracranial pressure. This, in turn, resulted in brain sagging, creating a subdural space where bilateral CSDH accumulated. Beyond the direct compressive effects of the hematomas, the brain sagging itself likely induced microcirculatory and metabolic disturbances in the brain, contributing to cognitive decline. Recently, the concept of “brain sagging syndrome” or “brain sagging dementia” has been proposed to describe this condition [ 1 , 6 ] with reported cases that were initially misdiagnosed as frontotemporal dementia.[ 9 ] Although brain sagging dementia is considered relatively rare, clinicians should remain aware of its possibility in cases of bilateral CSDH presenting with cognitive impairment. Early recognition of occult CSF leakage and appropriate intervention, such as epidural blood patch, are critical for addressing the underlying pathology and improving outcomes.

CONCLUSION

Cognitive impairments in patients with bilateral CSDH may be not only due to brain compression by the hematomas but also due to the brain sagging by the CSF leakage, leading to a nomenclature of sagging brain dementia. The absence of orthostatic headache may not necessarily exclude the presence of CSF leakage.

Ethical statement

The consent from all the participants (patient and family) had been obtained in a written and oral form.

Ethical approval

Institutional Review Board approval is not required.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent.

Financial support and sponsorship

Nil.

Conflict of interest

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

Disclaimer

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.

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