Intracranial Hypotension Causing Reversible Frontotemporal Dementia and Coma

Brain Sagging Dementia

PURPOSE OF REVIEW

Brain sagging dementia (BSD) is a rare but devastating form of early-onset dementia characterized by intracranial hypotension and behavioral changes resembling behavioral variant frontotemporal dementia. This review aims to provide a comprehensive overview of BSD, highlighting its pathomechanism, diagnostic tools, and available treatment options.

RECENT FINDINGS

BSD exhibits a complex clinical manifestation with insidious onset and gradual progression of behavioral disinhibition, apathy, inertia, and speech alterations. Additionally, patients may exhibit brainstem and cerebellar signs such as hypersomnolence and gait disturbance. Although headaches are common, they may not always demonstrate typical orthostatic features. Recent radiological advances have improved the detection of CSF leaks, enabling targeted treatment and favorable outcomes. Understanding the pathomechanism and available diagnostic tools for BSD is crucial for a systematic approach to timely diagnosis and treatment of this reversible form of early-onset dementia, as patients often endure a complex and lengthy clinical course.

The reversible impairment of behavioral variant frontotemporal brain sagging syndrome: Challenges and opportunities

Introduction

Due to loss of brain buoyancy, spontaneous spinal cerebrospinal fluid (CSF) leaks cause orthostatic headaches but also can cause symptoms indistinguishable from behavioral variant frontotemporal dementia (bvFTD) due to severe brain sagging (including the frontal and temporal lobes), as visualized on brain magnetic resonance imaging. However, the detection of these CSF leaks may require specialized spinal imaging techniques, such as digital subtraction myelography (DSM).

Methods

We performed DSM in the lateral decubitus position under general anesthesia in 21 consecutive patients with frontotemporal dementia brain sagging syndrome (4 women and 17 men; mean age 56.2 years [range: 31-70 years]).

Results

Nine patients (42.8%) were found to have a CSF-venous fistula, a recently discovered type of CSF leak that cannot be detected on conventional spinal imaging. All nine patients underwent uneventful surgical ligation of the fistula. Complete or near-complete and sustained resolution of bvFTD symptoms was obtained by all nine patients, accompanied by reversal of brain sagging, but in only three (25.0%) of the twelve patients in whom no CSF-venous fistula could be detected (P = 0.0011), and who were treated with non-targeted therapies.

Discussion

Concerns about a spinal CSF leak should not be dismissed in patients with frontotemporal brain sagging syndrome, even when conventional spinal imaging is normal. However, even with this specialized imaging the source of the loss of spinal CSF remains elusive in more than half of patients.

Brain Sagging Dementia -- Diagnosis, Treatment, and Outcome: A Review

Brain sagging dementia (BSD), caused by spontaneous intracranial hypotension (SIH), is a rare syndrome that is only recently recognized, mimicking the clinical findings of behavioral variant frontotemporal dementia (bvFTD). Being aware of its signs and symptoms is essential for early diagnosis and treatment in this potentially reversible form of dementia. Our objective was to identify cases with BSD in the literature and present its clinical characteristics, diagnostic workup, treatment options, and outcome.The review was reported according to PRISMA guidelines and registered with the PROSPERO database (CRD42020150709). MEDLINE, EMBASE, PsychINFO, and Cochrane Library were searched. There was no date restriction. The search was updated in April 2021.A total of 983 articles were screened and assessed for eligibility. Twenty-nine articles (25 case reports and four series) and 70 patients were selected for inclusion. No cranial leak cases were identified. BSD diagnosis should be made based on clinical signs and symptoms and radiological findings. There is a male predominance (F: M ratio 1:4) and a peak incidence in the 6^th decade of life. The main clinical manifestation is insidious onset, gradually progressive cognitive and behavioral changes characteristic for bvFTD. Headache is present in the majority of patients (89%). The presence of brain sagging and absence of frontotemporal atrophy is an absolute criterion for the diagnosis. The CSF leak is identified with myelography and digital subtraction myelography. The treatment and repair depend on the etiology and extent of the dural defect, although an epidural blood patch is the first-line treatment in most cases. With treatment, 81% experienced partial and 67% complete resolution of their symptoms. This review highlights the most important clinical aspects of BSD. Due to the sparse evidence and lack of BSD awareness, many patients are most likely left undiagnosed. Recognizing this condition is essential to provide early treatment to reverse the cognitive and behavioral changes that may otherwise progress and fully impair the patient. Moreover, patients with longstanding SIH must be carefully assessed for cognitive and behavioral changes.

Long-term telemetric intracerebral pressure monitoring as a tool in intracranial hypotension

Intracranial hypotension (IH) remains a difficult neurosurgical diagnosis. Relying solely on the symptomatology may be misleading for both diagnosis and assessment of treatment effect as symptoms may resemble other conditions not related to IH. As such, paraclinical supplements in both diagnosis and treatment follow-up are warranted. We present a 42-year-old male with IH treated with computed tomography-guided epidural blood patch. The diagnosis and treatment assessment included continual intracerebral pressure (ICP) monitoring. We found ICP monitoring helpful in IH diagnosis and long-term assessment of treatment and propose this modality as a supplement in difficult IH cases.

Frontotemporal brain sagging syndrome: Craniospinal hypovolemia secondary to a T6-T7 cerebrospinal fluid-venous fistula

Background:

The frontotemporal brain sagging syndrome (FTBSS) is defined as an insidious/progressive decline in behavior and executive functions, hypersomnolence, and orthostatic headaches attributed to cerebrospinal fluid (CSF) hypovolemia. Here, a T6 CSF-venous fistula (e.g., between the subarachnoid CSF and a paraspinal vein) resulted in a CSF leak responsible for craniospinal hypovolemia.

Case Description:

A 56-year-old male started with orthostatic headaches and fatigue after scuba diving. His symptoms included progressive, vertigo, tinnitus, nausea, lack of judgment, inappropriate behavior, memory dysfunction, apathy, tremor, orofacial dyskinesia, dysarthria, dysphagia, and hypersomnolence. The lumbar puncture revealed an opening pressure of 0 cm H2O. Magnetic resonance imaging (MRI) findings included brain sagging, bilateral temporal lobe herniation, and pachymeningeal enhancement. The computed tomography (CT) myelogram showed a thoracic diverticulum and a CSF-venous leak at the T6-T7 level. Surgery, which comprised a T6-T7 laminotomy, allowed for dissecting, clipping, and ligating the diverticulum/fistula. The patient improved postoperatively (e.g., cognitive, behavioral, and brainstem symptoms). The follow-up MRI’s showed the reversion of the sagging index/uncal herniation.

Conclusion:

The FTBSS should be considered in the differential diagnosis of an early onset frontotemporal dementia. Establishing the diagnosis and localizing the site of a spinal CSF/venous leak warrant both MRI and myelogram CT studies, to pinpoint the CSF leak site for proper surgical clipping/ligation of these thoracic diverticulum/CSF-venous leaks.

Spontaneous intracranial hypotension: key features for a frequently misdiagnosed disorder

Spontaneous intracranial hypotension (SIH) is a rare neurological condition caused by low cerebrospinal fluid (CSF) volume, most commonly due to a CSF leak. The most common presenting symptom is an orthostatic headache, but some patients may present with atypical neurological manifestations such as cranial nerve palsies, an altered mental status, and movement disorders, which complicate the clinical diagnosis. Therefore, the diagnosis is based on the combination of clinical signs and symptoms, neuroimaging, and/or a low cerebrospinal fluid pressure. In this review, we describe the wide variety of neurological manifestations and complications seen in patients with SIH as well as the most common features described on imaging studies, including both subjective and objective measurements, in order to lead the clinician to a correct diagnosis. The prompt and correct management of patients with SIH will help prevent the development of life-threatening complications, such as subdural hematomas, cerebral venous thrombosis, and coma, and avoid unnecessary invasive procedures.

Multilevel, ultra-large-volume epidural blood patch for the treatment of neurocognitive decline associated with spontaneous intracranial hypotension: case report

Spontaneous intracranial hypotension (SIH) is a progressive clinical syndrome characterized by orthostatic headaches, nausea, emesis, and occasionally focal neurological deficits. Rarely, SIH is associated with neurocognitive changes. An epidural blood patch (EBP) is commonly used to treat SIH when conservative measures are inadequate, although some patients require multiple EBP procedures or do not respond at all. Recently, the use of a large-volume (LV) EBP has been described to treat occult leak sites in treatment-refractory SIH. This article describes the management of a patient with profound neurocognitive decline associated with SIH, who was refractory to conservative management and multiple interventions. The authors describe the successful use of an ultra-LV-EBP of 120 ml across multiple levels, the largest volume reported in the literature, and describe the technical aspects of the procedure. This procedure has resulted in dramatic and sustained symptom resolution.

Coma

Objective

To review our experience with patients with spontaneous intracranial hypotension (SIH) and coma because, although disorders of consciousness may complicate SIH, no comprehensive study of such patients has been reported.

Methods

Using a prospectively maintained registry, we identified all patients with SIH in whom coma developed. Patients or their caregivers/families were contacted for follow-up. Patients were compared to a cohort of patients with SIH without coma.

Results

The mean age of the 12 men and 3 women with SIH was 56.2 years (range 34–72 years) at the time of onset of coma. In one-third of patients, coma developed after craniotomy for subdural hematomas or for an unrelated intracranial pathology. Imaging showed brain sagging, including bilateral temporal lobe herniation, in all 15 patients and brainstem edema in 8 patients (53%). Overall, coma was reversible in 7 of 15 patients treated with epidural blood patches, in 2 of 4 treated with percutaneous glue injections, and in 6 of 6 treated surgically. Only 1 patient had residual neurologic deficit related to coma (Glasgow Outcome Scale score 4 [moderate disability]). Compared to patients with SIH without coma (n = 568), those with coma were older, more often were male, and more often underwent surgery.

Conclusions

Coma in SIH is rare, reversible, and invariably associated with brain sagging. Coma due to SIH may be refractory to the usual percutaneous procedures, and surgical closure of the CSF leak may be required to regain consciousness.

Behavioral Variant Frontotemporal Dementia as a Serious Complication of Spontaneous Intracranial Hypotension

BACKGROUND

Behavioral variant frontotemporal dementia (bvFTD) is a devastating early onset dementia. Symptoms of bvFTD may be caused by spontaneous intracranial hypotension (SIH), a treatable disorder, but no comprehensive study of such patients has been reported.

OBJECTIVE

To describe detailed characteristics of a large cohort of patients with SIH and symptoms of bvFTD.

METHODS

We identified patients with SIH who met clinical criteria for bvFTD. Patients were compared to a cohort of SIH patients without bvFTD.

RESULTS

The mean age for the 21 men and 8 women was 52.9 yr (range, 37–65 yr). All 29 patients with bvFTD symptoms had hypersomnolence. Magnetic resonance imaging showed brain sagging in all patients, cerebrospinal fluid (CSF) opening pressure low in about half of patients, but a spinal CSF leak could not be detected in any patient. All patients underwent epidural blood patching, but 26 patients eventually underwent 1 or more surgical procedures. Overall, a good outcome was obtained in 21 patients (72%); 20 (91%) of 22 patients who had not undergone prior Chiari surgery compared to 1 (14%) of 7 patients who did undergo Chiari surgery (P < .003). Compared to SIH patients without symptoms of bvFTD (n = 547), those with bvFTD symptoms were older, more often male, less often demonstrated CSF leak on spinal imaging, and more often underwent surgery (P < .02).

CONCLUSION

bvFTD in SIH is rare and associated with brain sagging and hypersomnolence. Spinal CSF leaks are rarely detected. bvFTD symptoms are often refractory to the usual percutaneous procedures but most patients can be cured.

Atypical Presentations of Intracranial Hypotension: Comparison with Classic Spontaneous Intracranial Hypotension

BACKGROUND AND PURPOSE

Atypical clinical presentations of spontaneous intracranial hypotension include obtundation, memory deficits, dementia with frontotemporal features, parkinsonism, and ataxia. The purpose of this study was to compare clinical and imaging features of spontaneous intracranial hypotension with typical-versus-atypical presentations.

MATERIALS AND METHODS

Clinical records and neuroimaging of patients with spontaneous intracranial hypotension from September 2005 to August 2014 were retrospectively evaluated. Patients with classic spontaneous intracranial hypotension (n = 33; mean age, 41.7 ± 14.3 years) were compared with those with intracranial hypotension with atypical clinical presentation (n = 8; mean age, 55.9 ± 14.1 years) and 36 controls (mean age, 41.4 ± 11.2 years).

RESULTS

Patients with atypical spontaneous intracranial hypotension were older than those with classic spontaneous intracranial hypotension (55.9 ± 14.1 years versus 41.7 ± 14.3 years; P = .018). Symptom duration was shorter in classic compared with atypical spontaneous intracranial hypotension (3.78 ± 7.18 months versus 21.93 ± 18.43 months; P = .015). There was no significant difference in dural enhancement, subdural hematomas, or cerebellar tonsil herniation. Patients with atypical spontaneous intracranial hypotension had significantly more elongated anteroposterior midbrain diameter compared with those with classic spontaneous intracranial hypotension (33.6 ± 2.9 mm versus 27.3 ± 2.9 mm; P < .001) and shortened pontomammillary distance (2.8 ± 1 mm versus 5.15 ± 1.5 mm; P < .001). Patients with atypical spontaneous intracranial hypotension were less likely to become symptom-free, regardless of treatment, compared with those with classic spontaneous intracranial hypotension (χ(2) = 13.99, P < .001).

CONCLUSIONS

In this sample of 8 patients, atypical spontaneous intracranial hypotension was a more chronic syndrome compared with classic spontaneous intracranial hypotension, with more severe brain sagging, lower rates of clinical response, and frequent relapses. Awareness of atypical presentations of spontaneous intracranial hypotension is paramount.

Intracranial hypotension: clinical presentation, imaging findings, and imaging-guided therapy

PURPOSE OF REVIEW

To illustrate clinical presentations, imaging findings, and diagnostic and therapeutic approaches associated with various conditions of intracranial hypotension.

RECENT FINDINGS

Intracranial hypotension occurs spontaneously, following (lumbar) dural puncture, accidental dural opening, or excessive surgical cerebrospinal fluid drainage. The typical clinical manifestation - orthostatic headache - may be masqueraded by atypical clinical findings, including coma, frontotemporal dementia, leptomeningeal hemosiderosis-associated symptoms, and others. MRI signs are highly specific, but the imaging strategy to search for spinal cerebrospinal fluid leaks (none, computed tomography myelography, magnetic resonance myelography with gadolinium, digital subtraction myelography) is a matter of debate. The same is true for the mode of treatment (bed rest, blind, fluoroscopy or computed tomography-guided epidural blood patching, fibrin patching, surgery).

SUMMARY

Clinical presentation as well as diagnostic and therapeutic approaches in intracranial hypotension are very heterogenous.

Management of patients with spontaneous intracranial hypotension causing altered level of consciousness: report of two cases and review of literature

BACKGROUND

Decreased level of consciousness is a rare neurological manifestation of spontaneous intracranial hypotension (SIH), which typically presents with orthostatic headache. The optimal management of this uncommon presentation remains uncertain.

METHODS

We analyzed the presentation, management and outcome of two patients in our institution and reviewed 22 patients reported in the literature with SIH and decreased level of consciousness, defined as any decrease in the patient's Glasgow Coma Scale score.

RESULTS

There were 20 male and four female patients (M:F ratio of 5:1) with an average age of 52 years (range 37 to 68 years). There was a variable time interval of up to many months between the initial presentation of SIH and changes in the level of consciousness. An epidural autologous blood patch was eventually successful in 79% of the patients, although up to three trials were necessary in seven of these patients. Intrathecal saline infusion used as a temporizing measure resulted in excellent response within hours in five out of six patients who received this treatment. Drainage of the subdural collection either did not result in any sustained improvement or resulted in clinical deterioration in 12 out of 12 patients who received this treatment.

CONCLUSIONS

In the absence of a clinical trial because of the rarity of this entity, the treatment of SIH complicated by decreased level of consciousness remained controversial in the past. However, current collective experience supports early treatment of patients with SIH and decreased level of consciousness with one or more epidural blood patches. Fibrin glue and surgical duroplasty are the next steps in the management of patients in whom epidural blood patches fail. Drainage of the subdural collections may be detrimental.

Intracranial hypotension producing reversible coma: a systematic review, including three new cases

Intracranial hypotension is a disorder of CSF hypovolemia due to iatrogenic or spontaneous spinal CSF leakage. Rarely, positional headaches may progress to coma, with frequent misdiagnosis. The authors review reported cases of verified intracranial hypotension-associated coma, including 3 previously unpublished cases, totaling 29. Most patients presented with headache prior to neurological deterioration, with positional symptoms elicited in almost half. Eight patients had recently undergone a spinal procedure such as lumbar drainage. Diagnostic workup almost always began with a head CT scan. Subdural collections were present in 86%; however, intracranial hypotension was frequently unrecognized as the underlying cause. Twelve patients underwent one or more procedures to evacuate the collections, sometimes with transiently improved mental status. However, no patient experienced lasting neurological improvement after subdural fluid evacuation alone, and some deteriorated further. Intracranial hypotension was diagnosed in most patients via MRI studies, which were often obtained due to failure to improve after subdural hematoma (SDH) evacuation. Once the diagnosis of intracranial hypotension was made, placement of epidural blood patches was curative in 85% of patients. Twenty-seven patients (93%) experienced favorable outcomes after diagnosis and treatment; 1 patient died, and 1 patient had a morbid outcome secondary to duret hemorrhages. The literature review revealed that numerous additional patients with clinical histories consistent with intracranial hypotension but no radiological confirmation developed SDH following a spinal procedure. Several such patients experienced poor outcomes, and there were multiple deaths. To facilitate recognition of this treatable but potentially life-threatening condition, the authors propose criteria that should prompt intracranial hypotension workup in the comatose patient and present a stepwise management algorithm to guide the appropriate diagnosis and treatment of these patients.

Frontotemporal brain sagging syndrome: an SIH-like presentation mimicking FTD

BACKGROUND

Behavioral variant frontotemporal dementia (bvFTD) is a relatively well-defined clinical syndrome. It is associated with frontal and temporal lobe structural/metabolic changes and pathologic findings of a neurodegenerative disease. We have been evaluating patients with clinical and imaging features partially consistent with bvFTD but with evidence also suggestive of brain sagging, which we refer to as frontotemporal brain sagging syndrome (FBSS).

METHODS

Retrospective medical chart review to identify all patients seen at our institution between 1996 and 2010, who had a clinical diagnosis of FTD and imaging evidence of brain sag.

RESULTS

Eight patients, 7 male and 1 female, were diagnosed with FBSS. The median age at symptom onset was 53 years. All patients had insidious onset and slow progression of behavioral and cognitive dysfunction accompanied by daytime somnolence and headache. Of the 5 patients with functional imaging, all showed evidence of hypometabolism of the frontotemporal regions. On brain MRI, all patients had evidence of brain sagging with distortion of the brainstem; 3 patients had diffuse pachymeningeal enhancement. CSF opening pressure was varied and CSF protein was mildly elevated. A definite site of CSF leak was not identified by myelogram or cisternography, except in one patient with a site highly suggestive of leak who subsequently underwent surgery confirming a CSF leak. In 2 patients with a neuropathologic examination, there was no evidence of a neurodegenerative disease.

CONCLUSIONS

This case series demonstrates that FBSS may mimic typical bvFTD but should be recognized as an unusual presentation that is potentially treatable.