Behavioral Variant Frontotemporal Dementia like Syndrome –Atypical Presentation of Intracranial Hypotension

Case Report

Austin Alzheimers J Parkinsons Dis. 2023; 6(1): 1037.

Behavioral Variant Frontotemporal Dementia like Syndrome –Atypical Presentation of Intracranial Hypotension

Hiba Khan*; Kasia Gustaw Rothenberg

Lou Ruvo Center for Brain Health, Neurological Institute, Cleveland Clinic, USA

*Corresponding author: Hiba Khan Lou Ruvo Center for Brain Health, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, 44195 Cleveland, USA. Tel: 216-894-9673; Fax: 216-636-2645 Email: khanh3@ccf.org

Received: March 01, 2023 Accepted: April 06, 2023 Published: April 13, 2023

Abstract

Spontaneous Intracranial Hypotension (SIH) is an uncommon syndrome which may result from a Cerebrospinal Fluid (CSF) leak. Atypical SIH may present with neurobehavioral symptoms similar to those observed in behavioral variant Frontotemporal Dementia (bvFTD). We present a case of a 55-year-old male with postural headache and behavioral symptoms who was initially diagnosed with bvFTD. On re-evaluation in our clinic, imaging revealed caudal displacement of the midline structures suggestive of Cerebrospinal Fluid (CSF) hypotension. We hypothesized that with unmitigated CSF loss over a long period of time, the patient developed brain sagging clinically resulting in neurobehavioral, frontal lobe dysfunction. After multitude of investigative procedures, a CSF venous fistula originating from a T7 nerve root cyst was found and repaired. Surgical intervention and restoration of CSF volume resulted in resolution of cognitive as well as neurobehavioral symptoms.

Keywords: Behavioral variant frontotemporal dementia; Headache; CSF leak; Spontaneous intracranial hypotension; Sagging brain syndrome

Introduction

Behavioral Variant Frontotemporal Dementia (bvFTD) is a devastating neurodegenerative disease with relatively early onset. The characteristic clinical features of bvFTD include a change in personality and behavior, for example, disinhibition and executive dysfunction, resulting in poor planning, loss of judgment, difficulty with organization and loss of insight. Overeating, particularly of sweets may occur. Other features include apathy, utilization behaviors, and obsessive compulsive-like preservative behaviors. Patients often demonstrate lack of empathy, impaired insight and show little concern for friends or family members. Language deficits occur but may not the presenting feature [10].

Spontaneous Intracranial Hypotension (SIH) may result in symptoms similar to those seen in bvFTD [1,11]. Contrary to bvFTD however, SIH can be successfully treated resulting in reversal of the neuropsychiatric syndrome. SIH commonly manifests as a low-pressure orthostatic headache secondary to a reduction in the CSF pressure, without an apparent explanation. Any breach in the dura mater causes a reduction in CSF volume leading to gravitational traction and downward displacement of the brainstem and cerebellum [9]. Dural defects predispose to the formation of CSF venous fistulas (with unregulated CSF loss) because of communications between the spinal subarachnoid space and dilated paraspinal veins that accompany SIH [2].

SIH has a broad spectrum of clinical and imaging manifestations, and atypical cases have been reported. Atypical clinical presentations of SIH include parkinsonism, ataxia, obtundation, memory deficits and dementia with frontotemporal features [1,8,11]. Symptoms result from prolonged intracranial hypotension and mechanical disruption of frontotemporal anatomy with structural, metabolic or neurodegenerative changes, which can be reversed by restoration of CSF volume [4]. The main MRI finding is a characteristic diffuse pachymeningeal enhancement. Apart from this, MRI may also show caudal displacement of the midline structures of the brain such as sagging of the brain, pituitary enlargement, subdural fluid collection, posterior lobe pituitary hematoma, diffuse dural enhancement of the spinal canal, spinal epidural fluid collection, distension of the spinal epidural venous plexus, and abnormal intensity around the root sleeves [6]. Combination of this characteristic MRI picture and frontotemporal dementia like neurobehavioral syndrome is commonly referred to as Frontotemporal Brain Sagging Syndrome (FTBSS) [12]. FTBSS is defined as an insidious, often progressive decline in behavior and executive functions, hypersomnolence, and orthostatic headaches attributed to cerebrospinal fluid hypovolemia [5,12]. Here by we present a case of a 55 year-old-male diagnosed with bvFTD who in fact was suffering SIH clinically presented as FTBSS which resolved after the source of spinal fluid leak was found and repaired.

Case Report

Initial Case Presentation

The Patient (KW) is a 55 year-old-male who presented with headaches, confusion, and lack of attention. Family reported changes in behavior such as disengagement from surroundings and frequent repetition. Episodes of headaches had been ongoing for at least 14 months which the patient attributed to migraines or allergies. At first, his reported lack of attention was only affecting driving, but soon afterwards he lost two jobs because of cognitive problems. In addition to cognitive changes his behavior changed. Reportedly the patient started laughing and joking inappropriately. These symptoms led to neurological evaluation. He scored 20/30 on Montreal Cognitive Assessment (MoCA) with abnormal performance in: naming, attention, language fluency, abstraction and recall. Imaging was unremarkable and neuropsychological assessment suggestive of frontal as well as temporal lobe dysfunction.

Initial MRI (March 2016): There are a few punctate areas of high signal in the periventricular white matter that are likely related to chronic small vessel ischemic disease. Demyelination cannot be entirely excluded in a young patient. No acute brain parenchymal abnormality.

Initial Neuropsychological assessment (2016): There are prominent deficits in memory (recall and recognition are severely impaired, learning is suppressed). Aspects of executive function (switching/inhibition, errors, rule violations, verbal fluency) are impaired in addition to self-report and wife’s report of presence of significant apathy, disinhibition and executive dysfunction. Attention and processing speed are variable from extremely low to high average. Verbal reasoning, naming, perceptual reasoning, visuospatial functions are intact. Deficits are of moderate severity and suggest involvement of frontal and temporal lobes, concerning for major neurocognitive disorder likely frontotemporal lobar degeneration.

He had an extensive workup including a normal EEG and blood tests, which included, TSH, vitamin B12 level, lead and vitamin D levels, RPR, Lyme disease testing as well an autoimmune and paraneoplastic panel. The results of the above mentioned testing came back within normal range. A1C was in prediabetic range. Thiamine level was low. He was diagnosed with major neurocognitive disorder in the course of frontotemporal lobe degeneration. Treatment with Donepezil and Memantine was initiated and medications were titrated up to the maximum recommended doses.

Re-evaluation at the Center for Brain Health (CBH) Cleveland Clinic

Patient was referred to CBH to be considered for participation in clinical trials. Both the patient and his family were concerned about FTD diagnosis and were seeking re-evaluation. Patient’s cognitive and behavioral symptoms remained the same but in addition to initial clinical presentation he started exhibiting orthostatic headaches, swallowing difficulty and frequent hiccups. On repeat MoCA Patient scored 24/30 with deficits in delayed recall, language and abstraction. Repeated imaging however revealed caudal displacement of the midline brain structures concerning for CSF hypotension.

MRI 2017: Striking caudal displacement of the midline structures suggesting severe CSF hypotension. No significant generalized parenchymal volume loss by visual inspection and quantitative analysis. Hippocampal volumes were at the 53rd percentile when compared to age matched normal controls by quantitative analysis. Mild nonspecific supratentorial white matter disease was reported. Comparison with imaging from 2016 was suggestive of interval progression (Figure 1).

Citation: Khan H, Rothenberg KG. Behavioral Variant Frontotemporal Dementia like Syndrome –Atypical Presentation of Intracranial Hypotension. Austin Alzheimers J Parkinsons Dis. 2023; 6(1): 1037.