Spinal dementia: Don't miss it, it's treatable

Abstract

Background & purpose: Around 5% of dementia patients have a treatable cause. To estimate the prevalence of two rare diseases, in which the treatable cause is at the spinal level.

Methods: A radiology information system was searched using the terms CT myelography and the operation and classification system (OPS) code 3-241. The clinical charts of these patients were reviewed to identify patients with a significant cognitive decline.

Results: Among 205 patients with spontaneous intracranial hypotension (SIH) and proven CSF leaks we identified five patients with a so-called frontotemporal brain sagging syndrome: Four of those had CSF venous fistulas and significantly improved by occluding them either by surgery or transvenous embolization. Another 11 patients had infratentorial hemosiderosis and hearing problems and ataxia as guiding symptoms. Some cognitive decline was present in at least two of them. Ten patients had ventral dural tears in the thoracic spine and one patient a lateral dural tear at C2/3 respectively. Eight patients showed some improvement after surgery.

Discussion: It is mandatory to study the (thoracic) spine in cognitively impaired patients with brain sagging and/ or infratentorial hemosiderosis on MRI. We propose the term spinal dementia to draw attention to this region, which in turn is evaluated with dynamic digital subtraction and CT myelography.

Keywords: Dementia; Frontotemporal brain sagging syndrome; Infratentorial hemosiderosis – CT myelography; Spontaneous intracranial hypotension.

Fig. 1

A 57-year-old man presented with apathy, loss of interest, gait ataxia, and tremor. Over at least 6 years symptoms had progressed so that he was only sitting looking television the whole day. Sagittal (A) T2-weighted and contrast enhanced MPRAGE images (C) show a small angle between the vein of Galen and the straight sinus (C: angle). The vein of Galen is elongated as indicated by the distance from the confluence of the internal cerebral veins and the exit of the vein of Galen in the straight sinus (C: dashed arrow). Axial T2-weighted images (B, D) show a marked and progressive midbrain elongation indicated by a long a.p. diameter of the midbrain and a higher sag ratio a/b

Fig. 2

Study flowchart

Fig. 3

A 64-year-old man presented with disinhibition, dizziness and logorhoea so that he was not able to work as a teacher any longer. MRI shows severe midbrain sagging with an extremely low mamillo-pontine distance (A: arrow) and an elongated midbrain (B: arrow). Dynamic CT myelography discloses a CSF venous fistula at the right-sided T2 nerve root (C: arrow). Following transvenous embolization (F: arrow points to the Onyx cast), MRI changes are regredient (D, E: arrows) and the patient reported on marked improvement

Fig. 4

A 61-year-old man complained of vertigo progressive over some years. He could not walk stairs, had hearing difficulties, depression, and was unable to work. Initial MRI 2 years after onset of orthostatic headaches was considered normal but shows subtle infratentorial hemosiderosis (A, C: arrow). Six years later, hemosiderosis and cerebellar atrophy had progressed (B, D: arrow). A coronal SWI sequence shows the full extent of hemosiderosis (E). Work-up with dynamic DSM and CTM disclosed a ventral leak at T2/3 (F: arrow)

Fig. 5

A 54-year-old woman complained of headache, head pressure ear ringing, blurry vision, gait disorder, and cognitive “slowing”. Sagittal T2-weighted MRI of the cervical spine shows infratentorial hemosiderosis with hemosiderin in the foliae of the upper vermis (A: hollow arrow) and spinal longitudinal epidural fluid (SLEC) (A: arrow). A heavily T2-weighted fat-suppressed SPACE sequence allows the calculation of axial images with the majority of the epidural fluid ventral to the spinal cord (B, C: arrow). Digital subtraction myelography with a high temporal resolution (1 frame/ second) was needed to capture the time point of egress of contrast from the subarachnoid space (D: arrow) – here, a non-subtracted image is displayed