A follow-up ¹8F-FDG brain PET study in a case of Hashimoto's encephalopathy causing drug-resistant status epilepticus treated with plasmapheresis.

Hashimoto's encephalopathy (HE) is a rare neuropsychiatric syndrome associated with antithyroid antibodies. It may have an acute onset (episodes of cerebral ischemia, seizure, and psychosis) or it may present as an indolent form (depression, cognitive decline, myoclonus, tremors, and fluctuations in level of consciousness). We here describe a case of encephalopathy presenting as non-convulsive status epilepticus associated with Hashimoto's thyroiditis (HT), unresponsive to corticosteroid therapy, with improvement after plasma exchange treatment. A previously healthy 19-year-old woman, presented generalized tonic-clonic seizures. About a month later, she manifested a speech disorder characterized by difficulties in the production and comprehension of language. Within a few days she also developed confusion and difficulties in recognizing familiar places, with gradual worsening over time. EEG revealed a non-convulsive status epilepticus (NCSE). CSF examination showed slightly elevated cell count and four oligoclonal bands. MRI was unremarkable, and (18)F-FDG brain PET showed widespread hypometabolism, mostly in posterior regions bilaterally. Laboratory and ultrasound findings showed signs of HT. Treatment with steroid was introduced without any improvement. After five sessions of plasma exchange there was a decrease of antithyroid antibodies, as well as EEG and clinical improvement. Three months after discharge (18)F-FDG brain PET showed a complete normalization of the picture, and the patient was asymptomatic. This report emphasizes the successful treatment of HE with plasma exchange in a patient who presented with NCSE. Based on the actual evidence, the term "Encephalopathy associated with Hashimoto's thyroiditis" may be the most proper. Furthermore, to our knowledge, this is the first case of an adult patient studied twice with an (18)F-FDG brain PET: prior to treatment with plasma exchange, and at 3 months follow-up when the patient was clinically completely asymptomatic. Studies in more patients are needed to clarify the relevance of (18)F-FDG brain PET as a possible diagnostic tool for HE.

Evidence for cortical functional changes in patients with migraine and white matter abnormalities on conventional and diffusion tensor magnetic resonance imaging.

BACKGROUND: In this study, we used functional MRI (fMRI) to investigate the pattern of cortical activations after a simple motor task in patients with migraine and white matter (WM) abnormalities on conventional MRI scans of the brain. We also investigated whether the extent of brain activations was correlated with WM structural pathology measured using diffusion tensor (DT) MRI. METHODS: From 15 right-handed patients with migraine and 15 sex- and age-matched, right-handed healthy volunteers, we obtained the following: (1) fMRI (repetitive flexion-extension of the last 4 fingers of the right hand), (2) dual-echo turbo spin echo scans, and (3) pulsed-gradient spin-echo echo-planar sequence to calculate DT-MRI maps. fMRI analysis was performed using SPM99 and cluster detection. We measured the volume, the average mean diffusivity (), and the average fractional anisotropy of all lesions seen on the dual-echo scans. histograms of the normal-appearing WM were also produced. RESULTS: Compared with healthy volunteers, migraine patients had a larger relative activation of the contralateral primary sensorimotor cortex (P=0.01) and a rostral displacement of the supplementary motor area (P=0.03). The shapes of the curves reflecting the time course for fMRI signal intensity changes were similar between migraine patients and controls for all of the cortical areas we studied. Compared with healthy subjects, migraine patients had significantly lower histogram peak height of the normal-appearing WM histogram (P=0.02), which was found to be correlated with the extent of displacement of the supplementary motor area (r=-0.80, P<0.001). CONCLUSIONS: This study suggests that functional cortical changes occur in patients with migraine and brain MRI abnormalities and that they might be secondary to the extent of subcortical structural damage.

A diffusion tensor MRI study of basal ganglia from patients with ADEM.

Using diffusion tensor (DT) MRI and histogram analysis, we measured mean diffusivity ((-)D) of basal ganglia grey matter (GM) from eight patients with acute disseminated encephalomyelitis (ADEM), 10 patients with multiple sclerosis (MS), and 10 healthy controls. Patients with ADEM had higher average (-)D (p=0.02) and lower (-)D histogram peak height (p=0.008) of the basal ganglia GM than patients with MS. Microscopic tissue damage occurs in the basal ganglia of ADEM patients, but not in MS patients with a similar burden of MRI-visible brain lesions.

A preliminary study of magnetization transfer and diffusion tensor MRI of multiple sclerosis patients with fatigue.

To investigate whether multiple sclerosis (MS) tissue damage is associated with the presence and severity of fatigue, we obtained magnetization transfer (MT) and diffusion tensor (DT) magnetic resonance imaging from 28 patients with MS (14 with and 14 without fatigue). MT ratio and mean diffusivity did not differ between fatigued and non-fatigued MS patients. No correlation was found between Fatigue Severity Scale scores and any of the MT and DT MRI-derived quantities. This preliminary study suggests that the severity of overall MS pathology in the brain seems not to be a critical factor contributing to the development of fatigue in MS.

Frequency and patterns of subclinical cognitive impairment in patients with ANCA-associated small vessel vasculitides.

We investigated the prevalence of disease-related cognitive impairment in patients with anti-neutrophil cytoplasmic antibodies (ANCA)-associated small vessel vasculitides (SVV). We studied 43 patients with ANCA-associated SVV (Wegener's granulomatosis (WG), Churg-Strauss syndrome (CSS) and microscopic polyangiitis (MP)), with no evidence of focal neurological deficits and dementia and in whom other potential causes of cognitive decline were carefully excluded. All patients underwent a detailed neuropsychological evaluation and their performances were compared with those of matched healthy controls. Patients were considered to be affected by subclinical cognitive impairment when they had abnormal results in at least two neuropsychological tests. Magnetic resonance imaging (MRI) scans of the brain were also obtained in 11 patients.The average neuropsychological test scores were not significantly different between the SVV patients and the control subjects. Thirteen patients had abnormal results in two tests (seven patients) or three or more tests (six patients). Most frequently, abnormal tests were the Rey Figure Recall (six cases), the Wisconsin Card Sorting Test (six cases), and the reaction times (eight cases). The frequency and extent of brain MRI abnormalities were higher in impaired than in unimpaired patients. This study demonstrates that 30% of clinically nondemented SVV patients can have a subclinical neuropsychological impairment, characterized by mild abstract reasoning loss, mental speed reduction and nonverbal memory impairment. MRI findings in impaired patients are consistent with the presence of an SVV-mediated subcortical damage of the brain.