Lateralized periodic discharges frequency correlates with glucose metabolism.

OBJECTIVE: To investigate the correlation between characteristics of lateralized periodic discharges (LPDs) and glucose metabolism measured by 18F-fluorodeoxyglucose (FDG)-PET. METHODS: We retrospectively reviewed medical records to identify patients who underwent FDG-PET during EEG monitoring with LPDs present during the FDG uptake period. Two blinded board-certified neurophysiologists independently interpreted EEGs. FDG uptake was measured using standardized uptake value (SUV). Structural images were fused with PET images to aid with localization of SUV. Two PET readers independently measured maximum SUV. Relative SUV values were obtained by normalization of the maximum SUV to the SUV of pons (SUVRpons). LPD frequency was analyzed both as a categorical variable and as a continuous measure. Other secondary variables included duration, amplitude, presence of structural lesion, and "plus" EEG features such as rhythmic or fast sharp activity. RESULTS: Nine patients were identified and 7 had a structural etiology for LPDs. Analysis using frequency as a categorical variable and continuous variable showed an association between increased LPD frequency and increased ipsilateral SUVRpons (p = 0.02). Metabolism associated with LPDs (0.5 Hz as a baseline) increased by a median of 100% at 1 Hz and for frequencies >1 Hz increased by a median of 309%. There were no statistically significant differences in SUVRpons for other factors including duration (p = 0.10), amplitude (p = 0.80), structural etiology (p = 0.55), or "plus" features such as rhythmic or fast sharp activity (p = 0.84). CONCLUSIONS: Metabolic activity increases monotonically with LPD frequency. LPD frequency should be a measure of interest when developing neuroprotection strategies in critical neurologic illness.

Posterior Reversible Encephalopathy Syndrome on 18F-FDG PET/CT in a Pediatric Patient With Burkitt's Lymphoma.

We present a case of posterior reversible encephalopathy syndrome (PRES) in a pediatric patient with Burkitt's lymphoma predominantly involving the bone marrow. F-FDG PET/CT scan obtained after the first cycle of chemotherapy, complicated by acute kidney injury, hypertension, tumor lysis syndrome, and lethargy with focal neurological symptoms, showed a favorable marrow and lymph node response but increased FDG uptake in the bilateral frontal and occipital cortical/subcortical regions. Brain MRI was consistent with PRES. The patient was managed with IV hydration and blood pressure control with symptom resolution. This case shows the F-FDG uptake pattern of PRES in postchemotherapy setting.

Immune system activation in the pathogenesis of posterior reversible encephalopathy syndrome.

Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiological syndrome characterized by a variable combination of headaches, seizures, altered mental status, visual impairment, focal neurological signs and symmetric vasogenic edema in bilateral posterior cerebral circulation territory. The pathogenesis of PRES is still controversial. Most of the clinical conditions associated with PRES involve a systemic toxicity response in the entire organism with activation of the cells of the immune system and cytokines. These PRES related conditions induce T cell activation, cytokine release, and subsequent leukocyte adhesion and activation, resulting in endothelial damage and fluid leakage. This potential mechanism of immune system activation and endothelial dysfunction may play a critical role in the pathogenesis of PRES. In this review, the role of immune system activation and endothelial dysfunction in the pathogenesis of PRES is discussed, with the aim to improve our understanding of this disorder.

Factors associated with fatal outcome in posterior reversible encephalopathy syndrome: a retrospective analysis of the Berlin PRES study.

Although often reversible, fatal outcome in posterior reversible encephalopathy syndrome (PRES) is well known. However, data on predictors of PRES-associated in-hospital death are scarce. In this study, we aimed to investigate predictors of in-hospital death in a large cohort. Radiological report databases between January 1999 and February 2015 were retrospectively searched for patients with PRES. Patients were included if they met criteria for PRES after detailed investigation of clinical charts and imaging studies. Various clinical, paraclinical and brain MRI data as well as data on in-hospital mortality were analyzed. 151 patients were included into the study, 64% were female. Seventeen (11.2%) patients died during hospital stay. In univariate analyses, higher age (p = 0.04), higher levels of C-reactive protein (p < 0.001), etiology of PRES (sepsis and chemotherapy; p = 0.02), altered coagulation (p = 0.002), altered mental state at onset (p = 0.03), and subarachnoid hemorrhage (SAH; p = 0.01) were related to in-hospital death. In multivariate analyses adjusted for age and sex, elevated CRP levels (OR 1.1 95% CI 1.1-1.2), altered coagulation (OR 5.1 95% CI 1.8-14.7), subarachnoid hemorrhage (OR 10.1 95% CI 2.2-46.1) and altered mental state (OR 3.3; 95% CI 1.1-9.4) were independently associated with in-hospital death. Altered mental state, subarachnoid hemorrhage as well as the higher levels of CRP and altered coagulation were significantly more frequent in patients who died in hospital. However, prospective studies are warranted to establish predictors of fatality in patients with PRES.

Neuroimaging features and predictors of outcome in eclamptic encephalopathy: a prospective observational study.

BACKGROUND AND PURPOSE: Posterior reversible encephalopathy syndrome is associated with eclampsia. We assessed the distribution and nature of typical and atypical cranial MR imaging findings in these patients and their correlation with clinical and laboratory data and predictors of outcome. MATERIALS AND METHODS: Forty-five clinically confirmed cases of eclampsia were included in this prospective observational study. Subjects with hemolysis, elevated liver enzymes, and low platelets syndrome (n = 9) and pre-existing neurologic conditions (1 with cerebral solitary cysticercus granuloma) were excluded. Patients underwent blood investigations and cranial MR imaging. RESULTS: Twenty-seven patients had abnormal while 8 had normal MR imaging findings. Involvement of brain regions was as follows: frontal, 88.89%; temporal, 44.44%; parietal, 100%; occipital, 100%; deep gray matter, 29.63%; cerebellum, 22.22%; brain stem, 14.81%. Cytotoxic edema was present in 33.33% of cases; 66.67% of patients had mild posterior reversible encephalopathy syndrome; 25.92% had moderate posterior reversible encephalopathy syndrome; and 7.41% had severe posterior reversible encephalopathy syndrome. Abnormal neuroimaging findings were significantly associated with altered sensorium; visual disturbances; status epilepticus; and elevated serum creatinine, uric acid, and lactate dehydrogenase (P=.006, P=.018, P=.015, P=.019, P=.003, and P=.001, respectively). Serum creatinine, uric acid, and lactate dehydrogenase values and the presence of moderate or severe posterior reversible encephalopathy syndrome were significantly associated with mortality (P<.001, P<.001, P=.009, and P=.027, respectively). CONCLUSIONS: Neuroimaging in eclampsia demonstrates a higher incidence of atypical distributions and cytotoxic edema than previously thought. Altered sensorium; visual disturbances; status epilepticus; and elevated serum uric acid, lactate dehydrogenase, and creatinine are associated with abnormal neuroimaging findings. Higher serum creatinine, uric acid, and lactate dehydrogenase levels and moderate and severe forms of posterior reversible encephalopathy syndrome are possible predictors of poor outcome.

Serial MR spectroscopy in relapsing reversible posterior leukoencephalopathy syndrome.

BACKGROUND: Reversible posterior leukoencephalopathy syndrome (RPLS) in atypical locations is difficult to diagnose. Magnetic resonance spectroscopy (MRS) can help, but results to date are discrepant. We aimed to describe MRS findings in each phase of RPLS and evaluate their diagnostic potential. METHODS: We performed MRS, diffusion-weighted imaging and conventional MR during 2 episodes in a patient with hypertensive encephalopathy. RESULTS: There were multifocal edematous lesions in both frontal lobes, the left temporo-occipital region and both cerebellar hemispheres in the first episode, and in both cerebellar hemispheres and the left pons in the second. Apparent diffusion coefficient values were high. Choline was normal in the acute phase and elevated in the subacute period. N-acetylaspartate was low throughout, even after clinical recovery and disappearance of the lesion on conventional MR. No lactate peak was detected. CONCLUSIONS: MRS helps differentiate RPLS from several encephalopathies and a N-acetylaspartate decrease does not predict a poor outcome.