Neuropsychiatric Derangement by Polycythemia Vera: A Case Report of an Unexpected Disease Presentation and Review of the Literature.

Cerebral infarction as well as other thromboses, headaches, and visual complaints are well-known symptoms of polycythemia vera. However, chorea and neuropsychiatric disturbances are less recognized consequences of this chronic disease. Whereas chorea is a rare but acknowledged symptom of polycythemia vera, neuropsychiatric symptoms have only sporadically been reported. We depict 2 patients with an unusual presentation of polycythemia vera. Our first patient presented with right-sided hemiballism and psychosis, and the second patient had a long diagnostic trajectory of unexplained chorea. In both cases diagnosis of JAK2 positive polycythemia vera was established, and in both cases remarkable recovery occurred after the initiation of phlebotomies. The underlying pathophysiology of these symptoms has not been clearly elucidated. Because of the unfamiliarity of the link between especially neuropsychiatric symptoms and polycythemia, current reported numbers are probably an underestimation. Benefit of treatment appears to be large. We seek to create more awareness among physicians about this phenomenon.

Structural network changes in cerebral small vessel disease.

OBJECTIVES: To investigate whether longitudinal structural network efficiency is associated with cognitive decline and whether baseline network efficiency predicts mortality in cerebral small vessel disease (SVD). METHODS: A prospective, single-centre cohort consisting of 277 non-demented individuals with SVD was conducted. In 2011 and 2015, all participants were scanned with MRI and underwent neuropsychological assessment. We computed network properties using graph theory from probabilistic tractography and calculated changes in psychomotor speed and overall cognitive index. Multiple linear regressions were performed, while adjusting for potential confounders. We divided the group into mild-to-moderate white matter hyperintensities (WMH) and severe WMH group based on median split on WMH volume. RESULTS: The decline in global efficiency was significantly associated with a decline in psychomotor speed in the group with severe WMH (ß=0.18, p=0.03) and a trend with change in cognitive index (ß=0.14, p=0.068), which diminished after adjusting for imaging markers for SVD. Baseline global efficiency was associated with all-cause mortality (HR per decrease of 1 SD 0.43, 95% CI 0.23 to 0.80, p=0.008, C-statistic 0.76). CONCLUSION: Disruption of the network efficiency, a metric assessing the efficiency of network information transfer, plays an important role in explaining cognitive decline in SVD, which was however not independent of imaging markers of SVD. Furthermore, baseline network efficiency predicts risk of mortality in SVD that may reflect the global health status of the brain in SVD. This emphasises the importance of structural network analysis in the context of SVD research and the use of network measures as surrogate markers in research setting.