case_images: PMC10884170_01
case_images: Inconspicuous head CT on admission to the emergency department in 2017 (A,B); brain MRI acquired on day 6 after admission (C,D) appears nearly normal (note pachymeningeal thickening and hyperintensity on the right attributed to a recent lumbar puncture); follow-up brain MRI scan performed 12 weeks after initial head CT (E-H): in the left hemisphere extensive juxtacortical and deep white matter high T2 signal lesions on FLAIR (E,F), overlying cortex is atrophic and exhibits higher T1 signal than contralateral normally-appearing grey matter (G,H). Note that lesions are continuous across different vascular territories.
case_images: fneur-15-1359994-g001.jpg
case_images: PMC10884170_01_fneur-15-1359994-g001.jpg
case_images: fig1
case_images: Upon admission, multimodal CT with angiography and perfusion were normal (Figures 1A,B, year 2017). MRI performed on day 6 after the admission was unremarkable (Figures 1C,D). T2/dark fluid signal areas in temporo-occipital, frontal, parietal sub-and juxtacortical white matter regions with overlying cortex thinning and elevated T1 signal compared to normal cortex (Figures 1E-H). The changes were not adhering to arterial vascular territories.
case_images: Longitudinal MRI studies during 2017-2023 period showing progression of brain atrophy. (A,B) - year 2017, (C,D) - year 2018, (E,F) - year 2021, (G,H) - year 2023. During the follow-up years 2017-2021, atrophy was mostly pronounced in the left temporooccipital region (asterisks), but after the 2022 HM episode, significant atrophy of the right hemisphere also ensued.
case_images: fneur-15-1359994-g002.jpg
case_images: PMC10884170_01_fneur-15-1359994-g002.jpg
case_images: fig2
case_images: During a 4-year MRI follow-up (2017-2021) the progression of brain atrophy continued without any new focal lesions (Figures 2A-F). The latest follow-up MRI images are shown in Figures 2G,H.
case_images: Inconspicuous head CT on admission in 2022 (A); brain MRI with intravenous gadolinium-based contrast agent on day 6 after admission showing subtle cortical enhancement in right insular, frontal, temporal regions (B); follow-up head CT 8 weeks after the initial scan display hypodense white matter lesions in the right hemisphere (C).
case_images: fneur-15-1359994-g003.jpg
case_images: PMC10884170_01_fneur-15-1359994-g003.jpg
case_images: fig3
case_images: The patient did not visit a neurologist for another 3 years, until two consecutive episodes of HM with left arm and leg paresis, fever, and severe cognitive deterioration (MMSE score of 10) occurred in 1 week following a valproic acid dose reduction by the patient (Figures 3A-C, year 2022).