Acute and Evolving MRI of High-Altitude Cerebral Edema: Microbleeds, Edema, and Pathophysiology

Hackett, Peter H.; Yarnell, Philip R.; Weiland, David; Reynard, Kenneth

doi:10.3174/ajnr.a5897

Cited by 46 publications

(66 citation statements)

References 16 publications

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“…However, the corpus callosum appears to be particularly prone to hypoxia (Yamauchi et al, 1995). Both, vasogenic and cytotoxic edema have been implicated in severe high-altitude cerebral edema (Hackett et al, 1998(Hackett et al, , 2019. Our results are in line with others who also observed significant diffusion restrictions in the splenium of subjects suffering acute mountain sickness (Kallenberg et al, 2007).…”

supporting

confidence: 90%

“…Our result of prolonged brain swelling after 9 days at high altitude and after acute mountain sickness symptoms had completely abated are supported by two recent publications. In the first study, white matter vasogenic edema continued to increase in the first week in patients suffering high-altitude cerebral edema even though patients were clinically improving (Hackett et al, 2019). The second study, a hypobaric chamber study, investigated a challenging 24--minute single hypobaric exposure at 25,000 feet, including 2-4 minutes with oxygen desaturation to 65%-75%.…”

Section: Discussionmentioning

confidence: 99%

“…Gradual reoxygenation and recompression during transfer to the R + 12h measurements might have influenced brain physiology through increased oxygen stress and the formation of reactive oxygen species (Hoffmann et al, 2016). A recent report (Hackett et al, 2019) points into the same direction and raises the possibility of reoxygenation playing a role, since vasogenic and cytotoxic edema in some patients with high-altitude cerebral edema became worse over the first week. Other unknown effects during the descent may have also confounded our data.…”

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confidence: 99%

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An Observational Cerebral Magnetic Resonance Imaging Study Following 7 Days at 4554 m

Kühn

Gerlach

Noblé

et al. 2019

High Altitude Medicine & Biology

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Background: In human beings exposed to high altitude, cerebral magnetic resonance imaging (cMRI) revealed alterations ranging from subclinical cerebral edema formation to subtle brain abnormalities. Yet, brain structure after adaptation to high altitude and their recovery after return to lowlands have been rarely investigated. We, therefore, examined 10 healthy individuals by cMRI before, 12 hours after descent (R + 12h), and again 3.5 months (R + 3.5m) after a 7-day high altitude exposure at 4554 m. Results: After their 3-day lasting, stepwise ascent to 4554 m, all subjects suffered acute mountain sickness with a mean Lake Louise score of 5.8-1.7 after the first night at that altitude. Acute mountain sickness completely resolved after 4 days at 4554 m. While 12 hours after descent mean white and gray matter volumes were increased compared with before altitude exposure (p = 0.045 and p = 0.002), these volumes were normalized on R + 3.5m. Moreover, we observed significant focal volume alterations likely attributed to either vasogenic or cytotoxic edema formation. Two subjects presented new brain findings after altitude exposure. In one individual the number of preexisting white matter hyperintensities (WMHI) transiently increased, in the other individual a reversible splenial lesion syndrome (RESLES) emerged. Both findings had resolved 15 and 8 days after descent, respectively. None developed structural lesions like brain atrophy, cerebral infarcts, microbleeds, or highaltitude cerebral edema. Discussion: Three days after complete recovery from acute mountain sickness and after return to low altitude, subclinical vasogenic and cytotoxic edema, RESLES and WMHI are present in high-altitude acclimatized individuals. However, these cerebral alterations are reversible within months at lowland.

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supporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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An Observational Cerebral Magnetic Resonance Imaging Study Following 7 Days at 4554 m

Kühn

Gerlach

Noblé

et al. 2019

High Altitude Medicine & Biology

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“…Interestingly, the corpus callosum is also a predilection site for Susac's syndrome, characterized by autoimmune-mediated occlusions of precapillary arterioles due to endothelial autoantigens ( 22 ). The distribution of SWI abnormalities is also reminiscent of previous reports in thrombotic thrombocytopenic purpura ( 23 ), critical illness ( 24 ), H1N1-influenza with extracorporeal membrane oxygenation (ECMO)-treatment ( 25 ), high-altitude sickness ( 26 ), cerebral malaria ( 27 ), and hepatic encephalopathy ( 28 ). In our sample, only 1/10 ECMO-treated patients underwent brain MRI; that person had SWI abnormalities but with a low microbleed anatomical rating scale (MARS) score of 2.…”

Section: Discussionsupporting

confidence: 62%

Nervous System Involvement in Coronavirus Disease 2019: Results from a Retrospective Consecutive Neuroimaging Cohort

Klironomos¹,

Tzortzakakis²,

Kits³

et al. 2020

Radiology

107

151

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“…Similar imaging ndings are reported in severe acute respiratory distress syndromes [14], including high altitude cerebral edema (HACE). [15] Interestingly, in these published cases, microbleeds in the corpus callosum are associated with a restriction on diffusion-weighted sequences, as for cytotoxic edema.…”

Section: Discussionmentioning

confidence: 92%

Central Nervous System thrombotic microangiopathy in COVID-19 patients: an intriguing hypothesis?

Agostinis

Napolitano

Cava

et al. 2020

Preprint

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Objectives: Neurological manifestations of COVID-19 disease are being increasingly recognized. A growing number of studies has been showing CNS abnormalities on brain imaging.Purpose is to describe brain imaging findings of a population of COVID-19 patients with neurological manifestations and peculiar abnormalities on susceptibility weighted imaging (SWI) sequences.Methods: we retrospectively evaluated imaging data from 50 patients affected by SARS-CoV-2 infection, who underwent a brain MRI because of neurological symptoms between March and June 2020.We focused on those presenting with abnormalities on brain MRI on SWI (positive MRI, P-MRI). We also carried out comparative investigations using patients without SWI abnormalities (negative MRI, N-MRI) as a control group. Non-parametric tests were used. A p-value < 0.05 was considered significant.Results: From 50 patients presenting with neurological symptoms, 10 patients showed brain abnormalities on SWI (P-MRI). Mean age in P-MRI group was 63±12 years; 7 were men. Six patients were admitted to Intensive Care Units (ICUs) and needed invasive ventilation support. P-MRI subjects showed lymphopenia and significantly higher levels of inflammatory markers such as CRP, IL-6, and fibrinogen. No significant differences were found in the coagulation profile. MRI showed diffuse SWI hypointense lesions mostly in occipital and temporal lobes, predominantly located at the grey-white matter junction. Genu and splenium of corpus callosum were involved in 8 of 10 patients. No restricted diffusion or enhancement was associated to SWI lesions.Conclusions: SWI abnormalities in patients with COVID-19 with neurological symptoms may reflect microvascular endothelial damage in the setting of a pro-inflammatory state.

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Acute and Evolving MRI of High-Altitude Cerebral Edema: Microbleeds, Edema, and Pathophysiology

Cited by 46 publications

References 16 publications

An Observational Cerebral Magnetic Resonance Imaging Study Following 7 Days at 4554 m

An Observational Cerebral Magnetic Resonance Imaging Study Following 7 Days at 4554 m

Nervous System Involvement in Coronavirus Disease 2019: Results from a Retrospective Consecutive Neuroimaging Cohort

Central Nervous System thrombotic microangiopathy in COVID-19 patients: an intriguing hypothesis?

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