Brain Changes in Preeclampsia and Eclampsia: Hypoperfusion, Infarcts, and Edema Identified in Latest Research

Eclampsia, a severe complication of pregnancy, is linked to cerebral edema and infarctions, though its underlying pathophysiology remains poorly understood. To fill this knowledge gap, Lina Bergman, Department of Obstetrics and Gynecology, Stellenbosch University, Cape Town, South Africa, and colleagues conducted a study using specialized magnetic resonance imaging techniques to assess diffusion, perfusion, and vasospasm, aiming to gain deeper insights into the mechanisms driving eclampsia.

For this purpose, the researchers conducted a cross-sectional study that recruited consecutive pregnant women between April 2018 and November 2021 at Tygerberg Hospital in Cape Town, South Africa. Participants included women with eclampsia, preeclampsia, and normotensive pregnancies who underwent magnetic resonance imaging after childbirth.

The primary outcome measures were the presence of cerebral infarcts, edema, and perfusion assessed through intravoxel incoherent motion imaging, and vasospasm evaluated using magnetic resonance imaging angiography. The imaging protocol was defined before participant inclusion.

Based on the study, the researchers reported the following findings:

• The study included 49 women with eclampsia, 20 with preeclampsia, and 10 normotensive women.
• Cerebral infarcts were found in 34% of women with eclampsia and 5% of women with preeclampsia, with no cerebral infarcts observed in normotensive controls.
• Women with eclampsia were significantly more likely to have vasogenic cerebral edema compared to women with preeclampsia (80% versus 20%) and normotensive women (risk differences of 0.60 and 0.80, respectively).
• Diffusion was increased in women with eclampsia in the parieto-occipital white matter (mean difference, 0.02 × 10−3 mm²/s) and the caudate nucleus (mean difference, 0.02 × 10−3 mm²/s) compared with women with preeclampsia.
• Diffusion was also increased in women with eclampsia in the frontal white matter (mean difference, 0.07 × 10−3 mm²/s), parieto-occipital white matter (mean difference, 0.05 × 10−3 mm²/s), and caudate nucleus (mean difference, 0.04 × 10−3 mm²/s) compared with normotensive women.
• Perfusion was reduced in edematous regions, with hypoperfusion observed in the caudate nucleus of women with eclampsia (mean difference, -0.17 × 10−3 mm²/s) compared to preeclampsia. There was no hyperperfusion.
• Vasospasm was identified in 18% of women with eclampsia and 6% of women with preeclampsia, while no vasospasm was observed in normotensive controls.

The authors concluded that cerebral infarcts were observed in one-third of women with eclampsia, regardless of the disease's severity. Both preeclampsia and eclampsia were associated with preclinical cerebral edema, as indicated by increased diffusion, which may explain the presence of neurological signs and symptoms even when conventional MRI shows no evident cerebral edema.

"The findings suggest that hyperperfusion and forced capillary dilation are unlikely to be the underlying causes of cerebral edema in eclampsia. Instead, vasospasm leading to decreased capillary blood flow (hypoperfusion) is more likely to contribute to the development of cerebral edema and subsequent neuroinflammation in both preeclampsia and eclampsia. Furthermore, our study emphasizes that conventional MRI does not completely rule out underlying pathology in these conditions," they wrote.

Reference:

Bergman, L., Hannsberger, D., Schell, S., Imberg, H., Langenegger, E., Moodley, A., Pitcher, R., Griffith-Richards, S., Herrock, O., Hastie, R., Walker, S. P., Tong, S., Wikström, J., & Cluver, C. (2024). Cerebral infarcts, edema, hypoperfusion, and vasospasm in preeclampsia and eclampsia. American Journal of Obstetrics and Gynecology. https://doi.org/10.1016/j.ajog.2024.10.034