Decrease of thyroid function after ischemic stroke is related to stroke severity

Abstract

Background Thyroid hormones are of fundamental importance for brain function. While low triiodothyronine levels during acute ischemic stroke (AIS) are associated with worse clinical outcomes, dynamics of thyroid function after AIS remains unknown. Thus, we longitudinally evaluated thyroid hormones after stroke and related them to stroke severity. Methods We prospectively traced thyroid stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxin (fT4) levels from the hyper-acute (within 24 h) to acute (3–5 days) and chronic (3–6 months) stages of ischemic stroke using a mixed regression model. Then, we analyzed whether stroke severity at presentation, expressed by National Institute of Health Stroke Scale (NIHSS), is associated with change in thyroid function. Results Forty-five patients were evaluated in hyper-acute and acute stages, while 29 were followed through chronic stage. TSH levels decreased from hyper-acute (2.91 ± 0.65 μIU/mL) to acute (2.86 ± 0.46 μIU/mL) and chronic stages of stroke (1.93 ± 0.35 μIU/m, p = 0.95). fT3 levels decreased from hyper-acute (2.79 ± 0.09 pg/ml) to acute (2.37 ± 0.07 pg/ml) stages, but recovered in chronic stage (2.78 ± 0.10 pg/ml, p < 0.01). fT4 levels decreased from hyper-acute (1.64 ± 0.14 ng/dl) to acute (1.13 ± 0.03 ng/dl) stages, and increased in the chronic stage (1.16 ± 0.08 ng/dl, p = 0.02). One-unit increase in presenting NIHSS was associated with 0.04-unit decrease of fT3 from hyper-acute to the acute stage (p < 0.01). Conclusion There is a transient decrease of thyroid hormones after ischemic stroke, possibly driven by stroke severity. Larger studies are needed to validate these findings. Correction of thyroid function in acute stroke may be investigated to improve stroke outcomes.

Association between thyroid hormone levels in the acute stage of stroke and risk of poststroke depression: A meta‐analysis

“…Low T3 syndrome is characterized by low free T3 (FT3) level together with normal‐to‐low free T4 (FT4) and TSH levels (Gao et al., 2018 ), and it is reported that low T3 syndrome affects 32%–62% of patients undergoing acute cerebrovascular diseases (Bunevicius et al., 2015 ). Moreover, a recent study investigated dynamics of thyroid function after acute ischemic stroke, and they found that thyroid hormones, particularly FT3, declined shortly after the beginning of stroke, bottomed during the first days, and then recovered in the chronic stage (Sidorov et al., 2023 ). Additionally, thyroid abnormalities are indicated to be related to the occurrence and development of depression (Berent et al., 2014 ; Duntas & Maillis, 2013 ).…”