Clinical implications of free triiodothyronine levels and diagnostic revisions in antibody-negative autoimmune encephalitis.
A subset of patients initially diagnosed with antibody-negative autoimmune encephalitis received alternative diagnoses.
Clinical implications of free triiodothyronine levels and diagnostic revisions in antibody-negative autoimmune encephalitis.
Low triiodothyronine (T3) syndrome has been associated with initial clinical severity and poor long-term functional outcomes in autoimmune encephalitis (AE).
The objective of this study was to explore the clinical significance of low T3 syndrome in patients with antibody-negative AE, and to assess the clinical characteristics of patients reclassified with alternative diagnoses during follow-up.
Were divided into two groups based on the presence or absence of low T3 syndrome.
patients initially diagnosed with autoimmune brain inflammation were later reclassified
Of these, 23.68% presented with low T3 syndrome during the acute phase.
Subgroup analysis further showed that patients with low T3 syndrome had a higher incidence of consciousness disturbances (p = 0.048), more frequent motor impairments, and higher scores on the modified Rankin Scale (mRS) throughout hospitalization.
Overall, 61.84% (47/76) of patients achieved a favorable prognosis, whereas 38.16% (29/76) had an unfavorable outcome.
Discharge mRS was an independent predictor of unfavorable outcome (OR 0.293, 95% CI 0.103-0.834, p = 0.021).
Acute-phase low T3 syndrome is common in antibody-negative AE but appears to reflect disease severity rather than serving as an independent prognostic biomarker; discharge mRS is a more reliable predictor.
Larger prospective studies are needed to clarify the prognostic role of thyroid hormone alterations in this population.