Thyroid‐Stimulating Hormone (TSH) as a Blood Biomarker in the Acute Clinical Diagnosis of Adult Epilepsy

Epileptic seizures (ESs) are among the most common neurological disorders. Early diagnosis can be supported by laboratory parameters. However, no single biomarker is sufficient to confirm or exclude ES. This study investigates the role of thyroid‐stimulating hormone (TSH) in the acute diagnosis of bilateral tonic–clonic ES in adults. In this retrospective single‐center study, patients with bilateral tonic–clonic ES admitted between April 2024 and March 2025 were screened. Patients meeting predefined inclusion and exclusion criteria were analyzed. TSH levels were measured within the first hour after ES and on the following day as part of routine clinical care. Thirty‐four patients met the inclusion criteria (mean age: 68.4 ± 19.6 years). TSH levels were significantly elevated within the first hour after ES (mean: 6.39  μ U/mL) compared to the following day (mean: 2.37  μ U/mL), when values returned to the normal range ( p < 0.005; Cohen′s dz = 1.90). TSH levels show a transient postictal elevation in adult bilateral tonic–clonic ES. This finding suggests a potential role as an adjunctive biomarker in acute diagnostics. However, specificity remains uncertain and requires confirmation in prospective controlled studies.