Transient neurological deficit in patients with chronic subdural hematoma: a retrospective cohort analysis

Rationale: Symptoms of chronic subdural hematoma (CSDH) vary widely, including transient neurological deficit(s) (TND). The precise prevalence and the clinical aspects of TND are yet to be determined. Most TNDs are regarded and treated as symptomatic seizures, but the rationale for this decision is not always clear. Methods: Patients with temporary symptoms were selected from a retrospective cohort of CSDH patients. We analyzed the association of TND characteristics with patients being classified as having a symptomatic seizure and with functional outcome using logistic regression analysis. Results: Of the included 1307 CSDH patients, 113 (8.6%) had at least one episode of TND. Most common TNDs were aphasia/dysphasia, impaired awareness or clonic movements. Of these 113 patients, 50 (44%) were diagnosed with symptomatic seizure(s) by their treating physician. Impaired awareness, clonic movements and the presence of ‘positive symptoms’ showed the strongest association with the diagnosis symptomatic seizure (OR 36, 95% CI 7.8–163; OR 24, 95% CI 6.4–85; and OR 3.1, 95% CI 1.3–7.2). Aphasia/dysphasia lowered the chance of TND being classified as symptomatic seizure together with a longer TND duration (OR 0.2, 95% CI 0.1–0.6; and OR 0.91, 95% CI 0.84–0.99). Treatment with anti-epileptic drugs was related to unfavorable functional outcome (aOR 5.4, 95% CI 1.4–20.7). Conclusion: TND was not a rare phenomenon in our cohort of CSDH patients. A TND episode of 5 min, aphasia/dysphasia and/or absence of ‘positive’ symptoms are suggestive of a different TND pathophysiology than symptomatic seizures. Our results further suggest that treatment of TND in CSDH deserves careful consideration as management choices might influence patient outcome.