Tonic-Clonic Activity at Subarachnoid Hemorrhage Onset: Impact on Complications and Outcome

Objective: Tonic-clonic activity (TCA) at onset complicates 3% to 21% of cases of subarachnoid hemorrhage (SAH). The impact of onset TCA on in-hospital complications, including seizures, remains unclear. One study associated onset TCA with poor clinical outcome at 6 weeks after SAH, but to our knowledge no other studies have confirmed this relationship. This study aims to assess the impact of onset TCA on in-hospital complications, poor functional outcome, mortality, and epilepsy at 3 months. Methods: Analysis of a prospective study cohort of 1479 SAH patients admitted to Columbia University Medical Center between 1996 and 2012. TCA within 6 hours of hemorrhage onset was identified based on accounts of emergency care providers or family witnesses. Results: TCA at onset was described in 170 patients (11%). Patients with onset TCA were younger (P = 0.002), presented more often with poor clinical grade (55% vs. 26%, P<0.001) and had larger amounts of cisternal, intraventricular, and intracerebral blood than those without onset TCA (all, P<0.001). After adjusting for known confounders, onset TCA was significantly associated with in-hospital seizures (OR 3.80, 95%-CI: 2.43-5.96, P<0.001), in-hospital pneumonia (OR 1.56, 95%-CI: 1.06-2.31, p = 0.02), and delayed cerebral ischemia (OR 1.77, 95%-CI: 1.21-2.58, P = 0.003). At 3 months, however, onset TCA was not associated with poor functional outcome, mortality, and epilepsy after adjusting for age, admission clinical grade, and cisternal blood volume. Conclusions: Onset TCA is not a rare event as it complicates 11% of cases of SAH. New and clinically relevant findings are the association of onset TCA with in-hospital seizures, pneumonia and delayed cerebral ischemia. Despite the increased risk of in-hospital complications, onset TCA is not associated with disability, mortality, and epilepsy at 3 months.