Mind the guideline gap: emergent CT in patients with epilepsy for trauma rule-out-A retrospective cohort study.

Abstract

Background: Patients with epileptic seizures represent a significant proportion of emergency department (ED) admissions and are often referred for cranial imaging due to suspected or observed trauma. Neurological guidelines provide limited advice on indications for imaging in this scenario, and traumatological clinical decision rules on the use of CT in mild traumatic brain injury explicitly exclude patients with seizures preceding the trauma. This gap in recommendations may contribute to overimaging for trauma rule-out after a seizure.

Methods: We analysed medical records of patients with known epilepsy admitted to our ED after a seizure between January 2022 and March 2024. Using clinical data including the findings from cranial CT and risk factors for traumatic brain injury, we re-assessed the need for CT imaging by application of the Canadian CT head rule (CCHR) or in the context of head trauma under anticoagulation.

Results: During the observational period, 683 patients with known epilepsy were referred to our hospital due to a seizure (mean age 48.8 years, 57.7% male). A head CT scan was obtained in 337 (49.3%) of all encounters. In only two patients, CT diagnosed an acute seizure-related traumatic lesion, one focal subarachnoid haemorrhage and one skull base fracture. Twenty-six cases (3.8%) with seizure-related trauma were reassessed as requiring a CT for trauma-related injury evaluation. Particularly in the absence of head impact or risk factors, a high degree of variability regarding CT ordering practice was observed.

Conclusions: Our results demonstrate frequent use and low diagnostic yield of CT in ED seizure patients with respect to trauma-related head injury. Circumstantial factors, clinical signs or symptoms and medical risk factors variedly impact on clinicians' decision to perform imaging. The absence of clear recommendations regarding imaging for trauma apparently provokes frequent diagnostic rule-out even in patients with low risk for traumatic brain injury. We suggest an approach to identify patients not requiring a head CT by considering the CCHR, presence of anticoagulation and appreciating the postictal state as a feature specific to patients with seizures.