What investigations are recommended for a patient with recurrent seizures to rule out underlying causes?

For a patient presenting with recurrent seizures, a comprehensive investigation strategy is recommended to identify underlying causes and guide management. Initial assessment should include a detailed clinical history, eyewitness accounts, and if possible, video recordings of seizure events to help distinguish epileptic seizures from non-epileptic events NICE CKS. Electroencephalography (EEG) is advised to support diagnosis and help classify seizure type or epilepsy syndrome; a routine awake EEG should ideally be performed within 72 hours of a seizure, with consideration of sleep-deprived or ambulatory EEG if initial results are inconclusive NICE CKS,NICE NG217. Neuroimaging with MRI is the standard investigation to detect structural abnormalities such as tumours, vascular malformations, or cortical dysplasia that may underlie seizures; MRI should follow epilepsy-specific protocols and be performed within 6 weeks of referral unless contraindicated, in which case CT may be considered NICE CKS,NICE NG217. Cardiac evaluation with a 12-lead ECG is recommended to exclude cardiac causes mimicking seizures NICE NG217. Metabolic screening should be considered, as metabolic disturbances including hypoglycaemia can provoke seizures NICE NG217. Genetic testing may be appropriate in cases of epilepsy of unknown cause, especially in young children or those with additional clinical features suggestive of genetic syndromes, and should be discussed with specialists NICE NG217. Antibody testing for autoimmune encephalitis is advised if new-onset epilepsy raises suspicion of an autoimmune cause NICE NG217. These investigations should be coordinated with specialist input to ensure accurate diagnosis and tailored management NICE CKS,NICE NG217.