Bilateral tonic-clonic seizure Bilateral tonic-clonic seizure with focal onset Generalised tonic-clonic seizures with focal onset Secondary generalised tonic clonic seizures Partial seizures with secondary generalisation Secondary generalised tonic-clonic seizures Secondarily generalised tonic-clonic seizures Focal seizure with secondary generalization Generalized tonic-clonic seizure with focal onset Generalised tonic-clonic seizure with focal onset Secondary generalized tonic-clonic seizures Generalised tonic-clonic seizure with partial onset Secondarily generalized tonic-clonic seizures A bilateral tonic-clonic seizure with focal onset is a focal-onset seizure which progresses into a bilateral tonic-clonic phase. HP:0007334 Secondarily generalised tonic-clonic seizure UMLS:C0877017 Generalized tonic-clonic seizure with partial onset Partial seizures with secondary generalization Partial seizure with secondary generalization HP:0002602 The ILAE 2017 classification refers to this seizure type as a focal to bilateral tonic-clonic seizure. Previously it has been known as a secondarily generalized tonic-clonic seizure. The focal features of the seizure may be clinically manifest or alternatively, the spread in brain networks may be so rapid that no preceding focal symptom or sign is identified with demonstration of the focal onset resting on investigations. Note that not all instances of a Bilateral tonic-clonic seizure with focal onset will be a Focal motor seizure, some will be a Focal non-motor seizure, thus one can only say that there is a Focal-onset. Secondarily generalized tonic-clonic seizure Partial seizure with secondary generalisation Focal seizure with secondary generalisation Focal to bilateral tonic-clonic seizure Generalized tonic-clonic seizures with focal onset Secondary generalized tonic clonic seizures Focal-onset seizure