Seizure Bilateral tonic-clonic seizure Seizures, tonic-clonic HP:0001306 Bilateral convulsive seizures Grand mal A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase. HP:0002069 Tonic-clonic convulsions Generalised convulsion HP:0002407 Grand mal seizures Generalised tonic-clonic seizure (without specification of onset) Tonic-clonic convulsion Generalized tonic-clonic seizure (without specification of onset) Generalized convulsion SNOMEDCT_US:54200006 HP:0007252 A tonic-clonic seizure may be generalized from onset or progress from a focal seizure to a bilateral tonic clonic seizure. This term describes the observed semiology of the seizure without specifying whether the onset is focal or generalized. Thus it can be used for coding bilateral tonic-clonic seizures when the onset is not known. This form of seizure was formerly commonly called grand mal seizure. UMLS:C0494475