Abstracts

Rationale: Generalized paroxysmal fast activity on EEG is typically associated with tonic seizures in the setting of Lennox-Gastaut Syndrome. However, adults can present with this pattern and have a different clinical course and response to therapy. Methods: Four adults with abnormal movements had EEGs, clinical evaluations, and were treated with AEDs. Results: Case 1. A seventy-six year old man with hypertension, diabetes, and a history of generalized tonic-clonic seizures developed jerking in the setting of non-adherence to anticonvulsant therapy. EEG showed bursts of generalized paroxysmal fast activity lasting 1 to 3 seconds, associated with tonic posturing of the trunk and head without alteration of consciousness. MRI showed periventricular white matter changes. Levetiracetam controlled the tonic seizures. Case 2. A sixty year old man with hypertension, diabetes, and supraventricular tachycardia with implantable defibrillator presented with bizarre behavior, hallucinations, and jerking movements of the arms. He had no prior history of seizures. EEG showed bursts of generalized paroxysmal fast activity lasting 1 to 3 seconds, associated with tonic extension of the upper extremities and speech arrest (Fig 1). Head CT was unremarkable. Valproic acid significantly decreased the frequency of tonic seizures. Case 3. A sixty-four year old woman with liver cirrhosis, mechanical mitral valve, coronary artery bypass graft, anemia, hyponatremia, and diabetic neuropathy on gabapentin, presented with a three year history of whole body jerking and stiffening. She had no prior history of seizures. EEG showed bursts of generalized paroxysmal fast activity lasting 1 to 3 seconds, associated stiffening of head and arms, followed by shivering of the arms, without an alteration of consciousness. MRI showed periventricular white matter changes. Levetiracetam controlled the tonic seizures, but she developed behavioral changes and was transitioned to lacosamide which also controlled the tonic seizures. Case 4. A fifty-six year old man with diabetes and chronic kidney disease who had been treated for osteomyelitis developed jerking movements of his trunk and shoulders. He had no prior history of seizures. EEG showed bursts of generalized paroxysmal fact activity lasting 0.5 to 3 seconds, associated with tonic stiffening of trunk and facial muscles without an alteration of consciousness. MRI showed periventricular white matter changes. Clonazepam controlled the tonic seizures. Conclusions: We describe four cases of adults who presented with abnormal movements and were found to have tonic seizures that responded to AED therapy. Only one of the patients had a history of epilepsy, and all had complex medical histories and polypharmacy. Recognition of tonic seizures and differentiation from non-epileptic movements can play an important role in reducing morbidity in these patients.