First Time Seizures in Young Adults
Epidemiology: Many first seizures are unrecognized. The incidence of single seizures and recurrent epileptic seizures is estimated as 5-10% and the prevalence of epilepsy is 0.5-1% of the population. Epileptic seizures are responsible for 1% of hospital admissions and 3% of ED visits.
Recurrence and who may receive treatment after a first-time seizure:
- Low risk patients with first seizures that have no neurological deficits, normal MRI, and EEG have a 35% risk of recurrence at five years. They are not usually offered treatment.
- High risk patients with first seizures that have neurological deficits, MRI abnormalities, and/or EEG abnormalities have a 70% risk of recurrence at five years. They are typically offered treatment.
Per our neurology colleagues, the most common causes of a first time seizure in young adults are the following:
- Idiopathic (can account for up to 50% of cases)
- H/o trauma
- Head injury accounts for a relatively small proportion of first time seizures. The risk to an individual who suffers head trauma can vary widely from minimal risk in people with a concussive head injury in which LOC or amnesia is < 30 minutes to a 12-fold increased risk over 10 years in people who suffer trauma-induced amnesia > 30 minutes, had a subdural hematoma at time of initial trauma, o a brain contusion.
- H/o encephalitis
- Viral encephalitis
- Neurodevelopmental lesions* (e.g., cortical dysplasia in which there is a disruption in the proliferation of neuroblasts or abnormal migration of neurons to the developing cortex)
- Genetic epilepsy syndromes*
The * indicates diagnoses that are less common after the age of 20 years old.
Attached: A nice review article in BMJ from 2014 on first time seizures in adults from the epidemiology –> differential –> workup and management.