Authors :
Presenting Author: Matthew Moench, MD – University of Florida College of Medicine- Jacksonville
Joshua Perdue, DO – University of Florida College of Medicine- Jacksonville
Suparna Krishnaiengar, MD – University of Florida College of Medicine- Jacksonville
Rationale:
Lennox Gastaut syndrome (LGS) is a severe epileptic encephalopathy with onset typically in childhood before 8 years of age with the peak incidence from 3 to 5 years. Late-onset LGS, described as onset after 10 years of age, is a rare entity making up only 10-15% of all LGS cases. In a recent report, only 42 cases of late-onset LGS have been described. Among these cases, only 3 had their first seizure after 18 years of age. Methods:
We report a case of late-onset LGS presenting at 20 years of age with bilateral tonic clonic seizures (BTCS). Evolution of the disease process and possible association with retinitis pigmentosa are discussed. Results:
Our patient with encephalitis at 2 years of age and mild developmental delay presented to the neurology clinic at 20 years of age for new onset BTCS for which she was on low dose Lamotrigine 50 mg twice daily. MRI of the brain without contrast was unremarkable. The dose of lamotrigine was gradually increased due to breakthrough seizures over the next 2 years.
Difficulty with vision and tendency to bump into things in dim light prompted an ophthalmologic evaluation which revealed significant pigmentation of the retina which was initially presumed to be secondary to lamotrigine necessitating a transition to levetiracetam. At 22 years of age, she was admitted to the hospital for increasing seizure frequency. Continuous electroencephalogram (EEG) in the Epilepsy Monitoring Unit (EMU) showed generalized slow spike and wave discharges and background slowing suggestive of LGS. She had developed multiple seizure types including brief staring episodes, drop attacks, tonic seizures, and BTCS. At that time, she was having daily seizures. After a month, she was readmitted for breakthrough seizures which progressed to status epilepticus and her epilepsy became intractable, necessitating her to be on multiple antiseizure medications including phenytoin, clobazam, rufinamide, valproic acid, levetiracetam, and topiramate. Continuous EEG demonstrated generalized paroxysmal fast activity (GPFA) associated with head drop attacks which further confirmed the diagnosis of LGS.
Ophthalmologic findings included vitreous cells, 360-degree bone-spicule pigments in the peripheral retina, and epiretinal membranes with vessel attenuation supporting the diagnosis of retinitis pigmentosa (RP). Given the favorable response of seizures to lamotrigine and the diagnosis of RP, levetiracetam was replaced by lamotrigine in anticipation of improved seizure control. Though the convulsive seizure improved with subsequent addition of cannabidiol, she continued to have daily seizures of other types.
Conclusions:
This is an unusual case of late onset LGS that manifested in adulthood and rapidly became medically intractable. It was associated with simultaneous development of ophthalmologic findings suggestive of retinitis pigmentosa. Adult onset LGS has only been described in 3 cases in the literature. In addition, to our knowledge, adult onset LGS in association with RP has not been previously described. Funding: None