We describe a 35-year-old male patient presenting with depressed mood and emotional instability, who complained about severe anterograde and retrograde
memory deficits characterized by accelerated long-term forgetting and loss of autonoetic awareness regarding autobiographical memories of the last 3 years. Months before he had experienced two breakdowns of unknown etiology giving rise to the differential diagnosis of epileptic
seizures after various practitioners and clinics had suggested different etiologies such as a psychosomatic condition, burnout, depression, or
dissociative amnesia. Neuropsychological assessment indicated selectively impaired figural memory performance. Extended diagnostics confirmed accelerated forgetting of previously learned and retrievable verbal material. Structural imaging showed bilateral swelling and signal alterations of temporomesial structures (left >right). Video-EEG monitoring revealed a left temporal epileptic focus and subclincal seizure, but no overt
seizures. Antibody tests in serum and liquor were positive for
glutamic acid decarboxylase antibodies. These findings led to the diagnosis of
glutamic acid decarboxylase antibody related
limbic encephalitis. Monthly
steroid pulses over 6 months led to recovery of subjective memory and to intermediate improvement but subsequent worsening of objective memory performance. During the course of treatment, the patient reported de novo paroxysmal non-responsive states. Thus,
antiepileptic treatment was started and the patient finally became seizure free. At the last visit, vocational reintegration was successfully in progress. In conclusion, amygdala swelling, retrograde biographic memory impairment, accelerated long-term forgetting, and emotional instability may serve as indicators of
limbic encephalitis, even in the absence of overt epileptic
seizures. The monitoring of such patients calls for a standardized and concerted multilevel diagnostic approach with repeated assessments.