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Temporal Lobe Epilepsy with Isolated Amygdala Enlargement: Anatomo-electro-clinical Features and Long-term Outcome

Abstract number : 3.318
Submission category : 4. Clinical Epilepsy / 4B. Clinical Diagnosis
Year : 2024
Submission ID : 586
Source : www.aesnet.org
Presentation date : 12/9/2024 12:00:00 AM
Published date :

Authors :
Presenting Author: Giuseppe Didato, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta

Margarida Ferro, MD – Neurology Department, Hospital de S. José, Unidade Local de Saúde São José, Lisboa, Portugal
João Nuno Ramos, MD – Neuroradiology Department, Centro Hospitalar Lisboa Ocidental, Lisbon, Portugal
Elisa Visani, MSc – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Margherita Bevilacqua, MD – Postgraduate School in Radiodiagnostics, Università Degli Studi di Milano, 20122 Milan, Italy
Rita Garbelli, PhD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Valeria Cuccarini, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Gianluca Marucci, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Angelo Del Sole, MD – Department of Health Sciences, University of Milan, Milan, Italy
Michele Rizzi, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Flavio Villani, MD – Division of Neurophysiology and Epilepsy Centre, IRCCS San Martino Policlinic Hospital, Genoa, Italy
Francesco Deleo, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Andrea Stabile, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Annalisa Parente, MSc – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Chiara Pastori, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Rosalba Ferrario, MSc – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Roberta Di Giacomo, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Rui Quintas, MSc – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Marco de Curtis, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
Fabio Doniselli, MD – Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy

Rationale: Isolated amygdala enlargement (AE) has been described as a possible radiological biomarker in a significant number of temporal lobe epilepsy (TLE) cases, allowing the definition of a group of patients with TLE-AE1,2. The main described etiologies of TLE-AE are dysplasias or inflammatory/dysimmune changes2,3. We aim to describe the clinical features, outcomes, and pathological findings of patients with TLE-AE of different etiologies.

Methods: We conducted a retrospective cohort study identifying brain MRI scans with isolated AE between 2015 and 2021. Clinical and paraclinical data of patients with TLE-AE were collected.


Results: 41 subjects were included (20 males; AE: right 13; left 24; bilateral 4). Mean age at epilepsy onset 34,8±17.8 years (range 4-70). A strong correlation was found between AE and amygdala MRI T2-hyperintensity (right side, p< 0.001; left side, p=0.003). There was no history of febrile seizures; 85,4% had focal seizures with impaired awareness while 78,1% reported auras (epigastric sensation, déjà-vu and anxiety), 37% had psychiatric disturbances, and 48,6% cognitive impairment. There was a correlation between FDG-PET temporomesial hypometabolism and AE (right side: p=0.022; left side: p=0.053) and between AE and neurophysiological data (ambulatory-EEG [n=41] and long-term video-EEG monitoring [n=23]). Epilepsy surgery (n=17) revealed gliosis (n=4), inflammatory infiltrates (n=4) and low-grade glial tumours (n=5) in amygdala. There were also 5 cases of temporal neocortex FCD and two cases of hippocampal sclerosis type 1. Other treatments were immunotherapy (n=7) and only antiseizure medications (n=17). Regarding etiology of epilepsy, structural group had a significant younger age at epilepsy onset (p=0.05) and cognitive alterations were more prevalent in structural and inflammatory groups (p=0.037). General prognosis was good regardless of treatment choice with 58,1% being seizure free and 17,1% only with auras at last follow-up.

There was no correlation between seizure frequency variation and amygdala variation (n = 23) either in size or T2-hyperintensity.


Conclusions: AE should be searched in brain MRI, especially in patients with typical aura, psychiatric and/or neurocognitive disturbances. The strong correlations found between AE lateralization and neurophysiological, FDG-PET, and MRI data suggest involvement of AE in epileptogenic network. Drug resistance should prompt presurgical study. Inflammation in amygdala specimens and response after immunotherapy suggests an immune-mediated etiology in some TLE-AE cases.



References

1. Chakravarty K et al. Temporal lobe epilepsy with amygdala enlargement: A systematic review. Acta Neurol Scand. 2021;144(3):236–50

2. Makhalova J et al. Epileptogenic networks in drug-resistant epilepsy with amygdala enlargement: Assessment with stereo-EEG and 7 T MRI. Clinical Neurophysiology [Internet]. 2022;133:94–103

3. Malter MP et al. Suspected new-onset autoimmune temporal lobe epilepsy with amygdala enlargement. Epilepsia. 2016;57(9):1485–94


Funding: No funding


Clinical Epilepsy