Pathophysiology and long-term outcome of reversible tumor-like lesions induced by presenting status epilepticus.
OBJECTIVE
Within the spectrum of reversible neuroimaging abnormalities induced by status epilepticus (SE) tumor-like lesions (TLL) have been rarely described. Their etiology, pathophysiology, and long-term outcome remain uncertain. These issues could be clarified by long-term magnetic resonance imaging (MRI) studies in TLL induced by presenting SE.


METHODS
Prospective multi-sequence MRI and clinical and electroencephalographic long-term (18 to 60 months) follow-up studies were performed in 3 patients with reversible TLL induced by presenting SE.


RESULTS
In the peri-ictal MRI, TLL are hypointense in T1-weighted, hyperintense in T2-weighted, and fluid-attenuated inversion recovery images with a marked subcortical component and sulci effacement. The diffusion and MR-spectroscopy studies disclosed intermixed areas of increased/decreased diffusivity associated with a lactate peak and a decreased N-acetylaspartate. At long-term follow-up, none of the patients had seizure recurrence or electroencephalographic epileptiform abnormalities; MRI showed residual focal atrophy and gliosis associated with neuronal loss/dysfunction.


CONCLUSIONS
SE per se may induce TLL. MRI multi-sequence studies disclosed that they are mainly formed by focal vasogenic and cytotoxic edema resulting from the hypermetabolism associated with seizure activity. In spite of a clinical favorable long-term outcome, the demonstration of irreversible brain damage argues in favor of immediate treatment of SE.
Canas
Nuno
N
Department of Neurology, Hospital de Egas Moniz, 1349-019 Lisbon, Portugal. nunocanas@netcabo.pt
Soares
Pedro
P
Calado
Sofia
S
Pestana
Ricardo
R
Ribeiro
Constança
C
Vale
José
J
D000368:Aged; D001932:Brain Neoplasms / Q000150:complications* / Q000175:diagnosis*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D013226:Status Epilepticus / Q000150:complications* / Q000175:diagnosis*; D055815:Young Adult