March 17, 2022
A 67-year-old man with a history of postmalaria encephalitis 10 years prior develops acute behavioral changes and left-sided involuntary movements. Electroencephalogram fulfills criteria for epilepsia partialis continua.
T2-Weighted Hypointensity in Partial Status Epilepticus
- Background:
- Acute seizures are typically associated with diffusion restriction and T2 hyperintensity in the gray matter and/or subcortical white matter. Rarely, seizures can present with T2 hypointensities.
- The mechanism of this abnormal imaging signal remains unknown. Some of the proposed theories have attributed this signal change to accumulation of oxygen-free radicals or deoxyhemoglobin accumulation.
- Clinical Presentation:
- Documented generalized or focal seizure activity at the time of imaging
- Key Diagnostic Features:
- Hypointensity on T2/T2 FLAIR images present in the subcortical white matter, with sparing of the overlying cortex; in most cases there is corresponding low signal on gradient recalled-echo/SWI sequences.
- Most frequently the findings are unilateral and transient.
- EEG with epileptiform activity localized to the side of the MRI abnormality (and bilateral EEG changes in the case of bilateral MRI findings)
- Differential Diagnoses:
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Hyperglycemia-induced seizures present with similar imaging findings, and laboratory tests will confirm the diagnosis.
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Early cortical ischemia and infarction: Typically present a hypoperfusion pattern corresponding to a specific vascular territory
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Moyamoya disease: Findings include small, abnormal, netlike vessels with a “puff of smoke” appearance, microbleeds, and prominent deep medullary veins.
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Severe ischemic-anoxic insults: Lesions typically occur in watershed zones, basal ganglia, thalami, and cerebellum.
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Multiple sclerosis: Multiple periventricular lesions, usually with involvement of callososeptal interface
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Strokelike migraine attacks after radiation therapy (SMART) syndrome: Findings include transient unilateral hyperintense cortical signal on T2-weighted and FLAIR sequences with gyriform enhancement related to radiation therapy.
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Treatment:
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There is no specific treatment. Treatment of seizures and underlying associated conditions is required.
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