Abstracts

Rationale: MRI hyperintensity of the pulvinar nuclei is a known finding in patients with refractory seizures. To date, only one autopsy of a patient with new onset refractory status epilepticus with pulvinar lesions in diffusion MRI has been reported. Mechanisms for these imaging changes remains elusive.Methods: A 27 year old woman with a past history of two self-limited neonatal febrile seizures was admitted because of acute confusion and somnolence, preceded by 5 days of febrile flu-like illness. Day 2, she sustained 2 generalized tonic-clonic seizures followed by refractory Status Epilepticus(SE). EEG monitoring confirmed SE throughout with uncontrolled seizure activity, seen bilaterally and independently over both hemispheres, most frequent in the right fronto-temporal region. Seizures remained refractory to maximal anti-epileptic drug and anesthetic therapies. Despite extensive medical evaluation for an assumed encephalitic etiology, the cause for the refractory SE remained cryptogenic. Initial MRI Brain was normal. MRI on day 125 showed bilateral pulvinar T2/FLAIR hyperintensities, and selective right mesial temporal atrophy, although no significant mesial temporal hyperintensity. Following family-physician review meeting, medical care was withdrawn and the patient died on hospital day 162. An autopsy was pursued.Results: The autopsy revealed sharply defined, grey, soft, granular nodules present in the medial pulvinar nuclei. The nodular lesions in the 2 pulvinar nuclei consisted of sharply defined paucicellular areas with loss of neurons and myelin and with macrophages in their centers, surrounded by reactive astrocytes with spared axons. The right hippocampus had severe neuronal loss and reactive astrocytes, particularly in CA1, consistent with subacute damage. The spinal cord showed symmetric spongy vacuolation in the dorsal columns and lateral corticospinal tracts, with mild myelin loss, relatively preserved axons and macrophages.Conclusions: Prior pathology report of pulvinar lesions on MRI did not describe any macroscopic lesions and showed nonspecific response to neuronal cell loss. Our patient demonstrates demarcated pulvinar lesions, corresponding to imaging and visible to the naked eye. Microscopically they contained numerous macrophages with no remaining neurons and a peripheral reactive gliosis. These lesions were only found on repeat studies after 125 days of unrelenting status epileptcus supporting their acquisition over time. We hypothesize that the pulvinar lesions are due to an excessive metabolic demand, secondary to neuronal network over activation in the setting of SE. Metabolic demand in selective areas may also aggravate incipient nutritional or vitamin deficit. The pulvinar lesions found in this case are somewhat similar to the thalamic lesions described in Wernicke encephalopathy and those found in the spinal cord resembling B12 related subacute combined degeneration. Future consideration of additional nutritional support in Status Epilepticus may be appropriate. (References on request/Neuropath and Imaging studies to accompany)