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Bilateral claustrum hyperintensity on T2 weighted MRI (‘claustrum sign’) has been described in case reports in both autoimmune encephalitis and refractory status epilepticus.We report a case of new onset refractory status epilepticus (NORSE) in a 27-year-old woman of unclear etiology. She had a history of positive Beta 2 Glycoprotein antibodies with negative lupus anticoagulant and cardiolipin antibodies, without history of thrombosis. She presented with focal onset status epilepticus with altered awareness, and intermittent hyperkinetic motor seizures with left head version and eye deviation. There was no history of recent infection or prodrome.Electroencephalogram showed continuous right hemispheric lateralizing periodic discharges with spike and wave morphology consistent with right focal seizures. She had no muco-cutaneous or systemic symptoms. She was given levetiracetam, valproate, clobazam and lacosamide. Repeat MRI two days after seizure cessation showed symmetric restricted diffusion and T2/FLAIR hyperintensity of the claustra. CSF protein was 0.35, glucose of 3.9 with 3 monocytes and 13 red blood cells. While awaiting autoantibody results, she was commenced on five days of intravenous immunoglobulin and pulsed methylprednisolone. She remained seizure free. Antibodies to cell surface and intracellular neuronal antigens were negative. Repeat MRI brain after six months showed resolution of the claustrum sign. Steroid was subsequently weaned and ceased.The claustrum sign may pose difficulty in cases of NORSE where it is unclear if it is suggestive of an autoimmune encephalitis precipitating seizures or secondary to the seizures themselves. Empirical immunosuppression is not without risks, and serial imaging may be useful.