[Adult case of acute encephalopathy associated with bilateral thalamic lesions and peripheral neuropathy]

A 76-year-old woman developed fever and consciousness disturbance. The next day, she became delirious and was brought to our hospital. On arrival, she was unconscious and showed hypopnea and hypotension. She was immediately intubated and placed on a respirator. CSF protein was 65.8 mg/dl with 1 cell/microl, and no oligoclonal bands were present. An electroencephalogram showed diffuse theta background activity without epileptic discharges. A nerve conduction study showed damaged motor and sensory peripheral nerve functions in the upper and lower limbs. The neurological findings showed no improvement after methylprednisolone pulse therapy and administration of intravenous immunoglobulin. Magnetic resonance imaging of the brain, including diffusion-weighted images showed bilateral symmetric lesions in the thalamus, globus pallidus and pontine tegmentum. These radiologic findings are not typically, but are similar to those of acute necrotizing encephalopathy (ANE) of childhood as proposed by Mizuguchi et al. After 10 months, brain MRI showed bilateral brain atrophy and a reduction of the abnormal thalamic lesions. There are very few reports of adult cases of ANE, in which, pathologically, local breakdown of the blood-brain-barrier causes acute edema and necrosis involving both gray and white matter. ANE is thought a proinflammatory cytokine-related disease. In our case, the concentrations of some cytokines (IL-6, IL-10) were elevated in serum and cerebrospinal fluid, which might suggest a relationship with them and local breakdown of the blood-brain-barrier in the thalamus.